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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use canvas_traits::webgl::{WebGLChan, WebGLContextId, WebGLMsg, WebGLPipeline, WebGLReceiver};
use canvas_traits::webgl::{WebGLSender, WebVRCommand, WebVRRenderHandler};
use canvas_traits::webgl::DOMToTextureCommand;
use canvas_traits::webgl::webgl_channel;
use crate::gl_context::GLContextFactory;
use crate::webgl_thread::{WebGLExternalImageApi, WebGLExternalImageHandler, WebGLThread};
use euclid::Size2D;
use fnv::FnvHashMap;
use gleam::gl;
use servo_config::prefs::PREFS;
use std::rc::Rc;
use webrender;
use webrender_api;
/// WebGL Threading API entry point that lives in the constellation.
pub struct WebGLThreads(WebGLSender<WebGLMsg>);
impl WebGLThreads {
/// Creates a new WebGLThreads object
pub fn new(
gl_factory: GLContextFactory,
webrender_gl: Rc<gl::Gl>,
webrender_api_sender: webrender_api::RenderApiSender,
webvr_compositor: Option<Box<WebVRRenderHandler>>,
) -> (
WebGLThreads,
Box<webrender::ExternalImageHandler>,
Option<Box<webrender::OutputImageHandler>>,
) {
// This implementation creates a single `WebGLThread` for all the pipelines.
let channel = WebGLThread::start(
gl_factory,
webrender_api_sender,
webvr_compositor.map(|c| WebVRRenderWrapper(c)),
);
let output_handler = if PREFS.is_dom_to_texture_enabled() {
Some(Box::new(OutputHandler::new(
webrender_gl.clone(),
channel.clone(),
)))
} else {
None
};
let external =
WebGLExternalImageHandler::new(WebGLExternalImages::new(webrender_gl, channel.clone()));
(
WebGLThreads(channel),
Box::new(external),
output_handler.map(|b| b as Box<_>),
)
}
/// Gets the WebGLThread handle for each script pipeline.
pub fn pipeline(&self) -> WebGLPipeline {
// This mode creates a single thread, so the existing WebGLChan is just cloned.
WebGLPipeline(WebGLChan(self.0.clone()))
}
/// Sends a exit message to close the WebGLThreads and release all WebGLContexts.
pub fn exit(&self) -> Result<(), &'static str> {
self.0
.send(WebGLMsg::Exit)
.map_err(|_| "Failed to send Exit message")
}
}
/// Bridge between the webrender::ExternalImage callbacks and the WebGLThreads.
struct WebGLExternalImages {
webrender_gl: Rc<gl::Gl>,
webgl_channel: WebGLSender<WebGLMsg>,
// Used to avoid creating a new channel on each received WebRender request.
lock_channel: (
WebGLSender<(u32, Size2D<i32>, usize)>,
WebGLReceiver<(u32, Size2D<i32>, usize)>,
),
}
impl WebGLExternalImages {
fn new(webrender_gl: Rc<gl::Gl>, channel: WebGLSender<WebGLMsg>) -> Self {
Self {
webrender_gl,
webgl_channel: channel,
lock_channel: webgl_channel().unwrap(),
}
}
}
impl WebGLExternalImageApi for WebGLExternalImages {
fn lock(&mut self, ctx_id: WebGLContextId) -> (u32, Size2D<i32>) {
// WebGL Thread has it's own GL command queue that we need to synchronize with the WR GL command queue.
// The WebGLMsg::Lock message inserts a fence in the WebGL command queue.
self.webgl_channel
.send(WebGLMsg::Lock(ctx_id, self.lock_channel.0.clone()))
.unwrap();
let (image_id, size, gl_sync) = self.lock_channel.1.recv().unwrap();
// The next glWaitSync call is run on the WR thread and it's used to synchronize the two
// flows of OpenGL commands in order to avoid WR using a semi-ready WebGL texture.
// glWaitSync doesn't block WR thread, it affects only internal OpenGL subsystem.
self.webrender_gl
.wait_sync(gl_sync as gl::GLsync, 0, gl::TIMEOUT_IGNORED);
(image_id, size)
}
fn unlock(&mut self, ctx_id: WebGLContextId) {
self.webgl_channel.send(WebGLMsg::Unlock(ctx_id)).unwrap();
}
}
/// Wrapper to send WebVR commands used in `WebGLThread`.
struct WebVRRenderWrapper(Box<WebVRRenderHandler>);
impl WebVRRenderHandler for WebVRRenderWrapper {
fn handle(&mut self, command: WebVRCommand, texture: Option<(u32, Size2D<i32>)>) {
self.0.handle(command, texture);
}
}
/// struct used to implement DOMToTexture feature and webrender::OutputImageHandler trait.
type OutputHandlerData = Option<(u32, Size2D<i32>)>;
struct OutputHandler {
webrender_gl: Rc<gl::Gl>,
webgl_channel: WebGLSender<WebGLMsg>,
// Used to avoid creating a new channel on each received WebRender request.
lock_channel: (
WebGLSender<OutputHandlerData>,
WebGLReceiver<OutputHandlerData>,
),
sync_objects: FnvHashMap<webrender_api::PipelineId, gl::GLsync>,
}
impl OutputHandler {
fn new(webrender_gl: Rc<gl::Gl>, channel: WebGLSender<WebGLMsg>) -> Self {
Self {
webrender_gl,
webgl_channel: channel,
lock_channel: webgl_channel().unwrap(),
sync_objects: Default::default(),
}
}
}
/// Bridge between the WR frame outputs and WebGL to implement DOMToTexture synchronization.
impl webrender::OutputImageHandler for OutputHandler {
fn lock(
&mut self,
id: webrender_api::PipelineId,
) -> Option<(u32, webrender_api::DeviceIntSize)> {
// Insert a fence in the WR command queue
let gl_sync = self
.webrender_gl
.fence_sync(gl::SYNC_GPU_COMMANDS_COMPLETE, 0);
// The lock command adds a WaitSync call on the WebGL command flow.
let command = DOMToTextureCommand::Lock(id, gl_sync as usize, self.lock_channel.0.clone());
self.webgl_channel
.send(WebGLMsg::DOMToTextureCommand(command))
.unwrap();
self.lock_channel.1.recv().unwrap().map(|(tex_id, size)| {
(
tex_id,
webrender_api::DeviceIntSize::new(size.width, size.height),
)
})
}
fn unlock(&mut self, id: webrender_api::PipelineId) {
if let Some(gl_sync) = self.sync_objects.remove(&id) {
// Flush the Sync object into the GPU's command queue to guarantee that it it's signaled.
self.webrender_gl.flush();
// Mark the sync object for deletion.
self.webrender_gl.delete_sync(gl_sync);
}
}
}
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