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 ctx->API != API_OPENGLES
  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 (ctx->API != API_OPENGLES
 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 ctx->API != API_OPENGLES
 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 /**
 195  * Return the number of per-buffer blend states to update in
 196  * glBlendFunc, glBlendFuncSeparate, glBlendEquation, etc.
 197  */
 198 static inline unsigned
 199 num_buffers(const struct gl_context *ctx)
 200 {
 201    return ctx->Extensions.ARB_draw_buffers_blend
 202       ? ctx->Const.MaxDrawBuffers : 1;
 203 }
 204
 205
 206 /**
 207  * Set the separate blend source/dest factors for all draw buffers.
 208  *
 209  * \param sfactorRGB RGB source factor operator.
 210  * \param dfactorRGB RGB destination factor operator.
 211  * \param sfactorA alpha source factor operator.
 212  * \param dfactorA alpha destination factor operator.
 213  */
 214 void GLAPIENTRY
 215 _mesa_BlendFuncSeparate( GLenum sfactorRGB, GLenum dfactorRGB,
 216                             GLenum sfactorA, GLenum dfactorA )
 217 {
 218    GET_CURRENT_CONTEXT(ctx);
 219    const unsigned numBuffers = num_buffers(ctx);
 220    unsigned buf;
 221    bool changed = false;
 222
 223    if (MESA_VERBOSE & VERBOSE_API)
 224       _mesa_debug(ctx, "glBlendFuncSeparate %s %s %s %s\n",
 225                   _mesa_enum_to_string(sfactorRGB),
 226                   _mesa_enum_to_string(dfactorRGB),
 227                   _mesa_enum_to_string(sfactorA),
 228                   _mesa_enum_to_string(dfactorA));
 229
 230    /* Check if we're really changing any state.  If not, return early. */
 231    if (ctx->Color._BlendFuncPerBuffer) {
 232       /* Check all per-buffer states */
 233       for (buf = 0; buf < numBuffers; buf++) {
 234          if (ctx->Color.Blend[buf].SrcRGB != sfactorRGB ||
 235              ctx->Color.Blend[buf].DstRGB != dfactorRGB ||
 236              ctx->Color.Blend[buf].SrcA != sfactorA ||
 237              ctx->Color.Blend[buf].DstA != dfactorA) {
 238             changed = true;
 239             break;
 240          }
 241       }
 242    }
 243    else {
 244       /* only need to check 0th per-buffer state */
 245       if (ctx->Color.Blend[0].SrcRGB != sfactorRGB ||
 246           ctx->Color.Blend[0].DstRGB != dfactorRGB ||
 247           ctx->Color.Blend[0].SrcA != sfactorA ||
 248           ctx->Color.Blend[0].DstA != dfactorA) {
 249          changed = true;
 250       }
 251    }
 252
 253    if (!changed)
 254       return;
 255
 256    if (!validate_blend_factors(ctx, "glBlendFuncSeparate",
 257                                sfactorRGB, dfactorRGB,
 258                                sfactorA, dfactorA)) {
 259       return;
 260    }
 261
 262    FLUSH_VERTICES(ctx, _NEW_COLOR);
 263
 264    for (buf = 0; buf < numBuffers; buf++) {
 265       ctx->Color.Blend[buf].SrcRGB = sfactorRGB;
 266       ctx->Color.Blend[buf].DstRGB = dfactorRGB;
 267       ctx->Color.Blend[buf].SrcA = sfactorA;
 268       ctx->Color.Blend[buf].DstA = dfactorA;
 269    }
 270
 271    update_uses_dual_src(ctx, 0);
 272    for (buf = 1; buf < numBuffers; buf++) {
 273       ctx->Color.Blend[buf]._UsesDualSrc = ctx->Color.Blend[0]._UsesDualSrc;
 274    }
 275
 276    ctx->Color._BlendFuncPerBuffer = GL_FALSE;
 277
 278    if (ctx->Driver.BlendFuncSeparate) {
 279       ctx->Driver.BlendFuncSeparate(ctx, sfactorRGB, dfactorRGB,
 280                                     sfactorA, dfactorA);
 281    }
 282 }
 283
 284
 285 /**
 286  * Set blend source/dest factors for one color buffer/target.
 287  */
 288 void GLAPIENTRY
 289 _mesa_BlendFunciARB(GLuint buf, GLenum sfactor, GLenum dfactor)
 290 {
 291    _mesa_BlendFuncSeparateiARB(buf, sfactor, dfactor, sfactor, dfactor);
 292 }
 293
 294
 295 /**
 296  * Set separate blend source/dest factors for one color buffer/target.
 297  */
 298 void GLAPIENTRY
 299 _mesa_BlendFuncSeparateiARB(GLuint buf, GLenum sfactorRGB, GLenum dfactorRGB,
 300                          GLenum sfactorA, GLenum dfactorA)
 301 {
 302    GET_CURRENT_CONTEXT(ctx);
 303
 304    if (!ctx->Extensions.ARB_draw_buffers_blend) {
 305       _mesa_error(ctx, GL_INVALID_OPERATION, "glBlendFunc[Separate]i()");
 306       return;
 307    }
 308
 309    if (buf >= ctx->Const.MaxDrawBuffers) {
 310       _mesa_error(ctx, GL_INVALID_VALUE, "glBlendFuncSeparatei(buffer=%u)",
 311                   buf);
 312       return;
 313    }
 314
 315    if (ctx->Color.Blend[buf].SrcRGB == sfactorRGB &&
 316        ctx->Color.Blend[buf].DstRGB == dfactorRGB &&
 317        ctx->Color.Blend[buf].SrcA == sfactorA &&
 318        ctx->Color.Blend[buf].DstA == dfactorA)
 319       return; /* no change */
 320
 321    if (!validate_blend_factors(ctx, "glBlendFuncSeparatei",
 322                                sfactorRGB, dfactorRGB,
 323                                sfactorA, dfactorA)) {
 324       return;
 325    }
 326
 327    FLUSH_VERTICES(ctx, _NEW_COLOR);
 328
 329    ctx->Color.Blend[buf].SrcRGB = sfactorRGB;
 330    ctx->Color.Blend[buf].DstRGB = dfactorRGB;
 331    ctx->Color.Blend[buf].SrcA = sfactorA;
 332    ctx->Color.Blend[buf].DstA = dfactorA;
 333    update_uses_dual_src(ctx, buf);
 334    ctx->Color._BlendFuncPerBuffer = GL_TRUE;
 335 }
 336
 337
 338 /**
 339  * Return true if \p mode is a legal blending equation, excluding
 340  * GL_KHR_blend_equation_advanced modes.
 341  */
 342 static bool
 343 legal_simple_blend_equation(const struct gl_context *ctx, GLenum mode)
 344 {
 345    switch (mode) {
 346    case GL_FUNC_ADD:
 347    case GL_FUNC_SUBTRACT:
 348    case GL_FUNC_REVERSE_SUBTRACT:
 349       return GL_TRUE;
 350    case GL_MIN:
 351    case GL_MAX:
 352       return ctx->Extensions.EXT_blend_minmax;
 353    default:
 354       return GL_FALSE;
 355    }
 356 }
 357
 358 static enum gl_advanced_blend_mode
 359 advanced_blend_mode_from_gl_enum(GLenum mode)
 360 {
 361    switch (mode) {
 362    case GL_MULTIPLY_KHR:
 363       return BLEND_MULTIPLY;
 364    case GL_SCREEN_KHR:
 365       return BLEND_SCREEN;
 366    case GL_OVERLAY_KHR:
 367       return BLEND_OVERLAY;
 368    case GL_DARKEN_KHR:
 369       return BLEND_DARKEN;
 370    case GL_LIGHTEN_KHR:
 371       return BLEND_LIGHTEN;
 372    case GL_COLORDODGE_KHR:
 373       return BLEND_COLORDODGE;
 374    case GL_COLORBURN_KHR:
 375       return BLEND_COLORBURN;
 376    case GL_HARDLIGHT_KHR:
 377       return BLEND_HARDLIGHT;
 378    case GL_SOFTLIGHT_KHR:
 379       return BLEND_SOFTLIGHT;
 380    case GL_DIFFERENCE_KHR:
 381       return BLEND_DIFFERENCE;
 382    case GL_EXCLUSION_KHR:
 383       return BLEND_EXCLUSION;
 384    case GL_HSL_HUE_KHR:
 385       return BLEND_HSL_HUE;
 386    case GL_HSL_SATURATION_KHR:
 387       return BLEND_HSL_SATURATION;
 388    case GL_HSL_COLOR_KHR:
 389       return BLEND_HSL_COLOR;
 390    case GL_HSL_LUMINOSITY_KHR:
 391       return BLEND_HSL_LUMINOSITY;
 392    default:
 393       return BLEND_NONE;
 394    }
 395 }
 396
 397 /**
 398  * If \p mode is one of the advanced blending equations defined by
 399  * GL_KHR_blend_equation_advanced (and the extension is supported),
 400  * return the corresponding BLEND_* enum.  Otherwise, return BLEND_NONE
 401  * (which can also be treated as false).
 402  */
 403 static enum gl_advanced_blend_mode
 404 advanced_blend_mode(const struct gl_context *ctx, GLenum mode)
 405 {
 406    return _mesa_has_KHR_blend_equation_advanced(ctx) ?
 407           advanced_blend_mode_from_gl_enum(mode) : BLEND_NONE;
 408 }
 409
 410 /* This is really an extension function! */
 411 void GLAPIENTRY
 412 _mesa_BlendEquation( GLenum mode )
 413 {
 414    GET_CURRENT_CONTEXT(ctx);
 415    const unsigned numBuffers = num_buffers(ctx);
 416    unsigned buf;
 417    bool changed = false;
 418    enum gl_advanced_blend_mode advanced_mode = advanced_blend_mode(ctx, mode);
 419
 420    if (MESA_VERBOSE & VERBOSE_API)
 421       _mesa_debug(ctx, "glBlendEquation(%s)\n",
 422                   _mesa_enum_to_string(mode));
 423
 424    if (ctx->Color._BlendEquationPerBuffer) {
 425       /* Check all per-buffer states */
 426       for (buf = 0; buf < numBuffers; buf++) {
 427          if (ctx->Color.Blend[buf].EquationRGB != mode ||
 428              ctx->Color.Blend[buf].EquationA != mode) {
 429             changed = true;
 430             break;
 431          }
 432       }
 433    }
 434    else {
 435       /* only need to check 0th per-buffer state */
 436       if (ctx->Color.Blend[0].EquationRGB != mode ||
 437           ctx->Color.Blend[0].EquationA != mode) {
 438          changed = true;
 439       }
 440    }
 441
 442    if (!changed)
 443       return;
 444
 445
 446    if (!legal_simple_blend_equation(ctx, mode) && !advanced_mode) {
 447       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquation");
 448       return;
 449    }
 450
 451    FLUSH_VERTICES(ctx, _NEW_COLOR);
 452
 453    for (buf = 0; buf < numBuffers; buf++) {
 454       ctx->Color.Blend[buf].EquationRGB = mode;
 455       ctx->Color.Blend[buf].EquationA = mode;
 456    }
 457    ctx->Color._BlendEquationPerBuffer = GL_FALSE;
 458    ctx->Color._AdvancedBlendMode = advanced_mode;
 459
 460    if (ctx->Driver.BlendEquationSeparate)
 461       ctx->Driver.BlendEquationSeparate(ctx, mode, mode);
 462 }
 463
 464
 465 /**
 466  * Set blend equation for one color buffer/target.
 467  */
 468 void GLAPIENTRY
 469 _mesa_BlendEquationiARB(GLuint buf, GLenum mode)
 470 {
 471    GET_CURRENT_CONTEXT(ctx);
 472    enum gl_advanced_blend_mode advanced_mode = advanced_blend_mode(ctx, mode);
 473
 474    if (MESA_VERBOSE & VERBOSE_API)
 475       _mesa_debug(ctx, "glBlendEquationi(%u, %s)\n",
 476                   buf, _mesa_enum_to_string(mode));
 477
 478    if (buf >= ctx->Const.MaxDrawBuffers) {
 479       _mesa_error(ctx, GL_INVALID_VALUE, "glBlendEquationi(buffer=%u)",
 480                   buf);
 481       return;
 482    }
 483
 484    if (!legal_simple_blend_equation(ctx, mode) && !advanced_mode) {
 485       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationi");
 486       return;
 487    }
 488
 489    if (ctx->Color.Blend[buf].EquationRGB == mode &&
 490        ctx->Color.Blend[buf].EquationA == mode)
 491       return;  /* no change */
 492
 493    FLUSH_VERTICES(ctx, _NEW_COLOR);
 494    ctx->Color.Blend[buf].EquationRGB = mode;
 495    ctx->Color.Blend[buf].EquationA = mode;
 496    ctx->Color._BlendEquationPerBuffer = GL_TRUE;
 497
 498    if (buf == 0)
 499       ctx->Color._AdvancedBlendMode = advanced_mode;
 500 }
 501
 502
 503 void GLAPIENTRY
 504 _mesa_BlendEquationSeparate( GLenum modeRGB, GLenum modeA )
 505 {
 506    GET_CURRENT_CONTEXT(ctx);
 507    const unsigned numBuffers = num_buffers(ctx);
 508    unsigned buf;
 509    bool changed = false;
 510
 511    if (MESA_VERBOSE & VERBOSE_API)
 512       _mesa_debug(ctx, "glBlendEquationSeparateEXT(%s %s)\n",
 513                   _mesa_enum_to_string(modeRGB),
 514                   _mesa_enum_to_string(modeA));
 515
 516    if (ctx->Color._BlendEquationPerBuffer) {
 517       /* Check all per-buffer states */
 518       for (buf = 0; buf < numBuffers; buf++) {
 519          if (ctx->Color.Blend[buf].EquationRGB != modeRGB ||
 520              ctx->Color.Blend[buf].EquationA != modeA) {
 521             changed = true;
 522             break;
 523          }
 524       }
 525    }
 526    else {
 527       /* only need to check 0th per-buffer state */
 528       if (ctx->Color.Blend[0].EquationRGB != modeRGB ||
 529           ctx->Color.Blend[0].EquationA != modeA) {
 530          changed = true;
 531       }
 532    }
 533
 534    if (!changed)
 535       return;
 536
 537    if ( (modeRGB != modeA) && !ctx->Extensions.EXT_blend_equation_separate ) {
 538       _mesa_error(ctx, GL_INVALID_OPERATION,
 539                   "glBlendEquationSeparateEXT not supported by driver");
 540       return;
 541    }
 542
 543    /* Only allow simple blending equations.
 544     * The GL_KHR_blend_equation_advanced spec says:
 545     *
 546     *    "NOTE: These enums are not accepted by the <modeRGB> or <modeAlpha>
 547     *     parameters of BlendEquationSeparate or BlendEquationSeparatei."
 548     */
 549    if (!legal_simple_blend_equation(ctx, modeRGB)) {
 550       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeRGB)");
 551       return;
 552    }
 553
 554    if (!legal_simple_blend_equation(ctx, modeA)) {
 555       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparateEXT(modeA)");
 556       return;
 557    }
 558
 559    FLUSH_VERTICES(ctx, _NEW_COLOR);
 560
 561    for (buf = 0; buf < numBuffers; buf++) {
 562       ctx->Color.Blend[buf].EquationRGB = modeRGB;
 563       ctx->Color.Blend[buf].EquationA = modeA;
 564    }
 565    ctx->Color._BlendEquationPerBuffer = GL_FALSE;
 566    ctx->Color._AdvancedBlendMode = BLEND_NONE;
 567
 568    if (ctx->Driver.BlendEquationSeparate)
 569       ctx->Driver.BlendEquationSeparate(ctx, modeRGB, modeA);
 570 }
 571
 572
 573 /**
 574  * Set separate blend equations for one color buffer/target.
 575  */
 576 void GLAPIENTRY
 577 _mesa_BlendEquationSeparateiARB(GLuint buf, GLenum modeRGB, GLenum modeA)
 578 {
 579    GET_CURRENT_CONTEXT(ctx);
 580
 581    if (MESA_VERBOSE & VERBOSE_API)
 582       _mesa_debug(ctx, "glBlendEquationSeparatei(%u, %s %s)\n", buf,
 583                   _mesa_enum_to_string(modeRGB),
 584                   _mesa_enum_to_string(modeA));
 585
 586    if (buf >= ctx->Const.MaxDrawBuffers) {
 587       _mesa_error(ctx, GL_INVALID_VALUE, "glBlendEquationSeparatei(buffer=%u)",
 588                   buf);
 589       return;
 590    }
 591
 592    /* Only allow simple blending equations.
 593     * The GL_KHR_blend_equation_advanced spec says:
 594     *
 595     *    "NOTE: These enums are not accepted by the <modeRGB> or <modeAlpha>
 596     *     parameters of BlendEquationSeparate or BlendEquationSeparatei."
 597     */
 598    if (!legal_simple_blend_equation(ctx, modeRGB)) {
 599       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparatei(modeRGB)");
 600       return;
 601    }
 602
 603    if (!legal_simple_blend_equation(ctx, modeA)) {
 604       _mesa_error(ctx, GL_INVALID_ENUM, "glBlendEquationSeparatei(modeA)");
 605       return;
 606    }
 607
 608    if (ctx->Color.Blend[buf].EquationRGB == modeRGB &&
 609        ctx->Color.Blend[buf].EquationA == modeA)
 610       return;  /* no change */
 611
 612    FLUSH_VERTICES(ctx, _NEW_COLOR);
 613    ctx->Color.Blend[buf].EquationRGB = modeRGB;
 614    ctx->Color.Blend[buf].EquationA = modeA;
 615    ctx->Color._BlendEquationPerBuffer = GL_TRUE;
 616    ctx->Color._AdvancedBlendMode = BLEND_NONE;
 617 }
 618
 619
 620 /**
 621  * Set the blending color.
 622  *
 623  * \param red red color component.
 624  * \param green green color component.
 625  * \param blue blue color component.
 626  * \param alpha alpha color component.
 627  *
 628  * \sa glBlendColor().
 629  *
 630  * Clamps the parameters and updates gl_colorbuffer_attrib::BlendColor.  On a
 631  * change, flushes the vertices and notifies the driver via
 632  * dd_function_table::BlendColor callback.
 633  */
 634 void GLAPIENTRY
 635 _mesa_BlendColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
 636 {
 637    GLfloat tmp[4];
 638    GET_CURRENT_CONTEXT(ctx);
 639
 640    tmp[0] = red;
 641    tmp[1] = green;
 642    tmp[2] = blue;
 643    tmp[3] = alpha;
 644
 645    if (TEST_EQ_4V(tmp, ctx->Color.BlendColorUnclamped))
 646       return;
 647
 648    FLUSH_VERTICES(ctx, _NEW_COLOR);
 649    COPY_4FV( ctx->Color.BlendColorUnclamped, tmp );
 650
 651    ctx->Color.BlendColor[0] = CLAMP(tmp[0], 0.0F, 1.0F);
 652    ctx->Color.BlendColor[1] = CLAMP(tmp[1], 0.0F, 1.0F);
 653    ctx->Color.BlendColor[2] = CLAMP(tmp[2], 0.0F, 1.0F);
 654    ctx->Color.BlendColor[3] = CLAMP(tmp[3], 0.0F, 1.0F);
 655
 656    if (ctx->Driver.BlendColor)
 657       ctx->Driver.BlendColor(ctx, ctx->Color.BlendColor);
 658 }
 659
 660
 661 /**
 662  * Specify the alpha test function.
 663  *
 664  * \param func alpha comparison function.
 665  * \param ref reference value.
 666  *
 667  * Verifies the parameters and updates gl_colorbuffer_attrib.
 668  * On a change, flushes the vertices and notifies the driver via
 669  * dd_function_table::AlphaFunc callback.
 670  */
 671 void GLAPIENTRY
 672 _mesa_AlphaFunc( GLenum func, GLclampf ref )
 673 {
 674    GET_CURRENT_CONTEXT(ctx);
 675
 676    if (MESA_VERBOSE & VERBOSE_API)
 677       _mesa_debug(ctx, "glAlphaFunc(%s, %f)\n",
 678                   _mesa_enum_to_string(func), ref);
 679
 680    if (ctx->Color.AlphaFunc == func && ctx->Color.AlphaRefUnclamped == ref)
 681       return; /* no change */
 682
 683    switch (func) {
 684    case GL_NEVER:
 685    case GL_LESS:
 686    case GL_EQUAL:
 687    case GL_LEQUAL:
 688    case GL_GREATER:
 689    case GL_NOTEQUAL:
 690    case GL_GEQUAL:
 691    case GL_ALWAYS:
 692       FLUSH_VERTICES(ctx, _NEW_COLOR);
 693       ctx->Color.AlphaFunc = func;
 694       ctx->Color.AlphaRefUnclamped = ref;
 695       ctx->Color.AlphaRef = CLAMP(ref, 0.0F, 1.0F);
 696
 697       if (ctx->Driver.AlphaFunc)
 698          ctx->Driver.AlphaFunc(ctx, func, ctx->Color.AlphaRef);
 699       return;
 700
 701    default:
 702       _mesa_error( ctx, GL_INVALID_ENUM, "glAlphaFunc(func)" );
 703       return;
 704    }
 705 }
 706
 707
 708 /**
 709  * Specify a logic pixel operation for color index rendering.
 710  *
 711  * \param opcode operation.
 712  *
 713  * Verifies that \p opcode is a valid enum and updates
 714  * gl_colorbuffer_attrib::LogicOp.
 715  * On a change, flushes the vertices and notifies the driver via the
 716  * dd_function_table::LogicOpcode callback.
 717  */
 718 void GLAPIENTRY
 719 _mesa_LogicOp( GLenum opcode )
 720 {
 721    GET_CURRENT_CONTEXT(ctx);
 722
 723    if (MESA_VERBOSE & VERBOSE_API)
 724       _mesa_debug(ctx, "glLogicOp(%s)\n", _mesa_enum_to_string(opcode));
 725
 726    switch (opcode) {
 727       case GL_CLEAR:
 728       case GL_SET:
 729       case GL_COPY:
 730       case GL_COPY_INVERTED:
 731       case GL_NOOP:
 732       case GL_INVERT:
 733       case GL_AND:
 734       case GL_NAND:
 735       case GL_OR:
 736       case GL_NOR:
 737       case GL_XOR:
 738       case GL_EQUIV:
 739       case GL_AND_REVERSE:
 740       case GL_AND_INVERTED:
 741       case GL_OR_REVERSE:
 742       case GL_OR_INVERTED:
 743          break;
 744       default:
 745          _mesa_error( ctx, GL_INVALID_ENUM, "glLogicOp" );
 746          return;
 747    }
 748
 749    if (ctx->Color.LogicOp == opcode)
 750       return;
 751
 752    FLUSH_VERTICES(ctx, _NEW_COLOR);
 753    ctx->Color.LogicOp = opcode;
 754
 755    if (ctx->Driver.LogicOpcode)
 756       ctx->Driver.LogicOpcode( ctx, opcode );
 757 }
 758
 759
 760 void GLAPIENTRY
 761 _mesa_IndexMask( GLuint mask )
 762 {
 763    GET_CURRENT_CONTEXT(ctx);
 764
 765    if (ctx->Color.IndexMask == mask)
 766       return;
 767
 768    FLUSH_VERTICES(ctx, _NEW_COLOR);
 769    ctx->Color.IndexMask = mask;
 770 }
 771
 772
 773 /**
 774  * Enable or disable writing of frame buffer color components.
 775  *
 776  * \param red whether to mask writing of the red color component.
 777  * \param green whether to mask writing of the green color component.
 778  * \param blue whether to mask writing of the blue color component.
 779  * \param alpha whether to mask writing of the alpha color component.
 780  *
 781  * \sa glColorMask().
 782  *
 783  * Sets the appropriate value of gl_colorbuffer_attrib::ColorMask.  On a
 784  * change, flushes the vertices and notifies the driver via the
 785  * dd_function_table::ColorMask callback.
 786  */
 787 void GLAPIENTRY
 788 _mesa_ColorMask( GLboolean red, GLboolean green,
 789                  GLboolean blue, GLboolean alpha )
 790 {
 791    GET_CURRENT_CONTEXT(ctx);
 792    GLubyte tmp[4];
 793    GLuint i;
 794    GLboolean flushed;
 795
 796    if (MESA_VERBOSE & VERBOSE_API)
 797       _mesa_debug(ctx, "glColorMask(%d, %d, %d, %d)\n",
 798                   red, green, blue, alpha);
 799
 800    /* Shouldn't have any information about channel depth in core mesa
 801     * -- should probably store these as the native booleans:
 802     */
 803    tmp[RCOMP] = red    ? 0xff : 0x0;
 804    tmp[GCOMP] = green  ? 0xff : 0x0;
 805    tmp[BCOMP] = blue   ? 0xff : 0x0;
 806    tmp[ACOMP] = alpha  ? 0xff : 0x0;
 807
 808    flushed = GL_FALSE;
 809    for (i = 0; i < ctx->Const.MaxDrawBuffers; i++) {
 810       if (!TEST_EQ_4V(tmp, ctx->Color.ColorMask[i])) {
 811          if (!flushed) {
 812             FLUSH_VERTICES(ctx, _NEW_COLOR);
 813          }
 814          flushed = GL_TRUE;
 815          COPY_4UBV(ctx->Color.ColorMask[i], tmp);
 816       }
 817    }
 818
 819    if (ctx->Driver.ColorMask)
 820       ctx->Driver.ColorMask( ctx, red, green, blue, alpha );
 821 }
 822
 823
 824 /**
 825  * For GL_EXT_draw_buffers2 and GL3
 826  */
 827 void GLAPIENTRY
 828 _mesa_ColorMaski( GLuint buf, GLboolean red, GLboolean green,
 829                         GLboolean blue, GLboolean alpha )
 830 {
 831    GLubyte tmp[4];
 832    GET_CURRENT_CONTEXT(ctx);
 833
 834    if (MESA_VERBOSE & VERBOSE_API)
 835       _mesa_debug(ctx, "glColorMaskIndexed %u %d %d %d %d\n",
 836                   buf, red, green, blue, alpha);
 837
 838    if (buf >= ctx->Const.MaxDrawBuffers) {
 839       _mesa_error(ctx, GL_INVALID_VALUE, "glColorMaskIndexed(buf=%u)", buf);
 840       return;
 841    }
 842
 843    /* Shouldn't have any information about channel depth in core mesa
 844     * -- should probably store these as the native booleans:
 845     */
 846    tmp[RCOMP] = red    ? 0xff : 0x0;
 847    tmp[GCOMP] = green  ? 0xff : 0x0;
 848    tmp[BCOMP] = blue   ? 0xff : 0x0;
 849    tmp[ACOMP] = alpha  ? 0xff : 0x0;
 850
 851    if (TEST_EQ_4V(tmp, ctx->Color.ColorMask[buf]))
 852       return;
 853
 854    FLUSH_VERTICES(ctx, _NEW_COLOR);
 855    COPY_4UBV(ctx->Color.ColorMask[buf], tmp);
 856 }
 857
 858
 859 void GLAPIENTRY
 860 _mesa_ClampColor(GLenum target, GLenum clamp)
 861 {
 862    GET_CURRENT_CONTEXT(ctx);
 863
 864    if (clamp != GL_TRUE && clamp != GL_FALSE && clamp != GL_FIXED_ONLY_ARB) {
 865       _mesa_error(ctx, GL_INVALID_ENUM, "glClampColorARB(clamp)");
 866       return;
 867    }
 868
 869    switch (target) {
 870    case GL_CLAMP_VERTEX_COLOR_ARB:
 871       if (ctx->API == API_OPENGL_CORE &&
 872           !ctx->Extensions.ARB_color_buffer_float) {
 873          goto invalid_enum;
 874       }
 875       FLUSH_VERTICES(ctx, _NEW_LIGHT);
 876       ctx->Light.ClampVertexColor = clamp;
 877       _mesa_update_clamp_vertex_color(ctx, ctx->DrawBuffer);
 878       break;
 879    case GL_CLAMP_FRAGMENT_COLOR_ARB:
 880       if (ctx->API == API_OPENGL_CORE &&
 881           !ctx->Extensions.ARB_color_buffer_float) {
 882          goto invalid_enum;
 883       }
 884       FLUSH_VERTICES(ctx, _NEW_FRAG_CLAMP);
 885       ctx->Color.ClampFragmentColor = clamp;
 886       _mesa_update_clamp_fragment_color(ctx, ctx->DrawBuffer);
 887       break;
 888    case GL_CLAMP_READ_COLOR_ARB:
 889       ctx->Color.ClampReadColor = clamp;
 890       break;
 891    default:
 892       goto invalid_enum;
 893    }
 894    return;
 895
 896 invalid_enum:
 897    _mesa_error(ctx, GL_INVALID_ENUM, "glClampColor(%s)",
 898                _mesa_enum_to_string(target));
 899 }
 900
 901 static GLboolean
 902 get_clamp_color(const struct gl_framebuffer *fb, GLenum clamp)
 903 {
 904    if (clamp == GL_TRUE || clamp == GL_FALSE)
 905       return clamp;
 906
 907    assert(clamp == GL_FIXED_ONLY);
 908    if (!fb)
 909       return GL_TRUE;
 910
 911    return fb->_AllColorBuffersFixedPoint;
 912 }
 913
 914 GLboolean
 915 _mesa_get_clamp_fragment_color(const struct gl_context *ctx,
 916                                const struct gl_framebuffer *drawFb)
 917 {
 918    return get_clamp_color(drawFb, ctx->Color.ClampFragmentColor);
 919 }
 920
 921 GLboolean
 922 _mesa_get_clamp_vertex_color(const struct gl_context *ctx,
 923                              const struct gl_framebuffer *drawFb)
 924 {
 925    return get_clamp_color(drawFb, ctx->Light.ClampVertexColor);
 926 }
 927
 928 GLboolean
 929 _mesa_get_clamp_read_color(const struct gl_context *ctx,
 930                            const struct gl_framebuffer *readFb)
 931 {
 932    return get_clamp_color(readFb, ctx->Color.ClampReadColor);
 933 }
 934
 935 /**
 936  * Update the ctx->Color._ClampFragmentColor field
 937  */
 938 void
 939 _mesa_update_clamp_fragment_color(struct gl_context *ctx,
 940                                   const struct gl_framebuffer *drawFb)
 941 {
 942    /* Don't clamp if:
 943     * - there is no colorbuffer
 944     * - all colorbuffers are unsigned normalized, so clamping has no effect
 945     * - there is an integer colorbuffer
 946     */
 947    if (!drawFb || !drawFb->_HasSNormOrFloatColorBuffer ||
 948        drawFb->_IntegerBuffers)
 949       ctx->Color._ClampFragmentColor = GL_FALSE;
 950    else
 951       ctx->Color._ClampFragmentColor =
 952          _mesa_get_clamp_fragment_color(ctx, drawFb);
 953 }
 954
 955 /**
 956  * Update the ctx->Color._ClampVertexColor field
 957  */
 958 void
 959 _mesa_update_clamp_vertex_color(struct gl_context *ctx,
 960                                 const struct gl_framebuffer *drawFb)
 961 {
 962    ctx->Light._ClampVertexColor =
 963          _mesa_get_clamp_vertex_color(ctx, drawFb);
 964 }
 965
 966 /**
 967  * Returns an appropriate mesa_format for color rendering based on the
 968  * GL_FRAMEBUFFER_SRGB state.
 969  *
 970  * Some drivers implement GL_FRAMEBUFFER_SRGB using a flag on the blend state
 971  * (which GL_FRAMEBUFFER_SRGB maps to reasonably), but some have to do so by
 972  * overriding the format of the surface.  This is a helper for doing the
 973  * surface format override variant.
 974  */
 975 mesa_format
 976 _mesa_get_render_format(const struct gl_context *ctx, mesa_format format)
 977 {
 978    if (ctx->Color.sRGBEnabled)
 979       return format;
 980    else
 981       return _mesa_get_srgb_format_linear(format);
 982 }
 983
 984 /**********************************************************************/
 985 /** \name Initialization */
 986 /*@{*/
 987
 988 /**
 989  * Initialization of the context's Color attribute group.
 990  *
 991  * \param ctx GL context.
 992  *
 993  * Initializes the related fields in the context color attribute group,
 994  * __struct gl_contextRec::Color.
 995  */
 996 void _mesa_init_color( struct gl_context * ctx )
 997 {
 998    GLuint i;
 999
1000    /* Color buffer group */
1001    ctx->Color.IndexMask = ~0u;
1002    memset(ctx->Color.ColorMask, 0xff, sizeof(ctx->Color.ColorMask));
1003    ctx->Color.ClearIndex = 0;
1004    ASSIGN_4V( ctx->Color.ClearColor.f, 0, 0, 0, 0 );
1005    ctx->Color.AlphaEnabled = GL_FALSE;
1006    ctx->Color.AlphaFunc = GL_ALWAYS;
1007    ctx->Color.AlphaRef = 0;
1008    ctx->Color.BlendEnabled = 0x0;
1009    for (i = 0; i < ARRAY_SIZE(ctx->Color.Blend); i++) {
1010       ctx->Color.Blend[i].SrcRGB = GL_ONE;
1011       ctx->Color.Blend[i].DstRGB = GL_ZERO;
1012       ctx->Color.Blend[i].SrcA = GL_ONE;
1013       ctx->Color.Blend[i].DstA = GL_ZERO;
1014       ctx->Color.Blend[i].EquationRGB = GL_FUNC_ADD;
1015       ctx->Color.Blend[i].EquationA = GL_FUNC_ADD;
1016    }
1017    ASSIGN_4V( ctx->Color.BlendColor, 0.0, 0.0, 0.0, 0.0 );
1018    ASSIGN_4V( ctx->Color.BlendColorUnclamped, 0.0, 0.0, 0.0, 0.0 );
1019    ctx->Color.IndexLogicOpEnabled = GL_FALSE;
1020    ctx->Color.ColorLogicOpEnabled = GL_FALSE;
1021    ctx->Color.LogicOp = GL_COPY;
1022    ctx->Color.DitherFlag = GL_TRUE;
1023
1024    /* GL_FRONT is not possible on GLES. Instead GL_BACK will render to either
1025     * the front or the back buffer depending on the config */
1026    if (ctx->Visual.doubleBufferMode || _mesa_is_gles(ctx)) {
1027       ctx->Color.DrawBuffer[0] = GL_BACK;
1028    }
1029    else {
1030       ctx->Color.DrawBuffer[0] = GL_FRONT;
1031    }
1032
1033    ctx->Color.ClampFragmentColor = ctx->API == API_OPENGL_COMPAT ?
1034                                    GL_FIXED_ONLY_ARB : GL_FALSE;
1035    ctx->Color._ClampFragmentColor = GL_FALSE;
1036    ctx->Color.ClampReadColor = GL_FIXED_ONLY_ARB;
1037
1038    /* GLES 1/2/3 behaves as though GL_FRAMEBUFFER_SRGB is always enabled
1039     * if EGL_KHR_gl_colorspace has been used to request sRGB.
1040     */
1041    ctx->Color.sRGBEnabled = _mesa_is_gles(ctx);
1042
1043    ctx->Color.BlendCoherent = true;
1044 }
1045
1046 /*@}*/