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