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 some conflict 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  * Also, note that GL_ATI_separate_stencil is different as well:
  40  * glStencilFuncSeparateATI(GLenum frontfunc, GLenum backfunc, ...)  vs.
  41  * glStencilFuncSeparate(GLenum face, GLenum func, ...).
  42  *
  43  * This problem is solved by keeping three sets of stencil state:
  44  *  state[0] = GL_FRONT state.
  45  *  state[1] = OpenGL 2.0 / GL_ATI_separate_stencil GL_BACK state.
  46  *  state[2] = GL_EXT_stencil_two_side GL_BACK state.
  47  */
  48
  49
  50 #include "glheader.h"
  51 #include "imports.h"
  52 #include "context.h"
  53 #include "macros.h"
  54 #include "stencil.h"
  55 #include "mtypes.h"
  56
  57
  58 static GLboolean
  59 validate_stencil_op(GLcontext *ctx, GLenum op)
  60 {
  61    switch (op) {
  62    case GL_KEEP:
  63    case GL_ZERO:
  64    case GL_REPLACE:
  65    case GL_INCR:
  66    case GL_DECR:
  67    case GL_INVERT:
  68       return GL_TRUE;
  69    case GL_INCR_WRAP_EXT:
  70    case GL_DECR_WRAP_EXT:
  71       if (ctx->Extensions.EXT_stencil_wrap) {
  72          return GL_TRUE;
  73       }
  74       /* FALL-THROUGH */
  75    default:
  76       return GL_FALSE;
  77    }
  78 }
  79
  80
  81 static GLboolean
  82 validate_stencil_func(GLcontext *ctx, GLenum func)
  83 {
  84    switch (func) {
  85    case GL_NEVER:
  86    case GL_LESS:
  87    case GL_LEQUAL:
  88    case GL_GREATER:
  89    case GL_GEQUAL:
  90    case GL_EQUAL:
  91    case GL_NOTEQUAL:
  92    case GL_ALWAYS:
  93       return GL_TRUE;
  94    default:
  95       return GL_FALSE;
  96    }
  97 }
  98
  99
 100 /**
 101  * Set the clear value for the stencil buffer.
 102  *
 103  * \param s clear value.
 104  *
 105  * \sa glClearStencil().
 106  *
 107  * Updates gl_stencil_attrib::Clear. On change
 108  * flushes the vertices and notifies the driver via
 109  * the dd_function_table::ClearStencil callback.
 110  */
 111 void GLAPIENTRY
 112 _mesa_ClearStencil( GLint s )
 113 {
 114    GET_CURRENT_CONTEXT(ctx);
 115    ASSERT_OUTSIDE_BEGIN_END(ctx);
 116
 117    if (ctx->Stencil.Clear == (GLuint) s)
 118       return;
 119
 120    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 121    ctx->Stencil.Clear = (GLuint) s;
 122
 123    if (ctx->Driver.ClearStencil) {
 124       ctx->Driver.ClearStencil( ctx, s );
 125    }
 126 }
 127
 128
 129 /**
 130  * Set the function and reference value for stencil testing.
 131  *
 132  * \param frontfunc front test function.
 133  * \param backfunc back test function.
 134  * \param ref front and back reference value.
 135  * \param mask front and back bitmask.
 136  *
 137  * \sa glStencilFunc().
 138  *
 139  * Verifies the parameters and updates the respective values in
 140  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 141  * driver via the dd_function_table::StencilFunc callback.
 142  */
 143 void GLAPIENTRY
 144 _mesa_StencilFuncSeparateATI( GLenum frontfunc, GLenum backfunc, GLint ref, GLuint mask )
 145 {
 146    GET_CURRENT_CONTEXT(ctx);
 147    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 148    ASSERT_OUTSIDE_BEGIN_END(ctx);
 149
 150    if (!validate_stencil_func(ctx, frontfunc)) {
 151       _mesa_error(ctx, GL_INVALID_ENUM,
 152                   "glStencilFuncSeparateATI(frontfunc)");
 153       return;
 154    }
 155    if (!validate_stencil_func(ctx, backfunc)) {
 156       _mesa_error(ctx, GL_INVALID_ENUM,
 157                   "glStencilFuncSeparateATI(backfunc)");
 158       return;
 159    }
 160
 161    ref = CLAMP( ref, 0, stencilMax );
 162
 163    /* set both front and back state */
 164    if (ctx->Stencil.Function[0] == frontfunc &&
 165        ctx->Stencil.Function[1] == backfunc &&
 166        ctx->Stencil.ValueMask[0] == mask &&
 167        ctx->Stencil.ValueMask[1] == mask &&
 168        ctx->Stencil.Ref[0] == ref &&
 169        ctx->Stencil.Ref[1] == ref)
 170       return;
 171    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 172    ctx->Stencil.Function[0]  = frontfunc;
 173    ctx->Stencil.Function[1]  = backfunc;
 174    ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 175    ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 176    if (ctx->Driver.StencilFuncSeparate) {
 177       ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT,
 178                                       frontfunc, ref, mask);
 179       ctx->Driver.StencilFuncSeparate(ctx, GL_BACK,
 180                                       backfunc, ref, mask);
 181    }
 182 }
 183
 184
 185 /**
 186  * Set the function and reference value for stencil testing.
 187  *
 188  * \param func test function.
 189  * \param ref reference value.
 190  * \param mask bitmask.
 191  *
 192  * \sa glStencilFunc().
 193  *
 194  * Verifies the parameters and updates the respective values in
 195  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 196  * driver via the dd_function_table::StencilFunc callback.
 197  */
 198 void GLAPIENTRY
 199 _mesa_StencilFunc( GLenum func, GLint ref, GLuint mask )
 200 {
 201    GET_CURRENT_CONTEXT(ctx);
 202    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 203    const GLint face = ctx->Stencil.ActiveFace;
 204    ASSERT_OUTSIDE_BEGIN_END(ctx);
 205
 206    if (!validate_stencil_func(ctx, func)) {
 207       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFunc(func)");
 208       return;
 209    }
 210
 211    ref = CLAMP( ref, 0, stencilMax );
 212
 213    if (face != 0) {
 214       if (ctx->Stencil.Function[face] == func &&
 215           ctx->Stencil.ValueMask[face] == mask &&
 216           ctx->Stencil.Ref[face] == ref)
 217          return;
 218       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 219       ctx->Stencil.Function[face] = func;
 220       ctx->Stencil.Ref[face] = ref;
 221       ctx->Stencil.ValueMask[face] = mask;
 222
 223       /* Only propagate the change to the driver if EXT_stencil_two_side
 224        * is enabled.
 225        */
 226       if (ctx->Driver.StencilFuncSeparate && ctx->Stencil.TestTwoSide) {
 227          ctx->Driver.StencilFuncSeparate(ctx, GL_BACK, func, ref, mask);
 228       }
 229    }
 230    else {
 231       /* set both front and back state */
 232       if (ctx->Stencil.Function[0] == func &&
 233           ctx->Stencil.Function[1] == func &&
 234           ctx->Stencil.ValueMask[0] == mask &&
 235           ctx->Stencil.ValueMask[1] == mask &&
 236           ctx->Stencil.Ref[0] == ref &&
 237           ctx->Stencil.Ref[1] == ref)
 238          return;
 239       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 240       ctx->Stencil.Function[0]  = ctx->Stencil.Function[1]  = func;
 241       ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 242       ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 243       if (ctx->Driver.StencilFuncSeparate) {
 244          ctx->Driver.StencilFuncSeparate(ctx,
 245                                          ((ctx->Stencil.TestTwoSide)
 246                                           ? GL_FRONT : GL_FRONT_AND_BACK),
 247                                          func, ref, mask);
 248       }
 249    }
 250 }
 251
 252
 253 /**
 254  * Set the stencil writing mask.
 255  *
 256  * \param mask bit-mask to enable/disable writing of individual bits in the
 257  * stencil planes.
 258  *
 259  * \sa glStencilMask().
 260  *
 261  * Updates gl_stencil_attrib::WriteMask. On change flushes the vertices and
 262  * notifies the driver via the dd_function_table::StencilMask callback.
 263  */
 264 void GLAPIENTRY
 265 _mesa_StencilMask( GLuint mask )
 266 {
 267    GET_CURRENT_CONTEXT(ctx);
 268    const GLint face = ctx->Stencil.ActiveFace;
 269
 270    ASSERT_OUTSIDE_BEGIN_END(ctx);
 271
 272    if (face != 0) {
 273       /* Only modify the EXT_stencil_two_side back-face state.
 274        */
 275       if (ctx->Stencil.WriteMask[face] == mask)
 276          return;
 277       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 278       ctx->Stencil.WriteMask[face] = mask;
 279
 280       /* Only propagate the change to the driver if EXT_stencil_two_side
 281        * is enabled.
 282        */
 283       if (ctx->Driver.StencilMaskSeparate && ctx->Stencil.TestTwoSide) {
 284          ctx->Driver.StencilMaskSeparate(ctx, GL_BACK, mask);
 285       }
 286    }
 287    else {
 288       /* set both front and back state */
 289       if (ctx->Stencil.WriteMask[0] == mask &&
 290           ctx->Stencil.WriteMask[1] == mask)
 291          return;
 292       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 293       ctx->Stencil.WriteMask[0] = ctx->Stencil.WriteMask[1] = mask;
 294       if (ctx->Driver.StencilMaskSeparate) {
 295          ctx->Driver.StencilMaskSeparate(ctx,
 296                                          ((ctx->Stencil.TestTwoSide)
 297                                           ? GL_FRONT : GL_FRONT_AND_BACK),
 298                                           mask);
 299       }
 300    }
 301 }
 302
 303
 304 /**
 305  * Set the stencil test actions.
 306  *
 307  * \param fail action to take when stencil test fails.
 308  * \param zfail action to take when stencil test passes, but depth test fails.
 309  * \param zpass action to take when stencil test passes and the depth test
 310  * passes (or depth testing is not enabled).
 311  *
 312  * \sa glStencilOp().
 313  *
 314  * Verifies the parameters and updates the respective fields in
 315  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 316  * driver via the dd_function_table::StencilOp callback.
 317  */
 318 void GLAPIENTRY
 319 _mesa_StencilOp(GLenum fail, GLenum zfail, GLenum zpass)
 320 {
 321    GET_CURRENT_CONTEXT(ctx);
 322    const GLint face = ctx->Stencil.ActiveFace;
 323
 324    ASSERT_OUTSIDE_BEGIN_END(ctx);
 325
 326    if (!validate_stencil_op(ctx, fail)) {
 327       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(sfail)");
 328       return;
 329    }
 330    if (!validate_stencil_op(ctx, zfail)) {
 331       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zfail)");
 332       return;
 333    }
 334    if (!validate_stencil_op(ctx, zpass)) {
 335       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zpass)");
 336       return;
 337    }
 338
 339    if (face != 0) {
 340       /* only set active face state */
 341       if (ctx->Stencil.ZFailFunc[face] == zfail &&
 342           ctx->Stencil.ZPassFunc[face] == zpass &&
 343           ctx->Stencil.FailFunc[face] == fail)
 344          return;
 345       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 346       ctx->Stencil.ZFailFunc[face] = zfail;
 347       ctx->Stencil.ZPassFunc[face] = zpass;
 348       ctx->Stencil.FailFunc[face] = fail;
 349
 350       /* Only propagate the change to the driver if EXT_stencil_two_side
 351        * is enabled.
 352        */
 353       if (ctx->Driver.StencilOpSeparate && ctx->Stencil.TestTwoSide) {
 354          ctx->Driver.StencilOpSeparate(ctx, GL_BACK, fail, zfail, zpass);
 355       }
 356    }
 357    else {
 358       /* set both front and back state */
 359       if (ctx->Stencil.ZFailFunc[0] == zfail &&
 360           ctx->Stencil.ZFailFunc[1] == zfail &&
 361           ctx->Stencil.ZPassFunc[0] == zpass &&
 362           ctx->Stencil.ZPassFunc[1] == zpass &&
 363           ctx->Stencil.FailFunc[0] == fail &&
 364           ctx->Stencil.FailFunc[1] == fail)
 365          return;
 366       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 367       ctx->Stencil.ZFailFunc[0] = ctx->Stencil.ZFailFunc[1] = zfail;
 368       ctx->Stencil.ZPassFunc[0] = ctx->Stencil.ZPassFunc[1] = zpass;
 369       ctx->Stencil.FailFunc[0]  = ctx->Stencil.FailFunc[1]  = fail;
 370       if (ctx->Driver.StencilOpSeparate) {
 371          ctx->Driver.StencilOpSeparate(ctx,
 372                                        ((ctx->Stencil.TestTwoSide)
 373                                         ? GL_FRONT : GL_FRONT_AND_BACK),
 374                                        fail, zfail, zpass);
 375       }
 376    }
 377 }
 378
 379
 380
 381 #if _HAVE_FULL_GL
 382 /* GL_EXT_stencil_two_side */
 383 void GLAPIENTRY
 384 _mesa_ActiveStencilFaceEXT(GLenum face)
 385 {
 386    GET_CURRENT_CONTEXT(ctx);
 387    ASSERT_OUTSIDE_BEGIN_END(ctx);
 388
 389    if (!ctx->Extensions.EXT_stencil_two_side) {
 390       _mesa_error(ctx, GL_INVALID_OPERATION, "glActiveStencilFaceEXT");
 391       return;
 392    }
 393
 394    if (face == GL_FRONT || face == GL_BACK) {
 395       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 396       ctx->Stencil.ActiveFace = (face == GL_FRONT) ? 0 : 2;
 397    }
 398    else {
 399       _mesa_error(ctx, GL_INVALID_ENUM, "glActiveStencilFaceEXT(face)");
 400    }
 401 }
 402 #endif
 403
 404
 405
 406 /**
 407  * OpenGL 2.0 function.
 408  * \todo Make StencilOp() call this function.  And eventually remove the
 409  * ctx->Driver.StencilOp function and use ctx->Driver.StencilOpSeparate
 410  * instead.
 411  */
 412 void GLAPIENTRY
 413 _mesa_StencilOpSeparate(GLenum face, GLenum sfail, GLenum zfail, GLenum zpass)
 414 {
 415    GLboolean set = GL_FALSE;
 416    GET_CURRENT_CONTEXT(ctx);
 417    ASSERT_OUTSIDE_BEGIN_END(ctx);
 418
 419    if (!validate_stencil_op(ctx, sfail)) {
 420       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(sfail)");
 421       return;
 422    }
 423    if (!validate_stencil_op(ctx, zfail)) {
 424       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zfail)");
 425       return;
 426    }
 427    if (!validate_stencil_op(ctx, zpass)) {
 428       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zpass)");
 429       return;
 430    }
 431    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 432       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(face)");
 433       return;
 434    }
 435
 436    if (face != GL_BACK) {
 437       /* set front */
 438       if (ctx->Stencil.ZFailFunc[0] != zfail ||
 439           ctx->Stencil.ZPassFunc[0] != zpass ||
 440           ctx->Stencil.FailFunc[0] != sfail){
 441          FLUSH_VERTICES(ctx, _NEW_STENCIL);
 442          ctx->Stencil.ZFailFunc[0] = zfail;
 443          ctx->Stencil.ZPassFunc[0] = zpass;
 444          ctx->Stencil.FailFunc[0] = sfail;
 445          set = GL_TRUE;
 446       }
 447    }
 448    if (face != GL_FRONT) {
 449       /* set back */
 450       if (ctx->Stencil.ZFailFunc[1] != zfail ||
 451           ctx->Stencil.ZPassFunc[1] != zpass ||
 452           ctx->Stencil.FailFunc[1] != sfail) {
 453          FLUSH_VERTICES(ctx, _NEW_STENCIL);
 454          ctx->Stencil.ZFailFunc[1] = zfail;
 455          ctx->Stencil.ZPassFunc[1] = zpass;
 456          ctx->Stencil.FailFunc[1] = sfail;
 457          set = GL_TRUE;
 458       }
 459    }
 460    if (set && ctx->Driver.StencilOpSeparate) {
 461       ctx->Driver.StencilOpSeparate(ctx, face, sfail, zfail, zpass);
 462    }
 463 }
 464
 465
 466 /* OpenGL 2.0 */
 467 void GLAPIENTRY
 468 _mesa_StencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
 469 {
 470    GET_CURRENT_CONTEXT(ctx);
 471    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 472    ASSERT_OUTSIDE_BEGIN_END(ctx);
 473
 474    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 475       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(face)");
 476       return;
 477    }
 478    if (!validate_stencil_func(ctx, func)) {
 479       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(func)");
 480       return;
 481    }
 482
 483    ref = CLAMP(ref, 0, stencilMax);
 484
 485    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 486
 487    if (face != GL_BACK) {
 488       /* set front */
 489       ctx->Stencil.Function[0] = func;
 490       ctx->Stencil.Ref[0] = ref;
 491       ctx->Stencil.ValueMask[0] = mask;
 492    }
 493    if (face != GL_FRONT) {
 494       /* set back */
 495       ctx->Stencil.Function[1] = func;
 496       ctx->Stencil.Ref[1] = ref;
 497       ctx->Stencil.ValueMask[1] = mask;
 498    }
 499    if (ctx->Driver.StencilFuncSeparate) {
 500       ctx->Driver.StencilFuncSeparate(ctx, face, func, ref, mask);
 501    }
 502 }
 503
 504
 505 /* OpenGL 2.0 */
 506 void GLAPIENTRY
 507 _mesa_StencilMaskSeparate(GLenum face, GLuint mask)
 508 {
 509    GET_CURRENT_CONTEXT(ctx);
 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, "glStencilaMaskSeparate(face)");
 514       return;
 515    }
 516
 517    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 518
 519    if (face != GL_BACK) {
 520       ctx->Stencil.WriteMask[0] = mask;
 521    }
 522    if (face != GL_FRONT) {
 523       ctx->Stencil.WriteMask[1] = mask;
 524    }
 525    if (ctx->Driver.StencilMaskSeparate) {
 526       ctx->Driver.StencilMaskSeparate(ctx, face, mask);
 527    }
 528 }
 529
 530
 531 /**
 532  * Update derived stencil state.
 533  */
 534 void
 535 _mesa_update_stencil(GLcontext *ctx)
 536 {
 537    const GLint face = ctx->Stencil._BackFace;
 538
 539    ctx->Stencil._Enabled = (ctx->Stencil.Enabled &&
 540                             ctx->DrawBuffer->Visual.stencilBits > 0);
 541
 542     ctx->Stencil._TestTwoSide =
 543        ctx->Stencil._Enabled &&
 544        (ctx->Stencil.Function[0] != ctx->Stencil.Function[face] ||
 545         ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[face] ||
 546         ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[face] ||
 547         ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[face] ||
 548         ctx->Stencil.Ref[0] != ctx->Stencil.Ref[face] ||
 549         ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[face] ||
 550         ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[face]);
 551 }
 552
 553
 554 /**
 555  * Initialize the context stipple state.
 556  *
 557  * \param ctx GL context.
 558  *
 559  * Initializes __GLcontextRec::Stencil attribute group.
 560  */
 561 void
 562 _mesa_init_stencil(GLcontext *ctx)
 563 {
 564    ctx->Stencil.Enabled = GL_FALSE;
 565    ctx->Stencil.TestTwoSide = GL_FALSE;
 566    ctx->Stencil.ActiveFace = 0;  /* 0 = GL_FRONT, 2 = GL_BACK */
 567    ctx->Stencil.Function[0] = GL_ALWAYS;
 568    ctx->Stencil.Function[1] = GL_ALWAYS;
 569    ctx->Stencil.Function[2] = GL_ALWAYS;
 570    ctx->Stencil.FailFunc[0] = GL_KEEP;
 571    ctx->Stencil.FailFunc[1] = GL_KEEP;
 572    ctx->Stencil.FailFunc[2] = GL_KEEP;
 573    ctx->Stencil.ZPassFunc[0] = GL_KEEP;
 574    ctx->Stencil.ZPassFunc[1] = GL_KEEP;
 575    ctx->Stencil.ZPassFunc[2] = GL_KEEP;
 576    ctx->Stencil.ZFailFunc[0] = GL_KEEP;
 577    ctx->Stencil.ZFailFunc[1] = GL_KEEP;
 578    ctx->Stencil.ZFailFunc[2] = GL_KEEP;
 579    ctx->Stencil.Ref[0] = 0;
 580    ctx->Stencil.Ref[1] = 0;
 581    ctx->Stencil.Ref[2] = 0;
 582    ctx->Stencil.ValueMask[0] = ~0U;
 583    ctx->Stencil.ValueMask[1] = ~0U;
 584    ctx->Stencil.ValueMask[2] = ~0U;
 585    ctx->Stencil.WriteMask[0] = ~0U;
 586    ctx->Stencil.WriteMask[1] = ~0U;
 587    ctx->Stencil.WriteMask[2] = ~0U;
 588    ctx->Stencil.Clear = 0;
 589    ctx->Stencil._BackFace = 1;
 590 }