svn merge ^/branches/released . --username marha

1 files changed, 590 insertions, 0 deletions

diff --git a/mesalib/src/mesa/main/stencil.c b/mesalib/src/mesa/main/stencil.c
new file mode 100644
index 000000000..15c98e201
--- /dev/null
+++ b/mesalib/src/mesa/main/stencil.c
@@ -0,0 +1,590 @@
+/*
+ * Mesa 3-D graphics library
+ * Version:  7.1
+ *
+ * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+/**
+ * \file stencil.c
+ * Stencil operations.
+ *
+ * Note: There's some conflict between GL_EXT_stencil_two_side and
+ * OpenGL 2.0's two-sided stencil feature.
+ *
+ * With GL_EXT_stencil_two_side, calling glStencilOp/Func/Mask() only the
+ * front OR back face state (as set by glActiveStencilFaceEXT) is set.
+ *
+ * But with OpenGL 2.0, calling glStencilOp/Func/Mask() sets BOTH the
+ * front AND back state.
+ *
+ * Also, note that GL_ATI_separate_stencil is different as well:
+ * glStencilFuncSeparateATI(GLenum frontfunc, GLenum backfunc, ...)  vs.
+ * glStencilFuncSeparate(GLenum face, GLenum func, ...).
+ *
+ * This problem is solved by keeping three sets of stencil state:
+ *  state[0] = GL_FRONT state.
+ *  state[1] = OpenGL 2.0 / GL_ATI_separate_stencil GL_BACK state.
+ *  state[2] = GL_EXT_stencil_two_side GL_BACK state.
+ */
+
+
+#include "glheader.h"
+#include "imports.h"
+#include "context.h"
+#include "macros.h"
+#include "stencil.h"
+#include "mtypes.h"
+
+
+static GLboolean
+validate_stencil_op(GLcontext *ctx, GLenum op)
+{
+   switch (op) {
+   case GL_KEEP:
+   case GL_ZERO:
+   case GL_REPLACE:
+   case GL_INCR:
+   case GL_DECR:
+   case GL_INVERT:
+      return GL_TRUE;
+   case GL_INCR_WRAP_EXT:
+   case GL_DECR_WRAP_EXT:
+      if (ctx->Extensions.EXT_stencil_wrap) {
+         return GL_TRUE;
+      }
+      /* FALL-THROUGH */
+   default:
+      return GL_FALSE;
+   }
+}
+
+
+static GLboolean
+validate_stencil_func(GLcontext *ctx, GLenum func)
+{
+   switch (func) {
+   case GL_NEVER:
+   case GL_LESS:
+   case GL_LEQUAL:
+   case GL_GREATER:
+   case GL_GEQUAL:
+   case GL_EQUAL:
+   case GL_NOTEQUAL:
+   case GL_ALWAYS:
+      return GL_TRUE;
+   default:
+      return GL_FALSE;
+   }
+}
+
+
+/**
+ * Set the clear value for the stencil buffer.
+ *
+ * \param s clear value.
+ *
+ * \sa glClearStencil().
+ *
+ * Updates gl_stencil_attrib::Clear. On change
+ * flushes the vertices and notifies the driver via
+ * the dd_function_table::ClearStencil callback.
+ */
+void GLAPIENTRY
+_mesa_ClearStencil( GLint s )
+{
+   GET_CURRENT_CONTEXT(ctx);
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (ctx->Stencil.Clear == (GLuint) s)
+      return;
+
+   FLUSH_VERTICES(ctx, _NEW_STENCIL);
+   ctx->Stencil.Clear = (GLuint) s;
+
+   if (ctx->Driver.ClearStencil) {
+      ctx->Driver.ClearStencil( ctx, s );
+   }
+}
+
+
+/**
+ * Set the function and reference value for stencil testing.
+ *
+ * \param frontfunc front test function.
+ * \param backfunc back test function.
+ * \param ref front and back reference value.
+ * \param mask front and back bitmask.
+ *
+ * \sa glStencilFunc().
+ *
+ * Verifies the parameters and updates the respective values in
+ * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
+ * driver via the dd_function_table::StencilFunc callback.
+ */
+void GLAPIENTRY
+_mesa_StencilFuncSeparateATI( GLenum frontfunc, GLenum backfunc, GLint ref, GLuint mask )
+{
+   GET_CURRENT_CONTEXT(ctx);
+   const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (!validate_stencil_func(ctx, frontfunc)) {
+      _mesa_error(ctx, GL_INVALID_ENUM,
+                  "glStencilFuncSeparateATI(frontfunc)");
+      return;
+   }
+   if (!validate_stencil_func(ctx, backfunc)) {
+      _mesa_error(ctx, GL_INVALID_ENUM,
+                  "glStencilFuncSeparateATI(backfunc)");
+      return;
+   }
+
+   ref = CLAMP( ref, 0, stencilMax );
+
+   /* set both front and back state */
+   if (ctx->Stencil.Function[0] == frontfunc &&
+       ctx->Stencil.Function[1] == backfunc &&
+       ctx->Stencil.ValueMask[0] == mask &&
+       ctx->Stencil.ValueMask[1] == mask &&
+       ctx->Stencil.Ref[0] == ref &&
+       ctx->Stencil.Ref[1] == ref)
+      return;
+   FLUSH_VERTICES(ctx, _NEW_STENCIL);
+   ctx->Stencil.Function[0]  = frontfunc;
+   ctx->Stencil.Function[1]  = backfunc;
+   ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
+   ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
+   if (ctx->Driver.StencilFuncSeparate) {
+      ctx->Driver.StencilFuncSeparate(ctx, GL_FRONT,
+                                      frontfunc, ref, mask);
+      ctx->Driver.StencilFuncSeparate(ctx, GL_BACK,
+                                      backfunc, ref, mask);
+   }
+}
+
+
+/**
+ * Set the function and reference value for stencil testing.
+ *
+ * \param func test function.
+ * \param ref reference value.
+ * \param mask bitmask.
+ *
+ * \sa glStencilFunc().
+ *
+ * Verifies the parameters and updates the respective values in
+ * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
+ * driver via the dd_function_table::StencilFunc callback.
+ */
+void GLAPIENTRY
+_mesa_StencilFunc( GLenum func, GLint ref, GLuint mask )
+{
+   GET_CURRENT_CONTEXT(ctx);
+   const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
+   const GLint face = ctx->Stencil.ActiveFace;
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (!validate_stencil_func(ctx, func)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFunc(func)");
+      return;
+   }
+
+   ref = CLAMP( ref, 0, stencilMax );
+
+   if (face != 0) {
+      if (ctx->Stencil.Function[face] == func &&
+          ctx->Stencil.ValueMask[face] == mask &&
+          ctx->Stencil.Ref[face] == ref)
+         return;
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.Function[face] = func;
+      ctx->Stencil.Ref[face] = ref;
+      ctx->Stencil.ValueMask[face] = mask;
+
+      /* Only propagate the change to the driver if EXT_stencil_two_side
+       * is enabled.
+       */
+      if (ctx->Driver.StencilFuncSeparate && ctx->Stencil.TestTwoSide) {
+         ctx->Driver.StencilFuncSeparate(ctx, GL_BACK, func, ref, mask);
+      }
+   }
+   else {
+      /* set both front and back state */
+      if (ctx->Stencil.Function[0] == func &&
+          ctx->Stencil.Function[1] == func &&
+          ctx->Stencil.ValueMask[0] == mask &&
+          ctx->Stencil.ValueMask[1] == mask &&
+          ctx->Stencil.Ref[0] == ref &&
+          ctx->Stencil.Ref[1] == ref)
+         return;
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.Function[0]  = ctx->Stencil.Function[1]  = func;
+      ctx->Stencil.Ref[0]       = ctx->Stencil.Ref[1]       = ref;
+      ctx->Stencil.ValueMask[0] = ctx->Stencil.ValueMask[1] = mask;
+      if (ctx->Driver.StencilFuncSeparate) {
+         ctx->Driver.StencilFuncSeparate(ctx,
+					 ((ctx->Stencil.TestTwoSide)
+					  ? GL_FRONT : GL_FRONT_AND_BACK),
+                                         func, ref, mask);
+      }
+   }
+}
+
+
+/**
+ * Set the stencil writing mask.
+ *
+ * \param mask bit-mask to enable/disable writing of individual bits in the
+ * stencil planes.
+ *
+ * \sa glStencilMask().
+ *
+ * Updates gl_stencil_attrib::WriteMask. On change flushes the vertices and
+ * notifies the driver via the dd_function_table::StencilMask callback.
+ */
+void GLAPIENTRY
+_mesa_StencilMask( GLuint mask )
+{
+   GET_CURRENT_CONTEXT(ctx);
+   const GLint face = ctx->Stencil.ActiveFace;
+
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (face != 0) {
+      /* Only modify the EXT_stencil_two_side back-face state.
+       */
+      if (ctx->Stencil.WriteMask[face] == mask)
+         return;
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.WriteMask[face] = mask;
+
+      /* Only propagate the change to the driver if EXT_stencil_two_side
+       * is enabled.
+       */
+      if (ctx->Driver.StencilMaskSeparate && ctx->Stencil.TestTwoSide) {
+         ctx->Driver.StencilMaskSeparate(ctx, GL_BACK, mask);
+      }
+   }
+   else {
+      /* set both front and back state */
+      if (ctx->Stencil.WriteMask[0] == mask &&
+          ctx->Stencil.WriteMask[1] == mask)
+         return;
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.WriteMask[0] = ctx->Stencil.WriteMask[1] = mask;
+      if (ctx->Driver.StencilMaskSeparate) {
+         ctx->Driver.StencilMaskSeparate(ctx,
+					 ((ctx->Stencil.TestTwoSide)
+					  ? GL_FRONT : GL_FRONT_AND_BACK),
+					  mask);
+      }
+   }
+}
+
+
+/**
+ * Set the stencil test actions.
+ *
+ * \param fail action to take when stencil test fails.
+ * \param zfail action to take when stencil test passes, but depth test fails.
+ * \param zpass action to take when stencil test passes and the depth test
+ * passes (or depth testing is not enabled).
+ * 
+ * \sa glStencilOp().
+ * 
+ * Verifies the parameters and updates the respective fields in
+ * __GLcontextRec::Stencil. On change flushes the vertices and notifies the
+ * driver via the dd_function_table::StencilOp callback.
+ */
+void GLAPIENTRY
+_mesa_StencilOp(GLenum fail, GLenum zfail, GLenum zpass)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   const GLint face = ctx->Stencil.ActiveFace;
+
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (!validate_stencil_op(ctx, fail)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(sfail)");
+      return;
+   }
+   if (!validate_stencil_op(ctx, zfail)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zfail)");
+      return;
+   }
+   if (!validate_stencil_op(ctx, zpass)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOp(zpass)");
+      return;
+   }
+
+   if (face != 0) {
+      /* only set active face state */
+      if (ctx->Stencil.ZFailFunc[face] == zfail &&
+          ctx->Stencil.ZPassFunc[face] == zpass &&
+          ctx->Stencil.FailFunc[face] == fail)
+         return;
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.ZFailFunc[face] = zfail;
+      ctx->Stencil.ZPassFunc[face] = zpass;
+      ctx->Stencil.FailFunc[face] = fail;
+
+      /* Only propagate the change to the driver if EXT_stencil_two_side
+       * is enabled.
+       */
+      if (ctx->Driver.StencilOpSeparate && ctx->Stencil.TestTwoSide) {
+         ctx->Driver.StencilOpSeparate(ctx, GL_BACK, fail, zfail, zpass);
+      }
+   }
+   else {
+      /* set both front and back state */
+      if (ctx->Stencil.ZFailFunc[0] == zfail &&
+          ctx->Stencil.ZFailFunc[1] == zfail &&
+          ctx->Stencil.ZPassFunc[0] == zpass &&
+          ctx->Stencil.ZPassFunc[1] == zpass &&
+          ctx->Stencil.FailFunc[0] == fail &&
+          ctx->Stencil.FailFunc[1] == fail)
+         return;
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.ZFailFunc[0] = ctx->Stencil.ZFailFunc[1] = zfail;
+      ctx->Stencil.ZPassFunc[0] = ctx->Stencil.ZPassFunc[1] = zpass;
+      ctx->Stencil.FailFunc[0]  = ctx->Stencil.FailFunc[1]  = fail;
+      if (ctx->Driver.StencilOpSeparate) {
+         ctx->Driver.StencilOpSeparate(ctx,
+				       ((ctx->Stencil.TestTwoSide)
+					? GL_FRONT : GL_FRONT_AND_BACK),
+                                       fail, zfail, zpass);
+      }
+   }
+}
+
+
+
+#if _HAVE_FULL_GL
+/* GL_EXT_stencil_two_side */
+void GLAPIENTRY
+_mesa_ActiveStencilFaceEXT(GLenum face)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (!ctx->Extensions.EXT_stencil_two_side) {
+      _mesa_error(ctx, GL_INVALID_OPERATION, "glActiveStencilFaceEXT");
+      return;
+   }
+
+   if (face == GL_FRONT || face == GL_BACK) {
+      FLUSH_VERTICES(ctx, _NEW_STENCIL);
+      ctx->Stencil.ActiveFace = (face == GL_FRONT) ? 0 : 2;
+   }
+   else {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glActiveStencilFaceEXT(face)");
+   }
+}
+#endif
+
+
+
+/**
+ * OpenGL 2.0 function.
+ * \todo Make StencilOp() call this function.  And eventually remove the
+ * ctx->Driver.StencilOp function and use ctx->Driver.StencilOpSeparate
+ * instead.
+ */
+void GLAPIENTRY
+_mesa_StencilOpSeparate(GLenum face, GLenum sfail, GLenum zfail, GLenum zpass)
+{
+   GLboolean set = GL_FALSE;
+   GET_CURRENT_CONTEXT(ctx);
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (!validate_stencil_op(ctx, sfail)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(sfail)");
+      return;
+   }
+   if (!validate_stencil_op(ctx, zfail)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zfail)");
+      return;
+   }
+   if (!validate_stencil_op(ctx, zpass)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(zpass)");
+      return;
+   }
+   if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilOpSeparate(face)");
+      return;
+   }
+
+   if (face != GL_BACK) {
+      /* set front */
+      if (ctx->Stencil.ZFailFunc[0] != zfail ||
+          ctx->Stencil.ZPassFunc[0] != zpass ||
+          ctx->Stencil.FailFunc[0] != sfail){
+         FLUSH_VERTICES(ctx, _NEW_STENCIL);
+         ctx->Stencil.ZFailFunc[0] = zfail;
+         ctx->Stencil.ZPassFunc[0] = zpass;
+         ctx->Stencil.FailFunc[0] = sfail;
+         set = GL_TRUE;
+      }
+   }
+   if (face != GL_FRONT) {
+      /* set back */
+      if (ctx->Stencil.ZFailFunc[1] != zfail ||
+          ctx->Stencil.ZPassFunc[1] != zpass ||
+          ctx->Stencil.FailFunc[1] != sfail) {
+         FLUSH_VERTICES(ctx, _NEW_STENCIL);
+         ctx->Stencil.ZFailFunc[1] = zfail;
+         ctx->Stencil.ZPassFunc[1] = zpass;
+         ctx->Stencil.FailFunc[1] = sfail;
+         set = GL_TRUE;
+      }
+   }
+   if (set && ctx->Driver.StencilOpSeparate) {
+      ctx->Driver.StencilOpSeparate(ctx, face, sfail, zfail, zpass);
+   }
+}
+
+
+/* OpenGL 2.0 */
+void GLAPIENTRY
+_mesa_StencilFuncSeparate(GLenum face, GLenum func, GLint ref, GLuint mask)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   const GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(face)");
+      return;
+   }
+   if (!validate_stencil_func(ctx, func)) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilFuncSeparate(func)");
+      return;
+   }
+
+   ref = CLAMP(ref, 0, stencilMax);
+
+   FLUSH_VERTICES(ctx, _NEW_STENCIL);
+
+   if (face != GL_BACK) {
+      /* set front */
+      ctx->Stencil.Function[0] = func;
+      ctx->Stencil.Ref[0] = ref;
+      ctx->Stencil.ValueMask[0] = mask;
+   }
+   if (face != GL_FRONT) {
+      /* set back */
+      ctx->Stencil.Function[1] = func;
+      ctx->Stencil.Ref[1] = ref;
+      ctx->Stencil.ValueMask[1] = mask;
+   }
+   if (ctx->Driver.StencilFuncSeparate) {
+      ctx->Driver.StencilFuncSeparate(ctx, face, func, ref, mask);
+   }
+}
+
+
+/* OpenGL 2.0 */
+void GLAPIENTRY
+_mesa_StencilMaskSeparate(GLenum face, GLuint mask)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   ASSERT_OUTSIDE_BEGIN_END(ctx);
+
+   if (face != GL_FRONT && face != GL_BACK && face != GL_FRONT_AND_BACK) {
+      _mesa_error(ctx, GL_INVALID_ENUM, "glStencilaMaskSeparate(face)");
+      return;
+   }
+
+   FLUSH_VERTICES(ctx, _NEW_STENCIL);
+
+   if (face != GL_BACK) {
+      ctx->Stencil.WriteMask[0] = mask;
+   }
+   if (face != GL_FRONT) {
+      ctx->Stencil.WriteMask[1] = mask;
+   }
+   if (ctx->Driver.StencilMaskSeparate) {
+      ctx->Driver.StencilMaskSeparate(ctx, face, mask);
+   }
+}
+
+
+/**
+ * Update derived stencil state.
+ */
+void
+_mesa_update_stencil(GLcontext *ctx)
+{
+   const GLint face = ctx->Stencil._BackFace;
+
+   ctx->Stencil._Enabled = (ctx->Stencil.Enabled &&
+                            ctx->DrawBuffer->Visual.stencilBits > 0);
+
+    ctx->Stencil._TestTwoSide =
+       ctx->Stencil._Enabled &&
+       (ctx->Stencil.Function[0] != ctx->Stencil.Function[face] ||
+	ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[face] ||
+	ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[face] ||
+	ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[face] ||
+	ctx->Stencil.Ref[0] != ctx->Stencil.Ref[face] ||
+	ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[face] ||
+	ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[face]);
+}
+
+
+/**
+ * Initialize the context stipple state.
+ *
+ * \param ctx GL context.
+ *
+ * Initializes __GLcontextRec::Stencil attribute group.
+ */
+void
+_mesa_init_stencil(GLcontext *ctx)
+{
+   ctx->Stencil.Enabled = GL_FALSE;
+   ctx->Stencil.TestTwoSide = GL_FALSE;
+   ctx->Stencil.ActiveFace = 0;  /* 0 = GL_FRONT, 2 = GL_BACK */
+   ctx->Stencil.Function[0] = GL_ALWAYS;
+   ctx->Stencil.Function[1] = GL_ALWAYS;
+   ctx->Stencil.Function[2] = GL_ALWAYS;
+   ctx->Stencil.FailFunc[0] = GL_KEEP;
+   ctx->Stencil.FailFunc[1] = GL_KEEP;
+   ctx->Stencil.FailFunc[2] = GL_KEEP;
+   ctx->Stencil.ZPassFunc[0] = GL_KEEP;
+   ctx->Stencil.ZPassFunc[1] = GL_KEEP;
+   ctx->Stencil.ZPassFunc[2] = GL_KEEP;
+   ctx->Stencil.ZFailFunc[0] = GL_KEEP;
+   ctx->Stencil.ZFailFunc[1] = GL_KEEP;
+   ctx->Stencil.ZFailFunc[2] = GL_KEEP;
+   ctx->Stencil.Ref[0] = 0;
+   ctx->Stencil.Ref[1] = 0;
+   ctx->Stencil.Ref[2] = 0;
+   ctx->Stencil.ValueMask[0] = ~0U;
+   ctx->Stencil.ValueMask[1] = ~0U;
+   ctx->Stencil.ValueMask[2] = ~0U;
+   ctx->Stencil.WriteMask[0] = ~0U;
+   ctx->Stencil.WriteMask[1] = ~0U;
+   ctx->Stencil.WriteMask[2] = ~0U;
+   ctx->Stencil.Clear = 0;
+   ctx->Stencil._BackFace = 1;
+}