src/mesa/main/stencil.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   4  *
   5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /**
  27  * \file stencil.c
  28  * Stencil operations.
  29  *
  30  * Note: There's an incompatibility between GL_EXT_stencil_two_side and
  31  * OpenGL 2.0's two-sided stencil feature.
  32  *
  33  * With GL_EXT_stencil_two_side, calling glStencilOp/Func/Mask() only the
  34  * front OR back face state (as set by glActiveStencilFaceEXT) is set.
  35  *
  36  * But with OpenGL 2.0, calling glStencilOp/Func/Mask() sets BOTH the
  37  * front AND back state.
  38  *
  39  * So either we advertise the GL_EXT_stencil_two_side extension, or OpenGL
  40  * 2.0, but not both.
  41  *
  42  * Also, note that GL_ATI_separate_stencil is different as well:
  43  * glStencilFuncSeparateATI(GLenum frontfunc, GLenum backfunc, ...)  vs.
  44  * glStencilFuncSeparate(GLenum face, GLenum func, ...).
  45  */
  46
  47
  48 #include "glheader.h"
  49 #include "imports.h"
  50 #include "context.h"
  51 #include "macros.h"
  52 #include "stencil.h"
  53 #include "mtypes.h"
  54
  55
  56 static GLboolean
  57 validate_stencil_op(GLcontext *ctx, GLenum op)
  58 {
  59    switch (op) {
  60    case GL_KEEP:
  61    case GL_ZERO:
  62    case GL_REPLACE:
  63    case GL_INCR:
  64    case GL_DECR:
  65    case GL_INVERT:
  66       return GL_TRUE;
  67    case GL_INCR_WRAP_EXT:
  68    case GL_DECR_WRAP_EXT:
  69       if (ctx->Extensions.EXT_stencil_wrap) {
  70          return GL_TRUE;
  71       }
  72       /* FALL-THROUGH */
  73    default:
  74       return GL_FALSE;
  75    }
  76 }
  77
  78
  79 static GLboolean
  80 validate_stencil_func(GLcontext *ctx, GLenum func)
  81 {
  82    switch (func) {
  83    case GL_NEVER:
  84    case GL_LESS:
  85    case GL_LEQUAL:
  86    case GL_GREATER:
  87    case GL_GEQUAL:
  88    case GL_EQUAL:
  89    case GL_NOTEQUAL:
  90    case GL_ALWAYS:
  91       return GL_TRUE;
  92    default:
  93       return GL_FALSE;
  94    }
  95 }
  96
  97
  98 /**
  99  * Set the clear value for the stencil buffer.
 100  *
 101  * \param s clear value.
 102  *
 103  * \sa glClearStencil().
 104  *
 105  * Updates gl_stencil_attrib::Clear. On change
 106  * flushes the vertices and notifies the driver via
 107  * the dd_function_table::ClearStencil callback.
 108  */
 109 void GLAPIENTRY
 110 _mesa_ClearStencil( GLint s )
 111 {
 112    GET_CURRENT_CONTEXT(ctx);
 113    ASSERT_OUTSIDE_BEGIN_END(ctx);
 114
 115    if (ctx->Stencil.Clear == (GLuint) s)
 116       return;
 117
 118    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 119    ctx->Stencil.Clear = (GLuint) s;
 120
 121    if (ctx->Driver.ClearStencil) {
 122       ctx->Driver.ClearStencil( ctx, s );
 123    }
 124 }
 125
 126
 127 /**
 128  * Set the function and reference value for stencil testing.
 129  *
 130  * \param frontfunc front test function.
 131  * \param backfunc back test function.
 132  * \param ref front and back reference value.
 133  * \param mask front and back bitmask.
 134  *
 135  * \sa glStencilFunc().
 136  *
 137  * Verifies the parameters and updates the respective values in
 138  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 139  * driver via the dd_function_table::StencilFunc callback.
 140  */
 141 void GLAPIENTRY
 142 _mesa_StencilFuncSeparateATI( GLenum frontfunc, GLenum backfunc, GLint ref, GLuint mask )
 143 {
 144    GET_CURRENT_CONTEXT(ctx);
 145    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 146    ASSERT_OUTSIDE_BEGIN_END(ctx);
 147
 148    if (!validate_stencil_func(ctx, frontfunc)) {
 149       _mesa_error(ctx, GL_INVALID_ENUM,
 150                   "glStencilFuncSeparateATI(frontfunc)");
 151       return;
 152    }
 153    if (!validate_stencil_func(ctx, backfunc)) {
 154       _mesa_error(ctx, GL_INVALID_ENUM,
 155                   "glStencilFuncSeparateATI(backfunc)");
 156       return;
 157    }
 158
 159    ref = CLAMP( ref, 0, stencilMax );
 160
 161    /* set both front and back state */
 162    if (ctx->Stencil.Function[0] == frontfunc &&
 163        ctx->Stencil.Function[1] == backfunc &&
 164        ctx->Stencil.ValueMask[0] == mask &&
 165        ctx->Stencil.ValueMask[1] == mask &&
 166        ctx->Stencil.Ref[0] == ref &&
 167        ctx->Stencil.Ref[1] == ref)
 168       return;
 169    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 170    ctx->Stencil.Function[0]  = frontfunc;
 171    ctx->Stencil.Function[1]  = backfunc;
 172    ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 173    ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 174    if (ctx->Driver.StencilFuncSeparate) {
 175       ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT,
 176                                       frontfunc, ref, mask);
 177       ctx->Driver.StencilFuncSeparate(ctx, GL_BACK,
 178                                       backfunc, ref, mask);
 179    }
 180 }
 181
 182
 183 void APIENTRY
 184 _mesa_StencilOpSeparateATI(GLenum face, GLenum sfail, GLenum zfail, GLenum zpass)
 185 {
 186    GLboolean set = GL_FALSE;
 187    GET_CURRENT_CONTEXT(ctx);
 188    ASSERT_OUTSIDE_BEGIN_END(ctx);
 189
 190    if (!validate_stencil_op(ctx, sfail)) {
 191       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparateATI(sfail)");
 192       return;
 193    }
 194    if (!validate_stencil_op(ctx, zfail)) {
 195       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparateATI(zfail)");
 196       return;
 197    }
 198    if (!validate_stencil_op(ctx, zpass)) {
 199       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparateATI(zpass)");
 200       return;
 201    }
 202    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 203       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparateATI(face)");
 204       return;
 205    }
 206
 207    if (face != GL_BACK) {
 208       /* set front */
 209       if (ctx->Stencil.ZFailFunc[0] != zfail ||
 210           ctx->Stencil.ZPassFunc[0] != zpass ||
 211           ctx->Stencil.FailFunc[0] != sfail){
 212          FLUSH_VERTICES(ctx, _NEW_STENCIL);
 213          ctx->Stencil.ZFailFunc[0] = zfail;
 214          ctx->Stencil.ZPassFunc[0] = zpass;
 215          ctx->Stencil.FailFunc[0] = sfail;
 216          set = GL_TRUE;
 217       }
 218    }
 219    if (face != GL_FRONT) {
 220       /* set back */
 221       if (ctx->Stencil.ZFailFunc[1] != zfail ||
 222           ctx->Stencil.ZPassFunc[1] != zpass ||
 223           ctx->Stencil.FailFunc[1] != sfail) {
 224          FLUSH_VERTICES(ctx, _NEW_STENCIL);
 225          ctx->Stencil.ZFailFunc[1] = zfail;
 226          ctx->Stencil.ZPassFunc[1] = zpass;
 227          ctx->Stencil.FailFunc[1] = sfail;
 228          set = GL_TRUE;
 229       }
 230    }
 231    if (set && ctx->Driver.StencilOpSeparate) {
 232       ctx->Driver.StencilOpSeparate(ctx, face, sfail, zfail, zpass);
 233    }
 234 }
 235
 236
 237
 238 /**
 239  * Set the function and reference value for stencil testing.
 240  *
 241  * \param func test function.
 242  * \param ref reference value.
 243  * \param mask bitmask.
 244  *
 245  * \sa glStencilFunc().
 246  *
 247  * Verifies the parameters and updates the respective values in
 248  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 249  * driver via the dd_function_table::StencilFunc callback.
 250  */
 251 void GLAPIENTRY
 252 _mesa_StencilFunc( GLenum func, GLint ref, GLuint mask )
 253 {
 254    GET_CURRENT_CONTEXT(ctx);
 255    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 256    ASSERT_OUTSIDE_BEGIN_END(ctx);
 257
 258    if (!validate_stencil_func(ctx, func)) {
 259       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFunc(func)");
 260       return;
 261    }
 262
 263    ref = CLAMP( ref, 0, stencilMax );
 264
 265    if (ctx->Extensions.ATI_separate_stencil) {
 266       /* set both front and back state */
 267       if (ctx->Stencil.Function[0] == func &&
 268           ctx->Stencil.Function[1] == func &&
 269           ctx->Stencil.ValueMask[0] == mask &&
 270           ctx->Stencil.ValueMask[1] == mask &&
 271           ctx->Stencil.Ref[0] == ref &&
 272           ctx->Stencil.Ref[1] == ref)
 273          return;
 274       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 275       ctx->Stencil.Function[0]  = ctx->Stencil.Function[1]  = func;
 276       ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 277       ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 278       if (ctx->Driver.StencilFuncSeparate) {
 279          ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT_AND_BACK,
 280                                          func, ref, mask);
 281       }
 282    }
 283    else {
 284       /* only set active face state */
 285       const GLint face = ctx->Stencil.ActiveFace;
 286       if (ctx->Stencil.Function[face] == func &&
 287           ctx->Stencil.ValueMask[face] == mask &&
 288           ctx->Stencil.Ref[face] == ref)
 289          return;
 290       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 291       ctx->Stencil.Function[face] = func;
 292       ctx->Stencil.Ref[face] = ref;
 293       ctx->Stencil.ValueMask[face] = mask;
 294       if (ctx->Driver.StencilFuncSeparate) {
 295          ctx->Driver.StencilFuncSeparate(ctx, face ? GL_BACK : GL_FRONT,
 296                                          func, ref, mask);
 297       }
 298    }
 299 }
 300
 301
 302 /**
 303  * Set the stencil writing mask.
 304  *
 305  * \param mask bit-mask to enable/disable writing of individual bits in the
 306  * stencil planes.
 307  *
 308  * \sa glStencilMask().
 309  *
 310  * Updates gl_stencil_attrib::WriteMask. On change flushes the vertices and
 311  * notifies the driver via the dd_function_table::StencilMask callback.
 312  */
 313 void GLAPIENTRY
 314 _mesa_StencilMask( GLuint mask )
 315 {
 316    GET_CURRENT_CONTEXT(ctx);
 317    ASSERT_OUTSIDE_BEGIN_END(ctx);
 318
 319    if (ctx->Extensions.ATI_separate_stencil) {
 320       /* set both front and back state */
 321       if (ctx->Stencil.WriteMask[0] == mask &&
 322           ctx->Stencil.WriteMask[1] == mask)
 323          return;
 324       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 325       ctx->Stencil.WriteMask[0] = ctx->Stencil.WriteMask[1] = mask;
 326       if (ctx->Driver.StencilMaskSeparate) {
 327          ctx->Driver.StencilMaskSeparate(ctx, GL_FRONT_AND_BACK, mask);
 328       }
 329    }
 330    else {
 331       /* only set active face state */
 332       const GLint face = ctx->Stencil.ActiveFace;
 333       if (ctx->Stencil.WriteMask[face] == mask)
 334          return;
 335       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 336       ctx->Stencil.WriteMask[face] = mask;
 337       if (ctx->Driver.StencilMaskSeparate) {
 338          ctx->Driver.StencilMaskSeparate(ctx, face ? GL_BACK : GL_FRONT, mask);
 339       }
 340    }
 341 }
 342
 343
 344 /**
 345  * Set the stencil test actions.
 346  *
 347  * \param fail action to take when stencil test fails.
 348  * \param zfail action to take when stencil test passes, but depth test fails.
 349  * \param zpass action to take when stencil test passes and the depth test
 350  * passes (or depth testing is not enabled).
 351  *
 352  * \sa glStencilOp().
 353  *
 354  * Verifies the parameters and updates the respective fields in
 355  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 356  * driver via the dd_function_table::StencilOp callback.
 357  */
 358 void GLAPIENTRY
 359 _mesa_StencilOp(GLenum fail, GLenum zfail, GLenum zpass)
 360 {
 361    GET_CURRENT_CONTEXT(ctx);
 362    ASSERT_OUTSIDE_BEGIN_END(ctx);
 363
 364    if (!validate_stencil_op(ctx, fail)) {
 365       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(sfail)");
 366       return;
 367    }
 368    if (!validate_stencil_op(ctx, zfail)) {
 369       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zfail)");
 370       return;
 371    }
 372    if (!validate_stencil_op(ctx, zpass)) {
 373       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zpass)");
 374       return;
 375    }
 376
 377    if (ctx->Extensions.ATI_separate_stencil) {
 378       /* set both front and back state */
 379       if (ctx->Stencil.ZFailFunc[0] == zfail &&
 380           ctx->Stencil.ZFailFunc[1] == zfail &&
 381           ctx->Stencil.ZPassFunc[0] == zpass &&
 382           ctx->Stencil.ZPassFunc[1] == zpass &&
 383           ctx->Stencil.FailFunc[0] == fail &&
 384           ctx->Stencil.FailFunc[1] == fail)
 385          return;
 386       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 387       ctx->Stencil.ZFailFunc[0] = ctx->Stencil.ZFailFunc[1] = zfail;
 388       ctx->Stencil.ZPassFunc[0] = ctx->Stencil.ZPassFunc[1] = zpass;
 389       ctx->Stencil.FailFunc[0]  = ctx->Stencil.FailFunc[1]  = fail;
 390       if (ctx->Driver.StencilOpSeparate) {
 391          ctx->Driver.StencilOpSeparate(ctx, GL_FRONT_AND_BACK,
 392                                        fail, zfail, zpass);
 393       }
 394    }
 395    else {
 396       /* only set active face state */
 397       const GLint face = ctx->Stencil.ActiveFace;
 398       if (ctx->Stencil.ZFailFunc[face] == zfail &&
 399           ctx->Stencil.ZPassFunc[face] == zpass &&
 400           ctx->Stencil.FailFunc[face] == fail)
 401          return;
 402       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 403       ctx->Stencil.ZFailFunc[face] = zfail;
 404       ctx->Stencil.ZPassFunc[face] = zpass;
 405       ctx->Stencil.FailFunc[face] = fail;
 406       if (ctx->Driver.StencilOpSeparate) {
 407          ctx->Driver.StencilOpSeparate(ctx, face ? GL_BACK : GL_FRONT,
 408                                        fail, zfail, zpass);
 409       }
 410    }
 411 }
 412
 413
 414
 415 #if _HAVE_FULL_GL
 416 /* GL_EXT_stencil_two_side */
 417 void GLAPIENTRY
 418 _mesa_ActiveStencilFaceEXT(GLenum face)
 419 {
 420    GET_CURRENT_CONTEXT(ctx);
 421    ASSERT_OUTSIDE_BEGIN_END(ctx);
 422
 423    if (!ctx->Extensions.EXT_stencil_two_side) {
 424       _mesa_error(ctx, GL_INVALID_OPERATION, "glActiveStencilFaceEXT");
 425       return;
 426    }
 427
 428    if (face == GL_FRONT || face == GL_BACK) {
 429       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 430       ctx->Stencil.ActiveFace = (face == GL_FRONT) ? 0 : 1;
 431    }
 432    else {
 433       _mesa_error(ctx, GL_INVALID_ENUM, "glActiveStencilFaceEXT(face)");
 434    }
 435 }
 436 #endif
 437
 438
 439
 440 /**
 441  * OpenGL 2.0 function.
 442  * \todo Make StencilOp() call this function.  And eventually remove the
 443  * ctx->Driver.StencilOp function and use ctx->Driver.StencilOpSeparate
 444  * instead.
 445  */
 446 void GLAPIENTRY
 447 _mesa_StencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass)
 448 {
 449    GET_CURRENT_CONTEXT(ctx);
 450    ASSERT_OUTSIDE_BEGIN_END(ctx);
 451
 452    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 453       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(face)");
 454       return;
 455    }
 456
 457    if (!validate_stencil_op(ctx, fail)) {
 458       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(sfail)");
 459       return;
 460    }
 461    if (!validate_stencil_op(ctx, zfail)) {
 462       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zfail)");
 463       return;
 464    }
 465    if (!validate_stencil_op(ctx, zpass)) {
 466       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zpass)");
 467       return;
 468    }
 469
 470    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 471
 472    if (face != GL_BACK) {
 473       ctx->Stencil.FailFunc[0] = fail;
 474       ctx->Stencil.ZFailFunc[0] = zfail;
 475       ctx->Stencil.ZPassFunc[0] = zpass;
 476    }
 477    if (face != GL_FRONT) {
 478       ctx->Stencil.FailFunc[1] = fail;
 479       ctx->Stencil.ZFailFunc[1] = zfail;
 480       ctx->Stencil.ZPassFunc[1] = zpass;
 481    }
 482    if (ctx->Driver.StencilOpSeparate) {
 483       ctx->Driver.StencilOpSeparate(ctx, face, fail, zfail, zpass);
 484    }
 485 }
 486
 487
 488 /* OpenGL 2.0 */
 489 void GLAPIENTRY
 490 _mesa_StencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
 491 {
 492    GET_CURRENT_CONTEXT(ctx);
 493    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 494    ASSERT_OUTSIDE_BEGIN_END(ctx);
 495
 496    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 497       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(face)");
 498       return;
 499    }
 500    if (!validate_stencil_func(ctx, func)) {
 501       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(func)");
 502       return;
 503    }
 504
 505    ref = CLAMP(ref, 0, stencilMax);
 506
 507    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 508
 509    if (face == GL_FRONT || face == GL_FRONT_AND_BACK) {
 510       ctx->Stencil.Function[0] = func;
 511       ctx->Stencil.Ref[0] = ref;
 512       ctx->Stencil.ValueMask[0] = mask;
 513    }
 514    if (face == GL_BACK || face == GL_FRONT_AND_BACK) {
 515       ctx->Stencil.Function[1] = func;
 516       ctx->Stencil.Ref[1] = ref;
 517       ctx->Stencil.ValueMask[1] = mask;
 518    }
 519    if (ctx->Driver.StencilFuncSeparate) {
 520       ctx->Driver.StencilFuncSeparate(ctx, face, func, ref, mask);
 521    }
 522 }
 523
 524
 525 /* OpenGL 2.0 */
 526 void GLAPIENTRY
 527 _mesa_StencilMaskSeparate(GLenum face, GLuint mask)
 528 {
 529    GET_CURRENT_CONTEXT(ctx);
 530    ASSERT_OUTSIDE_BEGIN_END(ctx);
 531
 532    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 533       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilaMaskSeparate(face)");
 534       return;
 535    }
 536
 537    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 538
 539    if (face != GL_BACK) {
 540       ctx->Stencil.WriteMask[0] = mask;
 541    }
 542    if (face != GL_FRONT) {
 543       ctx->Stencil.WriteMask[1] = mask;
 544    }
 545    if (ctx->Driver.StencilMaskSeparate) {
 546       ctx->Driver.StencilMaskSeparate(ctx, face, mask);
 547    }
 548 }
 549
 550
 551 /**
 552  * Update derived stencil state.
 553  */
 554 void
 555 _mesa_update_stencil(GLcontext *ctx)
 556 {
 557    if (ctx->Extensions.EXT_stencil_two_side) {
 558       ctx->Stencil._TestTwoSide = ctx->Stencil.TestTwoSide;
 559    }
 560    else {
 561       ctx->Stencil._TestTwoSide =
 562          (ctx->Stencil.Function[0] != ctx->Stencil.Function[1] ||
 563           ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[1] ||
 564           ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[1] ||
 565           ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[1] ||
 566           ctx->Stencil.Ref[0] != ctx->Stencil.Ref[1] ||
 567           ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[1] ||
 568           ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[1]);
 569    }
 570 }
 571
 572
 573 /**
 574  * Initialize the context stipple state.
 575  *
 576  * \param ctx GL context.
 577  *
 578  * Initializes __GLcontextRec::Stencil attribute group.
 579  */
 580 void
 581 _mesa_init_stencil(GLcontext *ctx)
 582 {
 583    ctx->Stencil.Enabled = GL_FALSE;
 584    ctx->Stencil.TestTwoSide = GL_FALSE;
 585    ctx->Stencil.ActiveFace = 0;  /* 0 = GL_FRONT, 1 = GL_BACK */
 586    ctx->Stencil.Function[0] = GL_ALWAYS;
 587    ctx->Stencil.Function[1] = GL_ALWAYS;
 588    ctx->Stencil.FailFunc[0] = GL_KEEP;
 589    ctx->Stencil.FailFunc[1] = GL_KEEP;
 590    ctx->Stencil.ZPassFunc[0] = GL_KEEP;
 591    ctx->Stencil.ZPassFunc[1] = GL_KEEP;
 592    ctx->Stencil.ZFailFunc[0] = GL_KEEP;
 593    ctx->Stencil.ZFailFunc[1] = GL_KEEP;
 594    ctx->Stencil.Ref[0] = 0;
 595    ctx->Stencil.Ref[1] = 0;
 596    ctx->Stencil.ValueMask[0] = ~0U;
 597    ctx->Stencil.ValueMask[1] = ~0U;
 598    ctx->Stencil.WriteMask[0] = ~0U;
 599    ctx->Stencil.WriteMask[1] = ~0U;
 600    ctx->Stencil.Clear = 0;
 601 }