mesa: Add draw time validation for advanced blending modes.

[mesa.git] / src / mesa / main / stencil.h

diff --git a/src/mesa/main/stencil.h b/src/mesa/main/stencil.h
index 1d5e01c42044bccc651c4d8bad396fffe58e1258..3302cb947030a4329fdf7344b96b264e2985c3f9 100644 (file)
--- a/src/mesa/main/stencil.h
+++ b/src/mesa/main/stencil.h
@@ -5,7 +5,6 @@
 
 /*
  * Mesa 3-D graphics library
- * Version:  7.1
  *
  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
  *
@@ -34,6 +33,7 @@
 
 
 #include "glheader.h"
+#include "macros.h"
 
 struct gl_context;
 
@@ -79,4 +79,18 @@ _mesa_update_stencil(struct gl_context *ctx);
 extern void 
 _mesa_init_stencil( struct gl_context * ctx );
 
+/* From the GL 4.3 spec, 17.3.5:
+ *    "Stencil comparison operations and queries of <ref> clamp its value
+ *    to the range [0, 2^s-1], where <s> is the number of bits in the
+ *    stencil buffer attached to the draw framebuffer."
+ */
+
+static inline GLint
+_mesa_get_stencil_ref(struct gl_context const *ctx, int face)
+{
+   GLint stencilMax = (1 << ctx->DrawBuffer->Visual.stencilBits) - 1;
+   GLint ref = ctx->Stencil.Ref[face];
+   return CLAMP(ref, 0, stencilMax);
+}
+
 #endif