Implement WebGL extensions.

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

@@ -0,0 +1,57 @@
+/* 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::OESTextureHalfFloatBinding::{self, OESTextureHalfFloatConstants};
+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::{constants as webgl, ext_constants as gl, WebGLExtension, WebGLExtensions};
+
+#[dom_struct]
+pub struct OESTextureHalfFloat {
+    reflector_: Reflector,
+}
+
+impl OESTextureHalfFloat {
+    fn new_inherited() -> OESTextureHalfFloat {
+        Self {
+            reflector_: Reflector::new(),
+        }
+    }
+}
+
+impl WebGLExtension for OESTextureHalfFloat {
+    type Extension = OESTextureHalfFloat;
+    fn new(ctx: &WebGLRenderingContext) -> Root<OESTextureHalfFloat> {
+        reflect_dom_object(box OESTextureHalfFloat::new_inherited(),
+                           &*ctx.global(),
+                           OESTextureHalfFloatBinding::Wrap)
+    }
+
+    fn is_supported(ext: &WebGLExtensions) -> bool {
+        ext.supports_any_gl_extension(&["GL_OES_texture_half_float",
+                                        "GL_ARB_half_float_pixel",
+                                        "GL_NV_half_float"])
+    }
+
+    fn enable(ext: &WebGLExtensions) {
+        // Enable FLOAT text data type
+        let hf = OESTextureHalfFloatConstants::HALF_FLOAT_OES;
+        ext.enable_tex_type(hf);
+        let needs_replace = !ext.supports_gl_extension("GL_OES_texture_float");
+        if needs_replace {
+            // Special internal formats must be used to avoid clamped float values
+            ext.add_effective_tex_internal_format(webgl::RGBA, hf, gl::RGBA16F);
+            ext.add_effective_tex_internal_format(webgl::RGB, hf, gl::RGB16F);
+            ext.add_effective_tex_internal_format(webgl::LUMINANCE, hf, gl::LUMINANCE16F_ARB);
+            ext.add_effective_tex_internal_format(webgl::ALPHA, hf, gl::ALPHA16F_ARB);
+            ext.add_effective_tex_internal_format(webgl::LUMINANCE_ALPHA, hf, gl::LUMINANCE_ALPHA16F_ARB);
+        }
+    }
+
+    fn name() -> &'static str {
+        "OES_texture_half_float"
+    }
+}