Bug 696495 - set tex min filter before generateMipmap calls, to work around driver bugs - r=jgilbert, a=akeybl

content/canvas/src/WebGLContextGL.cpp

@@ -1933,7 +1933,19 @@ WebGLContext::GenerateMipmap(WebGLenum target)
     tex->SetGeneratedMipmap();
 
     MakeContextCurrent();
-    gl->fGenerateMipmap(target);
+
+    if (gl->WorkAroundDriverBugs()) {
+        // bug 696495 - to work around failures in the texture-mips.html test on various drivers, we
+        // set the minification filter before calling glGenerateMipmap. This should not carry a significant performance
+        // overhead so we do it unconditionally.
+        //
+        // note that the choice of GL_NEAREST_MIPMAP_NEAREST really matters. See Chromium bug 101105.
+        gl->fTexParameteri(target, LOCAL_GL_TEXTURE_MIN_FILTER, LOCAL_GL_NEAREST_MIPMAP_NEAREST);
+        gl->fGenerateMipmap(target);
+        gl->fTexParameteri(target, LOCAL_GL_TEXTURE_MIN_FILTER, tex->MinFilter());
+    } else {
+        gl->fGenerateMipmap(target);
+    }
     return NS_OK;
 }
 

content/canvas/test/webgl/failing_tests_mac.txt

@@ -1,4 +1,2 @@
 conformance/glsl/misc/glsl-function-nodes.html
 conformance/programs/program-test.html
-conformance/textures/texture-mips.html
-conformance/textures/texture-npot.html