Auto merge of #6380 - ecoal95:webgl-refactoring, r=jdm

Refactor WebGL implementation to move logic inside the DOM interfaces

This improves the encapsulation and consistency in our WebGL
implementation.

Also allows to implement new methods such as `getShaderSource()`.

It will also allow us to use `delete()` in the destructors of them (note
that we will probably want to keep track of them from the context before).

Some concerns:

**Trait method repetition**:
I'm aware that the traits `WebGL{Buffer,Renderbuffer,Framebuffer,Texture}Helpers` are basically the same, but `delete()` and `id()` methods are everywhere. I've thought something like:

```rust
pub trait WebGLIdentifiable {
    type WebGLId; // id is sometimes i32 (see WebGLUniformLocation)
    fn id(&self) -> Self::WebGLId;
}

pub trait WebGLBindable {
    fn bind(&self);
}

pub trait WebGLDeletable {
    fn delete(&self);
}
```

But I'd want to know your opinion first.

**`renderer` repetition**:
Thought of moving the field: `renderer: Sender<CanvasMsg>` to `WebGLObject`, but I think it makes it way more complicated to read, and also a bit unnecessary, at least IMO (`WebGLObject` will never interact with the field directly). It would also mean that all `WebGLObject`s should have one, which is true at this moment, but maybe not with WebGL 2, for example.

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1 files changed, 35 insertions, 5 deletions

diff --git a/components/script/dom/webglframebuffer.rs b/components/script/dom/webglframebuffer.rs
index f4bb4b2b043..26773ca4b17 100644
--- a/components/script/dom/webglframebuffer.rs
+++ b/components/script/dom/webglframebuffer.rs
@@ -9,31 +9,61 @@ use dom::bindings::js::Root;
 use dom::bindings::utils::reflect_dom_object;
 use dom::webglobject::WebGLObject;
 
+use canvas_traits::{CanvasMsg, CanvasWebGLMsg, WebGLFramebufferBindingRequest};
+use std::sync::mpsc::{channel, Sender};
+use std::cell::Cell;
+
 #[dom_struct]
 pub struct WebGLFramebuffer {
     webgl_object: WebGLObject,
     id: u32,
+    is_deleted: Cell<bool>,
+    renderer: Sender<CanvasMsg>,
 }
 
 impl WebGLFramebuffer {
-    fn new_inherited(id: u32) -> WebGLFramebuffer {
+    fn new_inherited(renderer: Sender<CanvasMsg>, id: u32) -> WebGLFramebuffer {
         WebGLFramebuffer {
             webgl_object: WebGLObject::new_inherited(),
             id: id,
+            is_deleted: Cell::new(false),
+            renderer: renderer,
         }
     }
 
-    pub fn new(global: GlobalRef, id: u32) -> Root<WebGLFramebuffer> {
-        reflect_dom_object(box WebGLFramebuffer::new_inherited(id), global, WebGLFramebufferBinding::Wrap)
+    pub fn maybe_new(global: GlobalRef, renderer: Sender<CanvasMsg>) -> Option<Root<WebGLFramebuffer>> {
+        let (sender, receiver) = channel();
+        renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CreateFramebuffer(sender))).unwrap();
+
+        let result = receiver.recv().unwrap();
+        result.map(|fb_id| WebGLFramebuffer::new(global, renderer, *fb_id))
+    }
+
+    pub fn new(global: GlobalRef, renderer: Sender<CanvasMsg>, id: u32) -> Root<WebGLFramebuffer> {
+        reflect_dom_object(box WebGLFramebuffer::new_inherited(renderer, id), global, WebGLFramebufferBinding::Wrap)
     }
 }
 
 pub trait WebGLFramebufferHelpers {
-    fn get_id(self) -> u32;
+    fn id(self) -> u32;
+    fn bind(self, target: u32);
+    fn delete(self);
 }
 
 impl<'a> WebGLFramebufferHelpers for &'a WebGLFramebuffer {
-    fn get_id(self) -> u32 {
+    fn id(self) -> u32 {
         self.id
     }
+
+    fn bind(self, target: u32) {
+        let cmd = CanvasWebGLMsg::BindFramebuffer(target, WebGLFramebufferBindingRequest::Explicit(self.id));
+        self.renderer.send(CanvasMsg::WebGL(cmd)).unwrap();
+    }
+
+    fn delete(self) {
+        if !self.is_deleted.get() {
+            self.is_deleted.set(true);
+            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteFramebuffer(self.id))).unwrap();
+        }
+    }
 }