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