1 /* Copyright (C) 2010-2015 The RetroArch team
2  *
3  * ---------------------------------------------------------------------------------------
4  * The following license statement only applies to this libretro API header (libretro.h).
5  * ---------------------------------------------------------------------------------------
6  *
7  * Permission is hereby granted, free of charge,
8  * to any person obtaining a copy of this software and associated documentation files (the "Software"),
9  * to deal in the Software without restriction, including without limitation the rights to
10  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
11  * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
16  * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
19  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21  */
22 
23 #ifndef LIBRETRO_H__
24 #define LIBRETRO_H__
25 
26 #include <stdint.h>
27 #include <stddef.h>
28 #include <limits.h>
29 
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33 
34 #ifndef __cplusplus
35 #if defined(_MSC_VER) && !defined(SN_TARGET_PS3)
36 /* Hack applied for MSVC when compiling in C89 mode
37  * as it isn't C99-compliant. */
38 #define bool unsigned char
39 #define true 1
40 #define false 0
41 #else
42 #include <stdbool.h>
43 #endif
44 #endif
45 
46 #ifndef RETRO_CALLCONV
47 #  if defined(__GNUC__) && defined(__i386__) && !defined(__x86_64__)
48 #    define RETRO_CALLCONV __attribute__((cdecl))
49 #  elif defined(_MSC_VER) && defined(_M_X86) && !defined(_M_X64)
50 #    define RETRO_CALLCONV __cdecl
51 #  else
52 #    define RETRO_CALLCONV /* all other platforms only have one calling convention each */
53 #  endif
54 #endif
55 
56 #ifndef RETRO_API
57 #  if defined(_WIN32) || defined(__CYGWIN__) || defined(__MINGW32__)
58 #    ifdef RETRO_IMPORT_SYMBOLS
59 #      ifdef __GNUC__
60 #        define RETRO_API RETRO_CALLCONV __attribute__((dllimport))
61 #      else
62 #        define RETRO_API RETRO_CALLCONV __declspec(dllimport)
63 #      endif
64 #    else
65 #      ifdef __GNUC__
66 #        define RETRO_API RETRO_CALLCONV __attribute__((dllexport))
67 #      else
68 #        define RETRO_API RETRO_CALLCONV __declspec(dllexport)
69 #      endif
70 #    endif
71 #  else
72 #      if defined(__GNUC__) && __GNUC__ >= 4 && !defined(__CELLOS_LV2__)
73 #        define RETRO_API RETRO_CALLCONV __attribute__((visibility("default")))
74 #      else
75 #        define RETRO_API RETRO_CALLCONV
76 #      endif
77 #  endif
78 #endif
79 
80 /* Used for checking API/ABI mismatches that can break libretro
81  * implementations.
82  * It is not incremented for compatible changes to the API.
83  */
84 #define RETRO_API_VERSION         1
85 
86 /*
87  * Libretro's fundamental device abstractions.
88  *
89  * Libretro's input system consists of some standardized device types,
90  * such as a joypad (with/without analog), mouse, keyboard, lightgun
91  * and a pointer.
92  *
93  * The functionality of these devices are fixed, and individual cores
94  * map their own concept of a controller to libretro's abstractions.
95  * This makes it possible for frontends to map the abstract types to a
96  * real input device, and not having to worry about binding input
97  * correctly to arbitrary controller layouts.
98  */
99 
100 #define RETRO_DEVICE_TYPE_SHIFT         8
101 #define RETRO_DEVICE_MASK               ((1 << RETRO_DEVICE_TYPE_SHIFT) - 1)
102 #define RETRO_DEVICE_SUBCLASS(base, id) (((id + 1) << RETRO_DEVICE_TYPE_SHIFT) | base)
103 
104 /* Input disabled. */
105 #define RETRO_DEVICE_NONE         0
106 
107 /* The JOYPAD is called RetroPad. It is essentially a Super Nintendo
108  * controller, but with additional L2/R2/L3/R3 buttons, similar to a
109  * PS1 DualShock. */
110 #define RETRO_DEVICE_JOYPAD       1
111 
112 /* The mouse is a simple mouse, similar to Super Nintendo's mouse.
113  * X and Y coordinates are reported relatively to last poll (poll callback).
114  * It is up to the libretro implementation to keep track of where the mouse
115  * pointer is supposed to be on the screen.
116  * The frontend must make sure not to interfere with its own hardware
117  * mouse pointer.
118  */
119 #define RETRO_DEVICE_MOUSE        2
120 
121 /* KEYBOARD device lets one poll for raw key pressed.
122  * It is poll based, so input callback will return with the current
123  * pressed state.
124  * For event/text based keyboard input, see
125  * RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK.
126  */
127 #define RETRO_DEVICE_KEYBOARD     3
128 
129 /* Lightgun X/Y coordinates are reported relatively to last poll,
130  * similar to mouse. */
131 #define RETRO_DEVICE_LIGHTGUN     4
132 
133 /* The ANALOG device is an extension to JOYPAD (RetroPad).
134  * Similar to DualShock it adds two analog sticks.
135  * This is treated as a separate device type as it returns values in the
136  * full analog range of [-0x8000, 0x7fff]. Positive X axis is right.
137  * Positive Y axis is down.
138  * Only use ANALOG type when polling for analog values of the axes.
139  */
140 #define RETRO_DEVICE_ANALOG       5
141 
142 /* Abstracts the concept of a pointing mechanism, e.g. touch.
143  * This allows libretro to query in absolute coordinates where on the
144  * screen a mouse (or something similar) is being placed.
145  * For a touch centric device, coordinates reported are the coordinates
146  * of the press.
147  *
148  * Coordinates in X and Y are reported as:
149  * [-0x7fff, 0x7fff]: -0x7fff corresponds to the far left/top of the screen,
150  * and 0x7fff corresponds to the far right/bottom of the screen.
151  * The "screen" is here defined as area that is passed to the frontend and
152  * later displayed on the monitor.
153  *
154  * The frontend is free to scale/resize this screen as it sees fit, however,
155  * (X, Y) = (-0x7fff, -0x7fff) will correspond to the top-left pixel of the
156  * game image, etc.
157  *
158  * To check if the pointer coordinates are valid (e.g. a touch display
159  * actually being touched), PRESSED returns 1 or 0.
160  *
161  * If using a mouse on a desktop, PRESSED will usually correspond to the
162  * left mouse button, but this is a frontend decision.
163  * PRESSED will only return 1 if the pointer is inside the game screen.
164  *
165  * For multi-touch, the index variable can be used to successively query
166  * more presses.
167  * If index = 0 returns true for _PRESSED, coordinates can be extracted
168  * with _X, _Y for index = 0. One can then query _PRESSED, _X, _Y with
169  * index = 1, and so on.
170  * Eventually _PRESSED will return false for an index. No further presses
171  * are registered at this point. */
172 #define RETRO_DEVICE_POINTER      6
173 
174 /* Buttons for the RetroPad (JOYPAD).
175  * The placement of these is equivalent to placements on the
176  * Super Nintendo controller.
177  * L2/R2/L3/R3 buttons correspond to the PS1 DualShock. */
178 #define RETRO_DEVICE_ID_JOYPAD_B        0
179 #define RETRO_DEVICE_ID_JOYPAD_Y        1
180 #define RETRO_DEVICE_ID_JOYPAD_SELECT   2
181 #define RETRO_DEVICE_ID_JOYPAD_START    3
182 #define RETRO_DEVICE_ID_JOYPAD_UP       4
183 #define RETRO_DEVICE_ID_JOYPAD_DOWN     5
184 #define RETRO_DEVICE_ID_JOYPAD_LEFT     6
185 #define RETRO_DEVICE_ID_JOYPAD_RIGHT    7
186 #define RETRO_DEVICE_ID_JOYPAD_A        8
187 #define RETRO_DEVICE_ID_JOYPAD_X        9
188 #define RETRO_DEVICE_ID_JOYPAD_L       10
189 #define RETRO_DEVICE_ID_JOYPAD_R       11
190 #define RETRO_DEVICE_ID_JOYPAD_L2      12
191 #define RETRO_DEVICE_ID_JOYPAD_R2      13
192 #define RETRO_DEVICE_ID_JOYPAD_L3      14
193 #define RETRO_DEVICE_ID_JOYPAD_R3      15
194 
195 /* Index / Id values for ANALOG device. */
196 #define RETRO_DEVICE_INDEX_ANALOG_LEFT   0
197 #define RETRO_DEVICE_INDEX_ANALOG_RIGHT  1
198 #define RETRO_DEVICE_ID_ANALOG_X         0
199 #define RETRO_DEVICE_ID_ANALOG_Y         1
200 
201 /* Id values for MOUSE. */
202 #define RETRO_DEVICE_ID_MOUSE_X                0
203 #define RETRO_DEVICE_ID_MOUSE_Y                1
204 #define RETRO_DEVICE_ID_MOUSE_LEFT             2
205 #define RETRO_DEVICE_ID_MOUSE_RIGHT            3
206 #define RETRO_DEVICE_ID_MOUSE_WHEELUP          4
207 #define RETRO_DEVICE_ID_MOUSE_WHEELDOWN        5
208 #define RETRO_DEVICE_ID_MOUSE_MIDDLE           6
209 #define RETRO_DEVICE_ID_MOUSE_HORIZ_WHEELUP    7
210 #define RETRO_DEVICE_ID_MOUSE_HORIZ_WHEELDOWN  8
211 
212 /* Id values for LIGHTGUN types. */
213 #define RETRO_DEVICE_ID_LIGHTGUN_X        0
214 #define RETRO_DEVICE_ID_LIGHTGUN_Y        1
215 #define RETRO_DEVICE_ID_LIGHTGUN_TRIGGER  2
216 #define RETRO_DEVICE_ID_LIGHTGUN_CURSOR   3
217 #define RETRO_DEVICE_ID_LIGHTGUN_TURBO    4
218 #define RETRO_DEVICE_ID_LIGHTGUN_PAUSE    5
219 #define RETRO_DEVICE_ID_LIGHTGUN_START    6
220 
221 /* Id values for POINTER. */
222 #define RETRO_DEVICE_ID_POINTER_X         0
223 #define RETRO_DEVICE_ID_POINTER_Y         1
224 #define RETRO_DEVICE_ID_POINTER_PRESSED   2
225 
226 /* Returned from retro_get_region(). */
227 #define RETRO_REGION_NTSC  0
228 #define RETRO_REGION_PAL   1
229 
230 /* Id values for LANGUAGE */
231 enum retro_language
232 {
233    RETRO_LANGUAGE_ENGLISH             =  0,
234    RETRO_LANGUAGE_JAPANESE            =  1,
235    RETRO_LANGUAGE_FRENCH              =  2,
236    RETRO_LANGUAGE_SPANISH             =  3,
237    RETRO_LANGUAGE_GERMAN              =  4,
238    RETRO_LANGUAGE_ITALIAN             =  5,
239    RETRO_LANGUAGE_DUTCH               =  6,
240    RETRO_LANGUAGE_PORTUGUESE          =  7,
241    RETRO_LANGUAGE_RUSSIAN             =  8,
242    RETRO_LANGUAGE_KOREAN              =  9,
243    RETRO_LANGUAGE_CHINESE_TRADITIONAL = 10,
244    RETRO_LANGUAGE_CHINESE_SIMPLIFIED  = 11,
245    RETRO_LANGUAGE_ESPERANTO           = 12,
246    RETRO_LANGUAGE_POLISH              = 13,
247    RETRO_LANGUAGE_LAST,
248 
249    /* Ensure sizeof(enum) == sizeof(int) */
250    RETRO_LANGUAGE_DUMMY          = INT_MAX
251 };
252 
253 /* Passed to retro_get_memory_data/size().
254  * If the memory type doesn't apply to the
255  * implementation NULL/0 can be returned.
256  */
257 #define RETRO_MEMORY_MASK        0xff
258 
259 /* Regular save RAM. This RAM is usually found on a game cartridge,
260  * backed up by a battery.
261  * If save game data is too complex for a single memory buffer,
262  * the SAVE_DIRECTORY (preferably) or SYSTEM_DIRECTORY environment
263  * callback can be used. */
264 #define RETRO_MEMORY_SAVE_RAM    0
265 
266 /* Some games have a built-in clock to keep track of time.
267  * This memory is usually just a couple of bytes to keep track of time.
268  */
269 #define RETRO_MEMORY_RTC         1
270 
271 /* System ram lets a frontend peek into a game systems main RAM. */
272 #define RETRO_MEMORY_SYSTEM_RAM  2
273 
274 /* Video ram lets a frontend peek into a game systems video RAM (VRAM). */
275 #define RETRO_MEMORY_VIDEO_RAM   3
276 
277 /* Keysyms used for ID in input state callback when polling RETRO_KEYBOARD. */
278 enum retro_key
279 {
280    RETROK_UNKNOWN        = 0,
281    RETROK_FIRST          = 0,
282    RETROK_BACKSPACE      = 8,
283    RETROK_TAB            = 9,
284    RETROK_CLEAR          = 12,
285    RETROK_RETURN         = 13,
286    RETROK_PAUSE          = 19,
287    RETROK_ESCAPE         = 27,
288    RETROK_SPACE          = 32,
289    RETROK_EXCLAIM        = 33,
290    RETROK_QUOTEDBL       = 34,
291    RETROK_HASH           = 35,
292    RETROK_DOLLAR         = 36,
293    RETROK_AMPERSAND      = 38,
294    RETROK_QUOTE          = 39,
295    RETROK_LEFTPAREN      = 40,
296    RETROK_RIGHTPAREN     = 41,
297    RETROK_ASTERISK       = 42,
298    RETROK_PLUS           = 43,
299    RETROK_COMMA          = 44,
300    RETROK_MINUS          = 45,
301    RETROK_PERIOD         = 46,
302    RETROK_SLASH          = 47,
303    RETROK_0              = 48,
304    RETROK_1              = 49,
305    RETROK_2              = 50,
306    RETROK_3              = 51,
307    RETROK_4              = 52,
308    RETROK_5              = 53,
309    RETROK_6              = 54,
310    RETROK_7              = 55,
311    RETROK_8              = 56,
312    RETROK_9              = 57,
313    RETROK_COLON          = 58,
314    RETROK_SEMICOLON      = 59,
315    RETROK_LESS           = 60,
316    RETROK_EQUALS         = 61,
317    RETROK_GREATER        = 62,
318    RETROK_QUESTION       = 63,
319    RETROK_AT             = 64,
320    RETROK_LEFTBRACKET    = 91,
321    RETROK_BACKSLASH      = 92,
322    RETROK_RIGHTBRACKET   = 93,
323    RETROK_CARET          = 94,
324    RETROK_UNDERSCORE     = 95,
325    RETROK_BACKQUOTE      = 96,
326    RETROK_a              = 97,
327    RETROK_b              = 98,
328    RETROK_c              = 99,
329    RETROK_d              = 100,
330    RETROK_e              = 101,
331    RETROK_f              = 102,
332    RETROK_g              = 103,
333    RETROK_h              = 104,
334    RETROK_i              = 105,
335    RETROK_j              = 106,
336    RETROK_k              = 107,
337    RETROK_l              = 108,
338    RETROK_m              = 109,
339    RETROK_n              = 110,
340    RETROK_o              = 111,
341    RETROK_p              = 112,
342    RETROK_q              = 113,
343    RETROK_r              = 114,
344    RETROK_s              = 115,
345    RETROK_t              = 116,
346    RETROK_u              = 117,
347    RETROK_v              = 118,
348    RETROK_w              = 119,
349    RETROK_x              = 120,
350    RETROK_y              = 121,
351    RETROK_z              = 122,
352    RETROK_DELETE         = 127,
353 
354    RETROK_KP0            = 256,
355    RETROK_KP1            = 257,
356    RETROK_KP2            = 258,
357    RETROK_KP3            = 259,
358    RETROK_KP4            = 260,
359    RETROK_KP5            = 261,
360    RETROK_KP6            = 262,
361    RETROK_KP7            = 263,
362    RETROK_KP8            = 264,
363    RETROK_KP9            = 265,
364    RETROK_KP_PERIOD      = 266,
365    RETROK_KP_DIVIDE      = 267,
366    RETROK_KP_MULTIPLY    = 268,
367    RETROK_KP_MINUS       = 269,
368    RETROK_KP_PLUS        = 270,
369    RETROK_KP_ENTER       = 271,
370    RETROK_KP_EQUALS      = 272,
371 
372    RETROK_UP             = 273,
373    RETROK_DOWN           = 274,
374    RETROK_RIGHT          = 275,
375    RETROK_LEFT           = 276,
376    RETROK_INSERT         = 277,
377    RETROK_HOME           = 278,
378    RETROK_END            = 279,
379    RETROK_PAGEUP         = 280,
380    RETROK_PAGEDOWN       = 281,
381 
382    RETROK_F1             = 282,
383    RETROK_F2             = 283,
384    RETROK_F3             = 284,
385    RETROK_F4             = 285,
386    RETROK_F5             = 286,
387    RETROK_F6             = 287,
388    RETROK_F7             = 288,
389    RETROK_F8             = 289,
390    RETROK_F9             = 290,
391    RETROK_F10            = 291,
392    RETROK_F11            = 292,
393    RETROK_F12            = 293,
394    RETROK_F13            = 294,
395    RETROK_F14            = 295,
396    RETROK_F15            = 296,
397 
398    RETROK_NUMLOCK        = 300,
399    RETROK_CAPSLOCK       = 301,
400    RETROK_SCROLLOCK      = 302,
401    RETROK_RSHIFT         = 303,
402    RETROK_LSHIFT         = 304,
403    RETROK_RCTRL          = 305,
404    RETROK_LCTRL          = 306,
405    RETROK_RALT           = 307,
406    RETROK_LALT           = 308,
407    RETROK_RMETA          = 309,
408    RETROK_LMETA          = 310,
409    RETROK_LSUPER         = 311,
410    RETROK_RSUPER         = 312,
411    RETROK_MODE           = 313,
412    RETROK_COMPOSE        = 314,
413 
414    RETROK_HELP           = 315,
415    RETROK_PRINT          = 316,
416    RETROK_SYSREQ         = 317,
417    RETROK_BREAK          = 318,
418    RETROK_MENU           = 319,
419    RETROK_POWER          = 320,
420    RETROK_EURO           = 321,
421    RETROK_UNDO           = 322,
422 
423    RETROK_LAST,
424 
425    RETROK_DUMMY          = INT_MAX /* Ensure sizeof(enum) == sizeof(int) */
426 };
427 
428 enum retro_mod
429 {
430    RETROKMOD_NONE       = 0x0000,
431 
432    RETROKMOD_SHIFT      = 0x01,
433    RETROKMOD_CTRL       = 0x02,
434    RETROKMOD_ALT        = 0x04,
435    RETROKMOD_META       = 0x08,
436 
437    RETROKMOD_NUMLOCK    = 0x10,
438    RETROKMOD_CAPSLOCK   = 0x20,
439    RETROKMOD_SCROLLOCK  = 0x40,
440 
441    RETROKMOD_DUMMY = INT_MAX /* Ensure sizeof(enum) == sizeof(int) */
442 };
443 
444 /* If set, this call is not part of the public libretro API yet. It can
445  * change or be removed at any time. */
446 #define RETRO_ENVIRONMENT_EXPERIMENTAL 0x10000
447 /* Environment callback to be used internally in frontend. */
448 #define RETRO_ENVIRONMENT_PRIVATE 0x20000
449 
450 /* Environment commands. */
451 #define RETRO_ENVIRONMENT_SET_ROTATION  1  /* const unsigned * --
452                                             * Sets screen rotation of graphics.
453                                             * Is only implemented if rotation can be accelerated by hardware.
454                                             * Valid values are 0, 1, 2, 3, which rotates screen by 0, 90, 180,
455                                             * 270 degrees counter-clockwise respectively.
456                                             */
457 #define RETRO_ENVIRONMENT_GET_OVERSCAN  2  /* bool * --
458                                             * Boolean value whether or not the implementation should use overscan,
459                                             * or crop away overscan.
460                                             */
461 #define RETRO_ENVIRONMENT_GET_CAN_DUPE  3  /* bool * --
462                                             * Boolean value whether or not frontend supports frame duping,
463                                             * passing NULL to video frame callback.
464                                             */
465 
466                                            /* Environ 4, 5 are no longer supported (GET_VARIABLE / SET_VARIABLES),
467                                             * and reserved to avoid possible ABI clash.
468                                             */
469 
470 #define RETRO_ENVIRONMENT_SET_MESSAGE   6  /* const struct retro_message * --
471                                             * Sets a message to be displayed in implementation-specific manner
472                                             * for a certain amount of 'frames'.
473                                             * Should not be used for trivial messages, which should simply be
474                                             * logged via RETRO_ENVIRONMENT_GET_LOG_INTERFACE (or as a
475                                             * fallback, stderr).
476                                             */
477 #define RETRO_ENVIRONMENT_SHUTDOWN      7  /* N/A (NULL) --
478                                             * Requests the frontend to shutdown.
479                                             * Should only be used if game has a specific
480                                             * way to shutdown the game from a menu item or similar.
481                                             */
482 #define RETRO_ENVIRONMENT_SET_PERFORMANCE_LEVEL 8
483                                            /* const unsigned * --
484                                             * Gives a hint to the frontend how demanding this implementation
485                                             * is on a system. E.g. reporting a level of 2 means
486                                             * this implementation should run decently on all frontends
487                                             * of level 2 and up.
488                                             *
489                                             * It can be used by the frontend to potentially warn
490                                             * about too demanding implementations.
491                                             *
492                                             * The levels are "floating".
493                                             *
494                                             * This function can be called on a per-game basis,
495                                             * as certain games an implementation can play might be
496                                             * particularly demanding.
497                                             * If called, it should be called in retro_load_game().
498                                             */
499 #define RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY 9
500                                            /* const char ** --
501                                             * Returns the "system" directory of the frontend.
502                                             * This directory can be used to store system specific
503                                             * content such as BIOSes, configuration data, etc.
504                                             * The returned value can be NULL.
505                                             * If so, no such directory is defined,
506                                             * and it's up to the implementation to find a suitable directory.
507                                             *
508                                             * NOTE: Some cores used this folder also for "save" data such as
509                                             * memory cards, etc, for lack of a better place to put it.
510                                             * This is now discouraged, and if possible, cores should try to
511                                             * use the new GET_SAVE_DIRECTORY.
512                                             */
513 #define RETRO_ENVIRONMENT_SET_PIXEL_FORMAT 10
514                                            /* const enum retro_pixel_format * --
515                                             * Sets the internal pixel format used by the implementation.
516                                             * The default pixel format is RETRO_PIXEL_FORMAT_0RGB1555.
517                                             * This pixel format however, is deprecated (see enum retro_pixel_format).
518                                             * If the call returns false, the frontend does not support this pixel
519                                             * format.
520                                             *
521                                             * This function should be called inside retro_load_game() or
522                                             * retro_get_system_av_info().
523                                             */
524 #define RETRO_ENVIRONMENT_SET_INPUT_DESCRIPTORS 11
525                                            /* const struct retro_input_descriptor * --
526                                             * Sets an array of retro_input_descriptors.
527                                             * It is up to the frontend to present this in a usable way.
528                                             * The array is terminated by retro_input_descriptor::description
529                                             * being set to NULL.
530                                             * This function can be called at any time, but it is recommended
531                                             * to call it as early as possible.
532                                             */
533 #define RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK 12
534                                            /* const struct retro_keyboard_callback * --
535                                             * Sets a callback function used to notify core about keyboard events.
536                                             */
537 #define RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE 13
538                                            /* const struct retro_disk_control_callback * --
539                                             * Sets an interface which frontend can use to eject and insert
540                                             * disk images.
541                                             * This is used for games which consist of multiple images and
542                                             * must be manually swapped out by the user (e.g. PSX).
543                                             */
544 #define RETRO_ENVIRONMENT_SET_HW_RENDER 14
545                                            /* struct retro_hw_render_callback * --
546                                             * Sets an interface to let a libretro core render with
547                                             * hardware acceleration.
548                                             * Should be called in retro_load_game().
549                                             * If successful, libretro cores will be able to render to a
550                                             * frontend-provided framebuffer.
551                                             * The size of this framebuffer will be at least as large as
552                                             * max_width/max_height provided in get_av_info().
553                                             * If HW rendering is used, pass only RETRO_HW_FRAME_BUFFER_VALID or
554                                             * NULL to retro_video_refresh_t.
555                                             */
556 #define RETRO_ENVIRONMENT_GET_VARIABLE 15
557                                            /* struct retro_variable * --
558                                             * Interface to acquire user-defined information from environment
559                                             * that cannot feasibly be supported in a multi-system way.
560                                             * 'key' should be set to a key which has already been set by
561                                             * SET_VARIABLES.
562                                             * 'data' will be set to a value or NULL.
563                                             */
564 #define RETRO_ENVIRONMENT_SET_VARIABLES 16
565                                            /* const struct retro_variable * --
566                                             * Allows an implementation to signal the environment
567                                             * which variables it might want to check for later using
568                                             * GET_VARIABLE.
569                                             * This allows the frontend to present these variables to
570                                             * a user dynamically.
571                                             * This should be called as early as possible (ideally in
572                                             * retro_set_environment).
573                                             *
574                                             * 'data' points to an array of retro_variable structs
575                                             * terminated by a { NULL, NULL } element.
576                                             * retro_variable::key should be namespaced to not collide
577                                             * with other implementations' keys. E.g. A core called
578                                             * 'foo' should use keys named as 'foo_option'.
579                                             * retro_variable::value should contain a human readable
580                                             * description of the key as well as a '|' delimited list
581                                             * of expected values.
582                                             *
583                                             * The number of possible options should be very limited,
584                                             * i.e. it should be feasible to cycle through options
585                                             * without a keyboard.
586                                             *
587                                             * First entry should be treated as a default.
588                                             *
589                                             * Example entry:
590                                             * { "foo_option", "Speed hack coprocessor X; false|true" }
591                                             *
592                                             * Text before first ';' is description. This ';' must be
593                                             * followed by a space, and followed by a list of possible
594                                             * values split up with '|'.
595                                             *
596                                             * Only strings are operated on. The possible values will
597                                             * generally be displayed and stored as-is by the frontend.
598                                             */
599 #define RETRO_ENVIRONMENT_GET_VARIABLE_UPDATE 17
600                                            /* bool * --
601                                             * Result is set to true if some variables are updated by
602                                             * frontend since last call to RETRO_ENVIRONMENT_GET_VARIABLE.
603                                             * Variables should be queried with GET_VARIABLE.
604                                             */
605 #define RETRO_ENVIRONMENT_SET_SUPPORT_NO_GAME 18
606                                            /* const bool * --
607                                             * If true, the libretro implementation supports calls to
608                                             * retro_load_game() with NULL as argument.
609                                             * Used by cores which can run without particular game data.
610                                             * This should be called within retro_set_environment() only.
611                                             */
612 #define RETRO_ENVIRONMENT_GET_LIBRETRO_PATH 19
613                                            /* const char ** --
614                                             * Retrieves the absolute path from where this libretro
615                                             * implementation was loaded.
616                                             * NULL is returned if the libretro was loaded statically
617                                             * (i.e. linked statically to frontend), or if the path cannot be
618                                             * determined.
619                                             * Mostly useful in cooperation with SET_SUPPORT_NO_GAME as assets can
620                                             * be loaded without ugly hacks.
621                                             */
622 
623                                            /* Environment 20 was an obsolete version of SET_AUDIO_CALLBACK.
624                                             * It was not used by any known core at the time,
625                                             * and was removed from the API. */
626 #define RETRO_ENVIRONMENT_SET_AUDIO_CALLBACK 22
627                                            /* const struct retro_audio_callback * --
628                                             * Sets an interface which is used to notify a libretro core about audio
629                                             * being available for writing.
630                                             * The callback can be called from any thread, so a core using this must
631                                             * have a thread safe audio implementation.
632                                             * It is intended for games where audio and video are completely
633                                             * asynchronous and audio can be generated on the fly.
634                                             * This interface is not recommended for use with emulators which have
635                                             * highly synchronous audio.
636                                             *
637                                             * The callback only notifies about writability; the libretro core still
638                                             * has to call the normal audio callbacks
639                                             * to write audio. The audio callbacks must be called from within the
640                                             * notification callback.
641                                             * The amount of audio data to write is up to the implementation.
642                                             * Generally, the audio callback will be called continously in a loop.
643                                             *
644                                             * Due to thread safety guarantees and lack of sync between audio and
645                                             * video, a frontend  can selectively disallow this interface based on
646                                             * internal configuration. A core using this interface must also
647                                             * implement the "normal" audio interface.
648                                             *
649                                             * A libretro core using SET_AUDIO_CALLBACK should also make use of
650                                             * SET_FRAME_TIME_CALLBACK.
651                                             */
652 #define RETRO_ENVIRONMENT_SET_FRAME_TIME_CALLBACK 21
653                                            /* const struct retro_frame_time_callback * --
654                                             * Lets the core know how much time has passed since last
655                                             * invocation of retro_run().
656                                             * The frontend can tamper with the timing to fake fast-forward,
657                                             * slow-motion, frame stepping, etc.
658                                             * In this case the delta time will use the reference value
659                                             * in frame_time_callback..
660                                             */
661 #define RETRO_ENVIRONMENT_GET_RUMBLE_INTERFACE 23
662                                            /* struct retro_rumble_interface * --
663                                             * Gets an interface which is used by a libretro core to set
664                                             * state of rumble motors in controllers.
665                                             * A strong and weak motor is supported, and they can be
666                                             * controlled indepedently.
667                                             */
668 #define RETRO_ENVIRONMENT_GET_INPUT_DEVICE_CAPABILITIES 24
669                                            /* uint64_t * --
670                                             * Gets a bitmask telling which device type are expected to be
671                                             * handled properly in a call to retro_input_state_t.
672                                             * Devices which are not handled or recognized always return
673                                             * 0 in retro_input_state_t.
674                                             * Example bitmask: caps = (1 << RETRO_DEVICE_JOYPAD) | (1 << RETRO_DEVICE_ANALOG).
675                                             * Should only be called in retro_run().
676                                             */
677 #define RETRO_ENVIRONMENT_GET_SENSOR_INTERFACE (25 | RETRO_ENVIRONMENT_EXPERIMENTAL)
678                                            /* struct retro_sensor_interface * --
679                                             * Gets access to the sensor interface.
680                                             * The purpose of this interface is to allow
681                                             * setting state related to sensors such as polling rate,
682                                             * enabling/disable it entirely, etc.
683                                             * Reading sensor state is done via the normal
684                                             * input_state_callback API.
685                                             */
686 #define RETRO_ENVIRONMENT_GET_CAMERA_INTERFACE (26 | RETRO_ENVIRONMENT_EXPERIMENTAL)
687                                            /* struct retro_camera_callback * --
688                                             * Gets an interface to a video camera driver.
689                                             * A libretro core can use this interface to get access to a
690                                             * video camera.
691                                             * New video frames are delivered in a callback in same
692                                             * thread as retro_run().
693                                             *
694                                             * GET_CAMERA_INTERFACE should be called in retro_load_game().
695                                             *
696                                             * Depending on the camera implementation used, camera frames
697                                             * will be delivered as a raw framebuffer,
698                                             * or as an OpenGL texture directly.
699                                             *
700                                             * The core has to tell the frontend here which types of
701                                             * buffers can be handled properly.
702                                             * An OpenGL texture can only be handled when using a
703                                             * libretro GL core (SET_HW_RENDER).
704                                             * It is recommended to use a libretro GL core when
705                                             * using camera interface.
706                                             *
707                                             * The camera is not started automatically. The retrieved start/stop
708                                             * functions must be used to explicitly
709                                             * start and stop the camera driver.
710                                             */
711 #define RETRO_ENVIRONMENT_GET_LOG_INTERFACE 27
712                                            /* struct retro_log_callback * --
713                                             * Gets an interface for logging. This is useful for
714                                             * logging in a cross-platform way
715                                             * as certain platforms cannot use use stderr for logging.
716                                             * It also allows the frontend to
717                                             * show logging information in a more suitable way.
718                                             * If this interface is not used, libretro cores should
719                                             * log to stderr as desired.
720                                             */
721 #define RETRO_ENVIRONMENT_GET_PERF_INTERFACE 28
722                                            /* struct retro_perf_callback * --
723                                             * Gets an interface for performance counters. This is useful
724                                             * for performance logging in a cross-platform way and for detecting
725                                             * architecture-specific features, such as SIMD support.
726                                             */
727 #define RETRO_ENVIRONMENT_GET_LOCATION_INTERFACE 29
728                                            /* struct retro_location_callback * --
729                                             * Gets access to the location interface.
730                                             * The purpose of this interface is to be able to retrieve
731                                             * location-based information from the host device,
732                                             * such as current latitude / longitude.
733                                             */
734 #define RETRO_ENVIRONMENT_GET_CONTENT_DIRECTORY 30 /* Old name, kept for compatibility. */
735 #define RETRO_ENVIRONMENT_GET_CORE_ASSETS_DIRECTORY 30
736                                            /* const char ** --
737                                             * Returns the "core assets" directory of the frontend.
738                                             * This directory can be used to store specific assets that the
739                                             * core relies upon, such as art assets,
740                                             * input data, etc etc.
741                                             * The returned value can be NULL.
742                                             * If so, no such directory is defined,
743                                             * and it's up to the implementation to find a suitable directory.
744                                             */
745 #define RETRO_ENVIRONMENT_GET_SAVE_DIRECTORY 31
746                                            /* const char ** --
747                                             * Returns the "save" directory of the frontend.
748                                             * This directory can be used to store SRAM, memory cards,
749                                             * high scores, etc, if the libretro core
750                                             * cannot use the regular memory interface (retro_get_memory_data()).
751                                             *
752                                             * NOTE: libretro cores used to check GET_SYSTEM_DIRECTORY for
753                                             * similar things before.
754                                             * They should still check GET_SYSTEM_DIRECTORY if they want to
755                                             * be backwards compatible.
756                                             * The path here can be NULL. It should only be non-NULL if the
757                                             * frontend user has set a specific save path.
758                                             */
759 #define RETRO_ENVIRONMENT_SET_SYSTEM_AV_INFO 32
760                                            /* const struct retro_system_av_info * --
761                                             * Sets a new av_info structure. This can only be called from
762                                             * within retro_run().
763                                             * This should *only* be used if the core is completely altering the
764                                             * internal resolutions, aspect ratios, timings, sampling rate, etc.
765                                             * Calling this can require a full reinitialization of video/audio
766                                             * drivers in the frontend,
767                                             *
768                                             * so it is important to call it very sparingly, and usually only with
769                                             * the users explicit consent.
770                                             * An eventual driver reinitialize will happen so that video and
771                                             * audio callbacks
772                                             * happening after this call within the same retro_run() call will
773                                             * target the newly initialized driver.
774                                             *
775                                             * This callback makes it possible to support configurable resolutions
776                                             * in games, which can be useful to
777                                             * avoid setting the "worst case" in max_width/max_height.
778                                             *
779                                             * ***HIGHLY RECOMMENDED*** Do not call this callback every time
780                                             * resolution changes in an emulator core if it's
781                                             * expected to be a temporary change, for the reasons of possible
782                                             * driver reinitialization.
783                                             * This call is not a free pass for not trying to provide
784                                             * correct values in retro_get_system_av_info(). If you need to change
785                                             * things like aspect ratio or nominal width/height,
786                                             * use RETRO_ENVIRONMENT_SET_GEOMETRY, which is a softer variant
787                                             * of SET_SYSTEM_AV_INFO.
788                                             *
789                                             * If this returns false, the frontend does not acknowledge a
790                                             * changed av_info struct.
791                                             */
792 #define RETRO_ENVIRONMENT_SET_PROC_ADDRESS_CALLBACK 33
793                                            /* const struct retro_get_proc_address_interface * --
794                                             * Allows a libretro core to announce support for the
795                                             * get_proc_address() interface.
796                                             * This interface allows for a standard way to extend libretro where
797                                             * use of environment calls are too indirect,
798                                             * e.g. for cases where the frontend wants to call directly into the core.
799                                             *
800                                             * If a core wants to expose this interface, SET_PROC_ADDRESS_CALLBACK
801                                             * **MUST** be called from within retro_set_environment().
802                                             */
803 #define RETRO_ENVIRONMENT_SET_SUBSYSTEM_INFO 34
804                                            /* const struct retro_subsystem_info * --
805                                             * This environment call introduces the concept of libretro "subsystems".
806                                             * A subsystem is a variant of a libretro core which supports
807                                             * different kinds of games.
808                                             * The purpose of this is to support e.g. emulators which might
809                                             * have special needs, e.g. Super Nintendo's Super GameBoy, Sufami Turbo.
810                                             * It can also be used to pick among subsystems in an explicit way
811                                             * if the libretro implementation is a multi-system emulator itself.
812                                             *
813                                             * Loading a game via a subsystem is done with retro_load_game_special(),
814                                             * and this environment call allows a libretro core to expose which
815                                             * subsystems are supported for use with retro_load_game_special().
816                                             * A core passes an array of retro_game_special_info which is terminated
817                                             * with a zeroed out retro_game_special_info struct.
818                                             *
819                                             * If a core wants to use this functionality, SET_SUBSYSTEM_INFO
820                                             * **MUST** be called from within retro_set_environment().
821                                             */
822 #define RETRO_ENVIRONMENT_SET_CONTROLLER_INFO 35
823                                            /* const struct retro_controller_info * --
824                                             * This environment call lets a libretro core tell the frontend
825                                             * which controller types are recognized in calls to
826                                             * retro_set_controller_port_device().
827                                             *
828                                             * Some emulators such as Super Nintendo
829                                             * support multiple lightgun types which must be specifically
830                                             * selected from.
831                                             * It is therefore sometimes necessary for a frontend to be able
832                                             * to tell the core about a special kind of input device which is
833                                             * not covered by the libretro input API.
834                                             *
835                                             * In order for a frontend to understand the workings of an input device,
836                                             * it must be a specialized type
837                                             * of the generic device types already defined in the libretro API.
838                                             *
839                                             * Which devices are supported can vary per input port.
840                                             * The core must pass an array of const struct retro_controller_info which
841                                             * is terminated with a blanked out struct. Each element of the struct
842                                             * corresponds to an ascending port index to
843                                             * retro_set_controller_port_device().
844                                             * Even if special device types are set in the libretro core,
845                                             * libretro should only poll input based on the base input device types.
846                                             */
847 #define RETRO_ENVIRONMENT_SET_MEMORY_MAPS (36 | RETRO_ENVIRONMENT_EXPERIMENTAL)
848                                            /* const struct retro_memory_map * --
849                                             * This environment call lets a libretro core tell the frontend
850                                             * about the memory maps this core emulates.
851                                             * This can be used to implement, for example, cheats in a core-agnostic way.
852                                             *
853                                             * Should only be used by emulators; it doesn't make much sense for
854                                             * anything else.
855                                             * It is recommended to expose all relevant pointers through
856                                             * retro_get_memory_* as well.
857                                             *
858                                             * Can be called from retro_init and retro_load_game.
859                                             */
860 #define RETRO_ENVIRONMENT_SET_GEOMETRY 37
861                                            /* const struct retro_game_geometry * --
862                                             * This environment call is similar to SET_SYSTEM_AV_INFO for changing
863                                             * video parameters, but provides a guarantee that drivers will not be
864                                             * reinitialized.
865                                             * This can only be called from within retro_run().
866                                             *
867                                             * The purpose of this call is to allow a core to alter nominal
868                                             * width/heights as well as aspect ratios on-the-fly, which can be
869                                             * useful for some emulators to change in run-time.
870                                             *
871                                             * max_width/max_height arguments are ignored and cannot be changed
872                                             * with this call as this could potentially require a reinitialization or a
873                                             * non-constant time operation.
874                                             * If max_width/max_height are to be changed, SET_SYSTEM_AV_INFO is required.
875                                             *
876                                             * A frontend must guarantee that this environment call completes in
877                                             * constant time.
878                                             */
879 #define RETRO_ENVIRONMENT_GET_USERNAME 38
880                                            /* const char **
881                                             * Returns the specified username of the frontend, if specified by the user.
882                                             * This username can be used as a nickname for a core that has online facilities
883                                             * or any other mode where personalization of the user is desirable.
884                                             * The returned value can be NULL.
885                                             * If this environ callback is used by a core that requires a valid username,
886                                             * a default username should be specified by the core.
887                                             */
888 #define RETRO_ENVIRONMENT_GET_LANGUAGE 39
889                                            /* unsigned * --
890                                             * Returns the specified language of the frontend, if specified by the user.
891                                             * It can be used by the core for localization purposes.
892                                             */
893 
894 #define RETRO_MEMDESC_CONST     (1 << 0)   /* The frontend will never change this memory area once retro_load_game has returned. */
895 #define RETRO_MEMDESC_BIGENDIAN (1 << 1)   /* The memory area contains big endian data. Default is little endian. */
896 #define RETRO_MEMDESC_ALIGN_2   (1 << 16)  /* All memory access in this area is aligned to their own size, or 2, whichever is smaller. */
897 #define RETRO_MEMDESC_ALIGN_4   (2 << 16)
898 #define RETRO_MEMDESC_ALIGN_8   (3 << 16)
899 #define RETRO_MEMDESC_MINSIZE_2 (1 << 24)  /* All memory in this region is accessed at least 2 bytes at the time. */
900 #define RETRO_MEMDESC_MINSIZE_4 (2 << 24)
901 #define RETRO_MEMDESC_MINSIZE_8 (3 << 24)
902 struct retro_memory_descriptor
903 {
904    uint64_t flags;
905 
906    /* Pointer to the start of the relevant ROM or RAM chip.
907     * It's strongly recommended to use 'offset' if possible, rather than
908     * doing math on the pointer.
909     *
910     * If the same byte is mapped my multiple descriptors, their descriptors
911     * must have the same pointer.
912     * If 'start' does not point to the first byte in the pointer, put the
913     * difference in 'offset' instead.
914     *
915     * May be NULL if there's nothing usable here (e.g. hardware registers and
916     * open bus). No flags should be set if the pointer is NULL.
917     * It's recommended to minimize the number of descriptors if possible,
918     * but not mandatory. */
919    void *ptr;
920    size_t offset;
921 
922    /* This is the location in the emulated address space
923     * where the mapping starts. */
924    size_t start;
925 
926    /* Which bits must be same as in 'start' for this mapping to apply.
927     * The first memory descriptor to claim a certain byte is the one
928     * that applies.
929     * A bit which is set in 'start' must also be set in this.
930     * Can be zero, in which case each byte is assumed mapped exactly once.
931     * In this case, 'len' must be a power of two. */
932    size_t select;
933 
934    /* If this is nonzero, the set bits are assumed not connected to the
935     * memory chip's address pins. */
936    size_t disconnect;
937 
938    /* This one tells the size of the current memory area.
939     * If, after start+disconnect are applied, the address is higher than
940     * this, the highest bit of the address is cleared.
941     *
942     * If the address is still too high, the next highest bit is cleared.
943     * Can be zero, in which case it's assumed to be infinite (as limited
944     * by 'select' and 'disconnect'). */
945    size_t len;
946 
947    /* To go from emulated address to physical address, the following
948     * order applies:
949     * Subtract 'start', pick off 'disconnect', apply 'len', add 'offset'.
950     *
951     * The address space name must consist of only a-zA-Z0-9_-,
952     * should be as short as feasible (maximum length is 8 plus the NUL),
953     * and may not be any other address space plus one or more 0-9A-F
954     * at the end.
955     * However, multiple memory descriptors for the same address space is
956     * allowed, and the address space name can be empty. NULL is treated
957     * as empty.
958     *
959     * Address space names are case sensitive, but avoid lowercase if possible.
960     * The same pointer may exist in multiple address spaces.
961     *
962     * Examples:
963     * blank+blank - valid (multiple things may be mapped in the same namespace)
964     * 'Sp'+'Sp' - valid (multiple things may be mapped in the same namespace)
965     * 'A'+'B' - valid (neither is a prefix of each other)
966     * 'S'+blank - valid ('S' is not in 0-9A-F)
967     * 'a'+blank - valid ('a' is not in 0-9A-F)
968     * 'a'+'A' - valid (neither is a prefix of each other)
969     * 'AR'+blank - valid ('R' is not in 0-9A-F)
970     * 'ARB'+blank - valid (the B can't be part of the address either, because
971     * there is no namespace 'AR')
972     * blank+'B' - not valid, because it's ambigous which address space B1234
973     * would refer to.
974     * The length can't be used for that purpose; the frontend may want
975     * to append arbitrary data to an address, without a separator. */
976    const char *addrspace;
977 };
978 
979 /* The frontend may use the largest value of 'start'+'select' in a
980  * certain namespace to infer the size of the address space.
981  *
982  * If the address space is larger than that, a mapping with .ptr=NULL
983  * should be at the end of the array, with .select set to all ones for
984  * as long as the address space is big.
985  *
986  * Sample descriptors (minus .ptr, and RETRO_MEMFLAG_ on the flags):
987  * SNES WRAM:
988  * .start=0x7E0000, .len=0x20000
989  * (Note that this must be mapped before the ROM in most cases; some of the
990  * ROM mappers
991  * try to claim $7E0000, or at least $7E8000.)
992  * SNES SPC700 RAM:
993  * .addrspace="S", .len=0x10000
994  * SNES WRAM mirrors:
995  * .flags=MIRROR, .start=0x000000, .select=0xC0E000, .len=0x2000
996  * .flags=MIRROR, .start=0x800000, .select=0xC0E000, .len=0x2000
997  * SNES WRAM mirrors, alternate equivalent descriptor:
998  * .flags=MIRROR, .select=0x40E000, .disconnect=~0x1FFF
999  * (Various similar constructions can be created by combining parts of
1000  * the above two.)
1001  * SNES LoROM (512KB, mirrored a couple of times):
1002  * .flags=CONST, .start=0x008000, .select=0x408000, .disconnect=0x8000, .len=512*1024
1003  * .flags=CONST, .start=0x400000, .select=0x400000, .disconnect=0x8000, .len=512*1024
1004  * SNES HiROM (4MB):
1005  * .flags=CONST,                 .start=0x400000, .select=0x400000, .len=4*1024*1024
1006  * .flags=CONST, .offset=0x8000, .start=0x008000, .select=0x408000, .len=4*1024*1024
1007  * SNES ExHiROM (8MB):
1008  * .flags=CONST, .offset=0,                  .start=0xC00000, .select=0xC00000, .len=4*1024*1024
1009  * .flags=CONST, .offset=4*1024*1024,        .start=0x400000, .select=0xC00000, .len=4*1024*1024
1010  * .flags=CONST, .offset=0x8000,             .start=0x808000, .select=0xC08000, .len=4*1024*1024
1011  * .flags=CONST, .offset=4*1024*1024+0x8000, .start=0x008000, .select=0xC08000, .len=4*1024*1024
1012  * Clarify the size of the address space:
1013  * .ptr=NULL, .select=0xFFFFFF
1014  * .len can be implied by .select in many of them, but was included for clarity.
1015  */
1016 
1017 struct retro_memory_map
1018 {
1019    const struct retro_memory_descriptor *descriptors;
1020    unsigned num_descriptors;
1021 };
1022 
1023 struct retro_controller_description
1024 {
1025    /* Human-readable description of the controller. Even if using a generic
1026     * input device type, this can be set to the particular device type the
1027     * core uses. */
1028    const char *desc;
1029 
1030    /* Device type passed to retro_set_controller_port_device(). If the device
1031     * type is a sub-class of a generic input device type, use the
1032     * RETRO_DEVICE_SUBCLASS macro to create an ID.
1033     *
1034     * E.g. RETRO_DEVICE_SUBCLASS(RETRO_DEVICE_JOYPAD, 1). */
1035    unsigned id;
1036 };
1037 
1038 struct retro_controller_info
1039 {
1040    const struct retro_controller_description *types;
1041    unsigned num_types;
1042 };
1043 
1044 struct retro_subsystem_memory_info
1045 {
1046    /* The extension associated with a memory type, e.g. "psram". */
1047    const char *extension;
1048 
1049    /* The memory type for retro_get_memory(). This should be at
1050     * least 0x100 to avoid conflict with standardized
1051     * libretro memory types. */
1052    unsigned type;
1053 };
1054 
1055 struct retro_subsystem_rom_info
1056 {
1057    /* Describes what the content is (SGB BIOS, GB ROM, etc). */
1058    const char *desc;
1059 
1060    /* Same definition as retro_get_system_info(). */
1061    const char *valid_extensions;
1062 
1063    /* Same definition as retro_get_system_info(). */
1064    bool need_fullpath;
1065 
1066    /* Same definition as retro_get_system_info(). */
1067    bool block_extract;
1068 
1069    /* This is set if the content is required to load a game.
1070     * If this is set to false, a zeroed-out retro_game_info can be passed. */
1071    bool required;
1072 
1073    /* Content can have multiple associated persistent
1074     * memory types (retro_get_memory()). */
1075    const struct retro_subsystem_memory_info *memory;
1076    unsigned num_memory;
1077 };
1078 
1079 struct retro_subsystem_info
1080 {
1081    /* Human-readable string of the subsystem type, e.g. "Super GameBoy" */
1082    const char *desc;
1083 
1084    /* A computer friendly short string identifier for the subsystem type.
1085     * This name must be [a-z].
1086     * E.g. if desc is "Super GameBoy", this can be "sgb".
1087     * This identifier can be used for command-line interfaces, etc.
1088     */
1089    const char *ident;
1090 
1091    /* Infos for each content file. The first entry is assumed to be the
1092     * "most significant" content for frontend purposes.
1093     * E.g. with Super GameBoy, the first content should be the GameBoy ROM,
1094     * as it is the most "significant" content to a user.
1095     * If a frontend creates new file paths based on the content used
1096     * (e.g. savestates), it should use the path for the first ROM to do so. */
1097    const struct retro_subsystem_rom_info *roms;
1098 
1099    /* Number of content files associated with a subsystem. */
1100    unsigned num_roms;
1101 
1102    /* The type passed to retro_load_game_special(). */
1103    unsigned id;
1104 };
1105 
1106 typedef void (*retro_proc_address_t)(void);
1107 
1108 /* libretro API extension functions:
1109  * (None here so far).
1110  *
1111  * Get a symbol from a libretro core.
1112  * Cores should only return symbols which are actual
1113  * extensions to the libretro API.
1114  *
1115  * Frontends should not use this to obtain symbols to standard
1116  * libretro entry points (static linking or dlsym).
1117  *
1118  * The symbol name must be equal to the function name,
1119  * e.g. if void retro_foo(void); exists, the symbol must be called "retro_foo".
1120  * The returned function pointer must be cast to the corresponding type.
1121  */
1122 typedef retro_proc_address_t (*retro_get_proc_address_t)(const char *sym);
1123 
1124 struct retro_get_proc_address_interface
1125 {
1126    retro_get_proc_address_t get_proc_address;
1127 };
1128 
1129 enum retro_log_level
1130 {
1131    RETRO_LOG_DEBUG = 0,
1132    RETRO_LOG_INFO,
1133    RETRO_LOG_WARN,
1134    RETRO_LOG_ERROR,
1135 
1136    RETRO_LOG_DUMMY = INT_MAX
1137 };
1138 
1139 /* Logging function. Takes log level argument as well. */
1140 typedef void (*retro_log_printf_t)(enum retro_log_level level,
1141       const char *fmt, ...);
1142 
1143 struct retro_log_callback
1144 {
1145    retro_log_printf_t log;
1146 };
1147 
1148 /* Performance related functions */
1149 
1150 /* ID values for SIMD CPU features */
1151 #define RETRO_SIMD_SSE      (1 << 0)
1152 #define RETRO_SIMD_SSE2     (1 << 1)
1153 #define RETRO_SIMD_VMX      (1 << 2)
1154 #define RETRO_SIMD_VMX128   (1 << 3)
1155 #define RETRO_SIMD_AVX      (1 << 4)
1156 #define RETRO_SIMD_NEON     (1 << 5)
1157 #define RETRO_SIMD_SSE3     (1 << 6)
1158 #define RETRO_SIMD_SSSE3    (1 << 7)
1159 #define RETRO_SIMD_MMX      (1 << 8)
1160 #define RETRO_SIMD_MMXEXT   (1 << 9)
1161 #define RETRO_SIMD_SSE4     (1 << 10)
1162 #define RETRO_SIMD_SSE42    (1 << 11)
1163 #define RETRO_SIMD_AVX2     (1 << 12)
1164 #define RETRO_SIMD_VFPU     (1 << 13)
1165 #define RETRO_SIMD_PS       (1 << 14)
1166 #define RETRO_SIMD_AES      (1 << 15)
1167 #define RETRO_SIMD_VFPV3    (1 << 16)
1168 #define RETRO_SIMD_VFPV4    (1 << 17)
1169 
1170 typedef uint64_t retro_perf_tick_t;
1171 typedef int64_t retro_time_t;
1172 
1173 struct retro_perf_counter
1174 {
1175    const char *ident;
1176    retro_perf_tick_t start;
1177    retro_perf_tick_t total;
1178    retro_perf_tick_t call_cnt;
1179 
1180    bool registered;
1181 };
1182 
1183 /* Returns current time in microseconds.
1184  * Tries to use the most accurate timer available.
1185  */
1186 typedef retro_time_t (*retro_perf_get_time_usec_t)(void);
1187 
1188 /* A simple counter. Usually nanoseconds, but can also be CPU cycles.
1189  * Can be used directly if desired (when creating a more sophisticated
1190  * performance counter system).
1191  * */
1192 typedef retro_perf_tick_t (*retro_perf_get_counter_t)(void);
1193 
1194 /* Returns a bit-mask of detected CPU features (RETRO_SIMD_*). */
1195 typedef uint64_t (*retro_get_cpu_features_t)(void);
1196 
1197 /* Asks frontend to log and/or display the state of performance counters.
1198  * Performance counters can always be poked into manually as well.
1199  */
1200 typedef void (*retro_perf_log_t)(void);
1201 
1202 /* Register a performance counter.
1203  * ident field must be set with a discrete value and other values in
1204  * retro_perf_counter must be 0.
1205  * Registering can be called multiple times. To avoid calling to
1206  * frontend redundantly, you can check registered field first. */
1207 typedef void (*retro_perf_register_t)(struct retro_perf_counter *counter);
1208 
1209 /* Starts a registered counter. */
1210 typedef void (*retro_perf_start_t)(struct retro_perf_counter *counter);
1211 
1212 /* Stops a registered counter. */
1213 typedef void (*retro_perf_stop_t)(struct retro_perf_counter *counter);
1214 
1215 /* For convenience it can be useful to wrap register, start and stop in macros.
1216  * E.g.:
1217  * #ifdef LOG_PERFORMANCE
1218  * #define RETRO_PERFORMANCE_INIT(perf_cb, name) static struct retro_perf_counter name = {#name}; if (!name.registered) perf_cb.perf_register(&(name))
1219  * #define RETRO_PERFORMANCE_START(perf_cb, name) perf_cb.perf_start(&(name))
1220  * #define RETRO_PERFORMANCE_STOP(perf_cb, name) perf_cb.perf_stop(&(name))
1221  * #else
1222  * ... Blank macros ...
1223  * #endif
1224  *
1225  * These can then be used mid-functions around code snippets.
1226  *
1227  * extern struct retro_perf_callback perf_cb;  * Somewhere in the core.
1228  *
1229  * void do_some_heavy_work(void)
1230  * {
1231  *    RETRO_PERFORMANCE_INIT(cb, work_1;
1232  *    RETRO_PERFORMANCE_START(cb, work_1);
1233  *    heavy_work_1();
1234  *    RETRO_PERFORMANCE_STOP(cb, work_1);
1235  *
1236  *    RETRO_PERFORMANCE_INIT(cb, work_2);
1237  *    RETRO_PERFORMANCE_START(cb, work_2);
1238  *    heavy_work_2();
1239  *    RETRO_PERFORMANCE_STOP(cb, work_2);
1240  * }
1241  *
1242  * void retro_deinit(void)
1243  * {
1244  *    perf_cb.perf_log();  * Log all perf counters here for example.
1245  * }
1246  */
1247 
1248 struct retro_perf_callback
1249 {
1250    retro_perf_get_time_usec_t    get_time_usec;
1251    retro_get_cpu_features_t      get_cpu_features;
1252 
1253    retro_perf_get_counter_t      get_perf_counter;
1254    retro_perf_register_t         perf_register;
1255    retro_perf_start_t            perf_start;
1256    retro_perf_stop_t             perf_stop;
1257    retro_perf_log_t              perf_log;
1258 };
1259 
1260 /* FIXME: Document the sensor API and work out behavior.
1261  * It will be marked as experimental until then.
1262  */
1263 enum retro_sensor_action
1264 {
1265    RETRO_SENSOR_ACCELEROMETER_ENABLE = 0,
1266    RETRO_SENSOR_ACCELEROMETER_DISABLE,
1267 
1268    RETRO_SENSOR_DUMMY = INT_MAX
1269 };
1270 
1271 /* Id values for SENSOR types. */
1272 #define RETRO_SENSOR_ACCELEROMETER_X 0
1273 #define RETRO_SENSOR_ACCELEROMETER_Y 1
1274 #define RETRO_SENSOR_ACCELEROMETER_Z 2
1275 
1276 typedef bool (*retro_set_sensor_state_t)(unsigned port,
1277       enum retro_sensor_action action, unsigned rate);
1278 
1279 typedef float (*retro_sensor_get_input_t)(unsigned port, unsigned id);
1280 
1281 struct retro_sensor_interface
1282 {
1283    retro_set_sensor_state_t set_sensor_state;
1284    retro_sensor_get_input_t get_sensor_input;
1285 };
1286 
1287 enum retro_camera_buffer
1288 {
1289    RETRO_CAMERA_BUFFER_OPENGL_TEXTURE = 0,
1290    RETRO_CAMERA_BUFFER_RAW_FRAMEBUFFER,
1291 
1292    RETRO_CAMERA_BUFFER_DUMMY = INT_MAX
1293 };
1294 
1295 /* Starts the camera driver. Can only be called in retro_run(). */
1296 typedef bool (*retro_camera_start_t)(void);
1297 
1298 /* Stops the camera driver. Can only be called in retro_run(). */
1299 typedef void (*retro_camera_stop_t)(void);
1300 
1301 /* Callback which signals when the camera driver is initialized
1302  * and/or deinitialized.
1303  * retro_camera_start_t can be called in initialized callback.
1304  */
1305 typedef void (*retro_camera_lifetime_status_t)(void);
1306 
1307 /* A callback for raw framebuffer data. buffer points to an XRGB8888 buffer.
1308  * Width, height and pitch are similar to retro_video_refresh_t.
1309  * First pixel is top-left origin.
1310  */
1311 typedef void (*retro_camera_frame_raw_framebuffer_t)(const uint32_t *buffer,
1312       unsigned width, unsigned height, size_t pitch);
1313 
1314 /* A callback for when OpenGL textures are used.
1315  *
1316  * texture_id is a texture owned by camera driver.
1317  * Its state or content should be considered immutable, except for things like
1318  * texture filtering and clamping.
1319  *
1320  * texture_target is the texture target for the GL texture.
1321  * These can include e.g. GL_TEXTURE_2D, GL_TEXTURE_RECTANGLE, and possibly
1322  * more depending on extensions.
1323  *
1324  * affine points to a packed 3x3 column-major matrix used to apply an affine
1325  * transform to texture coordinates. (affine_matrix * vec3(coord_x, coord_y, 1.0))
1326  * After transform, normalized texture coord (0, 0) should be bottom-left
1327  * and (1, 1) should be top-right (or (width, height) for RECTANGLE).
1328  *
1329  * GL-specific typedefs are avoided here to avoid relying on gl.h in
1330  * the API definition.
1331  */
1332 typedef void (*retro_camera_frame_opengl_texture_t)(unsigned texture_id,
1333       unsigned texture_target, const float *affine);
1334 
1335 struct retro_camera_callback
1336 {
1337    /* Set by libretro core.
1338     * Example bitmask: caps = (1 << RETRO_CAMERA_BUFFER_OPENGL_TEXTURE) | (1 << RETRO_CAMERA_BUFFER_RAW_FRAMEBUFFER).
1339     */
1340    uint64_t caps;
1341 
1342    unsigned width; /* Desired resolution for camera. Is only used as a hint. */
1343    unsigned height;
1344    retro_camera_start_t start; /* Set by frontend. */
1345    retro_camera_stop_t stop; /* Set by frontend. */
1346 
1347    /* Set by libretro core if raw framebuffer callbacks will be used. */
1348    retro_camera_frame_raw_framebuffer_t frame_raw_framebuffer;
1349    /* Set by libretro core if OpenGL texture callbacks will be used. */
1350    retro_camera_frame_opengl_texture_t frame_opengl_texture;
1351 
1352    /* Set by libretro core. Called after camera driver is initialized and
1353     * ready to be started.
1354     * Can be NULL, in which this callback is not called.
1355     */
1356    retro_camera_lifetime_status_t initialized;
1357 
1358    /* Set by libretro core. Called right before camera driver is
1359     * deinitialized.
1360     * Can be NULL, in which this callback is not called.
1361     */
1362    retro_camera_lifetime_status_t deinitialized;
1363 };
1364 
1365 /* Sets the interval of time and/or distance at which to update/poll
1366  * location-based data.
1367  *
1368  * To ensure compatibility with all location-based implementations,
1369  * values for both interval_ms and interval_distance should be provided.
1370  *
1371  * interval_ms is the interval expressed in milliseconds.
1372  * interval_distance is the distance interval expressed in meters.
1373  */
1374 typedef void (*retro_location_set_interval_t)(unsigned interval_ms,
1375       unsigned interval_distance);
1376 
1377 /* Start location services. The device will start listening for changes to the
1378  * current location at regular intervals (which are defined with
1379  * retro_location_set_interval_t). */
1380 typedef bool (*retro_location_start_t)(void);
1381 
1382 /* Stop location services. The device will stop listening for changes
1383  * to the current location. */
1384 typedef void (*retro_location_stop_t)(void);
1385 
1386 /* Get the position of the current location. Will set parameters to
1387  * 0 if no new  location update has happened since the last time. */
1388 typedef bool (*retro_location_get_position_t)(double *lat, double *lon,
1389       double *horiz_accuracy, double *vert_accuracy);
1390 
1391 /* Callback which signals when the location driver is initialized
1392  * and/or deinitialized.
1393  * retro_location_start_t can be called in initialized callback.
1394  */
1395 typedef void (*retro_location_lifetime_status_t)(void);
1396 
1397 struct retro_location_callback
1398 {
1399    retro_location_start_t         start;
1400    retro_location_stop_t          stop;
1401    retro_location_get_position_t  get_position;
1402    retro_location_set_interval_t  set_interval;
1403 
1404    retro_location_lifetime_status_t initialized;
1405    retro_location_lifetime_status_t deinitialized;
1406 };
1407 
1408 enum retro_rumble_effect
1409 {
1410    RETRO_RUMBLE_STRONG = 0,
1411    RETRO_RUMBLE_WEAK = 1,
1412 
1413    RETRO_RUMBLE_DUMMY = INT_MAX
1414 };
1415 
1416 /* Sets rumble state for joypad plugged in port 'port'.
1417  * Rumble effects are controlled independently,
1418  * and setting e.g. strong rumble does not override weak rumble.
1419  * Strength has a range of [0, 0xffff].
1420  *
1421  * Returns true if rumble state request was honored.
1422  * Calling this before first retro_run() is likely to return false. */
1423 typedef bool (*retro_set_rumble_state_t)(unsigned port,
1424       enum retro_rumble_effect effect, uint16_t strength);
1425 
1426 struct retro_rumble_interface
1427 {
1428    retro_set_rumble_state_t set_rumble_state;
1429 };
1430 
1431 /* Notifies libretro that audio data should be written. */
1432 typedef void (*retro_audio_callback_t)(void);
1433 
1434 /* True: Audio driver in frontend is active, and callback is
1435  * expected to be called regularily.
1436  * False: Audio driver in frontend is paused or inactive.
1437  * Audio callback will not be called until set_state has been
1438  * called with true.
1439  * Initial state is false (inactive).
1440  */
1441 typedef void (*retro_audio_set_state_callback_t)(bool enabled);
1442 
1443 struct retro_audio_callback
1444 {
1445    retro_audio_callback_t callback;
1446    retro_audio_set_state_callback_t set_state;
1447 };
1448 
1449 /* Notifies a libretro core of time spent since last invocation
1450  * of retro_run() in microseconds.
1451  *
1452  * It will be called right before retro_run() every frame.
1453  * The frontend can tamper with timing to support cases like
1454  * fast-forward, slow-motion and framestepping.
1455  *
1456  * In those scenarios the reference frame time value will be used. */
1457 typedef int64_t retro_usec_t;
1458 typedef void (*retro_frame_time_callback_t)(retro_usec_t usec);
1459 struct retro_frame_time_callback
1460 {
1461    retro_frame_time_callback_t callback;
1462    /* Represents the time of one frame. It is computed as
1463     * 1000000 / fps, but the implementation will resolve the
1464     * rounding to ensure that framestepping, etc is exact. */
1465    retro_usec_t reference;
1466 };
1467 
1468 /* Pass this to retro_video_refresh_t if rendering to hardware.
1469  * Passing NULL to retro_video_refresh_t is still a frame dupe as normal.
1470  * */
1471 #define RETRO_HW_FRAME_BUFFER_VALID ((void*)-1)
1472 
1473 /* Invalidates the current HW context.
1474  * Any GL state is lost, and must not be deinitialized explicitly.
1475  * If explicit deinitialization is desired by the libretro core,
1476  * it should implement context_destroy callback.
1477  * If called, all GPU resources must be reinitialized.
1478  * Usually called when frontend reinits video driver.
1479  * Also called first time video driver is initialized,
1480  * allowing libretro core to initialize resources.
1481  */
1482 typedef void (*retro_hw_context_reset_t)(void);
1483 
1484 /* Gets current framebuffer which is to be rendered to.
1485  * Could change every frame potentially.
1486  */
1487 typedef uintptr_t (*retro_hw_get_current_framebuffer_t)(void);
1488 
1489 /* Get a symbol from HW context. */
1490 typedef retro_proc_address_t (*retro_hw_get_proc_address_t)(const char *sym);
1491 
1492 enum retro_hw_context_type
1493 {
1494    RETRO_HW_CONTEXT_NONE             = 0,
1495    /* OpenGL 2.x. Driver can choose to use latest compatibility context. */
1496    RETRO_HW_CONTEXT_OPENGL           = 1,
1497    /* OpenGL ES 2.0. */
1498    RETRO_HW_CONTEXT_OPENGLES2        = 2,
1499    /* Modern desktop core GL context. Use version_major/
1500     * version_minor fields to set GL version. */
1501    RETRO_HW_CONTEXT_OPENGL_CORE      = 3,
1502    /* OpenGL ES 3.0 */
1503    RETRO_HW_CONTEXT_OPENGLES3        = 4,
1504    /* OpenGL ES 3.1+. Set version_major/version_minor. For GLES2 and GLES3,
1505     * use the corresponding enums directly. */
1506    RETRO_HW_CONTEXT_OPENGLES_VERSION = 5,
1507 
1508    RETRO_HW_CONTEXT_DUMMY = INT_MAX
1509 };
1510 
1511 struct retro_hw_render_callback
1512 {
1513    /* Which API to use. Set by libretro core. */
1514    enum retro_hw_context_type context_type;
1515 
1516    /* Called when a context has been created or when it has been reset.
1517     * An OpenGL context is only valid after context_reset() has been called.
1518     *
1519     * When context_reset is called, OpenGL resources in the libretro
1520     * implementation are guaranteed to be invalid.
1521     *
1522     * It is possible that context_reset is called multiple times during an
1523     * application lifecycle.
1524     * If context_reset is called without any notification (context_destroy),
1525     * the OpenGL context was lost and resources should just be recreated
1526     * without any attempt to "free" old resources.
1527     */
1528    retro_hw_context_reset_t context_reset;
1529 
1530    /* Set by frontend. */
1531    retro_hw_get_current_framebuffer_t get_current_framebuffer;
1532 
1533    /* Set by frontend. */
1534    retro_hw_get_proc_address_t get_proc_address;
1535 
1536    /* Set if render buffers should have depth component attached. */
1537    bool depth;
1538 
1539    /* Set if stencil buffers should be attached. */
1540    bool stencil;
1541 
1542    /* If depth and stencil are true, a packed 24/8 buffer will be added.
1543     * Only attaching stencil is invalid and will be ignored. */
1544 
1545    /* Use conventional bottom-left origin convention. If false,
1546     * standard libretro top-left origin semantics are used. */
1547    bool bottom_left_origin;
1548 
1549    /* Major version number for core GL context or GLES 3.1+. */
1550    unsigned version_major;
1551 
1552    /* Minor version number for core GL context or GLES 3.1+. */
1553    unsigned version_minor;
1554 
1555    /* If this is true, the frontend will go very far to avoid
1556     * resetting context in scenarios like toggling fullscreen, etc.
1557     */
1558    bool cache_context;
1559 
1560    /* The reset callback might still be called in extreme situations
1561     * such as if the context is lost beyond recovery.
1562     *
1563     * For optimal stability, set this to false, and allow context to be
1564     * reset at any time.
1565     */
1566 
1567    /* A callback to be called before the context is destroyed in a
1568     * controlled way by the frontend. */
1569    retro_hw_context_reset_t context_destroy;
1570 
1571    /* OpenGL resources can be deinitialized cleanly at this step.
1572     * context_destroy can be set to NULL, in which resources will
1573     * just be destroyed without any notification.
1574     *
1575     * Even when context_destroy is non-NULL, it is possible that
1576     * context_reset is called without any destroy notification.
1577     * This happens if context is lost by external factors (such as
1578     * notified by GL_ARB_robustness).
1579     *
1580     * In this case, the context is assumed to be already dead,
1581     * and the libretro implementation must not try to free any OpenGL
1582     * resources in the subsequent context_reset.
1583     */
1584 
1585    /* Creates a debug context. */
1586    bool debug_context;
1587 };
1588 
1589 /* Callback type passed in RETRO_ENVIRONMENT_SET_KEYBOARD_CALLBACK.
1590  * Called by the frontend in response to keyboard events.
1591  * down is set if the key is being pressed, or false if it is being released.
1592  * keycode is the RETROK value of the char.
1593  * character is the text character of the pressed key. (UTF-32).
1594  * key_modifiers is a set of RETROKMOD values or'ed together.
1595  *
1596  * The pressed/keycode state can be indepedent of the character.
1597  * It is also possible that multiple characters are generated from a
1598  * single keypress.
1599  * Keycode events should be treated separately from character events.
1600  * However, when possible, the frontend should try to synchronize these.
1601  * If only a character is posted, keycode should be RETROK_UNKNOWN.
1602  *
1603  * Similarily if only a keycode event is generated with no corresponding
1604  * character, character should be 0.
1605  */
1606 typedef void (*retro_keyboard_event_t)(bool down, unsigned keycode,
1607       uint32_t character, uint16_t key_modifiers);
1608 
1609 struct retro_keyboard_callback
1610 {
1611    retro_keyboard_event_t callback;
1612 };
1613 
1614 /* Callbacks for RETRO_ENVIRONMENT_SET_DISK_CONTROL_INTERFACE.
1615  * Should be set for implementations which can swap out multiple disk
1616  * images in runtime.
1617  *
1618  * If the implementation can do this automatically, it should strive to do so.
1619  * However, there are cases where the user must manually do so.
1620  *
1621  * Overview: To swap a disk image, eject the disk image with
1622  * set_eject_state(true).
1623  * Set the disk index with set_image_index(index). Insert the disk again
1624  * with set_eject_state(false).
1625  */
1626 
1627 /* If ejected is true, "ejects" the virtual disk tray.
1628  * When ejected, the disk image index can be set.
1629  */
1630 typedef bool (*retro_set_eject_state_t)(bool ejected);
1631 
1632 /* Gets current eject state. The initial state is 'not ejected'. */
1633 typedef bool (*retro_get_eject_state_t)(void);
1634 
1635 /* Gets current disk index. First disk is index 0.
1636  * If return value is >= get_num_images(), no disk is currently inserted.
1637  */
1638 typedef unsigned (*retro_get_image_index_t)(void);
1639 
1640 /* Sets image index. Can only be called when disk is ejected.
1641  * The implementation supports setting "no disk" by using an
1642  * index >= get_num_images().
1643  */
1644 typedef bool (*retro_set_image_index_t)(unsigned index);
1645 
1646 /* Gets total number of images which are available to use. */
1647 typedef unsigned (*retro_get_num_images_t)(void);
1648 
1649 struct retro_game_info;
1650 
1651 /* Replaces the disk image associated with index.
1652  * Arguments to pass in info have same requirements as retro_load_game().
1653  * Virtual disk tray must be ejected when calling this.
1654  *
1655  * Replacing a disk image with info = NULL will remove the disk image
1656  * from the internal list.
1657  * As a result, calls to get_image_index() can change.
1658  *
1659  * E.g. replace_image_index(1, NULL), and previous get_image_index()
1660  * returned 4 before.
1661  * Index 1 will be removed, and the new index is 3.
1662  */
1663 typedef bool (*retro_replace_image_index_t)(unsigned index,
1664       const struct retro_game_info *info);
1665 
1666 /* Adds a new valid index (get_num_images()) to the internal disk list.
1667  * This will increment subsequent return values from get_num_images() by 1.
1668  * This image index cannot be used until a disk image has been set
1669  * with replace_image_index. */
1670 typedef bool (*retro_add_image_index_t)(void);
1671 
1672 struct retro_disk_control_callback
1673 {
1674    retro_set_eject_state_t set_eject_state;
1675    retro_get_eject_state_t get_eject_state;
1676 
1677    retro_get_image_index_t get_image_index;
1678    retro_set_image_index_t set_image_index;
1679    retro_get_num_images_t  get_num_images;
1680 
1681    retro_replace_image_index_t replace_image_index;
1682    retro_add_image_index_t add_image_index;
1683 };
1684 
1685 enum retro_pixel_format
1686 {
1687    /* 0RGB1555, native endian.
1688     * 0 bit must be set to 0.
1689     * This pixel format is default for compatibility concerns only.
1690     * If a 15/16-bit pixel format is desired, consider using RGB565. */
1691    RETRO_PIXEL_FORMAT_0RGB1555 = 0,
1692 
1693    /* XRGB8888, native endian.
1694     * X bits are ignored. */
1695    RETRO_PIXEL_FORMAT_XRGB8888 = 1,
1696 
1697    /* RGB565, native endian.
1698     * This pixel format is the recommended format to use if a 15/16-bit
1699     * format is desired as it is the pixel format that is typically
1700     * available on a wide range of low-power devices.
1701     *
1702     * It is also natively supported in APIs like OpenGL ES. */
1703    RETRO_PIXEL_FORMAT_RGB565   = 2,
1704 
1705    /* Ensure sizeof() == sizeof(int). */
1706    RETRO_PIXEL_FORMAT_UNKNOWN  = INT_MAX
1707 };
1708 
1709 struct retro_message
1710 {
1711    const char *msg;        /* Message to be displayed. */
1712    unsigned    frames;     /* Duration in frames of message. */
1713 };
1714 
1715 /* Describes how the libretro implementation maps a libretro input bind
1716  * to its internal input system through a human readable string.
1717  * This string can be used to better let a user configure input. */
1718 struct retro_input_descriptor
1719 {
1720    /* Associates given parameters with a description. */
1721    unsigned port;
1722    unsigned device;
1723    unsigned index;
1724    unsigned id;
1725 
1726    /* Human readable description for parameters.
1727     * The pointer must remain valid until
1728     * retro_unload_game() is called. */
1729    const char *description;
1730 };
1731 
1732 struct retro_system_info
1733 {
1734    /* All pointers are owned by libretro implementation, and pointers must
1735     * remain valid until retro_deinit() is called. */
1736 
1737    const char *library_name;      /* Descriptive name of library. Should not
1738                                    * contain any version numbers, etc. */
1739    const char *library_version;   /* Descriptive version of core. */
1740 
1741    const char *valid_extensions;  /* A string listing probably content
1742                                    * extensions the core will be able to
1743                                    * load, separated with pipe.
1744                                    * I.e. "bin|rom|iso".
1745                                    * Typically used for a GUI to filter
1746                                    * out extensions. */
1747 
1748    /* If true, retro_load_game() is guaranteed to provide a valid pathname
1749     * in retro_game_info::path.
1750     * ::data and ::size are both invalid.
1751     *
1752     * If false, ::data and ::size are guaranteed to be valid, but ::path
1753     * might not be valid.
1754     *
1755     * This is typically set to true for libretro implementations that must
1756     * load from file.
1757     * Implementations should strive for setting this to false, as it allows
1758     * the frontend to perform patching, etc. */
1759    bool        need_fullpath;
1760 
1761    /* If true, the frontend is not allowed to extract any archives before
1762     * loading the real content.
1763     * Necessary for certain libretro implementations that load games
1764     * from zipped archives. */
1765    bool        block_extract;
1766 };
1767 
1768 struct retro_game_geometry
1769 {
1770    unsigned base_width;    /* Nominal video width of game. */
1771    unsigned base_height;   /* Nominal video height of game. */
1772    unsigned max_width;     /* Maximum possible width of game. */
1773    unsigned max_height;    /* Maximum possible height of game. */
1774 
1775    float    aspect_ratio;  /* Nominal aspect ratio of game. If
1776                             * aspect_ratio is <= 0.0, an aspect ratio
1777                             * of base_width / base_height is assumed.
1778                             * A frontend could override this setting,
1779                             * if desired. */
1780 };
1781 
1782 struct retro_system_timing
1783 {
1784    double fps;             /* FPS of video content. */
1785    double sample_rate;     /* Sampling rate of audio. */
1786 };
1787 
1788 struct retro_system_av_info
1789 {
1790    struct retro_game_geometry geometry;
1791    struct retro_system_timing timing;
1792 };
1793 
1794 struct retro_variable
1795 {
1796    /* Variable to query in RETRO_ENVIRONMENT_GET_VARIABLE.
1797     * If NULL, obtains the complete environment string if more
1798     * complex parsing is necessary.
1799     * The environment string is formatted as key-value pairs
1800     * delimited by semicolons as so:
1801     * "key1=value1;key2=value2;..."
1802     */
1803    const char *key;
1804 
1805    /* Value to be obtained. If key does not exist, it is set to NULL. */
1806    const char *value;
1807 };
1808 
1809 struct retro_game_info
1810 {
1811    const char *path;       /* Path to game, UTF-8 encoded.
1812                             * Usually used as a reference.
1813                             * May be NULL if rom was loaded from stdin
1814                             * or similar.
1815                             * retro_system_info::need_fullpath guaranteed
1816                             * that this path is valid. */
1817    const void *data;       /* Memory buffer of loaded game. Will be NULL
1818                             * if need_fullpath was set. */
1819    size_t      size;       /* Size of memory buffer. */
1820    const char *meta;       /* String of implementation specific meta-data. */
1821 };
1822 
1823 /* Callbacks */
1824 
1825 /* Environment callback. Gives implementations a way of performing
1826  * uncommon tasks. Extensible. */
1827 typedef bool (*retro_environment_t)(unsigned cmd, void *data);
1828 
1829 /* Render a frame. Pixel format is 15-bit 0RGB1555 native endian
1830  * unless changed (see RETRO_ENVIRONMENT_SET_PIXEL_FORMAT).
1831  *
1832  * Width and height specify dimensions of buffer.
1833  * Pitch specifices length in bytes between two lines in buffer.
1834  *
1835  * For performance reasons, it is highly recommended to have a frame
1836  * that is packed in memory, i.e. pitch == width * byte_per_pixel.
1837  * Certain graphic APIs, such as OpenGL ES, do not like textures
1838  * that are not packed in memory.
1839  */
1840 typedef void (*retro_video_refresh_t)(const void *data, unsigned width,
1841       unsigned height, size_t pitch);
1842 
1843 /* Renders a single audio frame. Should only be used if implementation
1844  * generates a single sample at a time.
1845  * Format is signed 16-bit native endian.
1846  */
1847 typedef void (*retro_audio_sample_t)(int16_t left, int16_t right);
1848 
1849 /* Renders multiple audio frames in one go.
1850  *
1851  * One frame is defined as a sample of left and right channels, interleaved.
1852  * I.e. int16_t buf[4] = { l, r, l, r }; would be 2 frames.
1853  * Only one of the audio callbacks must ever be used.
1854  */
1855 typedef size_t (*retro_audio_sample_batch_t)(const int16_t *data,
1856       size_t frames);
1857 
1858 /* Polls input. */
1859 typedef void (*retro_input_poll_t)(void);
1860 
1861 /* Queries for input for player 'port'. device will be masked with
1862  * RETRO_DEVICE_MASK.
1863  *
1864  * Specialization of devices such as RETRO_DEVICE_JOYPAD_MULTITAP that
1865  * have been set with retro_set_controller_port_device()
1866  * will still use the higher level RETRO_DEVICE_JOYPAD to request input.
1867  */
1868 typedef int16_t (*retro_input_state_t)(unsigned port, unsigned device,
1869       unsigned index, unsigned id);
1870 
1871 /* Sets callbacks. retro_set_environment() is guaranteed to be called
1872  * before retro_init().
1873  *
1874  * The rest of the set_* functions are guaranteed to have been called
1875  * before the first call to retro_run() is made. */
1876 RETRO_API void retro_set_environment(retro_environment_t);
1877 RETRO_API void retro_set_video_refresh(retro_video_refresh_t);
1878 RETRO_API void retro_set_audio_sample(retro_audio_sample_t);
1879 RETRO_API void retro_set_audio_sample_batch(retro_audio_sample_batch_t);
1880 RETRO_API void retro_set_input_poll(retro_input_poll_t);
1881 RETRO_API void retro_set_input_state(retro_input_state_t);
1882 
1883 /* Library global initialization/deinitialization. */
1884 RETRO_API void retro_init(void);
1885 RETRO_API void retro_deinit(void);
1886 
1887 /* Must return RETRO_API_VERSION. Used to validate ABI compatibility
1888  * when the API is revised. */
1889 RETRO_API unsigned retro_api_version(void);
1890 
1891 /* Gets statically known system info. Pointers provided in *info
1892  * must be statically allocated.
1893  * Can be called at any time, even before retro_init(). */
1894 RETRO_API void retro_get_system_info(struct retro_system_info *info);
1895 
1896 /* Gets information about system audio/video timings and geometry.
1897  * Can be called only after retro_load_game() has successfully completed.
1898  * NOTE: The implementation of this function might not initialize every
1899  * variable if needed.
1900  * E.g. geom.aspect_ratio might not be initialized if core doesn't
1901  * desire a particular aspect ratio. */
1902 RETRO_API void retro_get_system_av_info(struct retro_system_av_info *info);
1903 
1904 /* Sets device to be used for player 'port'.
1905  * By default, RETRO_DEVICE_JOYPAD is assumed to be plugged into all
1906  * available ports.
1907  * Setting a particular device type is not a guarantee that libretro cores
1908  * will only poll input based on that particular device type. It is only a
1909  * hint to the libretro core when a core cannot automatically detect the
1910  * appropriate input device type on its own. It is also relevant when a
1911  * core can change its behavior depending on device type. */
1912 RETRO_API void retro_set_controller_port_device(unsigned port, unsigned device);
1913 
1914 /* Resets the current game. */
1915 RETRO_API void retro_reset(void);
1916 
1917 /* Runs the game for one video frame.
1918  * During retro_run(), input_poll callback must be called at least once.
1919  *
1920  * If a frame is not rendered for reasons where a game "dropped" a frame,
1921  * this still counts as a frame, and retro_run() should explicitly dupe
1922  * a frame if GET_CAN_DUPE returns true.
1923  * In this case, the video callback can take a NULL argument for data.
1924  */
1925 RETRO_API void retro_run(void);
1926 
1927 /* Returns the amount of data the implementation requires to serialize
1928  * internal state (save states).
1929  * Between calls to retro_load_game() and retro_unload_game(), the
1930  * returned size is never allowed to be larger than a previous returned
1931  * value, to ensure that the frontend can allocate a save state buffer once.
1932  */
1933 RETRO_API size_t retro_serialize_size(void);
1934 
1935 /* Serializes internal state. If failed, or size is lower than
1936  * retro_serialize_size(), it should return false, true otherwise. */
1937 RETRO_API bool retro_serialize(void *data, size_t size);
1938 RETRO_API bool retro_unserialize(const void *data, size_t size);
1939 
1940 RETRO_API void retro_cheat_reset(void);
1941 RETRO_API void retro_cheat_set(unsigned index, bool enabled, const char *code);
1942 
1943 /* Loads a game. */
1944 RETRO_API bool retro_load_game(const struct retro_game_info *game);
1945 
1946 /* Loads a "special" kind of game. Should not be used,
1947  * except in extreme cases. */
1948 RETRO_API bool retro_load_game_special(
1949   unsigned game_type,
1950   const struct retro_game_info *info, size_t num_info
1951 );
1952 
1953 /* Unloads a currently loaded game. */
1954 RETRO_API void retro_unload_game(void);
1955 
1956 /* Gets region of game. */
1957 RETRO_API unsigned retro_get_region(void);
1958 
1959 /* Gets region of memory. */
1960 RETRO_API void *retro_get_memory_data(unsigned id);
1961 RETRO_API size_t retro_get_memory_size(unsigned id);
1962 
1963 #ifdef __cplusplus
1964 }
1965 #endif
1966 
1967 #endif
1968