src/mesa/main/stencil.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5.2
   4  *
   5  * Copyright (C) 1999-2006  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 /**
  57  * Set the clear value for the stencil buffer.
  58  *
  59  * \param s clear value.
  60  *
  61  * \sa glClearStencil().
  62  *
  63  * Updates gl_stencil_attrib::Clear. On change
  64  * flushes the vertices and notifies the driver via
  65  * the dd_function_table::ClearStencil callback.
  66  */
  67 void GLAPIENTRY
  68 _mesa_ClearStencil( GLint s )
  69 {
  70    GET_CURRENT_CONTEXT(ctx);
  71    ASSERT_OUTSIDE_BEGIN_END(ctx);
  72
  73    if (ctx->Stencil.Clear == (GLuint) s)
  74       return;
  75
  76    FLUSH_VERTICES(ctx, _NEW_STENCIL);
  77    ctx->Stencil.Clear = (GLuint) s;
  78
  79    if (ctx->Driver.ClearStencil) {
  80       ctx->Driver.ClearStencil( ctx, s );
  81    }
  82 }
  83
  84
  85 /**
  86  * Set the function and reference value for stencil testing.
  87  *
  88  * \param frontfunc front test function.
  89  * \param backfunc back test function.
  90  * \param ref front and back reference value.
  91  * \param mask front and back bitmask.
  92  *
  93  * \sa glStencilFunc().
  94  *
  95  * Verifies the parameters and updates the respective values in
  96  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
  97  * driver via the dd_function_table::StencilFunc callback.
  98  */
  99 void GLAPIENTRY
 100 _mesa_StencilFuncSeparateATI( GLenum frontfunc, GLenum backfunc, GLint ref, GLuint mask )
 101 {
 102    GET_CURRENT_CONTEXT(ctx);
 103    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 104    ASSERT_OUTSIDE_BEGIN_END(ctx);
 105
 106    switch (frontfunc) {
 107       case GL_NEVER:
 108       case GL_LESS:
 109       case GL_LEQUAL:
 110       case GL_GREATER:
 111       case GL_GEQUAL:
 112       case GL_EQUAL:
 113       case GL_NOTEQUAL:
 114       case GL_ALWAYS:
 115          break;
 116       default:
 117          _mesa_error( ctx, GL_INVALID_ENUM, "glStencilFuncSeparateATI (0x%04x)", frontfunc );
 118          return;
 119    }
 120
 121    switch (backfunc) {
 122       case GL_NEVER:
 123       case GL_LESS:
 124       case GL_LEQUAL:
 125       case GL_GREATER:
 126       case GL_GEQUAL:
 127       case GL_EQUAL:
 128       case GL_NOTEQUAL:
 129       case GL_ALWAYS:
 130          break;
 131       default:
 132          _mesa_error( ctx, GL_INVALID_ENUM, "glStencilFuncSeparateATI (0x%04x)", backfunc );
 133          return;
 134    }
 135
 136    ref = CLAMP( ref, 0, stencilMax );
 137
 138    /* set both front and back state */
 139    if (ctx->Stencil.Function[0] == frontfunc &&
 140        ctx->Stencil.Function[1] == backfunc &&
 141        ctx->Stencil.ValueMask[0] == mask &&
 142        ctx->Stencil.ValueMask[1] == mask &&
 143        ctx->Stencil.Ref[0] == ref &&
 144        ctx->Stencil.Ref[1] == ref)
 145       return;
 146    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 147    ctx->Stencil.Function[0]  = frontfunc;
 148    ctx->Stencil.Function[1]  = backfunc;
 149    ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 150    ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 151    if (ctx->Driver.StencilFuncSeparate) {
 152       ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT,
 153                                       frontfunc, ref, mask);
 154       ctx->Driver.StencilFuncSeparate(ctx, GL_BACK,
 155                                       backfunc, ref, mask);
 156    }
 157 }
 158
 159
 160 /**
 161  * Set the function and reference value for stencil testing.
 162  *
 163  * \param func test function.
 164  * \param ref reference value.
 165  * \param mask bitmask.
 166  *
 167  * \sa glStencilFunc().
 168  *
 169  * Verifies the parameters and updates the respective values in
 170  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 171  * driver via the dd_function_table::StencilFunc callback.
 172  */
 173 void GLAPIENTRY
 174 _mesa_StencilFunc( GLenum func, GLint ref, GLuint mask )
 175 {
 176    GET_CURRENT_CONTEXT(ctx);
 177    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 178    ASSERT_OUTSIDE_BEGIN_END(ctx);
 179
 180    switch (func) {
 181       case GL_NEVER:
 182       case GL_LESS:
 183       case GL_LEQUAL:
 184       case GL_GREATER:
 185       case GL_GEQUAL:
 186       case GL_EQUAL:
 187       case GL_NOTEQUAL:
 188       case GL_ALWAYS:
 189          break;
 190       default:
 191          _mesa_error( ctx, GL_INVALID_ENUM, "glStencilFunc (0x%04x)", func );
 192          return;
 193    }
 194
 195    ref = CLAMP( ref, 0, stencilMax );
 196
 197    if (ctx->Extensions.ATI_separate_stencil) {
 198       /* set both front and back state */
 199       if (ctx->Stencil.Function[0] == func &&
 200           ctx->Stencil.Function[1] == func &&
 201           ctx->Stencil.ValueMask[0] == mask &&
 202           ctx->Stencil.ValueMask[1] == mask &&
 203           ctx->Stencil.Ref[0] == ref &&
 204           ctx->Stencil.Ref[1] == ref)
 205          return;
 206       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 207       ctx->Stencil.Function[0]  = ctx->Stencil.Function[1]  = func;
 208       ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 209       ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 210       if (ctx->Driver.StencilFuncSeparate) {
 211          ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT_AND_BACK,
 212                                          func, ref, mask);
 213       }
 214    }
 215    else {
 216       /* only set active face state */
 217       const GLint face = ctx->Stencil.ActiveFace;
 218       if (ctx->Stencil.Function[face] == func &&
 219           ctx->Stencil.ValueMask[face] == mask &&
 220           ctx->Stencil.Ref[face] == ref)
 221          return;
 222       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 223       ctx->Stencil.Function[face] = func;
 224       ctx->Stencil.Ref[face] = ref;
 225       ctx->Stencil.ValueMask[face] = mask;
 226       if (ctx->Driver.StencilFuncSeparate) {
 227          ctx->Driver.StencilFuncSeparate(ctx, face ? GL_BACK : GL_FRONT,
 228                                          func, ref, mask);
 229       }
 230    }
 231 }
 232
 233
 234 /**
 235  * Set the stencil writing mask.
 236  *
 237  * \param mask bit-mask to enable/disable writing of individual bits in the
 238  * stencil planes.
 239  *
 240  * \sa glStencilMask().
 241  *
 242  * Updates gl_stencil_attrib::WriteMask. On change flushes the vertices and
 243  * notifies the driver via the dd_function_table::StencilMask callback.
 244  */
 245 void GLAPIENTRY
 246 _mesa_StencilMask( GLuint mask )
 247 {
 248    GET_CURRENT_CONTEXT(ctx);
 249    ASSERT_OUTSIDE_BEGIN_END(ctx);
 250
 251    if (ctx->Extensions.ATI_separate_stencil) {
 252       /* set both front and back state */
 253       if (ctx->Stencil.WriteMask[0] == mask &&
 254           ctx->Stencil.WriteMask[1] == mask)
 255          return;
 256       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 257       ctx->Stencil.WriteMask[0] = ctx->Stencil.WriteMask[1] = mask;
 258       if (ctx->Driver.StencilMaskSeparate) {
 259          ctx->Driver.StencilMaskSeparate(ctx, GL_FRONT_AND_BACK, mask);
 260       }
 261    }
 262    else {
 263       /* only set active face state */
 264       const GLint face = ctx->Stencil.ActiveFace;
 265       if (ctx->Stencil.WriteMask[face] == mask)
 266          return;
 267       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 268       ctx->Stencil.WriteMask[face] = mask;
 269       if (ctx->Driver.StencilMaskSeparate) {
 270          ctx->Driver.StencilMaskSeparate(ctx, face ? GL_BACK : GL_FRONT, mask);
 271       }
 272    }
 273 }
 274
 275
 276 /**
 277  * Set the stencil test actions.
 278  *
 279  * \param fail action to take when stencil test fails.
 280  * \param zfail action to take when stencil test passes, but depth test fails.
 281  * \param zpass action to take when stencil test passes and the depth test
 282  * passes (or depth testing is not enabled).
 283  *
 284  * \sa glStencilOp().
 285  *
 286  * Verifies the parameters and updates the respective fields in
 287  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 288  * driver via the dd_function_table::StencilOp callback.
 289  */
 290 void GLAPIENTRY
 291 _mesa_StencilOp(GLenum fail, GLenum zfail, GLenum zpass)
 292 {
 293    GET_CURRENT_CONTEXT(ctx);
 294    ASSERT_OUTSIDE_BEGIN_END(ctx);
 295
 296    switch (fail) {
 297       case GL_KEEP:
 298       case GL_ZERO:
 299       case GL_REPLACE:
 300       case GL_INCR:
 301       case GL_DECR:
 302       case GL_INVERT:
 303          break;
 304       case GL_INCR_WRAP_EXT:
 305       case GL_DECR_WRAP_EXT:
 306          if (ctx->Extensions.EXT_stencil_wrap) {
 307             break;
 308          }
 309          /* FALL-THROUGH */
 310       default:
 311          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp");
 312          return;
 313    }
 314    switch (zfail) {
 315       case GL_KEEP:
 316       case GL_ZERO:
 317       case GL_REPLACE:
 318       case GL_INCR:
 319       case GL_DECR:
 320       case GL_INVERT:
 321          break;
 322       case GL_INCR_WRAP_EXT:
 323       case GL_DECR_WRAP_EXT:
 324          if (ctx->Extensions.EXT_stencil_wrap) {
 325             break;
 326          }
 327          /* FALL-THROUGH */
 328       default:
 329          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp");
 330          return;
 331    }
 332    switch (zpass) {
 333       case GL_KEEP:
 334       case GL_ZERO:
 335       case GL_REPLACE:
 336       case GL_INCR:
 337       case GL_DECR:
 338       case GL_INVERT:
 339          break;
 340       case GL_INCR_WRAP_EXT:
 341       case GL_DECR_WRAP_EXT:
 342          if (ctx->Extensions.EXT_stencil_wrap) {
 343             break;
 344          }
 345          /* FALL-THROUGH */
 346       default:
 347          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp");
 348          return;
 349    }
 350
 351    if (ctx->Extensions.ATI_separate_stencil) {
 352       /* set both front and back state */
 353       if (ctx->Stencil.ZFailFunc[0] == zfail &&
 354           ctx->Stencil.ZFailFunc[1] == zfail &&
 355           ctx->Stencil.ZPassFunc[0] == zpass &&
 356           ctx->Stencil.ZPassFunc[1] == zpass &&
 357           ctx->Stencil.FailFunc[0] == fail &&
 358           ctx->Stencil.FailFunc[1] == fail)
 359          return;
 360       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 361       ctx->Stencil.ZFailFunc[0] = ctx->Stencil.ZFailFunc[1] = zfail;
 362       ctx->Stencil.ZPassFunc[0] = ctx->Stencil.ZPassFunc[1] = zpass;
 363       ctx->Stencil.FailFunc[0]  = ctx->Stencil.FailFunc[1]  = fail;
 364       if (ctx->Driver.StencilOpSeparate) {
 365          ctx->Driver.StencilOpSeparate(ctx, GL_FRONT_AND_BACK,
 366                                        fail, zfail, zpass);
 367       }
 368    }
 369    else {
 370       /* only set active face state */
 371       const GLint face = ctx->Stencil.ActiveFace;
 372       if (ctx->Stencil.ZFailFunc[face] == zfail &&
 373           ctx->Stencil.ZPassFunc[face] == zpass &&
 374           ctx->Stencil.FailFunc[face] == fail)
 375          return;
 376       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 377       ctx->Stencil.ZFailFunc[face] = zfail;
 378       ctx->Stencil.ZPassFunc[face] = zpass;
 379       ctx->Stencil.FailFunc[face] = fail;
 380       if (ctx->Driver.StencilOpSeparate) {
 381          ctx->Driver.StencilOpSeparate(ctx, face ? GL_BACK : GL_FRONT,
 382                                        fail, zfail, zpass);
 383       }
 384    }
 385 }
 386
 387
 388
 389 #if _HAVE_FULL_GL
 390 /* GL_EXT_stencil_two_side */
 391 void GLAPIENTRY
 392 _mesa_ActiveStencilFaceEXT(GLenum face)
 393 {
 394    GET_CURRENT_CONTEXT(ctx);
 395    ASSERT_OUTSIDE_BEGIN_END(ctx);
 396
 397    if (!ctx->Extensions.EXT_stencil_two_side) {
 398       _mesa_error(ctx, GL_INVALID_OPERATION, "glActiveStencilFaceEXT");
 399       return;
 400    }
 401
 402    if (face == GL_FRONT || face == GL_BACK) {
 403       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 404       ctx->Stencil.ActiveFace = (face == GL_FRONT) ? 0 : 1;
 405    }
 406    else {
 407       _mesa_error(ctx, GL_INVALID_ENUM, "glActiveStencilFaceEXT(face)");
 408    }
 409 }
 410 #endif
 411
 412
 413
 414 /**
 415  * OpenGL 2.0 function.
 416  * \todo Make StencilOp() call this function.  And eventually remove the
 417  * ctx->Driver.StencilOp function and use ctx->Driver.StencilOpSeparate
 418  * instead.
 419  */
 420 void GLAPIENTRY
 421 _mesa_StencilOpSeparate(GLenum face, GLenum fail, GLenum zfail, GLenum zpass)
 422 {
 423    GET_CURRENT_CONTEXT(ctx);
 424    ASSERT_OUTSIDE_BEGIN_END(ctx);
 425
 426    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 427       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(face)");
 428       return;
 429    }
 430
 431    switch (fail) {
 432       case GL_KEEP:
 433       case GL_ZERO:
 434       case GL_REPLACE:
 435       case GL_INCR:
 436       case GL_DECR:
 437       case GL_INVERT:
 438          break;
 439       case GL_INCR_WRAP_EXT:
 440       case GL_DECR_WRAP_EXT:
 441          if (ctx->Extensions.EXT_stencil_wrap) {
 442             break;
 443          }
 444          /* FALL-THROUGH */
 445       default:
 446          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(fail)");
 447          return;
 448    }
 449    switch (zfail) {
 450       case GL_KEEP:
 451       case GL_ZERO:
 452       case GL_REPLACE:
 453       case GL_INCR:
 454       case GL_DECR:
 455       case GL_INVERT:
 456          break;
 457       case GL_INCR_WRAP_EXT:
 458       case GL_DECR_WRAP_EXT:
 459          if (ctx->Extensions.EXT_stencil_wrap) {
 460             break;
 461          }
 462          /* FALL-THROUGH */
 463       default:
 464          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zfail)");
 465          return;
 466    }
 467    switch (zpass) {
 468       case GL_KEEP:
 469       case GL_ZERO:
 470       case GL_REPLACE:
 471       case GL_INCR:
 472       case GL_DECR:
 473       case GL_INVERT:
 474          break;
 475       case GL_INCR_WRAP_EXT:
 476       case GL_DECR_WRAP_EXT:
 477          if (ctx->Extensions.EXT_stencil_wrap) {
 478             break;
 479          }
 480          /* FALL-THROUGH */
 481       default:
 482          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zpass)");
 483          return;
 484    }
 485
 486    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 487
 488    if (face != GL_BACK) {
 489       ctx->Stencil.FailFunc[0] = fail;
 490       ctx->Stencil.ZFailFunc[0] = zfail;
 491       ctx->Stencil.ZPassFunc[0] = zpass;
 492    }
 493    if (face != GL_FRONT) {
 494       ctx->Stencil.FailFunc[1] = fail;
 495       ctx->Stencil.ZFailFunc[1] = zfail;
 496       ctx->Stencil.ZPassFunc[1] = zpass;
 497    }
 498    if (ctx->Driver.StencilOpSeparate) {
 499       ctx->Driver.StencilOpSeparate(ctx, face, fail, zfail, zpass);
 500    }
 501 }
 502
 503
 504 /* OpenGL 2.0 */
 505 void GLAPIENTRY
 506 _mesa_StencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
 507 {
 508    GET_CURRENT_CONTEXT(ctx);
 509    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 510    ASSERT_OUTSIDE_BEGIN_END(ctx);
 511
 512    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 513       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(face)");
 514       return;
 515    }
 516
 517    switch (func) {
 518       case GL_NEVER:
 519       case GL_LESS:
 520       case GL_LEQUAL:
 521       case GL_GREATER:
 522       case GL_GEQUAL:
 523       case GL_EQUAL:
 524       case GL_NOTEQUAL:
 525       case GL_ALWAYS:
 526          break;
 527       default:
 528          _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(func)");
 529          return;
 530    }
 531
 532    ref = CLAMP(ref, 0, stencilMax);
 533
 534    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 535
 536    if (face == GL_FRONT || face == GL_FRONT_AND_BACK) {
 537       ctx->Stencil.Function[0] = func;
 538       ctx->Stencil.Ref[0] = ref;
 539       ctx->Stencil.ValueMask[0] = mask;
 540    }
 541    if (face == GL_BACK || face == GL_FRONT_AND_BACK) {
 542       ctx->Stencil.Function[1] = func;
 543       ctx->Stencil.Ref[1] = ref;
 544       ctx->Stencil.ValueMask[1] = mask;
 545    }
 546    if (ctx->Driver.StencilFuncSeparate) {
 547       ctx->Driver.StencilFuncSeparate(ctx, face, func, ref, mask);
 548    }
 549 }
 550
 551
 552 /* OpenGL 2.0 */
 553 void GLAPIENTRY
 554 _mesa_StencilMaskSeparate(GLenum face, GLuint mask)
 555 {
 556    GET_CURRENT_CONTEXT(ctx);
 557    ASSERT_OUTSIDE_BEGIN_END(ctx);
 558
 559    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 560       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilaMaskSeparate(face)");
 561       return;
 562    }
 563
 564    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 565
 566    if (face != GL_BACK) {
 567       ctx->Stencil.WriteMask[0] = mask;
 568    }
 569    if (face != GL_FRONT) {
 570       ctx->Stencil.WriteMask[1] = mask;
 571    }
 572    if (ctx->Driver.StencilMaskSeparate) {
 573       ctx->Driver.StencilMaskSeparate(ctx, face, mask);
 574    }
 575 }
 576
 577
 578 /**
 579  * Update derived stencil state.
 580  */
 581 void
 582 _mesa_update_stencil(GLcontext *ctx)
 583 {
 584    if (ctx->Extensions.EXT_stencil_two_side) {
 585       ctx->Stencil._TestTwoSide = ctx->Stencil.TestTwoSide;
 586    }
 587    else {
 588       ctx->Stencil._TestTwoSide =
 589          (ctx->Stencil.Function[0] != ctx->Stencil.Function[1] ||
 590           ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[1] ||
 591           ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[1] ||
 592           ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[1] ||
 593           ctx->Stencil.Ref[0] != ctx->Stencil.Ref[1] ||
 594           ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[1] ||
 595           ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[1]);
 596    }
 597 }
 598
 599
 600 /**
 601  * Initialize the context stipple state.
 602  *
 603  * \param ctx GL context.
 604  *
 605  * Initializes __GLcontextRec::Stencil attribute group.
 606  */
 607 void
 608 _mesa_init_stencil(GLcontext *ctx)
 609 {
 610    ctx->Stencil.Enabled = GL_FALSE;
 611    ctx->Stencil.TestTwoSide = GL_FALSE;
 612    ctx->Stencil.ActiveFace = 0;  /* 0 = GL_FRONT, 1 = GL_BACK */
 613    ctx->Stencil.Function[0] = GL_ALWAYS;
 614    ctx->Stencil.Function[1] = GL_ALWAYS;
 615    ctx->Stencil.FailFunc[0] = GL_KEEP;
 616    ctx->Stencil.FailFunc[1] = GL_KEEP;
 617    ctx->Stencil.ZPassFunc[0] = GL_KEEP;
 618    ctx->Stencil.ZPassFunc[1] = GL_KEEP;
 619    ctx->Stencil.ZFailFunc[0] = GL_KEEP;
 620    ctx->Stencil.ZFailFunc[1] = GL_KEEP;
 621    ctx->Stencil.Ref[0] = 0;
 622    ctx->Stencil.Ref[1] = 0;
 623    ctx->Stencil.ValueMask[0] = ~0U;
 624    ctx->Stencil.ValueMask[1] = ~0U;
 625    ctx->Stencil.WriteMask[0] = ~0U;
 626    ctx->Stencil.WriteMask[1] = ~0U;
 627    ctx->Stencil.Clear = 0;
 628 }