Add missing compositing/mod.rs

src/servo/compositing/mod.rs

@@ -0,0 +1,303 @@
+/* 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 compositing::resize_rate_limiter::ResizeRateLimiter;
+use dom::event::Event;
+use platform::{Application, Window};
+
+use azure::azure_hl::{BackendType, B8G8R8A8, DataSourceSurface, DrawTarget, SourceSurfaceMethods};
+use core::cell::Cell;
+use core::comm::{Chan, SharedChan, Port};
+use core::util;
+use geom::matrix::identity;
+use geom::point::Point2D;
+use geom::rect::Rect;
+use geom::size::Size2D;
+use gfx::compositor::{Compositor, LayerBuffer, LayerBufferSet};
+use gfx::opts::Opts;
+use layers;
+use servo_util::time;
+
+mod resize_rate_limiter;
+
+/// Type of the function that is called when the screen is to be redisplayed.
+pub type CompositeCallback = @fn();
+
+/// Type of the function that is called when the window is resized.
+pub type ResizeCallback = @fn(uint, uint);
+
+/// The implementation of the layers-based compositor.
+#[deriving(Clone)]
+pub struct CompositorImpl {
+    chan: SharedChan<Msg>
+}
+
+impl CompositorImpl {
+    /// Creates a new compositor instance.
+    pub fn new(dom_event_chan: SharedChan<Event>, opts: Opts) -> CompositorImpl {
+        let dom_event_chan = Cell(dom_event_chan);
+        let chan: Chan<Msg> = do on_osmain |port| {
+            debug!("preparing to enter main loop");
+            mainloop(port, dom_event_chan.take(), &opts);
+        };
+
+        CompositorImpl {
+            chan: SharedChan::new(chan)
+        }
+    }
+}
+
+/// Messages to the compositor.
+pub enum Msg {
+    BeginDrawing(Chan<LayerBufferSet>),
+    Draw(Chan<LayerBufferSet>, LayerBufferSet),
+    AddKeyHandler(Chan<()>),
+    Exit
+}
+
+/// Azure surface wrapping to work with the layers infrastructure.
+struct AzureDrawTargetImageData {
+    draw_target: DrawTarget,
+    data_source_surface: DataSourceSurface,
+    size: Size2D<uint>
+}
+
+impl layers::layers::ImageData for AzureDrawTargetImageData {
+    fn size(&self) -> Size2D<uint> {
+        self.size
+    }
+    fn stride(&self) -> uint {
+        self.data_source_surface.stride() as uint
+    }
+    fn format(&self) -> layers::layers::Format {
+        // FIXME: This is not always correct. We should query the Azure draw target for the format.
+        layers::layers::ARGB32Format
+    }
+    fn with_data(&self, f: layers::layers::WithDataFn) { 
+        do self.data_source_surface.with_data |data| {
+            f(data);
+        }
+    }
+}
+
+fn mainloop(po: Port<Msg>, dom_event_chan: SharedChan<Event>, opts: &Opts) {
+    let key_handlers: @mut ~[Chan<()>] = @mut ~[];
+
+    let app = Application::new();
+    let window = Window::new(&app);
+
+    let surfaces = @mut SurfaceSet(opts.render_backend);
+
+    let context = layers::rendergl::init_render_context();
+
+    // Create an initial layer tree.
+    //
+    // TODO: There should be no initial layer tree until the renderer creates one from the display
+    // list. This is only here because we don't have that logic in the renderer yet.
+    let root_layer = @mut layers::layers::ContainerLayer();
+    let original_layer_transform;
+    {
+        let image_data = @layers::layers::BasicImageData::new(Size2D(0u, 0u),
+                                                              0,
+                                                              layers::layers::RGB24Format,
+                                                              ~[]);
+        let image = @mut layers::layers::Image::new(image_data as @layers::layers::ImageData);
+        let image_layer = @mut layers::layers::ImageLayer(image);
+        original_layer_transform = image_layer.common.transform;
+        image_layer.common.set_transform(original_layer_transform.scale(800.0, 600.0, 1.0));
+        root_layer.add_child(layers::layers::ImageLayerKind(image_layer));
+    }
+
+
+    let scene = @mut layers::scene::Scene(layers::layers::ContainerLayerKind(root_layer),
+                                          Size2D(800.0, 600.0),
+                                          identity());
+
+    let done = @mut false;
+    let resize_rate_limiter = @mut ResizeRateLimiter(dom_event_chan);
+    let check_for_messages: @fn() = || {
+        // Periodically check if content responded to our last resize event
+        resize_rate_limiter.check_resize_response();
+
+        // Handle messages
+        while po.peek() {
+            match po.recv() {
+                AddKeyHandler(key_ch) => key_handlers.push(key_ch),
+                BeginDrawing(sender) => lend_surface(surfaces, sender),
+                Draw(sender, draw_target) => {
+                    debug!("osmain: received new frame");
+                    return_surface(surfaces, draw_target);
+                    lend_surface(surfaces, sender);
+
+                    // Iterate over the children of the container layer.
+                    let mut current_layer_child = root_layer.first_child;
+
+                    // Replace the image layer data with the buffer data.
+                    let buffers = util::replace(&mut surfaces.front.layer_buffer_set.buffers, ~[]);
+                    for buffers.each |buffer| {
+                        let width = buffer.rect.size.width as uint;
+                        let height = buffer.rect.size.height as uint;
+
+                        debug!("osmain: compositing buffer rect %?", &buffer.rect);
+
+                        let image_data = @AzureDrawTargetImageData {
+                            draw_target: buffer.draw_target.clone(),
+                            data_source_surface: buffer.draw_target.snapshot().get_data_surface(),
+                            size: Size2D(width, height)
+                        };
+                        let image = @mut layers::layers::Image::new(image_data as @layers::layers::ImageData);
+
+                        // Find or create an image layer.
+                        let image_layer;
+                        current_layer_child = match current_layer_child {
+                            None => {
+                                debug!("osmain: adding new image layer");
+                                image_layer = @mut layers::layers::ImageLayer(image);
+                                root_layer.add_child(layers::layers::ImageLayerKind(image_layer));
+                                None
+                            }
+                            Some(layers::layers::ImageLayerKind(existing_image_layer)) => {
+                                image_layer = existing_image_layer;
+                                image_layer.set_image(image);
+
+                                // Move on to the next sibling.
+                                do current_layer_child.get().with_common |common| {
+                                    common.next_sibling
+                                }
+                            }
+                            Some(_) => fail!(~"found unexpected layer kind"),
+                        };
+
+                        // Set the layer's transform.
+                        let x = buffer.rect.origin.x as f32;
+                        let y = buffer.rect.origin.y as f32;
+                        image_layer.common.set_transform(
+                            original_layer_transform.translate(x, y, 0.0)
+                                .scale(width as f32, height as f32, 1.0));
+                    }
+                    surfaces.front.layer_buffer_set.buffers = buffers;
+                }
+                Exit => {
+                    *done = true;
+                }
+            }
+        }
+    };
+
+    do window.set_composite_callback {
+        do time::time(~"compositing") {
+            // Adjust the layer dimensions as necessary to correspond to the size of the window.
+            scene.size = window.size();
+
+            // Render the scene.
+            layers::rendergl::render_scene(context, scene);
+        }
+
+        window.present();
+    }
+
+    do window.set_resize_callback |width, height| {
+        debug!("osmain: window resized to %ux%u", width, height);
+        resize_rate_limiter.window_resized(width, height);
+    }
+
+    // Enter the main event loop.
+    while !*done {
+        // Check for new messages coming from the rendering task.
+        check_for_messages();
+
+        // Check for messages coming from the windowing system.
+        window.check_loop();
+    }
+}
+
+/// Implementation of the abstract `Compositor` interface.
+impl Compositor for CompositorImpl {
+    fn begin_drawing(&self, next_dt: Chan<LayerBufferSet>) {
+        self.chan.send(BeginDrawing(next_dt))
+    }
+    fn draw(&self, next_dt: Chan<LayerBufferSet>, draw_me: LayerBufferSet) {
+        self.chan.send(Draw(next_dt, draw_me))
+    }
+}
+
+struct SurfaceSet {
+    front: Surface,
+    back: Surface,
+}
+
+fn lend_surface(surfaces: &mut SurfaceSet, receiver: Chan<LayerBufferSet>) {
+    // We are in a position to lend out the surface?
+    assert!(surfaces.front.have);
+    // Ok then take it
+    let old_layer_buffers = util::replace(&mut surfaces.front.layer_buffer_set.buffers, ~[]);
+    let new_layer_buffers = do old_layer_buffers.map |layer_buffer| {
+        let draw_target_ref = &layer_buffer.draw_target;
+        let layer_buffer = LayerBuffer {
+            draw_target: draw_target_ref.clone(),
+            rect: copy layer_buffer.rect,
+            stride: layer_buffer.stride
+        };
+        debug!("osmain: lending surface %?", layer_buffer);
+        layer_buffer
+    };
+    surfaces.front.layer_buffer_set.buffers = old_layer_buffers;
+
+    let new_layer_buffer_set = LayerBufferSet { buffers: new_layer_buffers };
+    receiver.send(new_layer_buffer_set);
+    // Now we don't have it
+    surfaces.front.have = false;
+    // But we (hopefully) have another!
+    surfaces.front <-> surfaces.back;
+    // Let's look
+    assert!(surfaces.front.have);
+}
+
+fn return_surface(surfaces: &mut SurfaceSet, layer_buffer_set: LayerBufferSet) {
+    //#debug("osmain: returning surface %?", layer_buffer_set);
+    // We have room for a return
+    assert!(surfaces.front.have);
+    assert!(!surfaces.back.have);
+
+    surfaces.back.layer_buffer_set = layer_buffer_set;
+
+    // Now we have it again
+    surfaces.back.have = true;
+}
+
+fn SurfaceSet(backend: BackendType) -> SurfaceSet {
+    SurfaceSet { front: Surface(backend), back: Surface(backend) }
+}
+
+struct Surface {
+    layer_buffer_set: LayerBufferSet,
+    have: bool,
+}
+
+fn Surface(backend: BackendType) -> Surface {
+    let layer_buffer = LayerBuffer {
+        draw_target: DrawTarget::new(backend, Size2D(800i32, 600i32), B8G8R8A8),
+        rect: Rect(Point2D(0u, 0u), Size2D(800u, 600u)),
+        stride: 800 * 4
+    };
+    let layer_buffer_set = LayerBufferSet {
+        buffers: ~[ layer_buffer ]
+    };
+    Surface {
+        layer_buffer_set: layer_buffer_set,
+        have: true
+    }
+}
+
+/// A function for spawning into the platform's main thread.
+fn on_osmain<T: Owned>(f: ~fn(po: Port<T>)) -> Chan<T> {
+    let (setup_po, setup_ch) = comm::stream();
+    do task::task().sched_mode(task::PlatformThread).spawn {
+        let (po, ch) = comm::stream();
+        setup_ch.send(ch);
+        f(po);
+    }
+    setup_po.recv()
+}
+