1 files changed, 18 insertions, 3 deletions
diff --git a/mesalib/src/mesa/main/stencil.h b/mesalib/src/mesa/main/stencil.h
index b772bfd6e..f2f7d37c6 100644
--- a/mesalib/src/mesa/main/stencil.h
+++ b/mesalib/src/mesa/main/stencil.h
@@ -22,9 +22,10 @@
  * 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.
+ * THE AUTHORS OR COPYRIGHT HOLDERS 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.
  */
 
 
@@ -78,4 +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