Implement WebGL OES_standard_derivatives extension.

components/script/dom/webgl_extensions/ext/mod.rs

@@ -5,6 +5,7 @@
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
 use super::{ext_constants, WebGLExtension, WebGLExtensions};
 
+pub mod oesstandardderivatives;
 pub mod oestexturefloat;
 pub mod oestexturefloatlinear;
 pub mod oestexturehalffloat;

components/script/dom/webgl_extensions/ext/oesstandardderivatives.rs

@@ -0,0 +1,50 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use dom::bindings::codegen::Bindings::OESStandardDerivativesBinding;
+use dom::bindings::codegen::Bindings::OESStandardDerivativesBinding::OESStandardDerivativesConstants;
+use dom::bindings::js::Root;
+use dom::bindings::reflector::{DomObject, Reflector, reflect_dom_object};
+use dom::webglrenderingcontext::WebGLRenderingContext;
+use dom_struct::dom_struct;
+use super::{WebGLExtension, WebGLExtensions};
+
+#[dom_struct]
+pub struct OESStandardDerivatives {
+    reflector_: Reflector,
+}
+
+impl OESStandardDerivatives {
+    fn new_inherited() -> OESStandardDerivatives {
+        Self {
+            reflector_: Reflector::new(),
+        }
+    }
+}
+
+impl WebGLExtension for OESStandardDerivatives {
+    type Extension = OESStandardDerivatives;
+    fn new(ctx: &WebGLRenderingContext) -> Root<OESStandardDerivatives> {
+        reflect_dom_object(box OESStandardDerivatives::new_inherited(),
+                           &*ctx.global(),
+                           OESStandardDerivativesBinding::Wrap)
+    }
+
+    fn is_supported(ext: &WebGLExtensions) -> bool {
+        if cfg!(any(target_os = "android", target_os = "ios")) {
+            return ext.supports_any_gl_extension(&["GL_OES_standard_derivatives"]);
+        }
+        // The standard derivatives are always available in desktop OpenGL.
+        true
+    }
+
+    fn enable(ext: &WebGLExtensions) {
+        ext.enable_hint_target(OESStandardDerivativesConstants::FRAGMENT_SHADER_DERIVATIVE_HINT_OES);
+        ext.enable_get_parameter_name(OESStandardDerivativesConstants::FRAGMENT_SHADER_DERIVATIVE_HINT_OES);
+    }
+
+    fn name() -> &'static str {
+        "OES_standard_derivatives"
+    }
+}