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 /**
 184  * Set the function and reference value for stencil testing.
 185  *
 186  * \param func test function.
 187  * \param ref reference value.
 188  * \param mask bitmask.
 189  *
 190  * \sa glStencilFunc().
 191  *
 192  * Verifies the parameters and updates the respective values in
 193  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 194  * driver via the dd_function_table::StencilFunc callback.
 195  */
 196 void GLAPIENTRY
 197 _mesa_StencilFunc( GLenum func, GLint ref, GLuint mask )
 198 {
 199    GET_CURRENT_CONTEXT(ctx);
 200    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 201    ASSERT_OUTSIDE_BEGIN_END(ctx);
 202
 203    if (!validate_stencil_func(ctx, func)) {
 204       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFunc(func)");
 205       return;
 206    }
 207
 208    ref = CLAMP( ref, 0, stencilMax );
 209
 210    if (ctx->Extensions.EXT_stencil_two_side) {
 211       /* only set active face state */
 212       const GLint face = ctx->Stencil.ActiveFace;
 213       if (ctx->Stencil.Function[face] == func &&
 214           ctx->Stencil.ValueMask[face] == mask &&
 215           ctx->Stencil.Ref[face] == ref)
 216          return;
 217       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 218       ctx->Stencil.Function[face] = func;
 219       ctx->Stencil.Ref[face] = ref;
 220       ctx->Stencil.ValueMask[face] = mask;
 221       if (ctx->Driver.StencilFuncSeparate) {
 222          ctx->Driver.StencilFuncSeparate(ctx, face ? GL_BACK : GL_FRONT,
 223                                          func, ref, mask);
 224       }
 225    }
 226    else {
 227       /* set both front and back state */
 228       if (ctx->Stencil.Function[0] == func &&
 229           ctx->Stencil.Function[1] == func &&
 230           ctx->Stencil.ValueMask[0] == mask &&
 231           ctx->Stencil.ValueMask[1] == mask &&
 232           ctx->Stencil.Ref[0] == ref &&
 233           ctx->Stencil.Ref[1] == ref)
 234          return;
 235       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 236       ctx->Stencil.Function[0]  = ctx->Stencil.Function[1]  = func;
 237       ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
 238       ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
 239       if (ctx->Driver.StencilFuncSeparate) {
 240          ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT_AND_BACK,
 241                                          func, ref, mask);
 242       }
 243    }
 244 }
 245
 246
 247 /**
 248  * Set the stencil writing mask.
 249  *
 250  * \param mask bit-mask to enable/disable writing of individual bits in the
 251  * stencil planes.
 252  *
 253  * \sa glStencilMask().
 254  *
 255  * Updates gl_stencil_attrib::WriteMask. On change flushes the vertices and
 256  * notifies the driver via the dd_function_table::StencilMask callback.
 257  */
 258 void GLAPIENTRY
 259 _mesa_StencilMask( GLuint mask )
 260 {
 261    GET_CURRENT_CONTEXT(ctx);
 262    ASSERT_OUTSIDE_BEGIN_END(ctx);
 263
 264    if (ctx->Extensions.EXT_stencil_two_side) {
 265       /* only set active face state */
 266       const GLint face = ctx->Stencil.ActiveFace;
 267       if (ctx->Stencil.WriteMask[face] == mask)
 268          return;
 269       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 270       ctx->Stencil.WriteMask[face] = mask;
 271       if (ctx->Driver.StencilMaskSeparate) {
 272          ctx->Driver.StencilMaskSeparate(ctx, face ? GL_BACK : GL_FRONT, mask);
 273       }
 274    }
 275    else {
 276       /* set both front and back state */
 277       if (ctx->Stencil.WriteMask[0] == mask &&
 278           ctx->Stencil.WriteMask[1] == mask)
 279          return;
 280       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 281       ctx->Stencil.WriteMask[0] = ctx->Stencil.WriteMask[1] = mask;
 282       if (ctx->Driver.StencilMaskSeparate) {
 283          ctx->Driver.StencilMaskSeparate(ctx, GL_FRONT_AND_BACK, mask);
 284       }
 285    }
 286 }
 287
 288
 289 /**
 290  * Set the stencil test actions.
 291  *
 292  * \param fail action to take when stencil test fails.
 293  * \param zfail action to take when stencil test passes, but depth test fails.
 294  * \param zpass action to take when stencil test passes and the depth test
 295  * passes (or depth testing is not enabled).
 296  *
 297  * \sa glStencilOp().
 298  *
 299  * Verifies the parameters and updates the respective fields in
 300  * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
 301  * driver via the dd_function_table::StencilOp callback.
 302  */
 303 void GLAPIENTRY
 304 _mesa_StencilOp(GLenum fail, GLenum zfail, GLenum zpass)
 305 {
 306    GET_CURRENT_CONTEXT(ctx);
 307    ASSERT_OUTSIDE_BEGIN_END(ctx);
 308
 309    if (!validate_stencil_op(ctx, fail)) {
 310       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(sfail)");
 311       return;
 312    }
 313    if (!validate_stencil_op(ctx, zfail)) {
 314       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zfail)");
 315       return;
 316    }
 317    if (!validate_stencil_op(ctx, zpass)) {
 318       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zpass)");
 319       return;
 320    }
 321
 322    if (ctx->Extensions.EXT_stencil_two_side) {
 323       /* only set active face state */
 324       const GLint face = ctx->Stencil.ActiveFace;
 325       if (ctx->Stencil.ZFailFunc[face] == zfail &&
 326           ctx->Stencil.ZPassFunc[face] == zpass &&
 327           ctx->Stencil.FailFunc[face] == fail)
 328          return;
 329       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 330       ctx->Stencil.ZFailFunc[face] = zfail;
 331       ctx->Stencil.ZPassFunc[face] = zpass;
 332       ctx->Stencil.FailFunc[face] = fail;
 333       if (ctx->Driver.StencilOpSeparate) {
 334          ctx->Driver.StencilOpSeparate(ctx, face ? GL_BACK : GL_FRONT,
 335                                        fail, zfail, zpass);
 336       }
 337    }
 338    else {
 339       /* set both front and back state */
 340       if (ctx->Stencil.ZFailFunc[0] == zfail &&
 341           ctx->Stencil.ZFailFunc[1] == zfail &&
 342           ctx->Stencil.ZPassFunc[0] == zpass &&
 343           ctx->Stencil.ZPassFunc[1] == zpass &&
 344           ctx->Stencil.FailFunc[0] == fail &&
 345           ctx->Stencil.FailFunc[1] == fail)
 346          return;
 347       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 348       ctx->Stencil.ZFailFunc[0] = ctx->Stencil.ZFailFunc[1] = zfail;
 349       ctx->Stencil.ZPassFunc[0] = ctx->Stencil.ZPassFunc[1] = zpass;
 350       ctx->Stencil.FailFunc[0]  = ctx->Stencil.FailFunc[1]  = fail;
 351       if (ctx->Driver.StencilOpSeparate) {
 352          ctx->Driver.StencilOpSeparate(ctx, GL_FRONT_AND_BACK,
 353                                        fail, zfail, zpass);
 354       }
 355    }
 356 }
 357
 358
 359
 360 #if _HAVE_FULL_GL
 361 /* GL_EXT_stencil_two_side */
 362 void GLAPIENTRY
 363 _mesa_ActiveStencilFaceEXT(GLenum face)
 364 {
 365    GET_CURRENT_CONTEXT(ctx);
 366    ASSERT_OUTSIDE_BEGIN_END(ctx);
 367
 368    if (!ctx->Extensions.EXT_stencil_two_side) {
 369       _mesa_error(ctx, GL_INVALID_OPERATION, "glActiveStencilFaceEXT");
 370       return;
 371    }
 372
 373    if (face == GL_FRONT || face == GL_BACK) {
 374       FLUSH_VERTICES(ctx, _NEW_STENCIL);
 375       ctx->Stencil.ActiveFace = (face == GL_FRONT) ? 0 : 1;
 376    }
 377    else {
 378       _mesa_error(ctx, GL_INVALID_ENUM, "glActiveStencilFaceEXT(face)");
 379    }
 380 }
 381 #endif
 382
 383
 384
 385 /**
 386  * OpenGL 2.0 function.
 387  * \todo Make StencilOp() call this function.  And eventually remove the
 388  * ctx->Driver.StencilOp function and use ctx->Driver.StencilOpSeparate
 389  * instead.
 390  */
 391 void GLAPIENTRY
 392 _mesa_StencilOpSeparate(GLenum face, GLenum sfail, GLenum zfail, GLenum zpass)
 393 {
 394    GLboolean set = GL_FALSE;
 395    GET_CURRENT_CONTEXT(ctx);
 396    ASSERT_OUTSIDE_BEGIN_END(ctx);
 397
 398    if (!validate_stencil_op(ctx, sfail)) {
 399       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(sfail)");
 400       return;
 401    }
 402    if (!validate_stencil_op(ctx, zfail)) {
 403       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zfail)");
 404       return;
 405    }
 406    if (!validate_stencil_op(ctx, zpass)) {
 407       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zpass)");
 408       return;
 409    }
 410    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 411       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(face)");
 412       return;
 413    }
 414
 415    if (face != GL_BACK) {
 416       /* set front */
 417       if (ctx->Stencil.ZFailFunc[0] != zfail ||
 418           ctx->Stencil.ZPassFunc[0] != zpass ||
 419           ctx->Stencil.FailFunc[0] != sfail){
 420          FLUSH_VERTICES(ctx, _NEW_STENCIL);
 421          ctx->Stencil.ZFailFunc[0] = zfail;
 422          ctx->Stencil.ZPassFunc[0] = zpass;
 423          ctx->Stencil.FailFunc[0] = sfail;
 424          set = GL_TRUE;
 425       }
 426    }
 427    if (face != GL_FRONT) {
 428       /* set back */
 429       if (ctx->Stencil.ZFailFunc[1] != zfail ||
 430           ctx->Stencil.ZPassFunc[1] != zpass ||
 431           ctx->Stencil.FailFunc[1] != sfail) {
 432          FLUSH_VERTICES(ctx, _NEW_STENCIL);
 433          ctx->Stencil.ZFailFunc[1] = zfail;
 434          ctx->Stencil.ZPassFunc[1] = zpass;
 435          ctx->Stencil.FailFunc[1] = sfail;
 436          set = GL_TRUE;
 437       }
 438    }
 439    if (set && ctx->Driver.StencilOpSeparate) {
 440       ctx->Driver.StencilOpSeparate(ctx, face, sfail, zfail, zpass);
 441    }
 442 }
 443
 444
 445 /* OpenGL 2.0 */
 446 void GLAPIENTRY
 447 _mesa_StencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
 448 {
 449    GET_CURRENT_CONTEXT(ctx);
 450    const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
 451    ASSERT_OUTSIDE_BEGIN_END(ctx);
 452
 453    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 454       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(face)");
 455       return;
 456    }
 457    if (!validate_stencil_func(ctx, func)) {
 458       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(func)");
 459       return;
 460    }
 461
 462    ref = CLAMP(ref, 0, stencilMax);
 463
 464    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 465
 466    if (face != GL_BACK) {
 467       /* set front */
 468       ctx->Stencil.Function[0] = func;
 469       ctx->Stencil.Ref[0] = ref;
 470       ctx->Stencil.ValueMask[0] = mask;
 471    }
 472    if (face != GL_FRONT) {
 473       /* set back */
 474       ctx->Stencil.Function[1] = func;
 475       ctx->Stencil.Ref[1] = ref;
 476       ctx->Stencil.ValueMask[1] = mask;
 477    }
 478    if (ctx->Driver.StencilFuncSeparate) {
 479       ctx->Driver.StencilFuncSeparate(ctx, face, func, ref, mask);
 480    }
 481 }
 482
 483
 484 /* OpenGL 2.0 */
 485 void GLAPIENTRY
 486 _mesa_StencilMaskSeparate(GLenum face, GLuint mask)
 487 {
 488    GET_CURRENT_CONTEXT(ctx);
 489    ASSERT_OUTSIDE_BEGIN_END(ctx);
 490
 491    if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
 492       _mesa_error(ctx, GL_INVALID_ENUM, "glStencilaMaskSeparate(face)");
 493       return;
 494    }
 495
 496    FLUSH_VERTICES(ctx, _NEW_STENCIL);
 497
 498    if (face != GL_BACK) {
 499       ctx->Stencil.WriteMask[0] = mask;
 500    }
 501    if (face != GL_FRONT) {
 502       ctx->Stencil.WriteMask[1] = mask;
 503    }
 504    if (ctx->Driver.StencilMaskSeparate) {
 505       ctx->Driver.StencilMaskSeparate(ctx, face, mask);
 506    }
 507 }
 508
 509
 510 /**
 511  * Update derived stencil state.
 512  */
 513 void
 514 _mesa_update_stencil(GLcontext *ctx)
 515 {
 516    if (ctx->Extensions.EXT_stencil_two_side) {
 517       ctx->Stencil._TestTwoSide = ctx->Stencil.TestTwoSide;
 518    }
 519    else {
 520       ctx->Stencil._TestTwoSide =
 521          (ctx->Stencil.Function[0] != ctx->Stencil.Function[1] ||
 522           ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[1] ||
 523           ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[1] ||
 524           ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[1] ||
 525           ctx->Stencil.Ref[0] != ctx->Stencil.Ref[1] ||
 526           ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[1] ||
 527           ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[1]);
 528    }
 529 }
 530
 531
 532 /**
 533  * Initialize the context stipple state.
 534  *
 535  * \param ctx GL context.
 536  *
 537  * Initializes __GLcontextRec::Stencil attribute group.
 538  */
 539 void
 540 _mesa_init_stencil(GLcontext *ctx)
 541 {
 542    ctx->Stencil.Enabled = GL_FALSE;
 543    ctx->Stencil.TestTwoSide = GL_FALSE;
 544    ctx->Stencil.ActiveFace = 0;  /* 0 = GL_FRONT, 1 = GL_BACK */
 545    ctx->Stencil.Function[0] = GL_ALWAYS;
 546    ctx->Stencil.Function[1] = GL_ALWAYS;
 547    ctx->Stencil.FailFunc[0] = GL_KEEP;
 548    ctx->Stencil.FailFunc[1] = GL_KEEP;
 549    ctx->Stencil.ZPassFunc[0] = GL_KEEP;
 550    ctx->Stencil.ZPassFunc[1] = GL_KEEP;
 551    ctx->Stencil.ZFailFunc[0] = GL_KEEP;
 552    ctx->Stencil.ZFailFunc[1] = GL_KEEP;
 553    ctx->Stencil.Ref[0] = 0;
 554    ctx->Stencil.Ref[1] = 0;
 555    ctx->Stencil.ValueMask[0] = ~0U;
 556    ctx->Stencil.ValueMask[1] = ~0U;
 557    ctx->Stencil.WriteMask[0] = ~0U;
 558    ctx->Stencil.WriteMask[1] = ~0U;
 559    ctx->Stencil.Clear = 0;
 560 }