src/mesa/main/blend.c

   1 /**
   2  * \file blend.c
   3  * Blending operations.
   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
  32 #include "glheader.h"
  33 #include "blend.h"
  34 #include "context.h"
  35 #include "enums.h"
  36 #include "macros.h"
  37 #include "mtypes.h"
  38
  39
  40
  41 /**
  42  * Check if given blend source factor is legal.
  43  * \return GL_TRUE if legal, GL_FALSE otherwise.
  44  */
  45 static GLboolean
  46 legal_src_factor(const struct gl_context *ctx, GLenum factor)
  47 {
  48    switch (factor) {
  49    case GL_SRC_COLOR:
  50    case GL_ONE_MINUS_SRC_COLOR:
  51    case GL_ZERO:
  52    case GL_ONE:
  53    case GL_DST_COLOR:
  54    case GL_ONE_MINUS_DST_COLOR:
  55    case GL_SRC_ALPHA:
  56    case GL_ONE_MINUS_SRC_ALPHA:
  57    case GL_DST_ALPHA:
  58    case GL_ONE_MINUS_DST_ALPHA:
  59    case GL_SRC_ALPHA_SATURATE:
  60       return GL_TRUE;
  61    case GL_CONSTANT_COLOR:
  62    case GL_ONE_MINUS_CONSTANT_COLOR:
  63    case GL_CONSTANT_ALPHA:
  64    case GL_ONE_MINUS_CONSTANT_ALPHA:
  65       return _mesa_is_desktop_gl(ctx) || ctx->API == API_OPENGLES2;
  66    case GL_SRC1_COLOR:
  67    case GL_SRC1_ALPHA:
  68    case GL_ONE_MINUS_SRC1_COLOR:
  69    case GL_ONE_MINUS_SRC1_ALPHA:
  70       return _mesa_is_desktop_gl(ctx)
  71          && ctx->Extensions.ARB_blend_func_extended;
  72    default:
  73       return GL_FALSE;
  74    }
  75 }
  76
  77
  78 /**
  79  * Check if given blend destination factor is legal.
  80  * \return GL_TRUE if legal, GL_FALSE otherwise.
  81  */
  82 static GLboolean
  83 legal_dst_factor(const struct gl_context *ctx, GLenum factor)
  84 {
  85    switch (factor) {
  86    case GL_DST_COLOR:
  87    case GL_ONE_MINUS_DST_COLOR:
  88    case GL_ZERO:
  89    case GL_ONE:
  90    case GL_SRC_COLOR:
  91    case GL_ONE_MINUS_SRC_COLOR:
  92    case GL_SRC_ALPHA:
  93    case GL_ONE_MINUS_SRC_ALPHA:
  94    case GL_DST_ALPHA:
  95    case GL_ONE_MINUS_DST_ALPHA:
  96       return GL_TRUE;
  97    case GL_CONSTANT_COLOR:
  98    case GL_ONE_MINUS_CONSTANT_COLOR:
  99    case GL_CONSTANT_ALPHA:
 100    case GL_ONE_MINUS_CONSTANT_ALPHA:
 101       return _mesa_is_desktop_gl(ctx) || ctx->API == API_OPENGLES2;
 102    case GL_SRC_ALPHA_SATURATE:
 103       return (_mesa_is_desktop_gl(ctx)
 104               && ctx->Extensions.ARB_blend_func_extended)
 105          || _mesa_is_gles3(ctx);
 106    case GL_SRC1_COLOR:
 107    case GL_SRC1_ALPHA:
 108    case GL_ONE_MINUS_SRC1_COLOR:
 109    case GL_ONE_MINUS_SRC1_ALPHA:
 110       return _mesa_is_desktop_gl(ctx)
 111          && ctx->Extensions.ARB_blend_func_extended;
 112    default:
 113       return GL_FALSE;
 114    }
 115 }
 116
 117
 118 /**
 119  * Check if src/dest RGB/A blend factors are legal.  If not generate
 120  * a GL error.
 121  * \return GL_TRUE if factors are legal, GL_FALSE otherwise.
 122  */
 123 static GLboolean
 124 validate_blend_factors(struct gl_context *ctx, const char *func,
 125                        GLenum sfactorRGB, GLenum dfactorRGB,
 126                        GLenum sfactorA, GLenum dfactorA)
 127 {
 128    if (!legal_src_factor(ctx, sfactorRGB)) {
 129       _mesa_error(ctx, GL_INVALID_ENUM,
 130                   "%s(sfactorRGB = %s)", func,
 131                   _mesa_enum_to_string(sfactorRGB));
 132       return GL_FALSE;
 133    }
 134
 135    if (!legal_dst_factor(ctx, dfactorRGB)) {
 136       _mesa_error(ctx, GL_INVALID_ENUM,
 137                   "%s(dfactorRGB = %s)", func,
 138                   _mesa_enum_to_string(dfactorRGB));
 139       return GL_FALSE;
 140    }
 141
 142    if (sfactorA != sfactorRGB && !legal_src_factor(ctx, sfactorA)) {
 143       _mesa_error(ctx, GL_INVALID_ENUM,
 144                   "%s(sfactorA = %s)", func,
 145                   _mesa_enum_to_string(sfactorA));
 146       return GL_FALSE;
 147    }
 148
 149    if (dfactorA != dfactorRGB && !legal_dst_factor(ctx, dfactorA)) {
 150       _mesa_error(ctx, GL_INVALID_ENUM,
 151                   "%s(dfactorA = %s)", func,
 152                   _mesa_enum_to_string(dfactorA));
 153       return GL_FALSE;
 154    }
 155
 156    return GL_TRUE;
 157 }
 158
 159
 160 /**
 161  * Specify the blending operation.
 162  *
 163  * \param sfactor source factor operator.
 164  * \param dfactor destination factor operator.
 165  *
 166  * \sa glBlendFunc, glBlendFuncSeparateEXT
 167  */
 168 void GLAPIENTRY
 169 _mesa_BlendFunc( GLenum sfactor, GLenum dfactor )
 170 {
 171    _mesa_BlendFuncSeparate(sfactor, dfactor, sfactor, dfactor);
 172 }
 173
 174 static GLboolean
 175 blend_factor_is_dual_src(GLenum factor)
 176 {
 177    return (factor == GL_SRC1_COLOR ||
 178            factor == GL_SRC1_ALPHA ||
 179            factor == GL_ONE_MINUS_SRC1_COLOR ||
 180            factor == GL_ONE_MINUS_SRC1_ALPHA);
 181 }
 182
 183 static void
 184 update_uses_dual_src(struct gl_context *ctx, int buf)
 185 {
 186    ctx->Color.Blend[buf]._UsesDualSrc =
 187       (blend_factor_is_dual_src(ctx->Color.Blend[buf].SrcRGB) ||
 188        blend_factor_is_dual_src(ctx->Color.Blend[buf].DstRGB) ||
 189        blend_factor_is_dual_src(ctx->Color.Blend[buf].SrcA) ||
 190        blend_factor_is_dual_src(ctx->Color.Blend[buf].DstA));
 191 }
 192
 193 /**
 194  * Set the separate blend source/dest factors for all draw buffers.
 195  *
 196  * \param sfactorRGB RGB source factor operator.
 197  * \param dfactorRGB RGB destination factor operator.
 198  * \param sfactorA alpha source factor operator.
 199  * \param dfactorA alpha destination factor operator.
 200  */
 201 void GLAPIENTRY
 202 _mesa_BlendFuncSeparate( GLenum sfactorRGB, GLenum dfactorRGB,
 203                             GLenum sfactorA, GLenum dfactorA )
 204 {
 205    GLuint buf, numBuffers;
 206    bool changed = false;
 207    GET_CURRENT_CONTEXT(ctx);
 208
 209    if (MESA_VERBOSE & VERBOSE_API)
 210       _mesa_debug(ctx, "glBlendFuncSeparate %s %s %s %s\n",
 211                   _mesa_enum_to_string(sfactorRGB),
 212                   _mesa_enum_to_string(dfactorRGB),
 213                   _mesa_enum_to_string(sfactorA),
 214                   _mesa_enum_to_string(dfactorA));
 215
 216    numBuffers = ctx->Extensions.ARB_draw_buffers_blend
 217       ? ctx->Const.MaxDrawBuffers : 1;
 218
 219    /* Check if we're really changing any state.  If not, return early. */
 220    if (ctx->Color._BlendFuncPerBuffer) {
 221       /* Check all per-buffer states */
 222       for (buf = 0; buf < numBuffers; buf++) {
 223          if (ctx->Color.Blend[buf].SrcRGB != sfactorRGB ||
 224              ctx->Color.Blend[buf].DstRGB != dfactorRGB ||
 225              ctx->Color.Blend[buf].SrcA != sfactorA ||
 226              ctx->Color.Blend[buf].DstA != dfactorA) {
 227             changed = true;
 228             break;
 229          }
 230       }
 231    }
 232    else {
 233       /* only need to check 0th per-buffer state */
 234       if (ctx->Color.Blend[0].SrcRGB != sfactorRGB ||
 235           ctx->Color.Blend[0].DstRGB != dfactorRGB ||
 236           ctx->Color.Blend[0].SrcA != sfactorA ||
 237           ctx->Color.Blend[0].DstA != dfactorA) {
 238          changed = true;
 239       }
 240    }
 241
 242    if (!changed)
 243       return;
 244
 245    if (!validate_blend_factors(ctx, "glBlendFuncSeparate",
 246                                sfactorRGB, dfactorRGB,
 247                                sfactorA, dfactorA)) {
 248       return;
 249    }
 250
 251    FLUSH_VERTICES(ctx, _NEW_COLOR);
 252
 253    for (buf = 0; buf < numBuffers; buf++) {
 254       ctx->Color.Blend[buf].SrcRGB = sfactorRGB;
 255       ctx->Color.Blend[buf].DstRGB = dfactorRGB;
 256       ctx->Color.Blend[buf].SrcA = sfactorA;
 257       ctx->Color.Blend[buf].DstA = dfactorA;
 258       update_uses_dual_src(ctx, buf);
 259    }
 260    ctx->Color._BlendFuncPerBuffer = GL_FALSE;
 261
 262    if (ctx->Driver.BlendFuncSeparate) {
 263       ctx->Driver.BlendFuncSeparate(ctx, sfactorRGB, dfactorRGB,
 264                                     sfactorA, dfactorA);
 265    }
 266 }
 267
 268
 269 /**
 270  * Set blend source/dest factors for one color buffer/target.
 271  */
 272 void GLAPIENTRY
 273 _mesa_BlendFunciARB(GLuint buf, GLenum sfactor, GLenum dfactor)
 274 {
 275    _mesa_BlendFuncSeparateiARB(buf, sfactor, dfactor, sfactor, dfactor);
 276 }
 277
 278
 279 /**
 280  * Set separate blend source/dest factors for one color buffer/target.
 281  */
 282 void GLAPIENTRY
 283 _mesa_BlendFuncSeparateiARB(GLuint buf, GLenum sfactorRGB, GLenum dfactorRGB,
 284                          GLenum sfactorA, GLenum dfactorA)
 285 {
 286    GET_CURRENT_CONTEXT(ctx);
 287
 288    if (!ctx->Extensions.ARB_draw_buffers_blend) {
 289       _mesa_error(ctx, GL_INVALID_OPERATION, "glBlendFunc[Separate]i()");
 290       return;
 291    }
 292
 293    if (buf >= ctx->Const.MaxDrawBuffers) {
 294       _mesa_error(ctx, GL_INVALID_VALUE, "glBlendFuncSeparatei(buffer=%u)",
 295                   buf);
 296       return;
 297    }
 298
 299    if (!validate_blend_factors(ctx, "glBlendFuncSeparatei",
 300                                sfactorRGB, dfactorRGB,
 301                                sfactorA, dfactorA)) {
 302       return;
 303    }
 304
 305    if (ctx->Color.Blend[buf].SrcRGB == sfactorRGB &&
 306        ctx->Color.Blend[buf].DstRGB == dfactorRGB &&
 307        ctx->Color.Blend[buf].SrcA == sfactorA &&
 308        ctx->Color.Blend[buf].DstA == dfactorA)
 309       return; /* no change */
 310
 311    FLUSH_VERTICES(ctx, _NEW_COLOR);
 312
 313    ctx->Color.Blend[buf].SrcRGB = sfactorRGB;
 314    ctx->Color.Blend[buf].DstRGB = dfactorRGB;
 315    ctx->Color.Blend[buf].SrcA = sfactorA;
 316    ctx->Color.Blend[buf].DstA = dfactorA;
 317    update_uses_dual_src(ctx, buf);
 318    ctx->Color._BlendFuncPerBuffer = GL_TRUE;
 319 }
 320
 321
 322 /**
 323  * Check if given blend equation is legal.
 324  * \return GL_TRUE if legal, GL_FALSE otherwise.
 325  */
 326 static GLboolean
 327 legal_blend_equation(const struct gl_context *ctx, GLenum mode)
 328 {
 329    switch (mode) {
 330    case GL_FUNC_ADD:
 331    case GL_FUNC_SUBTRACT:
 332    case GL_FUNC_REVERSE_SUBTRACT:
 333       return GL_TRUE;
 334    case GL_MIN:
 335    case GL_MAX:
 336       return ctx->Extensions.EXT_blend_minmax;
 337    default:
 338       return GL_FALSE;
 339    }
 340 }
 341
 342
 343 /* This is really an extension function! */
 344 void GLAPIENTRY
 345 _mesa_BlendEquation( GLenum mode )
 346 {
 347    GLuint buf, numBuffers;
 348    bool changed = false;
 349    GET_CURRENT_CONTEXT(ctx);
 350
 351    if (MESA_VERBOSE & VERBOSE_API)
 352       _mesa_debug(ctx, "glBlendEquation(%s)\n",
 353                   _mesa_enum_to_string(mode));
 354
 355    numBuffers = ctx->Extensions.ARB_draw_buffers_blend
 356       ? ctx->Const.MaxDrawBuffers : 1;
 357
 358    if (ctx->Color._BlendEquationPerBuffer) {
 359       /* Check all per-buffer states */
 360       for (buf = 0; buf < numBuffers; buf++) {
 361          if (ctx->Color.Blend[buf].EquationRGB != mode ||
 362              ctx->Color.Blend[buf].EquationA != mode) {
 363             changed = true;
 364             break;
 365          }
 366       }
 367    }
 368    else {
 369       /* only need to check 0th per-buffer state */
 370       if (ctx->Color.Blend[0].EquationRGB != mode ||
 371           ctx->Color.Blend[0].EquationA != mode) {
 372          changed = true;
 373       }
 374    }
 375
 376    if (!changed)
 377       return;
 378
 379    if (!legal_blend_equation(ctx, mode)) {
 380       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquation");
 381       return;
 382    }
 383
 384    FLUSH_VERTICES(ctx, _NEW_COLOR);
 385
 386    for (buf = 0; buf < numBuffers; buf++) {
 387       ctx->Color.Blend[buf].EquationRGB = mode;
 388       ctx->Color.Blend[buf].EquationA = mode;
 389    }
 390    ctx->Color._BlendEquationPerBuffer = GL_FALSE;
 391
 392    if (ctx->Driver.BlendEquationSeparate)
 393       (*ctx->Driver.BlendEquationSeparate)( ctx, mode, mode );
 394 }
 395
 396
 397 /**
 398  * Set blend equation for one color buffer/target.
 399  */
 400 void GLAPIENTRY
 401 _mesa_BlendEquationiARB(GLuint buf, GLenum mode)
 402 {
 403    GET_CURRENT_CONTEXT(ctx);
 404
 405    if (MESA_VERBOSE & VERBOSE_API)
 406       _mesa_debug(ctx, "glBlendEquationi(%u, %s)\n",
 407                   buf, _mesa_enum_to_string(mode));
 408
 409    if (buf >= ctx->Const.MaxDrawBuffers) {
 410       _mesa_error(ctx, GL_INVALID_VALUE, "glBlendFuncSeparatei(buffer=%u)",
 411                   buf);
 412       return;
 413    }
 414
 415    if (!legal_blend_equation(ctx, mode)) {
 416       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationi");
 417       return;
 418    }
 419
 420    if (ctx->Color.Blend[buf].EquationRGB == mode &&
 421        ctx->Color.Blend[buf].EquationA == mode)
 422       return;  /* no change */
 423
 424    FLUSH_VERTICES(ctx, _NEW_COLOR);
 425    ctx->Color.Blend[buf].EquationRGB = mode;
 426    ctx->Color.Blend[buf].EquationA = mode;
 427    ctx->Color._BlendEquationPerBuffer = GL_TRUE;
 428 }
 429
 430
 431 void GLAPIENTRY
 432 _mesa_BlendEquationSeparate( GLenum modeRGB, GLenum modeA )
 433 {
 434    GLuint buf, numBuffers;
 435    bool changed = false;
 436    GET_CURRENT_CONTEXT(ctx);
 437
 438    if (MESA_VERBOSE & VERBOSE_API)
 439       _mesa_debug(ctx, "glBlendEquationSeparateEXT(%s %s)\n",
 440                   _mesa_enum_to_string(modeRGB),
 441                   _mesa_enum_to_string(modeA));
 442
 443    numBuffers = ctx->Extensions.ARB_draw_buffers_blend
 444       ? ctx->Const.MaxDrawBuffers : 1;
 445
 446    if (ctx->Color._BlendEquationPerBuffer) {
 447       /* Check all per-buffer states */
 448       for (buf = 0; buf < numBuffers; buf++) {
 449          if (ctx->Color.Blend[buf].EquationRGB != modeRGB ||
 450              ctx->Color.Blend[buf].EquationA != modeA) {
 451             changed = true;
 452             break;
 453          }
 454       }
 455    }
 456    else {
 457       /* only need to check 0th per-buffer state */
 458       if (ctx->Color.Blend[0].EquationRGB != modeRGB ||
 459           ctx->Color.Blend[0].EquationA != modeA) {
 460          changed = true;
 461       }
 462    }
 463
 464    if (!changed)
 465       return;
 466
 467    if ( (modeRGB != modeA) && !ctx->Extensions.EXT_blend_equation_separate ) {
 468       _mesa_error(ctx, GL_INVALID_OPERATION,
 469                   "glBlendEquationSeparateEXT not supported by driver");
 470       return;
 471    }
 472
 473    if (!legal_blend_equation(ctx, modeRGB)) {
 474       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeRGB)");
 475       return;
 476    }
 477
 478    if (!legal_blend_equation(ctx, modeA)) {
 479       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeA)");
 480       return;
 481    }
 482
 483    FLUSH_VERTICES(ctx, _NEW_COLOR);
 484
 485    for (buf = 0; buf < numBuffers; buf++) {
 486       ctx->Color.Blend[buf].EquationRGB = modeRGB;
 487       ctx->Color.Blend[buf].EquationA = modeA;
 488    }
 489    ctx->Color._BlendEquationPerBuffer = GL_FALSE;
 490
 491    if (ctx->Driver.BlendEquationSeparate)
 492       ctx->Driver.BlendEquationSeparate(ctx, modeRGB, modeA);
 493 }
 494
 495
 496 /**
 497  * Set separate blend equations for one color buffer/target.
 498  */
 499 void GLAPIENTRY
 500 _mesa_BlendEquationSeparateiARB(GLuint buf, GLenum modeRGB, GLenum modeA)
 501 {
 502    GET_CURRENT_CONTEXT(ctx);
 503
 504    if (MESA_VERBOSE & VERBOSE_API)
 505       _mesa_debug(ctx, "glBlendEquationSeparatei(%u, %s %s)\n", buf,
 506                   _mesa_enum_to_string(modeRGB),
 507                   _mesa_enum_to_string(modeA));
 508
 509    if (buf >= ctx->Const.MaxDrawBuffers) {
 510       _mesa_error(ctx, GL_INVALID_VALUE, "glBlendEquationSeparatei(buffer=%u)",
 511                   buf);
 512       return;
 513    }
 514
 515    if (!legal_blend_equation(ctx, modeRGB)) {
 516       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparatei(modeRGB)");
 517       return;
 518    }
 519
 520    if (!legal_blend_equation(ctx, modeA)) {
 521       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparatei(modeA)");
 522       return;
 523    }
 524
 525    if (ctx->Color.Blend[buf].EquationRGB == modeRGB &&
 526        ctx->Color.Blend[buf].EquationA == modeA)
 527       return;  /* no change */
 528
 529    FLUSH_VERTICES(ctx, _NEW_COLOR);
 530    ctx->Color.Blend[buf].EquationRGB = modeRGB;
 531    ctx->Color.Blend[buf].EquationA = modeA;
 532    ctx->Color._BlendEquationPerBuffer = GL_TRUE;
 533 }
 534
 535
 536 /**
 537  * Set the blending color.
 538  *
 539  * \param red red color component.
 540  * \param green green color component.
 541  * \param blue blue color component.
 542  * \param alpha alpha color component.
 543  *
 544  * \sa glBlendColor().
 545  *
 546  * Clamps the parameters and updates gl_colorbuffer_attrib::BlendColor.  On a
 547  * change, flushes the vertices and notifies the driver via
 548  * dd_function_table::BlendColor callback.
 549  */
 550 void GLAPIENTRY
 551 _mesa_BlendColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
 552 {
 553    GLfloat tmp[4];
 554    GET_CURRENT_CONTEXT(ctx);
 555
 556    tmp[0] = red;
 557    tmp[1] = green;
 558    tmp[2] = blue;
 559    tmp[3] = alpha;
 560
 561    if (TEST_EQ_4V(tmp, ctx->Color.BlendColorUnclamped))
 562       return;
 563
 564    FLUSH_VERTICES(ctx, _NEW_COLOR);
 565    COPY_4FV( ctx->Color.BlendColorUnclamped, tmp );
 566
 567    ctx->Color.BlendColor[0] = CLAMP(tmp[0], 0.0F, 1.0F);
 568    ctx->Color.BlendColor[1] = CLAMP(tmp[1], 0.0F, 1.0F);
 569    ctx->Color.BlendColor[2] = CLAMP(tmp[2], 0.0F, 1.0F);
 570    ctx->Color.BlendColor[3] = CLAMP(tmp[3], 0.0F, 1.0F);
 571
 572    if (ctx->Driver.BlendColor)
 573       (*ctx->Driver.BlendColor)(ctx, ctx->Color.BlendColor);
 574 }
 575
 576
 577 /**
 578  * Specify the alpha test function.
 579  *
 580  * \param func alpha comparison function.
 581  * \param ref reference value.
 582  *
 583  * Verifies the parameters and updates gl_colorbuffer_attrib.
 584  * On a change, flushes the vertices and notifies the driver via
 585  * dd_function_table::AlphaFunc callback.
 586  */
 587 void GLAPIENTRY
 588 _mesa_AlphaFunc( GLenum func, GLclampf ref )
 589 {
 590    GET_CURRENT_CONTEXT(ctx);
 591
 592    if (MESA_VERBOSE & VERBOSE_API)
 593       _mesa_debug(ctx, "glAlphaFunc(%s, %f)\n",
 594                   _mesa_enum_to_string(func), ref);
 595
 596    if (ctx->Color.AlphaFunc == func && ctx->Color.AlphaRefUnclamped == ref)
 597       return; /* no change */
 598
 599    switch (func) {
 600    case GL_NEVER:
 601    case GL_LESS:
 602    case GL_EQUAL:
 603    case GL_LEQUAL:
 604    case GL_GREATER:
 605    case GL_NOTEQUAL:
 606    case GL_GEQUAL:
 607    case GL_ALWAYS:
 608       FLUSH_VERTICES(ctx, _NEW_COLOR);
 609       ctx->Color.AlphaFunc = func;
 610       ctx->Color.AlphaRefUnclamped = ref;
 611       ctx->Color.AlphaRef = CLAMP(ref, 0.0F, 1.0F);
 612
 613       if (ctx->Driver.AlphaFunc)
 614          ctx->Driver.AlphaFunc(ctx, func, ctx->Color.AlphaRef);
 615       return;
 616
 617    default:
 618       _mesa_error( ctx, GL_INVALID_ENUM, "glAlphaFunc(func)" );
 619       return;
 620    }
 621 }
 622
 623
 624 /**
 625  * Specify a logic pixel operation for color index rendering.
 626  *
 627  * \param opcode operation.
 628  *
 629  * Verifies that \p opcode is a valid enum and updates
 630 gl_colorbuffer_attrib::LogicOp.
 631  * On a change, flushes the vertices and notifies the driver via the
 632  * dd_function_table::LogicOpcode callback.
 633  */
 634 void GLAPIENTRY
 635 _mesa_LogicOp( GLenum opcode )
 636 {
 637    GET_CURRENT_CONTEXT(ctx);
 638
 639    if (MESA_VERBOSE & VERBOSE_API)
 640       _mesa_debug(ctx, "glLogicOp(%s)\n", _mesa_enum_to_string(opcode));
 641
 642    switch (opcode) {
 643       case GL_CLEAR:
 644       case GL_SET:
 645       case GL_COPY:
 646       case GL_COPY_INVERTED:
 647       case GL_NOOP:
 648       case GL_INVERT:
 649       case GL_AND:
 650       case GL_NAND:
 651       case GL_OR:
 652       case GL_NOR:
 653       case GL_XOR:
 654       case GL_EQUIV:
 655       case GL_AND_REVERSE:
 656       case GL_AND_INVERTED:
 657       case GL_OR_REVERSE:
 658       case GL_OR_INVERTED:
 659          break;
 660       default:
 661          _mesa_error( ctx, GL_INVALID_ENUM, "glLogicOp" );
 662          return;
 663    }
 664
 665    if (ctx->Color.LogicOp == opcode)
 666       return;
 667
 668    FLUSH_VERTICES(ctx, _NEW_COLOR);
 669    ctx->Color.LogicOp = opcode;
 670
 671    if (ctx->Driver.LogicOpcode)
 672       ctx->Driver.LogicOpcode( ctx, opcode );
 673 }
 674
 675
 676 void GLAPIENTRY
 677 _mesa_IndexMask( GLuint mask )
 678 {
 679    GET_CURRENT_CONTEXT(ctx);
 680
 681    if (ctx->Color.IndexMask == mask)
 682       return;
 683
 684    FLUSH_VERTICES(ctx, _NEW_COLOR);
 685    ctx->Color.IndexMask = mask;
 686 }
 687
 688
 689 /**
 690  * Enable or disable writing of frame buffer color components.
 691  *
 692  * \param red whether to mask writing of the red color component.
 693  * \param green whether to mask writing of the green color component.
 694  * \param blue whether to mask writing of the blue color component.
 695  * \param alpha whether to mask writing of the alpha color component.
 696  *
 697  * \sa glColorMask().
 698  *
 699  * Sets the appropriate value of gl_colorbuffer_attrib::ColorMask.  On a
 700  * change, flushes the vertices and notifies the driver via the
 701  * dd_function_table::ColorMask callback.
 702  */
 703 void GLAPIENTRY
 704 _mesa_ColorMask( GLboolean red, GLboolean green,
 705                  GLboolean blue, GLboolean alpha )
 706 {
 707    GET_CURRENT_CONTEXT(ctx);
 708    GLubyte tmp[4];
 709    GLuint i;
 710    GLboolean flushed;
 711
 712    if (MESA_VERBOSE & VERBOSE_API)
 713       _mesa_debug(ctx, "glColorMask(%d, %d, %d, %d)\n",
 714                   red, green, blue, alpha);
 715
 716    /* Shouldn't have any information about channel depth in core mesa
 717     * -- should probably store these as the native booleans:
 718     */
 719    tmp[RCOMP] = red    ? 0xff : 0x0;
 720    tmp[GCOMP] = green  ? 0xff : 0x0;
 721    tmp[BCOMP] = blue   ? 0xff : 0x0;
 722    tmp[ACOMP] = alpha  ? 0xff : 0x0;
 723
 724    flushed = GL_FALSE;
 725    for (i = 0; i < ctx->Const.MaxDrawBuffers; i++) {
 726       if (!TEST_EQ_4V(tmp, ctx->Color.ColorMask[i])) {
 727          if (!flushed) {
 728             FLUSH_VERTICES(ctx, _NEW_COLOR);
 729          }
 730          flushed = GL_TRUE;
 731          COPY_4UBV(ctx->Color.ColorMask[i], tmp);
 732       }
 733    }
 734
 735    if (ctx->Driver.ColorMask)
 736       ctx->Driver.ColorMask( ctx, red, green, blue, alpha );
 737 }
 738
 739
 740 /**
 741  * For GL_EXT_draw_buffers2 and GL3
 742  */
 743 void GLAPIENTRY
 744 _mesa_ColorMaski( GLuint buf, GLboolean red, GLboolean green,
 745                         GLboolean blue, GLboolean alpha )
 746 {
 747    GLubyte tmp[4];
 748    GET_CURRENT_CONTEXT(ctx);
 749
 750    if (MESA_VERBOSE & VERBOSE_API)
 751       _mesa_debug(ctx, "glColorMaskIndexed %u %d %d %d %d\n",
 752                   buf, red, green, blue, alpha);
 753
 754    if (buf >= ctx->Const.MaxDrawBuffers) {
 755       _mesa_error(ctx, GL_INVALID_VALUE, "glColorMaskIndexed(buf=%u)", buf);
 756       return;
 757    }
 758
 759    /* Shouldn't have any information about channel depth in core mesa
 760     * -- should probably store these as the native booleans:
 761     */
 762    tmp[RCOMP] = red    ? 0xff : 0x0;
 763    tmp[GCOMP] = green  ? 0xff : 0x0;
 764    tmp[BCOMP] = blue   ? 0xff : 0x0;
 765    tmp[ACOMP] = alpha  ? 0xff : 0x0;
 766
 767    if (TEST_EQ_4V(tmp, ctx->Color.ColorMask[buf]))
 768       return;
 769
 770    FLUSH_VERTICES(ctx, _NEW_COLOR);
 771    COPY_4UBV(ctx->Color.ColorMask[buf], tmp);
 772 }
 773
 774
 775 void GLAPIENTRY
 776 _mesa_ClampColor(GLenum target, GLenum clamp)
 777 {
 778    GET_CURRENT_CONTEXT(ctx);
 779
 780    if (clamp != GL_TRUE && clamp != GL_FALSE && clamp != GL_FIXED_ONLY_ARB) {
 781       _mesa_error(ctx, GL_INVALID_ENUM, "glClampColorARB(clamp)");
 782       return;
 783    }
 784
 785    switch (target) {
 786    case GL_CLAMP_VERTEX_COLOR_ARB:
 787       if (ctx->API == API_OPENGL_CORE &&
 788           !ctx->Extensions.ARB_color_buffer_float) {
 789          goto invalid_enum;
 790       }
 791       FLUSH_VERTICES(ctx, _NEW_LIGHT);
 792       ctx->Light.ClampVertexColor = clamp;
 793       _mesa_update_clamp_vertex_color(ctx, ctx->DrawBuffer);
 794       break;
 795    case GL_CLAMP_FRAGMENT_COLOR_ARB:
 796       if (ctx->API == API_OPENGL_CORE &&
 797           !ctx->Extensions.ARB_color_buffer_float) {
 798          goto invalid_enum;
 799       }
 800       FLUSH_VERTICES(ctx, _NEW_FRAG_CLAMP);
 801       ctx->Color.ClampFragmentColor = clamp;
 802       _mesa_update_clamp_fragment_color(ctx, ctx->DrawBuffer);
 803       break;
 804    case GL_CLAMP_READ_COLOR_ARB:
 805       ctx->Color.ClampReadColor = clamp;
 806       break;
 807    default:
 808       goto invalid_enum;
 809    }
 810    return;
 811
 812 invalid_enum:
 813    _mesa_error(ctx, GL_INVALID_ENUM, "glClampColor(%s)",
 814                _mesa_enum_to_string(target));
 815 }
 816
 817 static GLboolean
 818 get_clamp_color(const struct gl_framebuffer *fb, GLenum clamp)
 819 {
 820    if (clamp == GL_TRUE || clamp == GL_FALSE)
 821       return clamp;
 822
 823    assert(clamp == GL_FIXED_ONLY);
 824    if (!fb)
 825       return GL_TRUE;
 826
 827    return fb->_AllColorBuffersFixedPoint;
 828 }
 829
 830 GLboolean
 831 _mesa_get_clamp_fragment_color(const struct gl_context *ctx,
 832                                const struct gl_framebuffer *drawFb)
 833 {
 834    return get_clamp_color(drawFb, ctx->Color.ClampFragmentColor);
 835 }
 836
 837 GLboolean
 838 _mesa_get_clamp_vertex_color(const struct gl_context *ctx,
 839                              const struct gl_framebuffer *drawFb)
 840 {
 841    return get_clamp_color(drawFb, ctx->Light.ClampVertexColor);
 842 }
 843
 844 GLboolean
 845 _mesa_get_clamp_read_color(const struct gl_context *ctx,
 846                            const struct gl_framebuffer *readFb)
 847 {
 848    return get_clamp_color(readFb, ctx->Color.ClampReadColor);
 849 }
 850
 851 /**
 852  * Update the ctx->Color._ClampFragmentColor field
 853  */
 854 void
 855 _mesa_update_clamp_fragment_color(struct gl_context *ctx,
 856                                   const struct gl_framebuffer *drawFb)
 857 {
 858    /* Don't clamp if:
 859     * - there is no colorbuffer
 860     * - all colorbuffers are unsigned normalized, so clamping has no effect
 861     * - there is an integer colorbuffer
 862     */
 863    if (!drawFb || !drawFb->_HasSNormOrFloatColorBuffer ||
 864        drawFb->_IntegerColor)
 865       ctx->Color._ClampFragmentColor = GL_FALSE;
 866    else
 867       ctx->Color._ClampFragmentColor =
 868          _mesa_get_clamp_fragment_color(ctx, drawFb);
 869 }
 870
 871 /**
 872  * Update the ctx->Color._ClampVertexColor field
 873  */
 874 void
 875 _mesa_update_clamp_vertex_color(struct gl_context *ctx,
 876                                 const struct gl_framebuffer *drawFb)
 877 {
 878    ctx->Light._ClampVertexColor =
 879          _mesa_get_clamp_vertex_color(ctx, drawFb);
 880 }
 881
 882 /**
 883  * Returns an appropriate mesa_format for color rendering based on the
 884  * GL_FRAMEBUFFER_SRGB state.
 885  *
 886  * Some drivers implement GL_FRAMEBUFFER_SRGB using a flag on the blend state
 887  * (which GL_FRAMEBUFFER_SRGB maps to reasonably), but some have to do so by
 888  * overriding the format of the surface.  This is a helper for doing the
 889  * surface format override variant.
 890  */
 891 mesa_format
 892 _mesa_get_render_format(const struct gl_context *ctx, mesa_format format)
 893 {
 894    if (ctx->Color.sRGBEnabled)
 895       return format;
 896    else
 897       return _mesa_get_srgb_format_linear(format);
 898 }
 899
 900 /**********************************************************************/
 901 /** \name Initialization */
 902 /*@{*/
 903
 904 /**
 905  * Initialization of the context's Color attribute group.
 906  *
 907  * \param ctx GL context.
 908  *
 909  * Initializes the related fields in the context color attribute group,
 910  * __struct gl_contextRec::Color.
 911  */
 912 void _mesa_init_color( struct gl_context * ctx )
 913 {
 914    GLuint i;
 915
 916    /* Color buffer group */
 917    ctx->Color.IndexMask = ~0u;
 918    memset(ctx->Color.ColorMask, 0xff, sizeof(ctx->Color.ColorMask));
 919    ctx->Color.ClearIndex = 0;
 920    ASSIGN_4V( ctx->Color.ClearColor.f, 0, 0, 0, 0 );
 921    ctx->Color.AlphaEnabled = GL_FALSE;
 922    ctx->Color.AlphaFunc = GL_ALWAYS;
 923    ctx->Color.AlphaRef = 0;
 924    ctx->Color.BlendEnabled = 0x0;
 925    for (i = 0; i < ARRAY_SIZE(ctx->Color.Blend); i++) {
 926       ctx->Color.Blend[i].SrcRGB = GL_ONE;
 927       ctx->Color.Blend[i].DstRGB = GL_ZERO;
 928       ctx->Color.Blend[i].SrcA = GL_ONE;
 929       ctx->Color.Blend[i].DstA = GL_ZERO;
 930       ctx->Color.Blend[i].EquationRGB = GL_FUNC_ADD;
 931       ctx->Color.Blend[i].EquationA = GL_FUNC_ADD;
 932    }
 933    ASSIGN_4V( ctx->Color.BlendColor, 0.0, 0.0, 0.0, 0.0 );
 934    ASSIGN_4V( ctx->Color.BlendColorUnclamped, 0.0, 0.0, 0.0, 0.0 );
 935    ctx->Color.IndexLogicOpEnabled = GL_FALSE;
 936    ctx->Color.ColorLogicOpEnabled = GL_FALSE;
 937    ctx->Color.LogicOp = GL_COPY;
 938    ctx->Color.DitherFlag = GL_TRUE;
 939
 940    /* GL_FRONT is not possible on GLES. Instead GL_BACK will render to either
 941     * the front or the back buffer depending on the config */
 942    if (ctx->Visual.doubleBufferMode || _mesa_is_gles(ctx)) {
 943       ctx->Color.DrawBuffer[0] = GL_BACK;
 944    }
 945    else {
 946       ctx->Color.DrawBuffer[0] = GL_FRONT;
 947    }
 948
 949    ctx->Color.ClampFragmentColor = ctx->API == API_OPENGL_COMPAT ?
 950                                    GL_FIXED_ONLY_ARB : GL_FALSE;
 951    ctx->Color._ClampFragmentColor = GL_FALSE;
 952    ctx->Color.ClampReadColor = GL_FIXED_ONLY_ARB;
 953
 954    /* GLES 1/2/3 behaves as though GL_FRAMEBUFFER_SRGB is always enabled
 955     * if EGL_KHR_gl_colorspace has been used to request sRGB.
 956     */
 957    ctx->Color.sRGBEnabled = _mesa_is_gles(ctx);
 958 }
 959
 960 /*@}*/