webgl: Update FBO status when textures or RBs are reallocated.

FBO status is supposed to depend on the size of the attachments all
matching, so we need to re-check when it changes.  We don't ensure
matching yet, but this will prevent regressions when we do.

components/script/dom/webglframebuffer.rs

@@ -254,7 +254,9 @@ impl WebGLFramebuffer {
         Ok(())
     }
 
-    pub fn detach_renderbuffer(&self, rb: &WebGLRenderbuffer) {
+    fn with_matching_renderbuffers<F>(&self, rb: &WebGLRenderbuffer, mut closure: F)
+        where F: FnMut(&DOMRefCell<Option<WebGLFramebufferAttachment>>)
+    {
         let attachments = [&self.color,
                            &self.depth,
                            &self.stencil,
@@ -270,13 +272,14 @@ impl WebGLFramebuffer {
             };
 
             if matched {
-                *attachment.borrow_mut() = None;
+                closure(attachment);
-                self.update_status();
             }
         }
     }
 
-    pub fn detach_texture(&self, texture: &WebGLTexture) {
+    fn with_matching_textures<F>(&self, texture: &WebGLTexture, mut closure: F)
+        where F: FnMut(&DOMRefCell<Option<WebGLFramebufferAttachment>>)
+    {
         let attachments = [&self.color,
                            &self.depth,
                            &self.stencil,
@@ -292,10 +295,35 @@ impl WebGLFramebuffer {
             };
 
             if matched {
-                *attachment.borrow_mut() = None;
+                closure(attachment);
+            }
+        }
+    }
+
+    pub fn detach_renderbuffer(&self, rb: &WebGLRenderbuffer) {
+        self.with_matching_renderbuffers(rb, |att| {
+            *att.borrow_mut() = None;
             self.update_status();
+        });
     }
+
+    pub fn detach_texture(&self, texture: &WebGLTexture) {
+        self.with_matching_textures(texture, |att| {
+            *att.borrow_mut() = None;
+            self.update_status();
+        });
     }
+
+    pub fn invalidate_renderbuffer(&self, rb: &WebGLRenderbuffer) {
+        self.with_matching_renderbuffers(rb, |_att| {
+            self.update_status();
+        });
+    }
+
+    pub fn invalidate_texture(&self, texture: &WebGLTexture) {
+        self.with_matching_textures(texture, |_att| {
+            self.update_status();
+        });
     }
 
     pub fn target(&self) -> Option<u32> {

components/script/dom/webglrenderingcontext.rs

@@ -465,7 +465,11 @@ impl WebGLRenderingContext {
 
         self.ipc_renderer
             .send(CanvasMsg::WebGL(msg))
-            .unwrap()
+            .unwrap();
+
+        if let Some(fb) = self.bound_framebuffer.get() {
+            fb.invalidate_texture(&*texture);
+        }
     }
 
     fn tex_sub_image_2d(&self,
@@ -2621,7 +2625,12 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
         }
 
         match self.bound_renderbuffer.get() {
-            Some(rb) => handle_potential_webgl_error!(self, rb.storage(internal_format, width, height)),
+            Some(rb) => {
+                handle_potential_webgl_error!(self, rb.storage(internal_format, width, height));
+                if let Some(fb) = self.bound_framebuffer.get() {
+                    fb.invalidate_renderbuffer(&*rb);
+                }
+            }
             None => self.webgl_error(InvalidOperation),
         };