joystick/windows/SDL_mmjoystick.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"

#ifdef SDL_JOYSTICK_WINMM

/* Win32 MultiMedia Joystick driver, contributed by Andrei de A. Formiga */

#include "../../core/windows/SDL_windows.h"
#include <mmsystem.h>
#include <regstr.h>

#include "SDL_events.h"
#include "SDL_joystick.h"
#include "../SDL_sysjoystick.h"
#include "../SDL_joystick_c.h"

#ifdef REGSTR_VAL_JOYOEMNAME
#undef REGSTR_VAL_JOYOEMNAME
#endif
#define REGSTR_VAL_JOYOEMNAME "OEMName"

#define MAX_JOYSTICKS   16
#define MAX_AXES    6       /* each joystick can have up to 6 axes */
#define MAX_BUTTONS 32      /* and 32 buttons                      */
#define AXIS_MIN    -32768  /* minimum value for axis coordinate */
#define AXIS_MAX    32767   /* maximum value for axis coordinate */
/* limit axis to 256 possible positions to filter out noise */
#define JOY_AXIS_THRESHOLD      (((AXIS_MAX)-(AXIS_MIN))/256)
#define JOY_BUTTON_FLAG(n)  (1<<n)


/* array to hold joystick ID values */
static UINT SYS_JoystickID[MAX_JOYSTICKS];
static JOYCAPSA SYS_Joystick[MAX_JOYSTICKS];
static char *SYS_JoystickName[MAX_JOYSTICKS];

/* The private structure used to keep track of a joystick */
struct joystick_hwdata
{
    /* joystick ID */
    UINT id;

    /* values used to translate device-specific coordinates into
       SDL-standard ranges */
    struct _transaxis
    {
        int offset;
        float scale;
    } transaxis[6];
};

/* Convert a Windows Multimedia API return code to a text message */
static void SetMMerror(char *function, int code);


static char *
GetJoystickName(int index, const char *szRegKey)
{
    /* added 7/24/2004 by Eckhard Stolberg */
    /*
       see if there is a joystick for the current
       index (1-16) listed in the registry
     */
    char *name = NULL;
    HKEY hTopKey;
    HKEY hKey;
    DWORD regsize;
    LONG regresult;
    char regkey[256];
    char regvalue[256];
    char regname[256];

    SDL_snprintf(regkey, SDL_arraysize(regkey), "%s\\%s\\%s",
                 REGSTR_PATH_JOYCONFIG, szRegKey, REGSTR_KEY_JOYCURR);
    hTopKey = HKEY_LOCAL_MACHINE;
    regresult = RegOpenKeyExA(hTopKey, regkey, 0, KEY_READ, &hKey);
    if (regresult != ERROR_SUCCESS) {
        hTopKey = HKEY_CURRENT_USER;
        regresult = RegOpenKeyExA(hTopKey, regkey, 0, KEY_READ, &hKey);
    }
    if (regresult != ERROR_SUCCESS) {
        return NULL;
    }

    /* find the registry key name for the joystick's properties */
    regsize = sizeof(regname);
    SDL_snprintf(regvalue, SDL_arraysize(regvalue), "Joystick%d%s", index + 1,
                 REGSTR_VAL_JOYOEMNAME);
    regresult =
        RegQueryValueExA(hKey, regvalue, 0, 0, (LPBYTE) regname, &regsize);
    RegCloseKey(hKey);

    if (regresult != ERROR_SUCCESS) {
        return NULL;
    }

    /* open that registry key */
    SDL_snprintf(regkey, SDL_arraysize(regkey), "%s\\%s", REGSTR_PATH_JOYOEM,
                 regname);
    regresult = RegOpenKeyExA(hTopKey, regkey, 0, KEY_READ, &hKey);
    if (regresult != ERROR_SUCCESS) {
        return NULL;
    }

    /* find the size for the OEM name text */
    regsize = sizeof(regvalue);
    regresult =
        RegQueryValueExA(hKey, REGSTR_VAL_JOYOEMNAME, 0, 0, NULL, &regsize);
    if (regresult == ERROR_SUCCESS) {
        /* allocate enough memory for the OEM name text ... */
        name = (char *) SDL_malloc(regsize);
        if (name) {
            /* ... and read it from the registry */
            regresult = RegQueryValueExA(hKey,
                                         REGSTR_VAL_JOYOEMNAME, 0, 0,
                                         (LPBYTE) name, &regsize);
        }
    }
    RegCloseKey(hKey);

    return (name);
}

static int SDL_SYS_numjoysticks = 0;

/* Function to scan the system for joysticks.
 * Joystick 0 should be the system default joystick.
 * It should return 0, or -1 on an unrecoverable fatal error.
 */
int
SDL_SYS_JoystickInit(void)
{
    int i;
    int maxdevs;
    JOYINFOEX joyinfo;
    JOYCAPSA joycaps;
    MMRESULT result;

    /* Reset the joystick ID & name mapping tables */
    for (i = 0; i < MAX_JOYSTICKS; ++i) {
        SYS_JoystickID[i] = 0;
        SYS_JoystickName[i] = NULL;
    }

    /* Loop over all potential joystick devices */
    SDL_SYS_numjoysticks = 0;
    maxdevs = joyGetNumDevs();
    for (i = JOYSTICKID1; i < maxdevs && SDL_SYS_numjoysticks < MAX_JOYSTICKS; ++i) {

        joyinfo.dwSize = sizeof(joyinfo);
        joyinfo.dwFlags = JOY_RETURNALL;
        result = joyGetPosEx(i, &joyinfo);
        if (result == JOYERR_NOERROR) {
            result = joyGetDevCapsA(i, &joycaps, sizeof(joycaps));
            if (result == JOYERR_NOERROR) {
                SYS_JoystickID[SDL_SYS_numjoysticks] = i;
                SYS_Joystick[SDL_SYS_numjoysticks] = joycaps;
                SYS_JoystickName[SDL_SYS_numjoysticks] =
                    GetJoystickName(i, joycaps.szRegKey);
                SDL_SYS_numjoysticks++;
            }
        }
    }
    return (SDL_SYS_numjoysticks);
}

int SDL_SYS_NumJoysticks()
{
    return SDL_SYS_numjoysticks;
}

void SDL_SYS_JoystickDetect()
{
}

/* Function to get the device-dependent name of a joystick */
const char *
SDL_SYS_JoystickNameForDeviceIndex(int device_index)
{
    if (SYS_JoystickName[device_index] != NULL) {
        return (SYS_JoystickName[device_index]);
    } else {
        return (SYS_Joystick[device_index].szPname);
    }
}

/* Function to perform the mapping from device index to the instance id for this index */
SDL_JoystickID SDL_SYS_GetInstanceIdOfDeviceIndex(int device_index)
{
    return device_index;
}

/* Function to open a joystick for use.
   The joystick to open is specified by the device index.
   This should fill the nbuttons and naxes fields of the joystick structure.
   It returns 0, or -1 if there is an error.
 */
int
SDL_SYS_JoystickOpen(SDL_Joystick * joystick, int device_index)
{
    int index, i;
    int caps_flags[MAX_AXES - 2] =
        { JOYCAPS_HASZ, JOYCAPS_HASR, JOYCAPS_HASU, JOYCAPS_HASV };
    int axis_min[MAX_AXES], axis_max[MAX_AXES];


    /* shortcut */
    index = device_index;
    axis_min[0] = SYS_Joystick[index].wXmin;
    axis_max[0] = SYS_Joystick[index].wXmax;
    axis_min[1] = SYS_Joystick[index].wYmin;
    axis_max[1] = SYS_Joystick[index].wYmax;
    axis_min[2] = SYS_Joystick[index].wZmin;
    axis_max[2] = SYS_Joystick[index].wZmax;
    axis_min[3] = SYS_Joystick[index].wRmin;
    axis_max[3] = SYS_Joystick[index].wRmax;
    axis_min[4] = SYS_Joystick[index].wUmin;
    axis_max[4] = SYS_Joystick[index].wUmax;
    axis_min[5] = SYS_Joystick[index].wVmin;
    axis_max[5] = SYS_Joystick[index].wVmax;

    /* allocate memory for system specific hardware data */
    joystick->instance_id = device_index;
    joystick->hwdata =
        (struct joystick_hwdata *) SDL_malloc(sizeof(*joystick->hwdata));
    if (joystick->hwdata == NULL) {
        return SDL_OutOfMemory();
    }
    SDL_memset(joystick->hwdata, 0, sizeof(*joystick->hwdata));

    /* set hardware data */
    joystick->hwdata->id = SYS_JoystickID[index];
    for (i = 0; i < MAX_AXES; ++i) {
        if ((i < 2) || (SYS_Joystick[index].wCaps & caps_flags[i - 2])) {
            joystick->hwdata->transaxis[i].offset = AXIS_MIN - axis_min[i];
            joystick->hwdata->transaxis[i].scale =
                (float) (AXIS_MAX - AXIS_MIN) / (axis_max[i] - axis_min[i]);
        } else {
            joystick->hwdata->transaxis[i].offset = 0;
            joystick->hwdata->transaxis[i].scale = 1.0; /* Just in case */
        }
    }

    /* fill nbuttons, naxes, and nhats fields */
    joystick->nbuttons = SYS_Joystick[index].wNumButtons;
    joystick->naxes = SYS_Joystick[index].wNumAxes;
    if (SYS_Joystick[index].wCaps & JOYCAPS_HASPOV) {
        joystick->nhats = 1;
    } else {
        joystick->nhats = 0;
    }
    return (0);
}

/* Function to determine if this joystick is attached to the system right now */
SDL_bool SDL_SYS_JoystickAttached(SDL_Joystick *joystick)
{
    return SDL_TRUE;
}

static Uint8
TranslatePOV(DWORD value)
{
    Uint8 pos;

    pos = SDL_HAT_CENTERED;
    if (value != JOY_POVCENTERED) {
        if ((value > JOY_POVLEFT) || (value < JOY_POVRIGHT)) {
            pos |= SDL_HAT_UP;
        }
        if ((value > JOY_POVFORWARD) && (value < JOY_POVBACKWARD)) {
            pos |= SDL_HAT_RIGHT;
        }
        if ((value > JOY_POVRIGHT) && (value < JOY_POVLEFT)) {
            pos |= SDL_HAT_DOWN;
        }
        if (value > JOY_POVBACKWARD) {
            pos |= SDL_HAT_LEFT;
        }
    }
    return (pos);
}

/* Function to update the state of a joystick - called as a device poll.
 * This function shouldn't update the joystick structure directly,
 * but instead should call SDL_PrivateJoystick*() to deliver events
 * and update joystick device state.
 */
void
SDL_SYS_JoystickUpdate(SDL_Joystick * joystick)
{
    MMRESULT result;
    int i;
    DWORD flags[MAX_AXES] = { JOY_RETURNX, JOY_RETURNY, JOY_RETURNZ,
        JOY_RETURNR, JOY_RETURNU, JOY_RETURNV
    };
    DWORD pos[MAX_AXES];
    struct _transaxis *transaxis;
    int value, change;
    JOYINFOEX joyinfo;

    joyinfo.dwSize = sizeof(joyinfo);
    joyinfo.dwFlags = JOY_RETURNALL | JOY_RETURNPOVCTS;
    if (!joystick->hats) {
        joyinfo.dwFlags &= ~(JOY_RETURNPOV | JOY_RETURNPOVCTS);
    }
    result = joyGetPosEx(joystick->hwdata->id, &joyinfo);
    if (result != JOYERR_NOERROR) {
        SetMMerror("joyGetPosEx", result);
        return;
    }

    /* joystick motion events */
    pos[0] = joyinfo.dwXpos;
    pos[1] = joyinfo.dwYpos;
    pos[2] = joyinfo.dwZpos;
    pos[3] = joyinfo.dwRpos;
    pos[4] = joyinfo.dwUpos;
    pos[5] = joyinfo.dwVpos;

    transaxis = joystick->hwdata->transaxis;
    for (i = 0; i < joystick->naxes; i++) {
        if (joyinfo.dwFlags & flags[i]) {
            value =
                (int) (((float) pos[i] +
                        transaxis[i].offset) * transaxis[i].scale);
            change = (value - joystick->axes[i]);
            if ((change < -JOY_AXIS_THRESHOLD)
                || (change > JOY_AXIS_THRESHOLD)) {
                SDL_PrivateJoystickAxis(joystick, (Uint8) i, (Sint16) value);
            }
        }
    }

    /* joystick button events */
    if (joyinfo.dwFlags & JOY_RETURNBUTTONS) {
        for (i = 0; i < joystick->nbuttons; ++i) {
            if (joyinfo.dwButtons & JOY_BUTTON_FLAG(i)) {
                if (!joystick->buttons[i]) {
                    SDL_PrivateJoystickButton(joystick, (Uint8) i,
                                              SDL_PRESSED);
                }
            } else {
                if (joystick->buttons[i]) {
                    SDL_PrivateJoystickButton(joystick, (Uint8) i,
                                              SDL_RELEASED);
                }
            }
        }
    }

    /* joystick hat events */
    if (joyinfo.dwFlags & JOY_RETURNPOV) {
        Uint8 pos;

        pos = TranslatePOV(joyinfo.dwPOV);
        if (pos != joystick->hats[0]) {
            SDL_PrivateJoystickHat(joystick, 0, pos);
        }
    }
}

/* Function to close a joystick after use */
void
SDL_SYS_JoystickClose(SDL_Joystick * joystick)
{
    SDL_free(joystick->hwdata);
}

/* Function to perform any system-specific joystick related cleanup */
void
SDL_SYS_JoystickQuit(void)
{
    int i;
    for (i = 0; i < MAX_JOYSTICKS; i++) {
        SDL_free(SYS_JoystickName[i]);
        SYS_JoystickName[i] = NULL;
    }
}

SDL_JoystickGUID SDL_SYS_JoystickGetDeviceGUID( int device_index )
{
    SDL_JoystickGUID guid;
    /* the GUID is just the first 16 chars of the name for now */
    const char *name = SDL_SYS_JoystickNameForDeviceIndex( device_index );
    SDL_zero( guid );
    SDL_memcpy( &guid, name, SDL_min( sizeof(guid), SDL_strlen( name ) ) );
    return guid;
}

SDL_JoystickGUID SDL_SYS_JoystickGetGUID(SDL_Joystick * joystick)
{
    SDL_JoystickGUID guid;
    /* the GUID is just the first 16 chars of the name for now */
    const char *name = joystick->name;
    SDL_zero( guid );
    SDL_memcpy( &guid, name, SDL_min( sizeof(guid), SDL_strlen( name ) ) );
    return guid;
}


/* implementation functions */
void
SetMMerror(char *function, int code)
{
    static char *error;
    static char errbuf[1024];

    errbuf[0] = 0;
    switch (code) {
    case MMSYSERR_NODRIVER:
        error = "Joystick driver not present";
        break;

    case MMSYSERR_INVALPARAM:
    case JOYERR_PARMS:
        error = "Invalid parameter(s)";
        break;

    case MMSYSERR_BADDEVICEID:
        error = "Bad device ID";
        break;

    case JOYERR_UNPLUGGED:
        error = "Joystick not attached";
        break;

    case JOYERR_NOCANDO:
        error = "Can't capture joystick input";
        break;

    default:
        SDL_snprintf(errbuf, SDL_arraysize(errbuf),
                     "%s: Unknown Multimedia system error: 0x%x",
                     function, code);
        break;
    }

    if (!errbuf[0]) {
        SDL_snprintf(errbuf, SDL_arraysize(errbuf), "%s: %s", function,
                     error);
    }
    SDL_SetError("%s", errbuf);
}

#endif /* SDL_JOYSTICK_WINMM */

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