src/mesa/main/macros.h

   1 /**
   2  * \file macros.h
   3  * A collection of useful macros.
   4  */
   5
   6 /*
   7  * Mesa 3-D graphics library
   8  * Version:  6.5.2
   9  *
  10  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a
  13  * copy of this software and associated documentation files (the "Software"),
  14  * to deal in the Software without restriction, including without limitation
  15  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  16  * and/or sell copies of the Software, and to permit persons to whom the
  17  * Software is furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included
  20  * in all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  23  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  25  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  26  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  27  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  28  * OTHER DEALINGS IN THE SOFTWARE.
  29  */
  30
  31
  32 #ifndef MACROS_H
  33 #define MACROS_H
  34
  35 #include "imports.h"
  36
  37
  38 /**
  39  * \name Integer / float conversion for colors, normals, etc.
  40  */
  41 /*@{*/
  42
  43 /** Convert GLubyte in [0,255] to GLfloat in [0.0,1.0] */
  44 extern GLfloat _mesa_ubyte_to_float_color_tab[256];
  45 #define UBYTE_TO_FLOAT(u) _mesa_ubyte_to_float_color_tab[(unsigned int)(u)]
  46
  47 /** Convert GLfloat in [0.0,1.0] to GLubyte in [0,255] */
  48 #define FLOAT_TO_UBYTE(X)   ((GLubyte) (GLint) ((X) * 255.0F))
  49
  50
  51 /** Convert GLbyte in [-128,127] to GLfloat in [-1.0,1.0] */
  52 #define BYTE_TO_FLOAT(B)    ((2.0F * (B) + 1.0F) * (1.0F/255.0F))
  53
  54 /** Convert GLfloat in [-1.0,1.0] to GLbyte in [-128,127] */
  55 #define FLOAT_TO_BYTE(X)    ( (((GLint) (255.0F * (X))) - 1) / 2 )
  56
  57
  58 /** Convert GLbyte to GLfloat while preserving zero */
  59 #define BYTE_TO_FLOATZ(B)   ((B) == 0 ? 0.0F : BYTE_TO_FLOAT(B))
  60
  61
  62 /** Convert GLbyte in [-128,127] to GLfloat in [-1.0,1.0], texture/fb data */
  63 #define BYTE_TO_FLOAT_TEX(B)    ((B) == -128 ? -1.0F : (B) * (1.0F/127.0F))
  64
  65 /** Convert GLfloat in [-1.0,1.0] to GLbyte in [-128,127], texture/fb data */
  66 #define FLOAT_TO_BYTE_TEX(X)    CLAMP( (GLint) (127.0F * (X)), -128, 127 )
  67
  68 /** Convert GLushort in [0,65535] to GLfloat in [0.0,1.0] */
  69 #define USHORT_TO_FLOAT(S)  ((GLfloat) (S) * (1.0F / 65535.0F))
  70
  71 /** Convert GLfloat in [0.0,1.0] to GLushort in [0, 65535] */
  72 #define FLOAT_TO_USHORT(X)   ((GLuint) ((X) * 65535.0F))
  73
  74
  75 /** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0] */
  76 #define SHORT_TO_FLOAT(S)   ((2.0F * (S) + 1.0F) * (1.0F/65535.0F))
  77
  78 /** Convert GLfloat in [-1.0,1.0] to GLshort in [-32768,32767] */
  79 #define FLOAT_TO_SHORT(X)   ( (((GLint) (65535.0F * (X))) - 1) / 2 )
  80
  81 /** Convert GLshort to GLfloat while preserving zero */
  82 #define SHORT_TO_FLOATZ(S)   ((S) == 0 ? 0.0F : SHORT_TO_FLOAT(S))
  83
  84
  85 /** Convert GLshort in [-32768,32767] to GLfloat in [-1.0,1.0], texture/fb data */
  86 #define SHORT_TO_FLOAT_TEX(S)    ((S) == -32768 ? -1.0F : (S) * (1.0F/32767.0F))
  87
  88 /** Convert GLfloat in [-1.0,1.0] to GLshort in [-32768,32767], texture/fb data */
  89 #define FLOAT_TO_SHORT_TEX(X)    ( (GLint) (32767.0F * (X)) )
  90
  91
  92 /** Convert GLuint in [0,4294967295] to GLfloat in [0.0,1.0] */
  93 #define UINT_TO_FLOAT(U)    ((GLfloat) ((U) * (1.0F / 4294967295.0)))
  94
  95 /** Convert GLfloat in [0.0,1.0] to GLuint in [0,4294967295] */
  96 #define FLOAT_TO_UINT(X)    ((GLuint) ((X) * 4294967295.0))
  97
  98
  99 /** Convert GLint in [-2147483648,2147483647] to GLfloat in [-1.0,1.0] */
 100 #define INT_TO_FLOAT(I)     ((GLfloat) ((2.0F * (I) + 1.0F) * (1.0F/4294967294.0)))
 101
 102 /** Convert GLfloat in [-1.0,1.0] to GLint in [-2147483648,2147483647] */
 103 /* causes overflow:
 104 #define FLOAT_TO_INT(X)     ( (((GLint) (4294967294.0 * (X))) - 1) / 2 )
 105 */
 106 /* a close approximation: */
 107 #define FLOAT_TO_INT(X)     ( (GLint) (2147483647.0 * (X)) )
 108
 109 /** Convert GLfloat in [-1.0,1.0] to GLint64 in [-(1<<63),(1 << 63) -1] */
 110 #define FLOAT_TO_INT64(X)     ( (GLint64) (9223372036854775807.0 * (double)(X)) )
 111
 112
 113 /** Convert GLint in [-2147483648,2147483647] to GLfloat in [-1.0,1.0], texture/fb data */
 114 #define INT_TO_FLOAT_TEX(I)    ((I) == -2147483648 ? -1.0F : (I) * (1.0F/2147483647.0))
 115
 116 /** Convert GLfloat in [-1.0,1.0] to GLint in [-2147483648,2147483647], texture/fb data */
 117 #define FLOAT_TO_INT_TEX(X)    ( (GLint) (2147483647.0 * (X)) )
 118
 119
 120 #define BYTE_TO_UBYTE(b)   ((GLubyte) ((b) < 0 ? 0 : (GLubyte) (b)))
 121 #define SHORT_TO_UBYTE(s)  ((GLubyte) ((s) < 0 ? 0 : (GLubyte) ((s) >> 7)))
 122 #define USHORT_TO_UBYTE(s) ((GLubyte) ((s) >> 8))
 123 #define INT_TO_UBYTE(i)    ((GLubyte) ((i) < 0 ? 0 : (GLubyte) ((i) >> 23)))
 124 #define UINT_TO_UBYTE(i)   ((GLubyte) ((i) >> 24))
 125
 126
 127 #define BYTE_TO_USHORT(b)  ((b) < 0 ? 0 : ((GLushort) (((b) * 65535) / 255)))
 128 #define UBYTE_TO_USHORT(b) (((GLushort) (b) << 8) | (GLushort) (b))
 129 #define SHORT_TO_USHORT(s) ((s) < 0 ? 0 : ((GLushort) (((s) * 65535 / 32767))))
 130 #define INT_TO_USHORT(i)   ((i) < 0 ? 0 : ((GLushort) ((i) >> 15)))
 131 #define UINT_TO_USHORT(i)  ((i) < 0 ? 0 : ((GLushort) ((i) >> 16)))
 132 #define UNCLAMPED_FLOAT_TO_USHORT(us, f)  \
 133         us = ( (GLushort) F_TO_I( CLAMP((f), 0.0F, 1.0F) * 65535.0F) )
 134 #define CLAMPED_FLOAT_TO_USHORT(us, f)  \
 135         us = ( (GLushort) F_TO_I( (f) * 65535.0F) )
 136
 137 #define UNCLAMPED_FLOAT_TO_SHORT(s, f)  \
 138         s = ( (GLshort) F_TO_I( CLAMP((f), -1.0F, 1.0F) * 32767.0F) )
 139
 140 /***
 141  *** UNCLAMPED_FLOAT_TO_UBYTE: clamp float to [0,1] and map to ubyte in [0,255]
 142  *** CLAMPED_FLOAT_TO_UBYTE: map float known to be in [0,1] to ubyte in [0,255]
 143  ***/
 144 #if defined(USE_IEEE) && !defined(DEBUG)
 145 #define IEEE_0996 0x3f7f0000    /* 0.996 or so */
 146 /* This function/macro is sensitive to precision.  Test very carefully
 147  * if you change it!
 148  */
 149 #define UNCLAMPED_FLOAT_TO_UBYTE(UB, F)                                 \
 150         do {                                                            \
 151            fi_type __tmp;                                               \
 152            __tmp.f = (F);                                               \
 153            if (__tmp.i < 0)                                             \
 154               UB = (GLubyte) 0;                                         \
 155            else if (__tmp.i >= IEEE_0996)                               \
 156               UB = (GLubyte) 255;                                       \
 157            else {                                                       \
 158               __tmp.f = __tmp.f * (255.0F/256.0F) + 32768.0F;           \
 159               UB = (GLubyte) __tmp.i;                                   \
 160            }                                                            \
 161         } while (0)
 162 #define CLAMPED_FLOAT_TO_UBYTE(UB, F)                                   \
 163         do {                                                            \
 164            fi_type __tmp;                                               \
 165            __tmp.f = (F) * (255.0F/256.0F) + 32768.0F;                  \
 166            UB = (GLubyte) __tmp.i;                                      \
 167         } while (0)
 168 #else
 169 #define UNCLAMPED_FLOAT_TO_UBYTE(ub, f) \
 170         ub = ((GLubyte) F_TO_I(CLAMP((f), 0.0F, 1.0F) * 255.0F))
 171 #define CLAMPED_FLOAT_TO_UBYTE(ub, f) \
 172         ub = ((GLubyte) F_TO_I((f) * 255.0F))
 173 #endif
 174
 175 static inline GLfloat INT_AS_FLT(GLint i)
 176 {
 177    fi_type tmp;
 178    tmp.i = i;
 179    return tmp.f;
 180 }
 181
 182 static inline GLfloat UINT_AS_FLT(GLuint u)
 183 {
 184    fi_type tmp;
 185    tmp.u = u;
 186    return tmp.f;
 187 }
 188
 189 /*@}*/
 190
 191
 192 /** Stepping a GLfloat pointer by a byte stride */
 193 #define STRIDE_F(p, i)  (p = (GLfloat *)((GLubyte *)p + i))
 194 /** Stepping a GLuint pointer by a byte stride */
 195 #define STRIDE_UI(p, i)  (p = (GLuint *)((GLubyte *)p + i))
 196 /** Stepping a GLubyte[4] pointer by a byte stride */
 197 #define STRIDE_4UB(p, i)  (p = (GLubyte (*)[4])((GLubyte *)p + i))
 198 /** Stepping a GLfloat[4] pointer by a byte stride */
 199 #define STRIDE_4F(p, i)  (p = (GLfloat (*)[4])((GLubyte *)p + i))
 200 /** Stepping a \p t pointer by a byte stride */
 201 #define STRIDE_T(p, t, i)  (p = (t)((GLubyte *)p + i))
 202
 203
 204 /**********************************************************************/
 205 /** \name 4-element vector operations */
 206 /*@{*/
 207
 208 /** Zero */
 209 #define ZERO_4V( DST )  (DST)[0] = (DST)[1] = (DST)[2] = (DST)[3] = 0
 210
 211 /** Test for equality */
 212 #define TEST_EQ_4V(a,b)  ((a)[0] == (b)[0] &&   \
 213               (a)[1] == (b)[1] &&   \
 214               (a)[2] == (b)[2] &&   \
 215               (a)[3] == (b)[3])
 216
 217 /** Test for equality (unsigned bytes) */
 218 static inline GLboolean
 219 TEST_EQ_4UBV(const GLubyte a[4], const GLubyte b[4])
 220 {
 221 #if defined(__i386__)
 222    return *((const GLuint *) a) == *((const GLuint *) b);
 223 #else
 224    return TEST_EQ_4V(a, b);
 225 #endif
 226 }
 227
 228
 229 /** Copy a 4-element vector */
 230 #define COPY_4V( DST, SRC )         \
 231 do {                                \
 232    (DST)[0] = (SRC)[0];             \
 233    (DST)[1] = (SRC)[1];             \
 234    (DST)[2] = (SRC)[2];             \
 235    (DST)[3] = (SRC)[3];             \
 236 } while (0)
 237
 238 /** Copy a 4-element unsigned byte vector */
 239 static inline void
 240 COPY_4UBV(GLubyte dst[4], const GLubyte src[4])
 241 {
 242 #if defined(__i386__)
 243    *((GLuint *) dst) = *((GLuint *) src);
 244 #else
 245    /* The GLuint cast might fail if DST or SRC are not dword-aligned (RISC) */
 246    COPY_4V(dst, src);
 247 #endif
 248 }
 249
 250 /** Copy a 4-element float vector */
 251 static inline void
 252 COPY_4FV(GLfloat dst[4], const GLfloat src[4])
 253 {
 254    /* memcpy seems to be most efficient */
 255    memcpy(dst, src, sizeof(GLfloat) * 4);
 256 }
 257
 258 /** Copy \p SZ elements into a 4-element vector */
 259 #define COPY_SZ_4V(DST, SZ, SRC)  \
 260 do {                              \
 261    switch (SZ) {                  \
 262    case 4: (DST)[3] = (SRC)[3];   \
 263    case 3: (DST)[2] = (SRC)[2];   \
 264    case 2: (DST)[1] = (SRC)[1];   \
 265    case 1: (DST)[0] = (SRC)[0];   \
 266    }                              \
 267 } while(0)
 268
 269 /** Copy \p SZ elements into a homegeneous (4-element) vector, giving
 270  * default values to the remaining */
 271 #define COPY_CLEAN_4V(DST, SZ, SRC)  \
 272 do {                                 \
 273       ASSIGN_4V( DST, 0, 0, 0, 1 );  \
 274       COPY_SZ_4V( DST, SZ, SRC );    \
 275 } while (0)
 276
 277 /** Subtraction */
 278 #define SUB_4V( DST, SRCA, SRCB )           \
 279 do {                                        \
 280       (DST)[0] = (SRCA)[0] - (SRCB)[0];     \
 281       (DST)[1] = (SRCA)[1] - (SRCB)[1];     \
 282       (DST)[2] = (SRCA)[2] - (SRCB)[2];     \
 283       (DST)[3] = (SRCA)[3] - (SRCB)[3];     \
 284 } while (0)
 285
 286 /** Addition */
 287 #define ADD_4V( DST, SRCA, SRCB )           \
 288 do {                                        \
 289       (DST)[0] = (SRCA)[0] + (SRCB)[0];     \
 290       (DST)[1] = (SRCA)[1] + (SRCB)[1];     \
 291       (DST)[2] = (SRCA)[2] + (SRCB)[2];     \
 292       (DST)[3] = (SRCA)[3] + (SRCB)[3];     \
 293 } while (0)
 294
 295 /** Element-wise multiplication */
 296 #define SCALE_4V( DST, SRCA, SRCB )         \
 297 do {                                        \
 298       (DST)[0] = (SRCA)[0] * (SRCB)[0];     \
 299       (DST)[1] = (SRCA)[1] * (SRCB)[1];     \
 300       (DST)[2] = (SRCA)[2] * (SRCB)[2];     \
 301       (DST)[3] = (SRCA)[3] * (SRCB)[3];     \
 302 } while (0)
 303
 304 /** In-place addition */
 305 #define ACC_4V( DST, SRC )          \
 306 do {                                \
 307       (DST)[0] += (SRC)[0];         \
 308       (DST)[1] += (SRC)[1];         \
 309       (DST)[2] += (SRC)[2];         \
 310       (DST)[3] += (SRC)[3];         \
 311 } while (0)
 312
 313 /** Element-wise multiplication and addition */
 314 #define ACC_SCALE_4V( DST, SRCA, SRCB )     \
 315 do {                                        \
 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 /** In-place scalar multiplication and addition */
 323 #define ACC_SCALE_SCALAR_4V( DST, S, SRCB ) \
 324 do {                                        \
 325       (DST)[0] += S * (SRCB)[0];            \
 326       (DST)[1] += S * (SRCB)[1];            \
 327       (DST)[2] += S * (SRCB)[2];            \
 328       (DST)[3] += S * (SRCB)[3];            \
 329 } while (0)
 330
 331 /** Scalar multiplication */
 332 #define SCALE_SCALAR_4V( DST, S, SRCB ) \
 333 do {                                    \
 334       (DST)[0] = S * (SRCB)[0];         \
 335       (DST)[1] = S * (SRCB)[1];         \
 336       (DST)[2] = S * (SRCB)[2];         \
 337       (DST)[3] = S * (SRCB)[3];         \
 338 } while (0)
 339
 340 /** In-place scalar multiplication */
 341 #define SELF_SCALE_SCALAR_4V( DST, S ) \
 342 do {                                   \
 343       (DST)[0] *= S;                   \
 344       (DST)[1] *= S;                   \
 345       (DST)[2] *= S;                   \
 346       (DST)[3] *= S;                   \
 347 } while (0)
 348
 349 /** Assignment */
 350 #define ASSIGN_4V( V, V0, V1, V2, V3 )  \
 351 do {                                    \
 352     V[0] = V0;                          \
 353     V[1] = V1;                          \
 354     V[2] = V2;                          \
 355     V[3] = V3;                          \
 356 } while(0)
 357
 358 /*@}*/
 359
 360
 361 /**********************************************************************/
 362 /** \name 3-element vector operations*/
 363 /*@{*/
 364
 365 /** Zero */
 366 #define ZERO_3V( DST )  (DST)[0] = (DST)[1] = (DST)[2] = 0
 367
 368 /** Test for equality */
 369 #define TEST_EQ_3V(a,b)  \
 370    ((a)[0] == (b)[0] &&  \
 371     (a)[1] == (b)[1] &&  \
 372     (a)[2] == (b)[2])
 373
 374 /** Copy a 3-element vector */
 375 #define COPY_3V( DST, SRC )         \
 376 do {                                \
 377    (DST)[0] = (SRC)[0];             \
 378    (DST)[1] = (SRC)[1];             \
 379    (DST)[2] = (SRC)[2];             \
 380 } while (0)
 381
 382 /** Copy a 3-element vector with cast */
 383 #define COPY_3V_CAST( DST, SRC, CAST )  \
 384 do {                                    \
 385    (DST)[0] = (CAST)(SRC)[0];           \
 386    (DST)[1] = (CAST)(SRC)[1];           \
 387    (DST)[2] = (CAST)(SRC)[2];           \
 388 } while (0)
 389
 390 /** Copy a 3-element float vector */
 391 #define COPY_3FV( DST, SRC )        \
 392 do {                                \
 393    const GLfloat *_tmp = (SRC);     \
 394    (DST)[0] = _tmp[0];              \
 395    (DST)[1] = _tmp[1];              \
 396    (DST)[2] = _tmp[2];              \
 397 } while (0)
 398
 399 /** Subtraction */
 400 #define SUB_3V( DST, SRCA, SRCB )        \
 401 do {                                     \
 402       (DST)[0] = (SRCA)[0] - (SRCB)[0];  \
 403       (DST)[1] = (SRCA)[1] - (SRCB)[1];  \
 404       (DST)[2] = (SRCA)[2] - (SRCB)[2];  \
 405 } while (0)
 406
 407 /** Addition */
 408 #define ADD_3V( DST, SRCA, SRCB )       \
 409 do {                                    \
 410       (DST)[0] = (SRCA)[0] + (SRCB)[0]; \
 411       (DST)[1] = (SRCA)[1] + (SRCB)[1]; \
 412       (DST)[2] = (SRCA)[2] + (SRCB)[2]; \
 413 } while (0)
 414
 415 /** In-place scalar multiplication */
 416 #define SCALE_3V( DST, SRCA, SRCB )     \
 417 do {                                    \
 418       (DST)[0] = (SRCA)[0] * (SRCB)[0]; \
 419       (DST)[1] = (SRCA)[1] * (SRCB)[1]; \
 420       (DST)[2] = (SRCA)[2] * (SRCB)[2]; \
 421 } while (0)
 422
 423 /** In-place element-wise multiplication */
 424 #define SELF_SCALE_3V( DST, SRC )   \
 425 do {                                \
 426       (DST)[0] *= (SRC)[0];         \
 427       (DST)[1] *= (SRC)[1];         \
 428       (DST)[2] *= (SRC)[2];         \
 429 } while (0)
 430
 431 /** In-place addition */
 432 #define ACC_3V( DST, SRC )          \
 433 do {                                \
 434       (DST)[0] += (SRC)[0];         \
 435       (DST)[1] += (SRC)[1];         \
 436       (DST)[2] += (SRC)[2];         \
 437 } while (0)
 438
 439 /** Element-wise multiplication and addition */
 440 #define ACC_SCALE_3V( DST, SRCA, SRCB )     \
 441 do {                                        \
 442       (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
 443       (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
 444       (DST)[2] += (SRCA)[2] * (SRCB)[2];    \
 445 } while (0)
 446
 447 /** Scalar multiplication */
 448 #define SCALE_SCALAR_3V( DST, S, SRCB ) \
 449 do {                                    \
 450       (DST)[0] = S * (SRCB)[0];         \
 451       (DST)[1] = S * (SRCB)[1];         \
 452       (DST)[2] = S * (SRCB)[2];         \
 453 } while (0)
 454
 455 /** In-place scalar multiplication and addition */
 456 #define ACC_SCALE_SCALAR_3V( DST, S, SRCB ) \
 457 do {                                        \
 458       (DST)[0] += S * (SRCB)[0];            \
 459       (DST)[1] += S * (SRCB)[1];            \
 460       (DST)[2] += S * (SRCB)[2];            \
 461 } while (0)
 462
 463 /** In-place scalar multiplication */
 464 #define SELF_SCALE_SCALAR_3V( DST, S ) \
 465 do {                                   \
 466       (DST)[0] *= S;                   \
 467       (DST)[1] *= S;                   \
 468       (DST)[2] *= S;                   \
 469 } while (0)
 470
 471 /** In-place scalar addition */
 472 #define ACC_SCALAR_3V( DST, S )     \
 473 do {                                \
 474       (DST)[0] += S;                \
 475       (DST)[1] += S;                \
 476       (DST)[2] += S;                \
 477 } while (0)
 478
 479 /** Assignment */
 480 #define ASSIGN_3V( V, V0, V1, V2 )  \
 481 do {                                \
 482     V[0] = V0;                      \
 483     V[1] = V1;                      \
 484     V[2] = V2;                      \
 485 } while(0)
 486
 487 /*@}*/
 488
 489
 490 /**********************************************************************/
 491 /** \name 2-element vector operations*/
 492 /*@{*/
 493
 494 /** Zero */
 495 #define ZERO_2V( DST )  (DST)[0] = (DST)[1] = 0
 496
 497 /** Copy a 2-element vector */
 498 #define COPY_2V( DST, SRC )         \
 499 do {                        \
 500    (DST)[0] = (SRC)[0];             \
 501    (DST)[1] = (SRC)[1];             \
 502 } while (0)
 503
 504 /** Copy a 2-element vector with cast */
 505 #define COPY_2V_CAST( DST, SRC, CAST )      \
 506 do {                        \
 507    (DST)[0] = (CAST)(SRC)[0];           \
 508    (DST)[1] = (CAST)(SRC)[1];           \
 509 } while (0)
 510
 511 /** Copy a 2-element float vector */
 512 #define COPY_2FV( DST, SRC )            \
 513 do {                        \
 514    const GLfloat *_tmp = (SRC);         \
 515    (DST)[0] = _tmp[0];              \
 516    (DST)[1] = _tmp[1];              \
 517 } while (0)
 518
 519 /** Subtraction */
 520 #define SUB_2V( DST, SRCA, SRCB )       \
 521 do {                        \
 522       (DST)[0] = (SRCA)[0] - (SRCB)[0];     \
 523       (DST)[1] = (SRCA)[1] - (SRCB)[1];     \
 524 } while (0)
 525
 526 /** Addition */
 527 #define ADD_2V( DST, SRCA, SRCB )       \
 528 do {                        \
 529       (DST)[0] = (SRCA)[0] + (SRCB)[0];     \
 530       (DST)[1] = (SRCA)[1] + (SRCB)[1];     \
 531 } while (0)
 532
 533 /** In-place scalar multiplication */
 534 #define SCALE_2V( DST, SRCA, SRCB )     \
 535 do {                        \
 536       (DST)[0] = (SRCA)[0] * (SRCB)[0];     \
 537       (DST)[1] = (SRCA)[1] * (SRCB)[1];     \
 538 } while (0)
 539
 540 /** In-place addition */
 541 #define ACC_2V( DST, SRC )          \
 542 do {                        \
 543       (DST)[0] += (SRC)[0];         \
 544       (DST)[1] += (SRC)[1];         \
 545 } while (0)
 546
 547 /** Element-wise multiplication and addition */
 548 #define ACC_SCALE_2V( DST, SRCA, SRCB )     \
 549 do {                        \
 550       (DST)[0] += (SRCA)[0] * (SRCB)[0];    \
 551       (DST)[1] += (SRCA)[1] * (SRCB)[1];    \
 552 } while (0)
 553
 554 /** Scalar multiplication */
 555 #define SCALE_SCALAR_2V( DST, S, SRCB )     \
 556 do {                        \
 557       (DST)[0] = S * (SRCB)[0];         \
 558       (DST)[1] = S * (SRCB)[1];         \
 559 } while (0)
 560
 561 /** In-place scalar multiplication and addition */
 562 #define ACC_SCALE_SCALAR_2V( DST, S, SRCB ) \
 563 do {                        \
 564       (DST)[0] += S * (SRCB)[0];        \
 565       (DST)[1] += S * (SRCB)[1];        \
 566 } while (0)
 567
 568 /** In-place scalar multiplication */
 569 #define SELF_SCALE_SCALAR_2V( DST, S )      \
 570 do {                        \
 571       (DST)[0] *= S;                \
 572       (DST)[1] *= S;                \
 573 } while (0)
 574
 575 /** In-place scalar addition */
 576 #define ACC_SCALAR_2V( DST, S )         \
 577 do {                        \
 578       (DST)[0] += S;                \
 579       (DST)[1] += S;                \
 580 } while (0)
 581
 582 /** Assign scalers to short vectors */
 583 #define ASSIGN_2V( V, V0, V1 )  \
 584 do {                            \
 585     V[0] = V0;                  \
 586     V[1] = V1;                  \
 587 } while(0)
 588
 589 /*@}*/
 590
 591 /** Copy \p sz elements into a homegeneous (4-element) vector, giving
 592  * default values to the remaining components.
 593  * The default values are chosen based on \p type.
 594  */
 595 static inline void
 596 COPY_CLEAN_4V_TYPE_AS_FLOAT(GLfloat dst[4], int sz, const GLfloat src[4],
 597                             GLenum type)
 598 {
 599    switch (type) {
 600    case GL_FLOAT:
 601       ASSIGN_4V(dst, 0, 0, 0, 1);
 602       break;
 603    case GL_INT:
 604       ASSIGN_4V(dst, INT_AS_FLT(0), INT_AS_FLT(0),
 605                      INT_AS_FLT(0), INT_AS_FLT(1));
 606       break;
 607    case GL_UNSIGNED_INT:
 608       ASSIGN_4V(dst, UINT_AS_FLT(0), UINT_AS_FLT(0),
 609                      UINT_AS_FLT(0), UINT_AS_FLT(1));
 610       break;
 611    default:
 612       ASSERT(0);
 613    }
 614    COPY_SZ_4V(dst, sz, src);
 615 }
 616
 617 /** \name Linear interpolation functions */
 618 /*@{*/
 619
 620 static inline GLfloat
 621 LINTERP(GLfloat t, GLfloat out, GLfloat in)
 622 {
 623    return out + t * (in - out);
 624 }
 625
 626 static inline void
 627 INTERP_3F(GLfloat t, GLfloat dst[3], const GLfloat out[3], const GLfloat in[3])
 628 {
 629    dst[0] = LINTERP( t, out[0], in[0] );
 630    dst[1] = LINTERP( t, out[1], in[1] );
 631    dst[2] = LINTERP( t, out[2], in[2] );
 632 }
 633
 634 static inline void
 635 INTERP_4F(GLfloat t, GLfloat dst[4], const GLfloat out[4], const GLfloat in[4])
 636 {
 637    dst[0] = LINTERP( t, out[0], in[0] );
 638    dst[1] = LINTERP( t, out[1], in[1] );
 639    dst[2] = LINTERP( t, out[2], in[2] );
 640    dst[3] = LINTERP( t, out[3], in[3] );
 641 }
 642
 643 /*@}*/
 644
 645
 646
 647 /** Clamp X to [MIN,MAX] */
 648 #define CLAMP( X, MIN, MAX )  ( (X)<(MIN) ? (MIN) : ((X)>(MAX) ? (MAX) : (X)) )
 649
 650 /** Minimum of two values: */
 651 #define MIN2( A, B )   ( (A)<(B) ? (A) : (B) )
 652
 653 /** Maximum of two values: */
 654 #define MAX2( A, B )   ( (A)>(B) ? (A) : (B) )
 655
 656 /** Minimum and maximum of three values: */
 657 #define MIN3( A, B, C ) ((A) < (B) ? MIN2(A, C) : MIN2(B, C))
 658 #define MAX3( A, B, C ) ((A) > (B) ? MAX2(A, C) : MAX2(B, C))
 659
 660 static inline unsigned
 661 minify(unsigned value, unsigned levels)
 662 {
 663     return MAX2(1, value >> levels);
 664 }
 665
 666 /**
 667  * Align a value up to an alignment value
 668  *
 669  * If \c value is not already aligned to the requested alignment value, it
 670  * will be rounded up.
 671  *
 672  * \param value  Value to be rounded
 673  * \param alignment  Alignment value to be used.  This must be a power of two.
 674  *
 675  * \sa ROUND_DOWN_TO()
 676  */
 677 #define ALIGN(value, alignment)  (((value) + alignment - 1) & ~(alignment - 1))
 678
 679
 680
 681 /** Cross product of two 3-element vectors */
 682 static inline void
 683 CROSS3(GLfloat n[3], const GLfloat u[3], const GLfloat v[3])
 684 {
 685    n[0] = u[1] * v[2] - u[2] * v[1];
 686    n[1] = u[2] * v[0] - u[0] * v[2];
 687    n[2] = u[0] * v[1] - u[1] * v[0];
 688 }
 689
 690
 691 /** Dot product of two 2-element vectors */
 692 static inline GLfloat
 693 DOT2(const GLfloat a[2], const GLfloat b[2])
 694 {
 695    return a[0] * b[0] + a[1] * b[1];
 696 }
 697
 698 static inline GLfloat
 699 DOT3(const GLfloat a[3], const GLfloat b[3])
 700 {
 701    return a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
 702 }
 703
 704 static inline GLfloat
 705 DOT4(const GLfloat a[4], const GLfloat b[4])
 706 {
 707    return a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3];
 708 }
 709
 710
 711 static inline GLfloat
 712 LEN_SQUARED_3FV(const GLfloat v[3])
 713 {
 714    return DOT3(v, v);
 715 }
 716
 717 static inline GLfloat
 718 LEN_SQUARED_2FV(const GLfloat v[2])
 719 {
 720    return DOT2(v, v);
 721 }
 722
 723
 724 static inline GLfloat
 725 LEN_3FV(const GLfloat v[3])
 726 {
 727    return sqrtf(LEN_SQUARED_3FV(v));
 728 }
 729
 730 static inline GLfloat
 731 LEN_2FV(const GLfloat v[2])
 732 {
 733    return sqrtf(LEN_SQUARED_2FV(v));
 734 }
 735
 736
 737 /* Normalize a 3-element vector to unit length. */
 738 static inline void
 739 NORMALIZE_3FV(GLfloat v[3])
 740 {
 741    GLfloat len = (GLfloat) LEN_SQUARED_3FV(v);
 742    if (len) {
 743       len = INV_SQRTF(len);
 744       v[0] *= len;
 745       v[1] *= len;
 746       v[2] *= len;
 747    }
 748 }
 749
 750
 751 /** Is float value negative? */
 752 static inline GLboolean
 753 IS_NEGATIVE(float x)
 754 {
 755    return signbit(x) != 0;
 756 }
 757
 758 /** Test two floats have opposite signs */
 759 static inline GLboolean
 760 DIFFERENT_SIGNS(GLfloat x, GLfloat y)
 761 {
 762    return signbit(x) != signbit(y);
 763 }
 764
 765
 766 /** Compute ceiling of integer quotient of A divided by B. */
 767 #define CEILING( A, B )  ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 )
 768
 769
 770 /** casts to silence warnings with some compilers */
 771 #define ENUM_TO_INT(E)     ((GLint)(E))
 772 #define ENUM_TO_FLOAT(E)   ((GLfloat)(GLint)(E))
 773 #define ENUM_TO_DOUBLE(E)  ((GLdouble)(GLint)(E))
 774 #define ENUM_TO_BOOLEAN(E) ((E) ? GL_TRUE : GL_FALSE)
 775
 776 /* Compute the size of an array */
 777 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
 778
 779
 780 #endif