Add initial support for WebGL2 read framebuffer

Adds support for binding to the read framebuffer slot and querying
its status.

1 files changed, 14 insertions, 10 deletions

diff --git a/components/script/dom/webglrenderbuffer.rs b/components/script/dom/webglrenderbuffer.rs
index ca75f83c336..8c8164f6243 100644
--- a/components/script/dom/webglrenderbuffer.rs
+++ b/components/script/dom/webglrenderbuffer.rs
@@ -96,20 +96,24 @@ impl WebGLRenderbuffer {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
 
+            let context = self.upcast::<WebGLObject>().context();
+
             /*
-            If a renderbuffer object is deleted while its image is attached to the currently
-            bound framebuffer, then it is as if FramebufferRenderbuffer had been called, with
-            a renderbuffer of 0, for each attachment point to which this image was attached
-            in the currently bound framebuffer.
-            - GLES 2.0, 4.4.3, "Attaching Renderbuffer Images to a Framebuffer"
-             */
-            let currently_bound_framebuffer =
-                self.upcast::<WebGLObject>().context().bound_framebuffer();
-            if let Some(fb) = currently_bound_framebuffer {
+            If a renderbuffer object is deleted while its image is attached to one or more
+            attachment points in a currently bound framebuffer object, then it is as if
+            FramebufferRenderbuffer had been called, with a renderbuffer of zero, for each
+            attachment point to which this image was attached in that framebuffer object.
+            In other words,the renderbuffer image is first detached from all attachment points
+            in that frame-buffer object.
+            - GLES 3.0, 4.4.2.3, "Attaching Renderbuffer Images to a Framebuffer"
+            */
+            if let Some(fb) = context.get_draw_framebuffer_slot().get() {
+                let _ = fb.detach_renderbuffer(self);
+            }
+            if let Some(fb) = context.get_read_framebuffer_slot().get() {
                 let _ = fb.detach_renderbuffer(self);
             }
 
-            let context = self.upcast::<WebGLObject>().context();
             let cmd = WebGLCommand::DeleteRenderbuffer(self.id);
             if fallible {
                 context.send_command_ignored(cmd);