3 files changed, 51 insertions, 2 deletions
diff --git a/components/script/dom/webgl2renderingcontext.rs b/components/script/dom/webgl2renderingcontext.rs
index 81a1688c68b..cb5e17dfe26 100644
--- a/components/script/dom/webgl2renderingcontext.rs
+++ b/components/script/dom/webgl2renderingcontext.rs
@@ -159,6 +159,17 @@ impl WebGL2RenderingContextMethods for WebGL2RenderingContext {
         self.base.GetFramebufferAttachmentParameter(cx, target, attachment, pname)
     }
 
+    #[allow(unsafe_code)]
+    /// https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.7
+    unsafe fn GetRenderbufferParameter(
+        &self,
+        cx: *mut JSContext,
+        target: u32,
+        pname: u32
+    ) -> JSVal {
+        self.base.GetRenderbufferParameter(cx, target, pname)
+    }
+
     /// https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.3
     fn ActiveTexture(&self, texture: u32) {
         self.base.ActiveTexture(texture)
diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index 8e4757a5841..d68f817dcd6 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -2348,6 +2348,45 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         Int32Value(receiver.recv().unwrap())
     }
 
+    #[allow(unsafe_code)]
+    // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.7
+    unsafe fn GetRenderbufferParameter(
+        &self,
+        _cx: *mut JSContext,
+        target: u32,
+        pname: u32
+    ) -> JSVal {
+        let target_matches = target == constants::RENDERBUFFER;
+
+        let pname_matches = match pname {
+            constants::RENDERBUFFER_WIDTH |
+            constants::RENDERBUFFER_HEIGHT |
+            constants::RENDERBUFFER_INTERNAL_FORMAT |
+            constants::RENDERBUFFER_RED_SIZE |
+            constants::RENDERBUFFER_GREEN_SIZE |
+            constants::RENDERBUFFER_BLUE_SIZE |
+            constants::RENDERBUFFER_ALPHA_SIZE |
+            constants::RENDERBUFFER_DEPTH_SIZE |
+            constants::RENDERBUFFER_STENCIL_SIZE => true,
+            _ => false,
+        };
+
+        if !target_matches || !pname_matches {
+            self.webgl_error(InvalidEnum);
+            return NullValue();
+        }
+
+        if self.bound_renderbuffer.get().is_none() {
+            self.webgl_error(InvalidOperation);
+            return NullValue();
+        }
+
+        let (sender, receiver) = webgl_channel().unwrap();
+        self.send_command(WebGLCommand::GetRenderbufferParameter(target, pname, sender));
+
+        Int32Value(receiver.recv().unwrap())
+    }
+
     // https://www.khronos.org/registry/webgl/specs/latest/1.0/#5.14.9
     fn GetProgramInfoLog(&self, program: &WebGLProgram) -> Option<DOMString> {
         match program.get_info_log() {
diff --git a/components/script/dom/webidls/WebGLRenderingContext.webidl b/components/script/dom/webidls/WebGLRenderingContext.webidl
index cd714b4c787..8ec02ce95ea 100644
--- a/components/script/dom/webidls/WebGLRenderingContext.webidl
+++ b/components/script/dom/webidls/WebGLRenderingContext.webidl
@@ -571,8 +571,7 @@ interface WebGLRenderingContextBase
                                           GLenum pname);
     any getProgramParameter(WebGLProgram program, GLenum pname);
     DOMString? getProgramInfoLog(WebGLProgram program);
-    // FIXME: https://github.com/servo/servo/issues/20514
-    // any getRenderbufferParameter(GLenum target, GLenum pname);
+    any getRenderbufferParameter(GLenum target, GLenum pname);
     any getShaderParameter(WebGLShader shader, GLenum pname);
     WebGLShaderPrecisionFormat? getShaderPrecisionFormat(GLenum shadertype, GLenum precisiontype);
     DOMString? getShaderInfoLog(WebGLShader shader);