Implement EXT_blend_minmax

5 files changed, 99 insertions, 21 deletions

diff --git a/components/script/dom/webgl_extensions/ext/extblendminmax.rs b/components/script/dom/webgl_extensions/ext/extblendminmax.rs
new file mode 100644
index 00000000000..70bf828ccc8
--- /dev/null
+++ b/components/script/dom/webgl_extensions/ext/extblendminmax.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 canvas_traits::webgl::WebGLVersion;
+use dom::bindings::codegen::Bindings::EXTBlendMinmaxBinding;
+use dom::bindings::reflector::{DomObject, Reflector, reflect_dom_object};
+use dom::bindings::root::DomRoot;
+use dom::webglrenderingcontext::WebGLRenderingContext;
+use dom_struct::dom_struct;
+use super::{WebGLExtension, WebGLExtensions, WebGLExtensionSpec};
+
+#[dom_struct]
+pub struct EXTBlendMinmax {
+    reflector_: Reflector,
+}
+
+impl EXTBlendMinmax {
+    fn new_inherited() -> Self {
+        Self { reflector_: Reflector::new() }
+    }
+}
+
+impl WebGLExtension for EXTBlendMinmax {
+    type Extension = Self;
+
+    fn new(ctx: &WebGLRenderingContext) -> DomRoot<Self> {
+        reflect_dom_object(
+            Box::new(Self::new_inherited()),
+            &*ctx.global(),
+            EXTBlendMinmaxBinding::Wrap,
+        )
+    }
+
+    fn spec() -> WebGLExtensionSpec {
+        WebGLExtensionSpec::Specific(WebGLVersion::WebGL1)
+    }
+
+    fn is_supported(ext: &WebGLExtensions) -> bool {
+        ext.supports_gl_extension("GL_EXT_blend_minmax")
+    }
+
+    fn enable(ext: &WebGLExtensions) {
+        ext.enable_blend_minmax();
+    }
+
+    fn name() -> &'static str {
+        "EXT_blend_minmax"
+    }
+}
diff --git a/components/script/dom/webgl_extensions/ext/mod.rs b/components/script/dom/webgl_extensions/ext/mod.rs
index e0c7b1f189a..bdf19d5327a 100644
--- a/components/script/dom/webgl_extensions/ext/mod.rs
+++ b/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, WebGLExtensionSpec};
 
+pub mod extblendminmax;
 pub mod extshadertexturelod;
 pub mod exttexturefilteranisotropic;
 pub mod oeselementindexuint;
diff --git a/components/script/dom/webgl_extensions/extensions.rs b/components/script/dom/webgl_extensions/extensions.rs
index ca81e2d10e8..c5413ea1eb2 100644
--- a/components/script/dom/webgl_extensions/extensions.rs
+++ b/components/script/dom/webgl_extensions/extensions.rs
@@ -70,6 +70,8 @@ struct WebGLExtensionFeatures {
     disabled_get_tex_parameter_names: FnvHashSet<GLenum>,
     /// WebGL OES_element_index_uint extension.
     element_index_uint_enabled: bool,
+    /// WebGL EXT_blend_minmax extension.
+    blend_minmax_enabled: bool,
 }
 
 impl WebGLExtensionFeatures {
@@ -79,6 +81,7 @@ impl WebGLExtensionFeatures {
             disabled_get_parameter_names,
             disabled_get_tex_parameter_names,
             element_index_uint_enabled,
+            blend_minmax_enabled,
         ) = match webgl_version {
             WebGLVersion::WebGL1 => {
                 (
@@ -86,10 +89,11 @@ impl WebGLExtensionFeatures {
                     DEFAULT_DISABLED_GET_PARAMETER_NAMES_WEBGL1.iter().cloned().collect(),
                     DEFAULT_DISABLED_GET_TEX_PARAMETER_NAMES_WEBGL1.iter().cloned().collect(),
                     false,
+                    false,
                 )
             },
             WebGLVersion::WebGL2 => {
-                (Default::default(), Default::default(), Default::default(), true)
+                (Default::default(), Default::default(), Default::default(), true, true)
             }
         };
         Self {
@@ -102,6 +106,7 @@ impl WebGLExtensionFeatures {
             disabled_get_parameter_names,
             disabled_get_tex_parameter_names,
             element_index_uint_enabled,
+            blend_minmax_enabled,
         }
     }
 }
@@ -265,6 +270,7 @@ impl WebGLExtensions {
     }
 
     fn register_all_extensions(&self) {
+        self.register::<ext::extblendminmax::EXTBlendMinmax>();
         self.register::<ext::extshadertexturelod::EXTShaderTextureLod>();
         self.register::<ext::exttexturefilteranisotropic::EXTTextureFilterAnisotropic>();
         self.register::<ext::oeselementindexuint::OESElementIndexUint>();
@@ -283,6 +289,14 @@ impl WebGLExtensions {
     pub fn is_element_index_uint_enabled(&self) -> bool {
         self.features.borrow().element_index_uint_enabled
     }
+
+    pub fn enable_blend_minmax(&self) {
+        self.features.borrow_mut().blend_minmax_enabled = true;
+    }
+
+    pub fn is_blend_minmax_enabled(&self) -> bool {
+        self.features.borrow().blend_minmax_enabled
+    }
 }
 
 // Helper structs
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index d712b8cc58a..7079bbcc76b 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -12,6 +12,7 @@ use canvas_traits::webgl::{WebGLResult, WebGLSLVersion, WebGLVersion};
 use canvas_traits::webgl::{WebVRCommand, webgl_channel};
 use canvas_traits::webgl::WebGLError::*;
 use dom::bindings::cell::DomRefCell;
+use dom::bindings::codegen::Bindings::EXTBlendMinmaxBinding::EXTBlendMinmaxConstants;
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::{self, WebGLContextAttributes};
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
 use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextMethods;
@@ -1193,6 +1194,21 @@ impl WebGLRenderingContext {
             _ => Err(WebGLError::InvalidEnum),
         }
     }
+
+    fn validate_blend_mode(&self, mode: u32) -> WebGLResult<()> {
+        match mode {
+            constants::FUNC_ADD |
+            constants::FUNC_SUBTRACT |
+            constants::FUNC_REVERSE_SUBTRACT => {
+                Ok(())
+            }
+            EXTBlendMinmaxConstants::MIN_EXT |
+            EXTBlendMinmaxConstants::MAX_EXT if self.extension_manager.is_blend_minmax_enabled() => {
+                Ok(())
+            }
+            _ => Err(InvalidEnum),
+        }
+    }
 }
 
 impl Drop for WebGLRenderingContext {
@@ -1547,30 +1563,14 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3
     fn BlendEquation(&self, mode: u32) {
-        match mode {
-            constants::FUNC_ADD |
-            constants::FUNC_SUBTRACT |
-            constants::FUNC_REVERSE_SUBTRACT => {
-                self.send_command(WebGLCommand::BlendEquation(mode))
-            }
-            _ => self.webgl_error(InvalidEnum),
-        }
+        handle_potential_webgl_error!(self, self.validate_blend_mode(mode), return);
+        self.send_command(WebGLCommand::BlendEquation(mode))
     }
 
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3
     fn BlendEquationSeparate(&self, mode_rgb: u32, mode_alpha: u32) {
-        match mode_rgb {
-            constants::FUNC_ADD |
-            constants::FUNC_SUBTRACT |
-            constants::FUNC_REVERSE_SUBTRACT => {},
-            _ => return self.webgl_error(InvalidEnum),
-        }
-        match mode_alpha {
-            constants::FUNC_ADD |
-            constants::FUNC_SUBTRACT |
-            constants::FUNC_REVERSE_SUBTRACT => {},
-            _ => return self.webgl_error(InvalidEnum),
-        }
+        handle_potential_webgl_error!(self, self.validate_blend_mode(mode_rgb), return);
+        handle_potential_webgl_error!(self, self.validate_blend_mode(mode_alpha), return);
         self.send_command(WebGLCommand::BlendEquationSeparate(mode_rgb, mode_alpha));
     }
 
diff --git a/components/script/dom/webidls/EXTBlendMinmax.webidl b/components/script/dom/webidls/EXTBlendMinmax.webidl
new file mode 100644
index 00000000000..bbdbee874f5
--- /dev/null
+++ b/components/script/dom/webidls/EXTBlendMinmax.webidl
@@ -0,0 +1,13 @@
+/* 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/. */
+/*
+ * WebGL IDL definitions scraped from the Khronos specification:
+ * https://www.khronos.org/registry/webgl/extensions/EXT_blend_minmax/
+ */
+
+[NoInterfaceObject]
+interface EXTBlendMinmax {
+  const GLenum MIN_EXT = 0x8007;
+  const GLenum MAX_EXT = 0x8008;
+};