Implement GLContextDispatcher trait for NativeGLContexts

webrender/src/internal_types.rs

@@ -9,7 +9,7 @@ use fnv::FnvHasher;
 use freelist::{FreeListItem, FreeListItemId};
 use num_traits::Zero;
 use offscreen_gl_context::{NativeGLContext, NativeGLContextHandle};
-use offscreen_gl_context::{GLContext, NativeGLContextMethods};
+use offscreen_gl_context::{GLContext, NativeGLContextMethods, GLContextDispatcher};
 use offscreen_gl_context::{OSMesaContext, OSMesaContextHandle};
 use offscreen_gl_context::{ColorAttachmentType, GLContextAttributes, GLLimits};
 use profiler::BackendProfileCounters;
@@ -42,20 +42,23 @@ impl GLContextHandleWrapper {
 
     pub fn new_context(&self,
                        size: Size2D<i32>,
-                       attributes: GLContextAttributes) -> Result<GLContextWrapper, &'static str> {
+                       attributes: GLContextAttributes,
+                       dispatcher: Option<Box<GLContextDispatcher>>) -> Result<GLContextWrapper, &'static str> {
         match *self {
             GLContextHandleWrapper::Native(ref handle) => {
-                let ctx = GLContext::<NativeGLContext>::new(size,
-                                                            attributes,
-                                                            ColorAttachmentType::Texture,
-                                                            Some(handle));
+                let ctx = GLContext::<NativeGLContext>::new_shared_with_dispatcher(size,
+                                                                                   attributes,
+                                                                                   ColorAttachmentType::Texture,
+                                                                                   Some(handle),
+                                                                                   dispatcher);
                 ctx.map(GLContextWrapper::Native)
             }
             GLContextHandleWrapper::OSMesa(ref handle) => {
-                let ctx = GLContext::<OSMesaContext>::new(size,
-                                                          attributes,
-                                                          ColorAttachmentType::Texture,
-                                                          Some(handle));
+                let ctx = GLContext::<OSMesaContext>::new_shared_with_dispatcher(size,
+                                                                                 attributes,
+                                                                                 ColorAttachmentType::Texture,
+                                                                                 Some(handle),
+                                                                                 dispatcher);
                 ctx.map(GLContextWrapper::OSMesa)
             }
         }

webrender/src/render_backend.rs

@@ -16,12 +16,13 @@ use std::sync::{Arc, Mutex};
 use std::sync::mpsc::Sender;
 use texture_cache::TextureCache;
 use webrender_traits::{ApiMsg, AuxiliaryLists, BuiltDisplayList, IdNamespace};
-use webrender_traits::{RenderNotifier, WebGLContextId};
+use webrender_traits::{RenderNotifier, WebGLContextId, RenderDispatcher};
 use batch::new_id;
 use device::TextureId;
 use record;
 use tiling::FrameBuilderConfig;
 use gleam::gl;
+use offscreen_gl_context::GLContextDispatcher;
 
 pub struct RenderBackend {
     api_rx: IpcReceiver<ApiMsg>,
@@ -42,6 +43,7 @@ pub struct RenderBackend {
     webgl_contexts: HashMap<WebGLContextId, GLContextWrapper>,
     current_bound_webgl_context_id: Option<WebGLContextId>,
     enable_recording: bool,
+    main_thread_dispatcher: Arc<Mutex<Option<Box<RenderDispatcher>>>>
 }
 
 impl RenderBackend {
@@ -56,7 +58,8 @@ impl RenderBackend {
                webrender_context_handle: Option<GLContextHandleWrapper>,
                config: FrameBuilderConfig,
                debug: bool,
-               enable_recording:bool) -> RenderBackend {
+               enable_recording:bool,
+               main_thread_dispatcher:  Arc<Mutex<Option<Box<RenderDispatcher>>>>) -> RenderBackend {
         let resource_cache = ResourceCache::new(texture_cache,
                                                 device_pixel_ratio,
                                                 enable_aa);
@@ -76,6 +79,7 @@ impl RenderBackend {
             webgl_contexts: HashMap::new(),
             current_bound_webgl_context_id: None,
             enable_recording:enable_recording,
+            main_thread_dispatcher: main_thread_dispatcher
         }
     }
 
@@ -261,7 +265,15 @@ impl RenderBackend {
                         }
                         ApiMsg::RequestWebGLContext(size, attributes, tx) => {
                             if let Some(ref wrapper) = self.webrender_context_handle {
-                                let result = wrapper.new_context(size, attributes);
+                                let dispatcher: Option<Box<GLContextDispatcher>> = if cfg!(target_os = "windows") {
+                                    Some(Box::new(WebRenderGLDispatcher {
+                                        dispatcher: self.main_thread_dispatcher.clone()
+                                    }))
+                                } else {
+                                    None
+                                };
+
+                                let result = wrapper.new_context(size, attributes, dispatcher);
 
                                 match result {
                                     Ok(ctx) => {
@@ -417,3 +429,14 @@ impl RenderBackend {
     }
 }
 
+struct WebRenderGLDispatcher {
+    dispatcher: Arc<Mutex<Option<Box<RenderDispatcher>>>>
+}
+
+impl GLContextDispatcher for WebRenderGLDispatcher {
+    fn dispatch(&self, f: Box<Fn() + Send>) {
+        let mut dispatcher = self.dispatcher.lock();
+        dispatcher.as_mut().unwrap().as_mut().unwrap().dispatch(f);
+    }
+}
+

webrender/src/renderer.rs

@@ -38,7 +38,7 @@ use texture_cache::{BorderType, TextureCache, TextureInsertOp};
 use tiling::{self, Frame, FrameBuilderConfig, GLYPHS_PER_TEXT_RUN, PrimitiveBatchData};
 use tiling::{TransformedRectKind, RenderTarget, ClearTile};
 use time::precise_time_ns;
-use webrender_traits::{ColorF, Epoch, PipelineId, RenderNotifier};
+use webrender_traits::{ColorF, Epoch, PipelineId, RenderNotifier, RenderDispatcher};
 use webrender_traits::{ImageFormat, RenderApiSender, RendererKind};
 
 pub const BLUR_INFLATION_FACTOR: u32 = 3;
@@ -362,6 +362,9 @@ pub struct Renderer {
     layer_texture: VertexDataTexture,
     render_task_texture: VertexDataTexture,
     pipeline_epoch_map: HashMap<PipelineId, Epoch, BuildHasherDefault<FnvHasher>>,
+    /// Used to dispatch functions to the main thread's event loop.
+    /// Required to allow GLContext sharing in some implementations like WGL.
+    main_thread_dispatcher: Arc<Mutex<Option<Box<RenderDispatcher>>>>
 }
 
 impl Renderer {
@@ -580,7 +583,9 @@ impl Renderer {
 
         device.end_frame();
 
+        let main_thread_dispatcher = Arc::new(Mutex::new(None));
         let backend_notifier = notifier.clone();
+        let backend_main_thread_dispatcher = main_thread_dispatcher.clone();
 
         // We need a reference to the webrender context from the render backend in order to share
         // texture ids
@@ -607,7 +612,8 @@ impl Renderer {
                                                  context_handle,
                                                  config,
                                                  debug,
-                                                 enable_recording);
+                                                 enable_recording,
+                                                 backend_main_thread_dispatcher);
             backend.run();
         });
 
@@ -655,6 +661,7 @@ impl Renderer {
             layer_texture: layer_texture,
             render_task_texture: render_task_texture,
             pipeline_epoch_map: HashMap::with_hasher(Default::default()),
+            main_thread_dispatcher: main_thread_dispatcher
         };
 
         renderer.update_uniform_locations();
@@ -691,6 +698,14 @@ impl Renderer {
         *notifier_arc = Some(notifier);
     }
 
+    /// Sets the new MainThreadDispatcher.
+    ///
+    /// Allows to dispatch functions to the main thread's event loop.
+    pub fn set_main_thread_dispatcher(&self, dispatcher: Box<RenderDispatcher>) {
+        let mut dispatcher_arc = self.main_thread_dispatcher.lock().unwrap();
+        *dispatcher_arc = Some(dispatcher);
+    }
+
     /// Returns the Epoch of the current frame in a pipeline.
     pub fn current_epoch(&self, pipeline_id: PipelineId) -> Option<Epoch> {
         self.pipeline_epoch_map.get(&pipeline_id).map(|epoch| *epoch)

webrender_traits/Cargo.toml

@@ -17,7 +17,7 @@ byteorder = "0.5"
 euclid = "0.10"
 gleam = "0.2.22"
 heapsize = "0.3.6"
-offscreen_gl_context = {version = "0.4.0", features = ["serde_serialization"]}
+offscreen_gl_context = {version = "0.4.5", features = ["serde_serialization"]}
 serde = "0.8"
 serde_derive = {version = "0.8", optional = true}
 ipc-channel = "0.5.0"

webrender_traits/src/types.rs

@@ -369,6 +369,11 @@ pub trait RenderNotifier: Send {
     fn pipeline_size_changed(&mut self, pipeline_id: PipelineId, size: Option<Size2D<f32>>);
 }
 
+// Trait to allow dispatching functions to a specific thread or event loop.
+pub trait RenderDispatcher: Send {
+    fn dispatch(&self, Box<Fn() + Send>);
+}
+
 #[derive(Clone, Copy, Debug, Deserialize, Serialize)]
 pub struct ResourceId(pub u32);