[Bf-blender-cvs] [6ca12d1] master: Fix T45909: Garbage output in Viewport with OpenSubdiv device set to GLSL Compute

[Sergey Sharybin]

Commit: 6ca12d157fbfdf1a71a06a87fb5f258ae98ebe02
Author: Sergey Sharybin
Date:   Wed Aug 26 12:10:24 2015 +0200
Branches: master
https://developer.blender.org/rB6ca12d157fbfdf1a71a06a87fb5f258ae98ebe02

Fix T45909: Garbage output in Viewport with OpenSubdiv device set to GLSL Compute

This isn't a Blender issue and the same bug happens with official OpenSubdiv
examples. For until it's either worked around from OpenSubdiv side or fixed
in the driver we'll force disable GLSL Compute for AMD hardware.

===================================================================

M	intern/opensubdiv/opensubdiv_utils_capi.cc

===================================================================

diff --git a/intern/opensubdiv/opensubdiv_utils_capi.cc b/intern/opensubdiv/opensubdiv_utils_capi.cc
index 5a2d017..a3aff53 100644
--- a/intern/opensubdiv/opensubdiv_utils_capi.cc
+++ b/intern/opensubdiv/opensubdiv_utils_capi.cc
@@ -26,6 +26,7 @@
 
 #include "opensubdiv_capi.h"
 
+#include <cstring>
 #include <GL/glew.h>
 
 #ifdef _MSC_VER
@@ -71,7 +72,24 @@ int openSubdiv_getAvailableEvaluators(void)
 #endif  /* OPENSUBDIV_HAS_GLSL_TRANSFORM_FEEDBACK */
 
 #ifdef OPENSUBDIV_HAS_GLSL_COMPUTE
-	flags |= OPENSUBDIV_EVALUATOR_GLSL_COMPUTE;
+	static bool vendor_checked = false;
+	static bool disable_glsl_compute = false;
+	/* Force disable GLSL Compute on AMD hardware because it has really
+	 * hard time evaluating required shaders.
+	 */
+	if (!vendor_checked) {
+		const char *vendor = (const char *)glGetString(GL_VENDOR);
+		const char *renderer = (const char *)glGetString(GL_RENDERER);
+		if (strstr(vendor, "ATI") ||
+			strstr(renderer, "Mesa DRI R") ||
+			(strstr(renderer, "Gallium ") && strstr(renderer, " on ATI ")))
+		{
+			disable_glsl_compute = true;
+		}
+	}
+	if (!disable_glsl_compute) {
+		flags |= OPENSUBDIV_EVALUATOR_GLSL_COMPUTE;
+	}
 #endif  /* OPENSUBDIV_HAS_GLSL_COMPUTE */
 
 	return flags;