Bug 1491221 - Mark EXT_shader_texture_lod feature unsupported for OpenGL ES3 and above. r=jgilbert

MozReview-Commit-ID: G51cg7pqvBb

Differential Revision: https://phabricator.services.mozilla.com/D6863

--HG--
extra : moz-landing-system : lando

dom/canvas/WebGLContextExtensions.cpp

@@ -184,7 +184,7 @@ WebGLContext::IsExtensionSupported(WebGLExtensionID ext) const
         case WebGLExtensionID::EXT_frag_depth:
             return WebGLExtensionFragDepth::IsSupported(this);
         case WebGLExtensionID::EXT_shader_texture_lod:
-            return gl->IsSupported(gl::GLFeature::shader_texture_lod);
+            return WebGLExtensionShaderTextureLod::IsSupported(this);
         case WebGLExtensionID::EXT_sRGB:
             return WebGLExtensionSRGB::IsSupported(this);
 

dom/canvas/WebGLExtensionShaderTextureLod.cpp

@@ -14,12 +14,25 @@ namespace mozilla {
 WebGLExtensionShaderTextureLod::WebGLExtensionShaderTextureLod(WebGLContext* webgl)
     : WebGLExtensionBase(webgl)
 {
+    MOZ_ASSERT(IsSupported(webgl), "Don't construct extension if unsupported.");
 }
 
 WebGLExtensionShaderTextureLod::~WebGLExtensionShaderTextureLod()
 {
 }
 
+bool
+WebGLExtensionShaderTextureLod::IsSupported(const WebGLContext* webgl)
+{
+    gl::GLContext* gl = webgl->GL();
+    if (gl->IsGLES() && gl->Version() >= 300) {
+        // ANGLE's shader translator doesn't yet translate
+        // WebGL1+EXT_shader_texture_lod to ES3. (Bug 1491221)
+        return false;
+    }
+    return gl->IsSupported(gl::GLFeature::shader_texture_lod);
+}
+
 IMPL_WEBGL_EXTENSION_GOOP(WebGLExtensionShaderTextureLod, EXT_shader_texture_lod)
 
 } // namespace mozilla

dom/canvas/WebGLExtensions.h

@@ -251,6 +251,8 @@ public:
     explicit WebGLExtensionShaderTextureLod(WebGLContext*);
     virtual ~WebGLExtensionShaderTextureLod();
 
+    static bool IsSupported(const WebGLContext* context);
+
     DECL_WEBGL_EXTENSION_GOOP
 };