gallium: Add utility helper for packing combined depth/stencil values.

src/gallium/auxiliary/util/u_pack_color.h

@@ -440,6 +440,26 @@ util_pack_z(enum pipe_format format, double z)
       return 0;
    }
 }
+ 
+
+/**
+ * Note: it's assumed that z is in [0,1] and s in [0,255]
+ */
+static INLINE uint
+util_pack_z_stencil(enum pipe_format format, double z, uint s)
+{
+   switch (format) {
+   case PIPE_FORMAT_S8Z24_UNORM:
+      return util_pack_z(format, z) | s << 24;
+   case PIPE_FORMAT_Z24S8_UNORM:
+      return util_pack_z(format, z) | s;
+   default:
+      debug_print_format("gallium: unhandled format in util_pack_z_stencil()",
+                         format);
+      assert(0);
+      return 0;
+   }
+}
 
 
 /**

src/mesa/state_tracker/st_cb_clear.c

@@ -460,19 +460,9 @@ clear_depth_stencil_buffer(GLcontext *ctx, struct gl_renderbuffer *rb)
    }
    else {
       /* clear whole buffer w/out masking */
-      GLuint clearValue = util_pack_z(strb->surface->format, ctx->Depth.Clear);
+      GLuint clearValue = util_pack_z_stencil(strb->surface->format,
-
+                                              ctx->Depth.Clear,
-      switch (strb->surface->format) {
+                                              ctx->Stencil.Clear);
-      case PIPE_FORMAT_S8Z24_UNORM:
-         clearValue |= ctx->Stencil.Clear << 24;
-         break;
-      case PIPE_FORMAT_Z24S8_UNORM:
-         clearValue |= ctx->Stencil.Clear;
-         break;
-      default:
-         assert(0);
-      }  
-
       ctx->st->pipe->clear(ctx->st->pipe, strb->surface, clearValue);
    }
 }