1 /**
2  * \file macros.h
3  * A collection of useful macros.
4  */
5 
6 /*
7  * Mesa 3-D graphics library
8  *
9  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
10  *
11  * Permission is hereby granted, free of charge, to any person obtaining a
12  * copy of this software and associated documentation files (the "Software"),
13  * to deal in the Software without restriction, including without limitation
14  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
15  * and/or sell copies of the Software, and to permit persons to whom the
16  * Software is furnished to do so, subject to the following conditions:
17  *
18  * The above copyright notice and this permission notice shall be included
19  * in all copies or substantial portions of the Software.
20  *
21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
22  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
24  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
25  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
26  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
27  * OTHER DEALINGS IN THE SOFTWARE.
28  */
29 
30 
31 #ifndef MACROS_H
32 #define MACROS_H
33 
34 #include "imports.h"
35 
36 
37 /**
38  * \name Integer / float conversion for colors, normals, etc.
39  */
40 /*@{*/
41 
42 /** Convert GLubyte in [0,255] to GLfloat in [0.0,1.0] */
43 extern GLfloat _mesa_ubyte_to_float_color_tab[256];
44 #define UBYTE_TO_FLOAT(u) _mesa_ubyte_to_float_color_tab[(unsigned int)(u)]
45 
46 /** Convert GLfloat in [0.0,1.0] to GLubyte in [0,255] */
47 #define FLOAT_TO_UBYTE(X)   ((GLubyte) (GLint) ((X) * 255.0F))
48 
49 
50 /** Convert GLbyte in [-128,127] to GLfloat in [-1.0,1.0] */
51 #define BYTE_TO_FLOAT(B)    ((2.0F * (B) + 1.0F) * (1.0F/255.0F))
52 
53 /** Convert GLfloat in [-1.0,1.0] to GLbyte in [-128,127] */
54 #define FLOAT_TO_BYTE(X)    ( (((GLint) (255.0F * (X))) - 1) / 2 )
55 
56 
57 /** Convert GLbyte to GLfloat while preserving zero */
58 #define BYTE_TO_FLOATZ(B)   ((B) == 0 ? 0.0F : BYTE_TO_FLOAT(B))
59 
60 
61 /** Convert GLbyte in [-128,127] to GLfloat in [-1.0,1.0], texture/fb data */
62 #define BYTE_TO_FLOAT_TEX(B)    ((B) == -128 ? -1.0F : (B) * (1.0F/127.0F))
63 
64 /** Convert GLfloat in [-1.0,1.0] to GLbyte in [-128,127], texture/fb data */
65 #define FLOAT_TO_BYTE_TEX(X)    CLAMP( (GLint) (127.0F * (X)), -128, 127 )
66 
67 /** Convert GLushort in [0,65535] to GLfloat in [0.0,1.0] */
68 #define USHORT_TO_FLOAT(S)  ((GLfloat) (S) * (1.0F / 65535.0F))
69 
70 /** Convert GLfloat in [0.0,1.0] to GLushort in [0, 65535] */
71 #define FLOAT_TO_USHORT(X)   ((GLuint) ((X) * 65535.0F))
72 
73 
74 /** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0] */
75 #define SHORT_TO_FLOAT(S)   ((2.0F * (S) + 1.0F) * (1.0F/65535.0F))
76 
77 /** Convert GLfloat in [-1.0,1.0] to GLshort in [-32768,32767] */
78 #define FLOAT_TO_SHORT(X)   ( (((GLint) (65535.0F * (X))) - 1) / 2 )
79 
80 /** Convert GLshort to GLfloat while preserving zero */
81 #define SHORT_TO_FLOATZ(S)   ((S) == 0 ? 0.0F : SHORT_TO_FLOAT(S))
82 
83 
84 /** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0], texture/fb data */
85 #define SHORT_TO_FLOAT_TEX(S)    ((S) == -32768 ? -1.0F : (S) * (1.0F/32767.0F))
86 
87 /** Convert GLfloat in [-1.0,1.0] to GLshort in [-32768,32767], texture/fb data */
88 #define FLOAT_TO_SHORT_TEX(X)    ( (GLint) (32767.0F * (X)) )
89 
90 
91 /** Convert GLuint in [0,4294967295] to GLfloat in [0.0,1.0] */
92 #define UINT_TO_FLOAT(U)    ((GLfloat) ((U) * (1.0F / 4294967295.0)))
93 
94 /** Convert GLfloat in [0.0,1.0] to GLuint in [0,4294967295] */
95 #define FLOAT_TO_UINT(X)    ((GLuint) ((X) * 4294967295.0))
96 
97 
98 /** Convert GLint in [-2147483648,2147483647] to GLfloat in [-1.0,1.0] */
99 #define INT_TO_FLOAT(I)     ((GLfloat) ((2.0F * (I) + 1.0F) * (1.0F/4294967294.0)))
100 
101 /** Convert GLfloat in [-1.0,1.0] to GLint in [-2147483648,2147483647] */
102 /* causes overflow:
103 #define FLOAT_TO_INT(X)     ( (((GLint) (4294967294.0 * (X))) - 1) / 2 )
104 */
105 /* a close approximation: */
106 #define FLOAT_TO_INT(X)     ( (GLint) (2147483647.0 * (X)) )
107 
108 /** Convert GLint in [-2147483648,2147483647] to GLfloat in [-1.0,1.0], texture/fb data */
109 #define INT_TO_FLOAT_TEX(I)    ((I) == -2147483648 ? -1.0F : (I) * (1.0F/2147483647.0))
110 
111 /** Convert GLfloat in [-1.0,1.0] to GLint in [-2147483648,2147483647], texture/fb data */
112 #define FLOAT_TO_INT_TEX(X)    ( (GLint) (2147483647.0 * (X)) )
113 
114 
115 #define BYTE_TO_UBYTE(b)   ((GLubyte) ((b) < 0 ? 0 : (GLubyte) (b)))
116 #define SHORT_TO_UBYTE(s)  ((GLubyte) ((s) < 0 ? 0 : (GLubyte) ((s) >> 7)))
117 #define USHORT_TO_UBYTE(s) ((GLubyte) ((s) >> 8))
118 #define INT_TO_UBYTE(i)    ((GLubyte) ((i) < 0 ? 0 : (GLubyte) ((i) >> 23)))
119 #define UINT_TO_UBYTE(i)   ((GLubyte) ((i) >> 24))
120 
121 
122 #define BYTE_TO_USHORT(b)  ((b) < 0 ? 0 : ((GLushort) (((b) * 65535) / 255)))
123 #define UBYTE_TO_USHORT(b) (((GLushort) (b) << 8) | (GLushort) (b))
124 #define SHORT_TO_USHORT(s) ((s) < 0 ? 0 : ((GLushort) (((s) * 65535 / 32767))))
125 #define INT_TO_USHORT(i)   ((i) < 0 ? 0 : ((GLushort) ((i) >> 15)))
126 #define UINT_TO_USHORT(i)  ((i) < 0 ? 0 : ((GLushort) ((i) >> 16)))
127 #define UNCLAMPED_FLOAT_TO_USHORT(us, f)  \
128         us = ( (GLushort) F_TO_I( CLAMP((f), 0.0F, 1.0F) * 65535.0F) )
129 #define CLAMPED_FLOAT_TO_USHORT(us, f)  \
130         us = ( (GLushort) F_TO_I( (f) * 65535.0F) )
131 
132 #define UNCLAMPED_FLOAT_TO_SHORT(s, f)  \
133         s = ( (GLshort) F_TO_I( CLAMP((f), -1.0F, 1.0F) * 32767.0F) )
134 
135 /***
136  *** UNCLAMPED_FLOAT_TO_UBYTE: clamp float to [0,1] and map to ubyte in [0,255]
137  *** CLAMPED_FLOAT_TO_UBYTE: map float known to be in [0,1] to ubyte in [0,255]
138  ***/
139 #ifndef DEBUG
140 /* This function/macro is sensitive to precision.  Test very carefully
141  * if you change it!
142  */
143 #define UNCLAMPED_FLOAT_TO_UBYTE(UB, FLT)				\
144         do {								\
145            fi_type __tmp;						\
146            __tmp.f = (FLT);						\
147            if (__tmp.i < 0)						\
148               UB = (GLubyte) 0;						\
149            else if (__tmp.i >= IEEE_ONE)				\
150               UB = (GLubyte) 255;					\
151            else {							\
152               __tmp.f = __tmp.f * (255.0F/256.0F) + 32768.0F;		\
153               UB = (GLubyte) __tmp.i;					\
154            }								\
155         } while (0)
156 #define CLAMPED_FLOAT_TO_UBYTE(UB, FLT)					\
157         do {								\
158            fi_type __tmp;						\
159            __tmp.f = (FLT) * (255.0F/256.0F) + 32768.0F;		\
160            UB = (GLubyte) __tmp.i;					\
161         } while (0)
162 #else
163 #define UNCLAMPED_FLOAT_TO_UBYTE(ub, f) \
164 	ub = ((GLubyte) F_TO_I(CLAMP((f), 0.0F, 1.0F) * 255.0F))
165 #define CLAMPED_FLOAT_TO_UBYTE(ub, f) \
166 	ub = ((GLubyte) F_TO_I((f) * 255.0F))
167 #endif
168 
169 static inline GLfloat INT_AS_FLT(GLint i)
170 {
171    fi_type tmp;
172    tmp.i = i;
173    return tmp.f;
174 }
175 
176 static inline GLfloat UINT_AS_FLT(GLuint u)
177 {
178    fi_type tmp;
179    tmp.u = u;
180    return tmp.f;
181 }
182 
183 static inline unsigned FLT_AS_UINT(float f)
184 {
185    fi_type tmp;
186    tmp.f = f;
187    return tmp.u;
188 }
189 
190 /**
191  * Convert a floating point value to an unsigned fixed point value.
192  *
193  * \param frac_bits   The number of bits used to store the fractional part.
194  */
195 static inline uint32_t
196 U_FIXED(float value, uint32_t frac_bits)
197 {
198    value *= (1 << frac_bits);
199    return value < 0.0f ? 0 : (uint32_t) value;
200 }
201 
202 /**
203  * Convert a floating point value to an signed fixed point value.
204  *
205  * \param frac_bits   The number of bits used to store the fractional part.
206  */
207 static inline int32_t
208 S_FIXED(float value, uint32_t frac_bits)
209 {
210    return (int32_t) (value * (1 << frac_bits));
211 }
212 /*@}*/
213 
214 
215 /** Stepping a GLfloat pointer by a byte stride */
216 #define STRIDE_F(p, i)  (p = (GLfloat *)((GLubyte *)p + i))
217 /** Stepping a GLuint pointer by a byte stride */
218 #define STRIDE_UI(p, i)  (p = (GLuint *)((GLubyte *)p + i))
219 /** Stepping a GLubyte[4] pointer by a byte stride */
220 #define STRIDE_4UB(p, i)  (p = (GLubyte (*)[4])((GLubyte *)p + i))
221 /** Stepping a GLfloat[4] pointer by a byte stride */
222 #define STRIDE_4F(p, i)  (p = (GLfloat (*)[4])((GLubyte *)p + i))
223 /** Stepping a \p t pointer by a byte stride */
224 #define STRIDE_T(p, t, i)  (p = (t)((GLubyte *)p + i))
225 
226 
227 /**********************************************************************/
228 /** \name 4-element vector operations */
229 /*@{*/
230 
231 /** Zero */
232 #define ZERO_4V( DST )  (DST)[0] = (DST)[1] = (DST)[2] = (DST)[3] = 0
233 
234 /** Test for equality */
235 #define TEST_EQ_4V(a,b)  ((a)[0] == (b)[0] &&   \
236               (a)[1] == (b)[1] &&   \
237               (a)[2] == (b)[2] &&   \
238               (a)[3] == (b)[3])
239 
240 /** Test for equality (unsigned bytes) */
241 static inline GLboolean
242 TEST_EQ_4UBV(const GLubyte a[4], const GLubyte b[4])
243 {
244 #if defined(__i386__)
245    return *((const GLuint *) a) == *((const GLuint *) b);
246 #else
247    return TEST_EQ_4V(a, b);
248 #endif
249 }
250 
251 
252 /** Copy a 4-element vector */
253 #define COPY_4V( DST, SRC )         \
254 do {                                \
255    (DST)[0] = (SRC)[0];             \
256    (DST)[1] = (SRC)[1];             \
257    (DST)[2] = (SRC)[2];             \
258    (DST)[3] = (SRC)[3];             \
259 } while (0)
260 
261 /** Copy a 4-element unsigned byte vector */
262 static inline void
263 COPY_4UBV(GLubyte dst[4], const GLubyte src[4])
264 {
265 #if defined(__i386__)
266    *((GLuint *) dst) = *((GLuint *) src);
267 #else
268    /* The GLuint cast might fail if DST or SRC are not dword-aligned (RISC) */
269    COPY_4V(dst, src);
270 #endif
271 }
272 
273 /** Copy a 4-element float vector */
274 static inline void
275 COPY_4FV(GLfloat dst[4], const GLfloat src[4])
276 {
277    /* memcpy seems to be most efficient */
278    memcpy(dst, src, sizeof(GLfloat) * 4);
279 }
280 
281 /** Copy \p SZ elements into a 4-element vector */
282 #define COPY_SZ_4V(DST, SZ, SRC)  \
283 do {                              \
284    switch (SZ) {                  \
285    case 4: (DST)[3] = (SRC)[3];   \
286    case 3: (DST)[2] = (SRC)[2];   \
287    case 2: (DST)[1] = (SRC)[1];   \
288    case 1: (DST)[0] = (SRC)[0];   \
289    }                              \
290 } while(0)
291 
292 /** Copy \p SZ elements into a homegeneous (4-element) vector, giving
293  * default values to the remaining */
294 #define COPY_CLEAN_4V(DST, SZ, SRC)  \
295 do {                                 \
296       ASSIGN_4V( DST, 0, 0, 0, 1 );  \
297       COPY_SZ_4V( DST, SZ, SRC );    \
298 } while (0)
299 
300 /** Subtraction */
301 #define SUB_4V( DST, SRCA, SRCB )           \
302 do {                                        \
303       (DST)[0] = (SRCA)[0] - (SRCB)[0];     \
304       (DST)[1] = (SRCA)[1] - (SRCB)[1];     \
305       (DST)[2] = (SRCA)[2] - (SRCB)[2];     \
306       (DST)[3] = (SRCA)[3] - (SRCB)[3];     \
307 } while (0)
308 
309 /** Addition */
310 #define ADD_4V( DST, SRCA, SRCB )           \
311 do {                                        \
312       (DST)[0] = (SRCA)[0] + (SRCB)[0];     \
313       (DST)[1] = (SRCA)[1] + (SRCB)[1];     \
314       (DST)[2] = (SRCA)[2] + (SRCB)[2];     \
315       (DST)[3] = (SRCA)[3] + (SRCB)[3];     \
316 } while (0)
317 
318 /** Element-wise multiplication */
319 #define SCALE_4V( DST, SRCA, SRCB )         \
320 do {                                        \
321       (DST)[0] = (SRCA)[0] * (SRCB)[0];     \
322       (DST)[1] = (SRCA)[1] * (SRCB)[1];     \
323       (DST)[2] = (SRCA)[2] * (SRCB)[2];     \
324       (DST)[3] = (SRCA)[3] * (SRCB)[3];     \
325 } while (0)
326 
327 /** In-place addition */
328 #define ACC_4V( DST, SRC )          \
329 do {                                \
330       (DST)[0] += (SRC)[0];         \
331       (DST)[1] += (SRC)[1];         \
332       (DST)[2] += (SRC)[2];         \
333       (DST)[3] += (SRC)[3];         \
334 } while (0)
335 
336 /** Element-wise multiplication and addition */
337 #define ACC_SCALE_4V( DST, SRCA, SRCB )     \
338 do {                                        \
339       (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
340       (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
341       (DST)[2] += (SRCA)[2] * (SRCB)[2];    \
342       (DST)[3] += (SRCA)[3] * (SRCB)[3];    \
343 } while (0)
344 
345 /** In-place scalar multiplication and addition */
346 #define ACC_SCALE_SCALAR_4V( DST, S, SRCB ) \
347 do {                                        \
348       (DST)[0] += S * (SRCB)[0];            \
349       (DST)[1] += S * (SRCB)[1];            \
350       (DST)[2] += S * (SRCB)[2];            \
351       (DST)[3] += S * (SRCB)[3];            \
352 } while (0)
353 
354 /** Scalar multiplication */
355 #define SCALE_SCALAR_4V( DST, S, SRCB ) \
356 do {                                    \
357       (DST)[0] = S * (SRCB)[0];         \
358       (DST)[1] = S * (SRCB)[1];         \
359       (DST)[2] = S * (SRCB)[2];         \
360       (DST)[3] = S * (SRCB)[3];         \
361 } while (0)
362 
363 /** In-place scalar multiplication */
364 #define SELF_SCALE_SCALAR_4V( DST, S ) \
365 do {                                   \
366       (DST)[0] *= S;                   \
367       (DST)[1] *= S;                   \
368       (DST)[2] *= S;                   \
369       (DST)[3] *= S;                   \
370 } while (0)
371 
372 /** Assignment */
373 #define ASSIGN_4V( V, V0, V1, V2, V3 )  \
374 do {                                    \
375     V[0] = V0;                          \
376     V[1] = V1;                          \
377     V[2] = V2;                          \
378     V[3] = V3;                          \
379 } while(0)
380 
381 /*@}*/
382 
383 
384 /**********************************************************************/
385 /** \name 3-element vector operations*/
386 /*@{*/
387 
388 /** Zero */
389 #define ZERO_3V( DST )  (DST)[0] = (DST)[1] = (DST)[2] = 0
390 
391 /** Test for equality */
392 #define TEST_EQ_3V(a,b)  \
393    ((a)[0] == (b)[0] &&  \
394     (a)[1] == (b)[1] &&  \
395     (a)[2] == (b)[2])
396 
397 /** Copy a 3-element vector */
398 #define COPY_3V( DST, SRC )         \
399 do {                                \
400    (DST)[0] = (SRC)[0];             \
401    (DST)[1] = (SRC)[1];             \
402    (DST)[2] = (SRC)[2];             \
403 } while (0)
404 
405 /** Copy a 3-element vector with cast */
406 #define COPY_3V_CAST( DST, SRC, CAST )  \
407 do {                                    \
408    (DST)[0] = (CAST)(SRC)[0];           \
409    (DST)[1] = (CAST)(SRC)[1];           \
410    (DST)[2] = (CAST)(SRC)[2];           \
411 } while (0)
412 
413 /** Copy a 3-element float vector */
414 #define COPY_3FV( DST, SRC )        \
415 do {                                \
416    const GLfloat *_tmp = (SRC);     \
417    (DST)[0] = _tmp[0];              \
418    (DST)[1] = _tmp[1];              \
419    (DST)[2] = _tmp[2];              \
420 } while (0)
421 
422 /** Subtraction */
423 #define SUB_3V( DST, SRCA, SRCB )        \
424 do {                                     \
425       (DST)[0] = (SRCA)[0] - (SRCB)[0];  \
426       (DST)[1] = (SRCA)[1] - (SRCB)[1];  \
427       (DST)[2] = (SRCA)[2] - (SRCB)[2];  \
428 } while (0)
429 
430 /** Addition */
431 #define ADD_3V( DST, SRCA, SRCB )       \
432 do {                                    \
433       (DST)[0] = (SRCA)[0] + (SRCB)[0]; \
434       (DST)[1] = (SRCA)[1] + (SRCB)[1]; \
435       (DST)[2] = (SRCA)[2] + (SRCB)[2]; \
436 } while (0)
437 
438 /** In-place scalar multiplication */
439 #define SCALE_3V( DST, SRCA, SRCB )     \
440 do {                                    \
441       (DST)[0] = (SRCA)[0] * (SRCB)[0]; \
442       (DST)[1] = (SRCA)[1] * (SRCB)[1]; \
443       (DST)[2] = (SRCA)[2] * (SRCB)[2]; \
444 } while (0)
445 
446 /** In-place element-wise multiplication */
447 #define SELF_SCALE_3V( DST, SRC )   \
448 do {                                \
449       (DST)[0] *= (SRC)[0];         \
450       (DST)[1] *= (SRC)[1];         \
451       (DST)[2] *= (SRC)[2];         \
452 } while (0)
453 
454 /** In-place addition */
455 #define ACC_3V( DST, SRC )          \
456 do {                                \
457       (DST)[0] += (SRC)[0];         \
458       (DST)[1] += (SRC)[1];         \
459       (DST)[2] += (SRC)[2];         \
460 } while (0)
461 
462 /** Element-wise multiplication and addition */
463 #define ACC_SCALE_3V( DST, SRCA, SRCB )     \
464 do {                                        \
465       (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
466       (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
467       (DST)[2] += (SRCA)[2] * (SRCB)[2];    \
468 } while (0)
469 
470 /** Scalar multiplication */
471 #define SCALE_SCALAR_3V( DST, S, SRCB ) \
472 do {                                    \
473       (DST)[0] = S * (SRCB)[0];         \
474       (DST)[1] = S * (SRCB)[1];         \
475       (DST)[2] = S * (SRCB)[2];         \
476 } while (0)
477 
478 /** In-place scalar multiplication and addition */
479 #define ACC_SCALE_SCALAR_3V( DST, S, SRCB ) \
480 do {                                        \
481       (DST)[0] += S * (SRCB)[0];            \
482       (DST)[1] += S * (SRCB)[1];            \
483       (DST)[2] += S * (SRCB)[2];            \
484 } while (0)
485 
486 /** In-place scalar multiplication */
487 #define SELF_SCALE_SCALAR_3V( DST, S ) \
488 do {                                   \
489       (DST)[0] *= S;                   \
490       (DST)[1] *= S;                   \
491       (DST)[2] *= S;                   \
492 } while (0)
493 
494 /** In-place scalar addition */
495 #define ACC_SCALAR_3V( DST, S )     \
496 do {                                \
497       (DST)[0] += S;                \
498       (DST)[1] += S;                \
499       (DST)[2] += S;                \
500 } while (0)
501 
502 /** Assignment */
503 #define ASSIGN_3V( V, V0, V1, V2 )  \
504 do {                                \
505     V[0] = V0;                      \
506     V[1] = V1;                      \
507     V[2] = V2;                      \
508 } while(0)
509 
510 /*@}*/
511 
512 
513 /**********************************************************************/
514 /** \name 2-element vector operations*/
515 /*@{*/
516 
517 /** Zero */
518 #define ZERO_2V( DST )  (DST)[0] = (DST)[1] = 0
519 
520 /** Copy a 2-element vector */
521 #define COPY_2V( DST, SRC )         \
522 do {                        \
523    (DST)[0] = (SRC)[0];             \
524    (DST)[1] = (SRC)[1];             \
525 } while (0)
526 
527 /** Copy a 2-element vector with cast */
528 #define COPY_2V_CAST( DST, SRC, CAST )      \
529 do {                        \
530    (DST)[0] = (CAST)(SRC)[0];           \
531    (DST)[1] = (CAST)(SRC)[1];           \
532 } while (0)
533 
534 /** Copy a 2-element float vector */
535 #define COPY_2FV( DST, SRC )            \
536 do {                        \
537    const GLfloat *_tmp = (SRC);         \
538    (DST)[0] = _tmp[0];              \
539    (DST)[1] = _tmp[1];              \
540 } while (0)
541 
542 /** Subtraction */
543 #define SUB_2V( DST, SRCA, SRCB )       \
544 do {                        \
545       (DST)[0] = (SRCA)[0] - (SRCB)[0];     \
546       (DST)[1] = (SRCA)[1] - (SRCB)[1];     \
547 } while (0)
548 
549 /** Addition */
550 #define ADD_2V( DST, SRCA, SRCB )       \
551 do {                        \
552       (DST)[0] = (SRCA)[0] + (SRCB)[0];     \
553       (DST)[1] = (SRCA)[1] + (SRCB)[1];     \
554 } while (0)
555 
556 /** In-place scalar multiplication */
557 #define SCALE_2V( DST, SRCA, SRCB )     \
558 do {                        \
559       (DST)[0] = (SRCA)[0] * (SRCB)[0];     \
560       (DST)[1] = (SRCA)[1] * (SRCB)[1];     \
561 } while (0)
562 
563 /** In-place addition */
564 #define ACC_2V( DST, SRC )          \
565 do {                        \
566       (DST)[0] += (SRC)[0];         \
567       (DST)[1] += (SRC)[1];         \
568 } while (0)
569 
570 /** Element-wise multiplication and addition */
571 #define ACC_SCALE_2V( DST, SRCA, SRCB )     \
572 do {                        \
573       (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
574       (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
575 } while (0)
576 
577 /** Scalar multiplication */
578 #define SCALE_SCALAR_2V( DST, S, SRCB )     \
579 do {                        \
580       (DST)[0] = S * (SRCB)[0];         \
581       (DST)[1] = S * (SRCB)[1];         \
582 } while (0)
583 
584 /** In-place scalar multiplication and addition */
585 #define ACC_SCALE_SCALAR_2V( DST, S, SRCB ) \
586 do {                        \
587       (DST)[0] += S * (SRCB)[0];        \
588       (DST)[1] += S * (SRCB)[1];        \
589 } while (0)
590 
591 /** In-place scalar multiplication */
592 #define SELF_SCALE_SCALAR_2V( DST, S )      \
593 do {                        \
594       (DST)[0] *= S;                \
595       (DST)[1] *= S;                \
596 } while (0)
597 
598 /** In-place scalar addition */
599 #define ACC_SCALAR_2V( DST, S )         \
600 do {                        \
601       (DST)[0] += S;                \
602       (DST)[1] += S;                \
603 } while (0)
604 
605 /** Assign scalers to short vectors */
606 #define ASSIGN_2V( V, V0, V1 )	\
607 do {				\
608     V[0] = V0;			\
609     V[1] = V1;			\
610 } while(0)
611 
612 /*@}*/
613 
614 /** Copy \p sz elements into a homegeneous (4-element) vector, giving
615  * default values to the remaining components.
616  * The default values are chosen based on \p type.
617  */
618 static inline void
619 COPY_CLEAN_4V_TYPE_AS_FLOAT(GLfloat dst[4], int sz, const GLfloat src[4],
620                             GLenum type)
621 {
622    switch (type) {
623    case GL_FLOAT:
624       ASSIGN_4V(dst, 0, 0, 0, 1);
625       break;
626    case GL_INT:
627       ASSIGN_4V(dst, INT_AS_FLT(0), INT_AS_FLT(0),
628                      INT_AS_FLT(0), INT_AS_FLT(1));
629       break;
630    case GL_UNSIGNED_INT:
631       ASSIGN_4V(dst, UINT_AS_FLT(0), UINT_AS_FLT(0),
632                      UINT_AS_FLT(0), UINT_AS_FLT(1));
633       break;
634    default:
635       ASSIGN_4V(dst, 0.0f, 0.0f, 0.0f, 1.0f); /* silence warnings */
636       ASSERT(!"Unexpected type in COPY_CLEAN_4V_TYPE_AS_FLOAT macro");
637    }
638    COPY_SZ_4V(dst, sz, src);
639 }
640 
641 /** \name Linear interpolation functions */
642 /*@{*/
643 
644 static inline GLfloat
645 LINTERP(GLfloat t, GLfloat out, GLfloat in)
646 {
647    return out + t * (in - out);
648 }
649 
650 static inline void
651 INTERP_3F(GLfloat t, GLfloat dst[3], const GLfloat out[3], const GLfloat in[3])
652 {
653    dst[0] = LINTERP( t, out[0], in[0] );
654    dst[1] = LINTERP( t, out[1], in[1] );
655    dst[2] = LINTERP( t, out[2], in[2] );
656 }
657 
658 static inline void
659 INTERP_4F(GLfloat t, GLfloat dst[4], const GLfloat out[4], const GLfloat in[4])
660 {
661    dst[0] = LINTERP( t, out[0], in[0] );
662    dst[1] = LINTERP( t, out[1], in[1] );
663    dst[2] = LINTERP( t, out[2], in[2] );
664    dst[3] = LINTERP( t, out[3], in[3] );
665 }
666 
667 /*@}*/
668 
669 
670 
671 /** Clamp X to [MIN,MAX] */
672 #define CLAMP( X, MIN, MAX )  ( (X)<(MIN) ? (MIN) : ((X)>(MAX) ? (MAX) : (X)) )
673 
674 /** Minimum of two values: */
675 #define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
676 
677 /** Maximum of two values: */
678 #define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
679 
680 /** Minimum and maximum of three values: */
681 #define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
682 #define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
683 
684 static inline unsigned
685 minify(unsigned value, unsigned levels)
686 {
687     return MAX2(1, value >> levels);
688 }
689 
690 /**
691  * Return true if the given value is a power of two.
692  *
693  * Note that this considers 0 a power of two.
694  */
695 static inline bool
696 is_power_of_two(unsigned value)
697 {
698    return (value & (value - 1)) == 0;
699 }
700 
701 /**
702  * Align a value up to an alignment value
703  *
704  * If \c value is not already aligned to the requested alignment value, it
705  * will be rounded up.
706  *
707  * \param value  Value to be rounded
708  * \param alignment  Alignment value to be used.  This must be a power of two.
709  *
710  * \sa ROUND_DOWN_TO()
711  */
712 #define ALIGN(value, alignment)  (((value) + (alignment) - 1) & ~((alignment) - 1))
713 
714 /**
715  * Align a value down to an alignment value
716  *
717  * If \c value is not already aligned to the requested alignment value, it
718  * will be rounded down.
719  *
720  * \param value  Value to be rounded
721  * \param alignment  Alignment value to be used.  This must be a power of two.
722  *
723  * \sa ALIGN()
724  */
725 #define ROUND_DOWN_TO(value, alignment) ((value) & ~(alignment - 1))
726 
727 
728 /** Cross product of two 3-element vectors */
729 static inline void
730 CROSS3(GLfloat n[3], const GLfloat u[3], const GLfloat v[3])
731 {
732    n[0] = u[1] * v[2] - u[2] * v[1];
733    n[1] = u[2] * v[0] - u[0] * v[2];
734    n[2] = u[0] * v[1] - u[1] * v[0];
735 }
736 
737 
738 /** Dot product of two 2-element vectors */
739 static inline GLfloat
740 DOT2(const GLfloat a[2], const GLfloat b[2])
741 {
742    return a[0] * b[0] + a[1] * b[1];
743 }
744 
745 static inline GLfloat
746 DOT3(const GLfloat a[3], const GLfloat b[3])
747 {
748    return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
749 }
750 
751 static inline GLfloat
752 DOT4(const GLfloat a[4], const GLfloat b[4])
753 {
754    return a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3];
755 }
756 
757 
758 static inline GLfloat
759 LEN_SQUARED_3FV(const GLfloat v[3])
760 {
761    return DOT3(v, v);
762 }
763 
764 static inline GLfloat
765 LEN_SQUARED_2FV(const GLfloat v[2])
766 {
767    return DOT2(v, v);
768 }
769 
770 
771 static inline GLfloat
772 LEN_3FV(const GLfloat v[3])
773 {
774    return sqrtf(LEN_SQUARED_3FV(v));
775 }
776 
777 static inline GLfloat
778 LEN_2FV(const GLfloat v[2])
779 {
780    return sqrtf(LEN_SQUARED_2FV(v));
781 }
782 
783 
784 /* Normalize a 3-element vector to unit length. */
785 static inline void
786 NORMALIZE_3FV(GLfloat v[3])
787 {
788    GLfloat len = (GLfloat) LEN_SQUARED_3FV(v);
789    if (len) {
790       len = INV_SQRTF(len);
791       v[0] *= len;
792       v[1] *= len;
793       v[2] *= len;
794    }
795 }
796 
797 
798 /** Test two floats have opposite signs */
799 static inline GLboolean
800 DIFFERENT_SIGNS(GLfloat x, GLfloat y)
801 {
802    return signbit(x) != signbit(y);
803 }
804 
805 
806 /** Compute ceiling of integer quotient of A divided by B. */
807 #define CEILING( A, B )  ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 )
808 
809 
810 /** casts to silence warnings with some compilers */
811 #define ENUM_TO_INT(E)     ((GLint)(E))
812 #define ENUM_TO_FLOAT(E)   ((GLfloat)(GLint)(E))
813 #define ENUM_TO_DOUBLE(E)  ((GLdouble)(GLint)(E))
814 #define ENUM_TO_BOOLEAN(E) ((E) ? GL_TRUE : GL_FALSE)
815 
816 /* Compute the size of an array */
817 #ifndef ARRAY_SIZE
818 #  define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
819 #endif
820 
821 /* Stringify */
822 #define STRINGIFY(x) #x
823 
824 #endif
825