Auto merge of #66 - asajeffrey:glwindow, r=paulrouget

 Add glwindow implementation, that renders to a GlWindow

Add glwindow implementation, that renders to a GlWindow, mainly for testing, but also this forms a basis for VRDisplays that have code that needs to run in the main thread.

Fixes #52 and #65.

rust-webvr-api/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rust-webvr-api"
-version = "0.10.3"
+version = "0.10.4"
 authors = ["The Servo Project Developers"]
 
 homepage = "https://github.com/servo/rust-webvr"

rust-webvr-api/src/lib.rs

@@ -38,6 +38,7 @@ pub mod vr_stage_parameters;
 pub mod vr_event;
 pub mod vr_field_view;
 pub mod vr_gamepad;
+pub mod vr_main_thread_heartbeat;
 
 pub use vr_display::{VRDisplay,VRDisplayPtr};
 pub use vr_service::{VRService,VRServiceCreator};
@@ -56,3 +57,4 @@ pub use vr_event::{VREvent, VRDisplayEvent, VRDisplayEventReason, VRGamepadEvent
 pub use vr_field_view::VRFieldOfView;
 pub use vr_gamepad::{VRGamepad, VRGamepadPtr, VRGamepadHand,
                      VRGamepadData, VRGamepadState, VRGamepadButton};
+pub use vr_main_thread_heartbeat::VRMainThreadHeartbeat;

rust-webvr-api/src/vr_main_thread_heartbeat.rs

@@ -0,0 +1,10 @@
+/// Each VR service may have some code which needs to run on the main thread,
+/// for example window creation on MacOS is only supported on the main thread.
+/// Implementations of this trait will usually be neither `Sync` nor `Send`.
+pub trait VRMainThreadHeartbeat {
+    /// Run the heartbeat on the main thread.
+    fn heartbeat(&mut self);
+
+    /// Is the heartbeat expecting to be called every frame?
+    fn heart_racing(&self) -> bool;
+}

rust-webvr/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rust-webvr"
-version = "0.10.1"
+version = "0.10.2"
 authors = ["The Servo Project Developers"]
 
 homepage = "https://github.com/servo/rust-webvr"
@@ -21,18 +21,23 @@ build = "build.rs"
 [features]
 default = ["vrexternal", "openvr", "mock"]
 vrexternal = []
+glwindow = ["euclid", "gleam", "glutin", "winit"]
 openvr = ["libloading"]
 mock = []
 googlevr = ["gvr-sys"]
 oculusvr = ["ovr-mobile-sys"]
 
 [dependencies]
-rust-webvr-api = { path = "../rust-webvr-api", version = "0.10" }
+rust-webvr-api = { path = "../rust-webvr-api", version = "0.10.4" }
 log  = "0.4"
 libloading = { version = "0.5", optional = true, default-features = false }
 gvr-sys = { version = "0.7", optional = true }
 ovr-mobile-sys = { version = "0.4", optional = true }
 libc = "0.2"
+euclid = { version = "0.19", optional = true }
+gleam = { version = "0.6", optional = true }
+glutin = { version = "0.19", optional = true }
+winit = { version = "0.18", optional = true }
 
 [build-dependencies]
 gl_generator = "0.10"

rust-webvr/src/api/glwindow/display.rs

@@ -0,0 +1,261 @@
+use euclid::Angle;
+use euclid::Trig;
+use gleam::gl;
+use gleam::gl::Gl;
+use rust_webvr_api::utils;
+use rust_webvr_api::VRDisplay;
+use rust_webvr_api::VRDisplayCapabilities;
+use rust_webvr_api::VRDisplayData;
+use rust_webvr_api::VREyeParameters;
+use rust_webvr_api::VRFieldOfView;
+use rust_webvr_api::VRFrameData;
+use rust_webvr_api::VRFutureFrameData;
+use rust_webvr_api::VRFramebuffer;
+use rust_webvr_api::VRFramebufferAttributes;
+use rust_webvr_api::VRLayer;
+use rust_webvr_api::VRViewport;
+use std::cell::RefCell;
+use std::sync::Arc;
+use std::sync::mpsc::Sender;
+use super::heartbeat::GlWindowVRMessage;
+use winit::dpi::PhysicalSize;
+
+// Fake a display with a distance between eyes of 5cm.
+const EYE_DISTANCE: f32 = 0.05;
+
+pub type GlWindowVRDisplayPtr = Arc<RefCell<GlWindowVRDisplay>>;
+
+pub struct GlWindowVRDisplay {
+    id: u32,
+    name: String,
+    size: PhysicalSize,
+    sender: Sender<GlWindowVRMessage>,
+    pool: ArcPool<Vec<u8>>,
+}
+
+unsafe impl Sync for GlWindowVRDisplay {}
+
+impl Drop for GlWindowVRDisplay {
+    fn drop(&mut self) {
+        self.stop_present();
+    }
+}
+
+impl VRDisplay for GlWindowVRDisplay {
+    fn id(&self) -> u32 {
+        self.id
+    }
+
+    fn data(&self) -> VRDisplayData {
+        let capabilities = VRDisplayCapabilities {
+            has_position: false,
+            has_orientation: false,
+            has_external_display: true,
+            can_present: true,
+            presented_by_browser: false,
+            max_layers: 1,
+        };
+
+        let fov_right = GlWindowVRDisplay::fov_right(self.size).to_degrees();
+        let fov_up = GlWindowVRDisplay::fov_up(self.size).to_degrees();
+
+        let field_of_view = VRFieldOfView {
+            down_degrees: fov_up,
+            left_degrees: fov_right,
+            right_degrees: fov_right,
+            up_degrees: fov_up,
+        };
+
+        let left_eye_parameters = VREyeParameters {
+            offset: [-EYE_DISTANCE / 2.0, 0.0, 0.0],
+            render_width: self.size.width as u32 / 2,
+            render_height: self.size.height as u32,
+            field_of_view: field_of_view,
+        };
+
+        let right_eye_parameters = VREyeParameters {
+            offset: [EYE_DISTANCE / 2.0, 0.0, 0.0],
+            ..left_eye_parameters.clone()
+        };
+
+        VRDisplayData {
+            display_id: self.id,
+            display_name: self.name.clone(),
+            connected: true,
+            capabilities: capabilities,
+            stage_parameters: None,
+            left_eye_parameters: left_eye_parameters,
+            right_eye_parameters: right_eye_parameters,
+        }
+    }
+
+    fn immediate_frame_data(&self, near: f64, far: f64) -> VRFrameData {
+        GlWindowVRDisplay::frame_data(0.0, self.size, near, far)
+    }
+
+    fn synced_frame_data(&self, near: f64, far: f64) -> VRFrameData {
+        self.immediate_frame_data(near, far)
+    }
+
+    fn reset_pose(&mut self) {}
+
+    fn sync_poses(&mut self) {}
+
+    fn future_frame_data(&mut self, near: f64, far: f64) -> VRFutureFrameData {
+        let (resolver, result) = VRFutureFrameData::blocked();
+        let _ = self.sender.send(GlWindowVRMessage::StartFrame(near, far, resolver));
+        result
+    }
+
+    fn bind_framebuffer(&mut self, _eye_index: u32) {}
+
+    fn get_framebuffers(&self) -> Vec<VRFramebuffer> {
+        let left_viewport = VRViewport {
+            x: 0,
+            y: 0,
+            width: (self.size.width as i32) / 2,
+            height: self.size.height as i32,
+        };
+
+        let right_viewport = VRViewport {
+            x: self.size.width as i32 - left_viewport.width,
+            ..left_viewport
+        };
+
+        vec![
+            VRFramebuffer {
+                eye_index: 0,
+                attributes: VRFramebufferAttributes::default(),
+                viewport: left_viewport,
+            },
+            VRFramebuffer {
+                eye_index: 1,
+                attributes: VRFramebufferAttributes::default(),
+                viewport: right_viewport,
+            },
+        ]
+    }
+
+    fn render_layer(&mut self, _layer: &VRLayer) {
+        unreachable!()
+    }
+
+    fn submit_frame(&mut self) {
+        unreachable!()
+    }
+
+    fn submit_layer(&mut self, gl: &Gl, layer: &VRLayer) {
+        // TODO: this assumes that the current GL framebuffer contains the texture
+        // TODO: what to do if the layer has no texture_size?
+        if let Some((width, height)) = layer.texture_size {
+            let num_bytes = (width as usize) * (height as usize) * 4;
+            let mut buffer = self.pool.remove().unwrap_or_else(Vec::new);
+            buffer.resize(num_bytes, 0);
+            gl.read_pixels_into_buffer(
+                0,
+                0,
+                width as gl::GLsizei,
+                height as gl::GLsizei,
+                gl::RGBA,
+                gl::UNSIGNED_BYTE,
+                &mut buffer[..],
+            );
+            let buffer = self.pool.add(buffer);
+            let _ = self.sender.send(GlWindowVRMessage::StopFrame(width, height, buffer));
+        }
+    }
+
+    fn start_present(&mut self, _attributes: Option<VRFramebufferAttributes>) {
+        let _ = self.sender.send(GlWindowVRMessage::StartPresenting);
+    }
+
+    fn stop_present(&mut self) {
+        let _ = self.sender.send(GlWindowVRMessage::StopPresenting);
+    }
+}
+
+impl GlWindowVRDisplay {
+    pub(crate) fn new(
+        name: String,
+        size: PhysicalSize,
+        sender: Sender<GlWindowVRMessage>
+    ) -> GlWindowVRDisplay {
+        GlWindowVRDisplay {
+            id: utils::new_id(),
+            name: name,
+            size: size,
+            sender: sender,
+            pool: ArcPool::new(),
+        }
+    }
+
+    fn fov_up(size: PhysicalSize) -> Angle<f64> {
+        Angle::radians(f64::fast_atan2(
+            2.0 * size.height as f64,
+            size.width as f64,
+        ))
+    }
+
+    fn fov_right(size: PhysicalSize) -> Angle<f64> {
+        Angle::radians(f64::fast_atan2(
+            2.0 * size.width as f64,
+            size.height as f64,
+        ))
+    }
+
+    fn perspective(size: PhysicalSize, near: f64, far: f64) -> [f32; 16] {
+        // https://github.com/toji/gl-matrix/blob/bd3307196563fbb331b40fc6ebecbbfcc2a4722c/src/mat4.js#L1271
+        let near = near as f32;
+        let far = far as f32;
+        let f = 1.0 / GlWindowVRDisplay::fov_up(size).radians.tan() as f32;
+        let nf = 1.0 / (near - far);
+        let aspect = ((size.width / 2.0) as f32) / (size.height as f32);
+
+        // Dear rustfmt, This is a 4x4 matrix, please leave it alone. Best, ajeffrey.
+        {#[rustfmt::skip] 
+            return [
+                f / aspect, 0.0, 0.0,                   0.0,
+                0.0,        f,   0.0,                   0.0,
+                0.0,        0.0, (far + near) * nf,     -1.0,
+                0.0,        0.0, 2.0 * far * near * nf, 0.0,
+            ];
+        }
+    }
+
+    pub(crate) fn frame_data(timestamp: f64, size: PhysicalSize, near: f64, far: f64) -> VRFrameData {
+        let left_projection_matrix = GlWindowVRDisplay::perspective(size, near, far);
+        let right_projection_matrix = left_projection_matrix.clone();
+
+        VRFrameData {
+            timestamp: timestamp,
+            // TODO: adjust matrices for stereoscopic vision
+            left_projection_matrix: left_projection_matrix,
+            right_projection_matrix: right_projection_matrix,
+            ..VRFrameData::default()
+        }
+    }
+}
+
+// A pool of Arc<T>'s.
+// You can add a T into the pool, and get back an Arc<T>.
+// You can request a T from the pool, if there's an Arc<T> with no other owners,
+// it will be removed from the pool, unwrapped and returned.
+
+struct ArcPool<T>(Vec<Arc<T>>);
+
+impl<T> ArcPool<T> {
+    fn new() -> ArcPool<T> {
+        ArcPool(Vec::new())
+    }
+
+    fn add(&mut self, val: T) -> Arc<T> {
+        let result = Arc::new(val);
+        self.0.push(result.clone());
+        result
+    }
+
+    fn remove(&mut self) -> Option<T> {
+        let i = self.0.iter().position(|arc| Arc::strong_count(arc) == 1);
+        i.and_then(|i| Arc::try_unwrap(self.0.swap_remove(i)).ok())
+    }
+}