macros.h revision 848b8605
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] */
43extern 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 GLfloat in [-1.0,1.0] to GLint64 in [-(1<<63),(1 << 63) -1] */
109#define FLOAT_TO_INT64(X)     ( (GLint64) (9223372036854775807.0 * (double)(X)) )
110
111
112/** Convert GLint in [-2147483648,2147483647] to GLfloat in [-1.0,1.0], texture/fb data */
113#define INT_TO_FLOAT_TEX(I)    ((I) == -2147483648 ? -1.0F : (I) * (1.0F/2147483647.0))
114
115/** Convert GLfloat in [-1.0,1.0] to GLint in [-2147483648,2147483647], texture/fb data */
116#define FLOAT_TO_INT_TEX(X)    ( (GLint) (2147483647.0 * (X)) )
117
118
119#define BYTE_TO_UBYTE(b)   ((GLubyte) ((b) < 0 ? 0 : (GLubyte) (b)))
120#define SHORT_TO_UBYTE(s)  ((GLubyte) ((s) < 0 ? 0 : (GLubyte) ((s) >> 7)))
121#define USHORT_TO_UBYTE(s) ((GLubyte) ((s) >> 8))
122#define INT_TO_UBYTE(i)    ((GLubyte) ((i) < 0 ? 0 : (GLubyte) ((i) >> 23)))
123#define UINT_TO_UBYTE(i)   ((GLubyte) ((i) >> 24))
124
125
126#define BYTE_TO_USHORT(b)  ((b) < 0 ? 0 : ((GLushort) (((b) * 65535) / 255)))
127#define UBYTE_TO_USHORT(b) (((GLushort) (b) << 8) | (GLushort) (b))
128#define SHORT_TO_USHORT(s) ((s) < 0 ? 0 : ((GLushort) (((s) * 65535 / 32767))))
129#define INT_TO_USHORT(i)   ((i) < 0 ? 0 : ((GLushort) ((i) >> 15)))
130#define UINT_TO_USHORT(i)  ((i) < 0 ? 0 : ((GLushort) ((i) >> 16)))
131#define UNCLAMPED_FLOAT_TO_USHORT(us, f)  \
132        us = ( (GLushort) F_TO_I( CLAMP((f), 0.0F, 1.0F) * 65535.0F) )
133#define CLAMPED_FLOAT_TO_USHORT(us, f)  \
134        us = ( (GLushort) F_TO_I( (f) * 65535.0F) )
135
136#define UNCLAMPED_FLOAT_TO_SHORT(s, f)  \
137        s = ( (GLshort) F_TO_I( CLAMP((f), -1.0F, 1.0F) * 32767.0F) )
138
139/***
140 *** UNCLAMPED_FLOAT_TO_UBYTE: clamp float to [0,1] and map to ubyte in [0,255]
141 *** CLAMPED_FLOAT_TO_UBYTE: map float known to be in [0,1] to ubyte in [0,255]
142 ***/
143#ifndef DEBUG
144/* This function/macro is sensitive to precision.  Test very carefully
145 * if you change it!
146 */
147#define UNCLAMPED_FLOAT_TO_UBYTE(UB, FLT)				\
148        do {								\
149           fi_type __tmp;						\
150           __tmp.f = (FLT);						\
151           if (__tmp.i < 0)						\
152              UB = (GLubyte) 0;						\
153           else if (__tmp.i >= IEEE_ONE)				\
154              UB = (GLubyte) 255;					\
155           else {							\
156              __tmp.f = __tmp.f * (255.0F/256.0F) + 32768.0F;		\
157              UB = (GLubyte) __tmp.i;					\
158           }								\
159        } while (0)
160#define CLAMPED_FLOAT_TO_UBYTE(UB, FLT)					\
161        do {								\
162           fi_type __tmp;						\
163           __tmp.f = (FLT) * (255.0F/256.0F) + 32768.0F;		\
164           UB = (GLubyte) __tmp.i;					\
165        } while (0)
166#else
167#define UNCLAMPED_FLOAT_TO_UBYTE(ub, f) \
168	ub = ((GLubyte) F_TO_I(CLAMP((f), 0.0F, 1.0F) * 255.0F))
169#define CLAMPED_FLOAT_TO_UBYTE(ub, f) \
170	ub = ((GLubyte) F_TO_I((f) * 255.0F))
171#endif
172
173static inline GLfloat INT_AS_FLT(GLint i)
174{
175   fi_type tmp;
176   tmp.i = i;
177   return tmp.f;
178}
179
180static inline GLfloat UINT_AS_FLT(GLuint u)
181{
182   fi_type tmp;
183   tmp.u = u;
184   return tmp.f;
185}
186
187static inline unsigned FLT_AS_UINT(float f)
188{
189   fi_type tmp;
190   tmp.f = f;
191   return tmp.u;
192}
193
194/**
195 * Convert a floating point value to an unsigned fixed point value.
196 *
197 * \param frac_bits   The number of bits used to store the fractional part.
198 */
199static INLINE uint32_t
200U_FIXED(float value, uint32_t frac_bits)
201{
202   value *= (1 << frac_bits);
203   return value < 0.0f ? 0 : (uint32_t) value;
204}
205
206/**
207 * Convert a floating point value to an signed fixed point value.
208 *
209 * \param frac_bits   The number of bits used to store the fractional part.
210 */
211static INLINE int32_t
212S_FIXED(float value, uint32_t frac_bits)
213{
214   return (int32_t) (value * (1 << frac_bits));
215}
216/*@}*/
217
218
219/** Stepping a GLfloat pointer by a byte stride */
220#define STRIDE_F(p, i)  (p = (GLfloat *)((GLubyte *)p + i))
221/** Stepping a GLuint pointer by a byte stride */
222#define STRIDE_UI(p, i)  (p = (GLuint *)((GLubyte *)p + i))
223/** Stepping a GLubyte[4] pointer by a byte stride */
224#define STRIDE_4UB(p, i)  (p = (GLubyte (*)[4])((GLubyte *)p + i))
225/** Stepping a GLfloat[4] pointer by a byte stride */
226#define STRIDE_4F(p, i)  (p = (GLfloat (*)[4])((GLubyte *)p + i))
227/** Stepping a \p t pointer by a byte stride */
228#define STRIDE_T(p, t, i)  (p = (t)((GLubyte *)p + i))
229
230
231/**********************************************************************/
232/** \name 4-element vector operations */
233/*@{*/
234
235/** Zero */
236#define ZERO_4V( DST )  (DST)[0] = (DST)[1] = (DST)[2] = (DST)[3] = 0
237
238/** Test for equality */
239#define TEST_EQ_4V(a,b)  ((a)[0] == (b)[0] &&   \
240              (a)[1] == (b)[1] &&   \
241              (a)[2] == (b)[2] &&   \
242              (a)[3] == (b)[3])
243
244/** Test for equality (unsigned bytes) */
245static inline GLboolean
246TEST_EQ_4UBV(const GLubyte a[4], const GLubyte b[4])
247{
248#if defined(__i386__)
249   return *((const GLuint *) a) == *((const GLuint *) b);
250#else
251   return TEST_EQ_4V(a, b);
252#endif
253}
254
255
256/** Copy a 4-element vector */
257#define COPY_4V( DST, SRC )         \
258do {                                \
259   (DST)[0] = (SRC)[0];             \
260   (DST)[1] = (SRC)[1];             \
261   (DST)[2] = (SRC)[2];             \
262   (DST)[3] = (SRC)[3];             \
263} while (0)
264
265/** Copy a 4-element unsigned byte vector */
266static inline void
267COPY_4UBV(GLubyte dst[4], const GLubyte src[4])
268{
269#if defined(__i386__)
270   *((GLuint *) dst) = *((GLuint *) src);
271#else
272   /* The GLuint cast might fail if DST or SRC are not dword-aligned (RISC) */
273   COPY_4V(dst, src);
274#endif
275}
276
277/** Copy a 4-element float vector */
278static inline void
279COPY_4FV(GLfloat dst[4], const GLfloat src[4])
280{
281   /* memcpy seems to be most efficient */
282   memcpy(dst, src, sizeof(GLfloat) * 4);
283}
284
285/** Copy \p SZ elements into a 4-element vector */
286#define COPY_SZ_4V(DST, SZ, SRC)  \
287do {                              \
288   switch (SZ) {                  \
289   case 4: (DST)[3] = (SRC)[3];   \
290   case 3: (DST)[2] = (SRC)[2];   \
291   case 2: (DST)[1] = (SRC)[1];   \
292   case 1: (DST)[0] = (SRC)[0];   \
293   }                              \
294} while(0)
295
296/** Copy \p SZ elements into a homegeneous (4-element) vector, giving
297 * default values to the remaining */
298#define COPY_CLEAN_4V(DST, SZ, SRC)  \
299do {                                 \
300      ASSIGN_4V( DST, 0, 0, 0, 1 );  \
301      COPY_SZ_4V( DST, SZ, SRC );    \
302} while (0)
303
304/** Subtraction */
305#define SUB_4V( DST, SRCA, SRCB )           \
306do {                                        \
307      (DST)[0] = (SRCA)[0] - (SRCB)[0];     \
308      (DST)[1] = (SRCA)[1] - (SRCB)[1];     \
309      (DST)[2] = (SRCA)[2] - (SRCB)[2];     \
310      (DST)[3] = (SRCA)[3] - (SRCB)[3];     \
311} while (0)
312
313/** Addition */
314#define ADD_4V( DST, SRCA, SRCB )           \
315do {                                        \
316      (DST)[0] = (SRCA)[0] + (SRCB)[0];     \
317      (DST)[1] = (SRCA)[1] + (SRCB)[1];     \
318      (DST)[2] = (SRCA)[2] + (SRCB)[2];     \
319      (DST)[3] = (SRCA)[3] + (SRCB)[3];     \
320} while (0)
321
322/** Element-wise multiplication */
323#define SCALE_4V( DST, SRCA, SRCB )         \
324do {                                        \
325      (DST)[0] = (SRCA)[0] * (SRCB)[0];     \
326      (DST)[1] = (SRCA)[1] * (SRCB)[1];     \
327      (DST)[2] = (SRCA)[2] * (SRCB)[2];     \
328      (DST)[3] = (SRCA)[3] * (SRCB)[3];     \
329} while (0)
330
331/** In-place addition */
332#define ACC_4V( DST, SRC )          \
333do {                                \
334      (DST)[0] += (SRC)[0];         \
335      (DST)[1] += (SRC)[1];         \
336      (DST)[2] += (SRC)[2];         \
337      (DST)[3] += (SRC)[3];         \
338} while (0)
339
340/** Element-wise multiplication and addition */
341#define ACC_SCALE_4V( DST, SRCA, SRCB )     \
342do {                                        \
343      (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
344      (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
345      (DST)[2] += (SRCA)[2] * (SRCB)[2];    \
346      (DST)[3] += (SRCA)[3] * (SRCB)[3];    \
347} while (0)
348
349/** In-place scalar multiplication and addition */
350#define ACC_SCALE_SCALAR_4V( DST, S, SRCB ) \
351do {                                        \
352      (DST)[0] += S * (SRCB)[0];            \
353      (DST)[1] += S * (SRCB)[1];            \
354      (DST)[2] += S * (SRCB)[2];            \
355      (DST)[3] += S * (SRCB)[3];            \
356} while (0)
357
358/** Scalar multiplication */
359#define SCALE_SCALAR_4V( DST, S, SRCB ) \
360do {                                    \
361      (DST)[0] = S * (SRCB)[0];         \
362      (DST)[1] = S * (SRCB)[1];         \
363      (DST)[2] = S * (SRCB)[2];         \
364      (DST)[3] = S * (SRCB)[3];         \
365} while (0)
366
367/** In-place scalar multiplication */
368#define SELF_SCALE_SCALAR_4V( DST, S ) \
369do {                                   \
370      (DST)[0] *= S;                   \
371      (DST)[1] *= S;                   \
372      (DST)[2] *= S;                   \
373      (DST)[3] *= S;                   \
374} while (0)
375
376/** Assignment */
377#define ASSIGN_4V( V, V0, V1, V2, V3 )  \
378do {                                    \
379    V[0] = V0;                          \
380    V[1] = V1;                          \
381    V[2] = V2;                          \
382    V[3] = V3;                          \
383} while(0)
384
385/*@}*/
386
387
388/**********************************************************************/
389/** \name 3-element vector operations*/
390/*@{*/
391
392/** Zero */
393#define ZERO_3V( DST )  (DST)[0] = (DST)[1] = (DST)[2] = 0
394
395/** Test for equality */
396#define TEST_EQ_3V(a,b)  \
397   ((a)[0] == (b)[0] &&  \
398    (a)[1] == (b)[1] &&  \
399    (a)[2] == (b)[2])
400
401/** Copy a 3-element vector */
402#define COPY_3V( DST, SRC )         \
403do {                                \
404   (DST)[0] = (SRC)[0];             \
405   (DST)[1] = (SRC)[1];             \
406   (DST)[2] = (SRC)[2];             \
407} while (0)
408
409/** Copy a 3-element vector with cast */
410#define COPY_3V_CAST( DST, SRC, CAST )  \
411do {                                    \
412   (DST)[0] = (CAST)(SRC)[0];           \
413   (DST)[1] = (CAST)(SRC)[1];           \
414   (DST)[2] = (CAST)(SRC)[2];           \
415} while (0)
416
417/** Copy a 3-element float vector */
418#define COPY_3FV( DST, SRC )        \
419do {                                \
420   const GLfloat *_tmp = (SRC);     \
421   (DST)[0] = _tmp[0];              \
422   (DST)[1] = _tmp[1];              \
423   (DST)[2] = _tmp[2];              \
424} while (0)
425
426/** Subtraction */
427#define SUB_3V( DST, SRCA, SRCB )        \
428do {                                     \
429      (DST)[0] = (SRCA)[0] - (SRCB)[0];  \
430      (DST)[1] = (SRCA)[1] - (SRCB)[1];  \
431      (DST)[2] = (SRCA)[2] - (SRCB)[2];  \
432} while (0)
433
434/** Addition */
435#define ADD_3V( DST, SRCA, SRCB )       \
436do {                                    \
437      (DST)[0] = (SRCA)[0] + (SRCB)[0]; \
438      (DST)[1] = (SRCA)[1] + (SRCB)[1]; \
439      (DST)[2] = (SRCA)[2] + (SRCB)[2]; \
440} while (0)
441
442/** In-place scalar multiplication */
443#define SCALE_3V( DST, SRCA, SRCB )     \
444do {                                    \
445      (DST)[0] = (SRCA)[0] * (SRCB)[0]; \
446      (DST)[1] = (SRCA)[1] * (SRCB)[1]; \
447      (DST)[2] = (SRCA)[2] * (SRCB)[2]; \
448} while (0)
449
450/** In-place element-wise multiplication */
451#define SELF_SCALE_3V( DST, SRC )   \
452do {                                \
453      (DST)[0] *= (SRC)[0];         \
454      (DST)[1] *= (SRC)[1];         \
455      (DST)[2] *= (SRC)[2];         \
456} while (0)
457
458/** In-place addition */
459#define ACC_3V( DST, SRC )          \
460do {                                \
461      (DST)[0] += (SRC)[0];         \
462      (DST)[1] += (SRC)[1];         \
463      (DST)[2] += (SRC)[2];         \
464} while (0)
465
466/** Element-wise multiplication and addition */
467#define ACC_SCALE_3V( DST, SRCA, SRCB )     \
468do {                                        \
469      (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
470      (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
471      (DST)[2] += (SRCA)[2] * (SRCB)[2];    \
472} while (0)
473
474/** Scalar multiplication */
475#define SCALE_SCALAR_3V( DST, S, SRCB ) \
476do {                                    \
477      (DST)[0] = S * (SRCB)[0];         \
478      (DST)[1] = S * (SRCB)[1];         \
479      (DST)[2] = S * (SRCB)[2];         \
480} while (0)
481
482/** In-place scalar multiplication and addition */
483#define ACC_SCALE_SCALAR_3V( DST, S, SRCB ) \
484do {                                        \
485      (DST)[0] += S * (SRCB)[0];            \
486      (DST)[1] += S * (SRCB)[1];            \
487      (DST)[2] += S * (SRCB)[2];            \
488} while (0)
489
490/** In-place scalar multiplication */
491#define SELF_SCALE_SCALAR_3V( DST, S ) \
492do {                                   \
493      (DST)[0] *= S;                   \
494      (DST)[1] *= S;                   \
495      (DST)[2] *= S;                   \
496} while (0)
497
498/** In-place scalar addition */
499#define ACC_SCALAR_3V( DST, S )     \
500do {                                \
501      (DST)[0] += S;                \
502      (DST)[1] += S;                \
503      (DST)[2] += S;                \
504} while (0)
505
506/** Assignment */
507#define ASSIGN_3V( V, V0, V1, V2 )  \
508do {                                \
509    V[0] = V0;                      \
510    V[1] = V1;                      \
511    V[2] = V2;                      \
512} while(0)
513
514/*@}*/
515
516
517/**********************************************************************/
518/** \name 2-element vector operations*/
519/*@{*/
520
521/** Zero */
522#define ZERO_2V( DST )  (DST)[0] = (DST)[1] = 0
523
524/** Copy a 2-element vector */
525#define COPY_2V( DST, SRC )         \
526do {                        \
527   (DST)[0] = (SRC)[0];             \
528   (DST)[1] = (SRC)[1];             \
529} while (0)
530
531/** Copy a 2-element vector with cast */
532#define COPY_2V_CAST( DST, SRC, CAST )      \
533do {                        \
534   (DST)[0] = (CAST)(SRC)[0];           \
535   (DST)[1] = (CAST)(SRC)[1];           \
536} while (0)
537
538/** Copy a 2-element float vector */
539#define COPY_2FV( DST, SRC )            \
540do {                        \
541   const GLfloat *_tmp = (SRC);         \
542   (DST)[0] = _tmp[0];              \
543   (DST)[1] = _tmp[1];              \
544} while (0)
545
546/** Subtraction */
547#define SUB_2V( DST, SRCA, SRCB )       \
548do {                        \
549      (DST)[0] = (SRCA)[0] - (SRCB)[0];     \
550      (DST)[1] = (SRCA)[1] - (SRCB)[1];     \
551} while (0)
552
553/** Addition */
554#define ADD_2V( DST, SRCA, SRCB )       \
555do {                        \
556      (DST)[0] = (SRCA)[0] + (SRCB)[0];     \
557      (DST)[1] = (SRCA)[1] + (SRCB)[1];     \
558} while (0)
559
560/** In-place scalar multiplication */
561#define SCALE_2V( DST, SRCA, SRCB )     \
562do {                        \
563      (DST)[0] = (SRCA)[0] * (SRCB)[0];     \
564      (DST)[1] = (SRCA)[1] * (SRCB)[1];     \
565} while (0)
566
567/** In-place addition */
568#define ACC_2V( DST, SRC )          \
569do {                        \
570      (DST)[0] += (SRC)[0];         \
571      (DST)[1] += (SRC)[1];         \
572} while (0)
573
574/** Element-wise multiplication and addition */
575#define ACC_SCALE_2V( DST, SRCA, SRCB )     \
576do {                        \
577      (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
578      (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
579} while (0)
580
581/** Scalar multiplication */
582#define SCALE_SCALAR_2V( DST, S, SRCB )     \
583do {                        \
584      (DST)[0] = S * (SRCB)[0];         \
585      (DST)[1] = S * (SRCB)[1];         \
586} while (0)
587
588/** In-place scalar multiplication and addition */
589#define ACC_SCALE_SCALAR_2V( DST, S, SRCB ) \
590do {                        \
591      (DST)[0] += S * (SRCB)[0];        \
592      (DST)[1] += S * (SRCB)[1];        \
593} while (0)
594
595/** In-place scalar multiplication */
596#define SELF_SCALE_SCALAR_2V( DST, S )      \
597do {                        \
598      (DST)[0] *= S;                \
599      (DST)[1] *= S;                \
600} while (0)
601
602/** In-place scalar addition */
603#define ACC_SCALAR_2V( DST, S )         \
604do {                        \
605      (DST)[0] += S;                \
606      (DST)[1] += S;                \
607} while (0)
608
609/** Assign scalers to short vectors */
610#define ASSIGN_2V( V, V0, V1 )	\
611do {				\
612    V[0] = V0;			\
613    V[1] = V1;			\
614} while(0)
615
616/*@}*/
617
618/** Copy \p sz elements into a homegeneous (4-element) vector, giving
619 * default values to the remaining components.
620 * The default values are chosen based on \p type.
621 */
622static inline void
623COPY_CLEAN_4V_TYPE_AS_FLOAT(GLfloat dst[4], int sz, const GLfloat src[4],
624                            GLenum type)
625{
626   switch (type) {
627   case GL_FLOAT:
628      ASSIGN_4V(dst, 0, 0, 0, 1);
629      break;
630   case GL_INT:
631      ASSIGN_4V(dst, INT_AS_FLT(0), INT_AS_FLT(0),
632                     INT_AS_FLT(0), INT_AS_FLT(1));
633      break;
634   case GL_UNSIGNED_INT:
635      ASSIGN_4V(dst, UINT_AS_FLT(0), UINT_AS_FLT(0),
636                     UINT_AS_FLT(0), UINT_AS_FLT(1));
637      break;
638   default:
639      ASSIGN_4V(dst, 0.0f, 0.0f, 0.0f, 1.0f); /* silence warnings */
640      ASSERT(!"Unexpected type in COPY_CLEAN_4V_TYPE_AS_FLOAT macro");
641   }
642   COPY_SZ_4V(dst, sz, src);
643}
644
645/** \name Linear interpolation functions */
646/*@{*/
647
648static inline GLfloat
649LINTERP(GLfloat t, GLfloat out, GLfloat in)
650{
651   return out + t * (in - out);
652}
653
654static inline void
655INTERP_3F(GLfloat t, GLfloat dst[3], const GLfloat out[3], const GLfloat in[3])
656{
657   dst[0] = LINTERP( t, out[0], in[0] );
658   dst[1] = LINTERP( t, out[1], in[1] );
659   dst[2] = LINTERP( t, out[2], in[2] );
660}
661
662static inline void
663INTERP_4F(GLfloat t, GLfloat dst[4], const GLfloat out[4], const GLfloat in[4])
664{
665   dst[0] = LINTERP( t, out[0], in[0] );
666   dst[1] = LINTERP( t, out[1], in[1] );
667   dst[2] = LINTERP( t, out[2], in[2] );
668   dst[3] = LINTERP( t, out[3], in[3] );
669}
670
671/*@}*/
672
673
674
675/** Clamp X to [MIN,MAX] */
676#define CLAMP( X, MIN, MAX )  ( (X)<(MIN) ? (MIN) : ((X)>(MAX) ? (MAX) : (X)) )
677
678/** Minimum of two values: */
679#define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
680
681/** Maximum of two values: */
682#define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
683
684/** Minimum and maximum of three values: */
685#define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
686#define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
687
688static inline unsigned
689minify(unsigned value, unsigned levels)
690{
691    return MAX2(1, value >> levels);
692}
693
694/**
695 * Return true if the given value is a power of two.
696 *
697 * Note that this considers 0 a power of two.
698 */
699static inline bool
700is_power_of_two(unsigned value)
701{
702   return (value & (value - 1)) == 0;
703}
704
705/**
706 * Align a value up to an alignment value
707 *
708 * If \c value is not already aligned to the requested alignment value, it
709 * will be rounded up.
710 *
711 * \param value  Value to be rounded
712 * \param alignment  Alignment value to be used.  This must be a power of two.
713 *
714 * \sa ROUND_DOWN_TO()
715 */
716#define ALIGN(value, alignment)  (((value) + (alignment) - 1) & ~((alignment) - 1))
717
718/**
719 * Align a value down to an alignment value
720 *
721 * If \c value is not already aligned to the requested alignment value, it
722 * will be rounded down.
723 *
724 * \param value  Value to be rounded
725 * \param alignment  Alignment value to be used.  This must be a power of two.
726 *
727 * \sa ALIGN()
728 */
729#define ROUND_DOWN_TO(value, alignment) ((value) & ~(alignment - 1))
730
731
732/** Cross product of two 3-element vectors */
733static inline void
734CROSS3(GLfloat n[3], const GLfloat u[3], const GLfloat v[3])
735{
736   n[0] = u[1] * v[2] - u[2] * v[1];
737   n[1] = u[2] * v[0] - u[0] * v[2];
738   n[2] = u[0] * v[1] - u[1] * v[0];
739}
740
741
742/** Dot product of two 2-element vectors */
743static inline GLfloat
744DOT2(const GLfloat a[2], const GLfloat b[2])
745{
746   return a[0] * b[0] + a[1] * b[1];
747}
748
749static inline GLfloat
750DOT3(const GLfloat a[3], const GLfloat b[3])
751{
752   return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
753}
754
755static inline GLfloat
756DOT4(const GLfloat a[4], const GLfloat b[4])
757{
758   return a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3];
759}
760
761
762static inline GLfloat
763LEN_SQUARED_3FV(const GLfloat v[3])
764{
765   return DOT3(v, v);
766}
767
768static inline GLfloat
769LEN_SQUARED_2FV(const GLfloat v[2])
770{
771   return DOT2(v, v);
772}
773
774
775static inline GLfloat
776LEN_3FV(const GLfloat v[3])
777{
778   return sqrtf(LEN_SQUARED_3FV(v));
779}
780
781static inline GLfloat
782LEN_2FV(const GLfloat v[2])
783{
784   return sqrtf(LEN_SQUARED_2FV(v));
785}
786
787
788/* Normalize a 3-element vector to unit length. */
789static inline void
790NORMALIZE_3FV(GLfloat v[3])
791{
792   GLfloat len = (GLfloat) LEN_SQUARED_3FV(v);
793   if (len) {
794      len = INV_SQRTF(len);
795      v[0] *= len;
796      v[1] *= len;
797      v[2] *= len;
798   }
799}
800
801
802/** Is float value negative? */
803static inline GLboolean
804IS_NEGATIVE(float x)
805{
806   return signbit(x) != 0;
807}
808
809/** Test two floats have opposite signs */
810static inline GLboolean
811DIFFERENT_SIGNS(GLfloat x, GLfloat y)
812{
813   return signbit(x) != signbit(y);
814}
815
816
817/** Compute ceiling of integer quotient of A divided by B. */
818#define CEILING( A, B )  ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 )
819
820
821/** casts to silence warnings with some compilers */
822#define ENUM_TO_INT(E)     ((GLint)(E))
823#define ENUM_TO_FLOAT(E)   ((GLfloat)(GLint)(E))
824#define ENUM_TO_DOUBLE(E)  ((GLdouble)(GLint)(E))
825#define ENUM_TO_BOOLEAN(E) ((E) ? GL_TRUE : GL_FALSE)
826
827/* Compute the size of an array */
828#ifndef ARRAY_SIZE
829#  define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
830#endif
831
832/* Stringify */
833#define STRINGIFY(x) #x
834
835#endif
836