stencil.c

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      if (ctx->Driver.StencilMaskSeparate) {
         ctx->Driver.StencilMaskSeparate(ctx, 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);
   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 (ctx->Extensions.EXT_stencil_two_side) {
      /* only set active face state */
      const GLint face = ctx->Stencil.ActiveFace;
      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;
      if (ctx->Driver.StencilOpSeparate) {
         ctx->Driver.StencilOpSeparate(ctx, face ? GL_BACK : GL_FRONT,
                                       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, 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 : 1;
   }
   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)
{
   if (ctx->Extensions.EXT_stencil_two_side) {
      ctx->Stencil._TestTwoSide = ctx->Stencil.TestTwoSide;
   }
   else {
      ctx->Stencil._TestTwoSide = 
         (ctx->Stencil.Function[0] != ctx->Stencil.Function[1] ||
          ctx->Stencil.FailFunc[0] != ctx->Stencil.FailFunc[1] ||
          ctx->Stencil.ZPassFunc[0] != ctx->Stencil.ZPassFunc[1] ||
          ctx->Stencil.ZFailFunc[0] != ctx->Stencil.ZFailFunc[1] ||
          ctx->Stencil.Ref[0] != ctx->Stencil.Ref[1] ||
          ctx->Stencil.ValueMask[0] != ctx->Stencil.ValueMask[1] ||
          ctx->Stencil.WriteMask[0] != ctx->Stencil.WriteMask[1]);
   }
}


/**
 * 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, 1 = GL_BACK */
   ctx->Stencil.Function[0] = GL_ALWAYS;
   ctx->Stencil.Function[1] = GL_ALWAYS;
   ctx->Stencil.FailFunc[0] = GL_KEEP;
   ctx->Stencil.FailFunc[1] = GL_KEEP;
   ctx->Stencil.ZPassFunc[0] = GL_KEEP;
   ctx->Stencil.ZPassFunc[1] = GL_KEEP;
   ctx->Stencil.ZFailFunc[0] = GL_KEEP;
   ctx->Stencil.ZFailFunc[1] = GL_KEEP;
   ctx->Stencil.Ref[0] = 0;
   ctx->Stencil.Ref[1] = 0;
   ctx->Stencil.ValueMask[0] = ~0U;
   ctx->Stencil.ValueMask[1] = ~0U;
   ctx->Stencil.WriteMask[0] = ~0U;
   ctx->Stencil.WriteMask[1] = ~0U;
   ctx->Stencil.Clear = 0;
}