servo/components/script/dom/vrdisplay.rs
2017-06-18 13:21:49 +02:00

645 lines
26 KiB
Rust

/* 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::CanvasMsg;
use core::ops::Deref;
use dom::bindings::callback::ExceptionHandling;
use dom::bindings::cell::DOMRefCell;
use dom::bindings::codegen::Bindings::PerformanceBinding::PerformanceBinding::PerformanceMethods;
use dom::bindings::codegen::Bindings::VRDisplayBinding;
use dom::bindings::codegen::Bindings::VRDisplayBinding::VRDisplayMethods;
use dom::bindings::codegen::Bindings::VRDisplayBinding::VREye;
use dom::bindings::codegen::Bindings::VRLayerBinding::VRLayer;
use dom::bindings::codegen::Bindings::WindowBinding::FrameRequestCallback;
use dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
use dom::bindings::inheritance::Castable;
use dom::bindings::js::{MutNullableJS, MutJS, Root};
use dom::bindings::num::Finite;
use dom::bindings::refcounted::Trusted;
use dom::bindings::reflector::{DomObject, reflect_dom_object};
use dom::bindings::str::DOMString;
use dom::event::Event;
use dom::eventtarget::EventTarget;
use dom::globalscope::GlobalScope;
use dom::promise::Promise;
use dom::vrdisplaycapabilities::VRDisplayCapabilities;
use dom::vrdisplayevent::VRDisplayEvent;
use dom::vreyeparameters::VREyeParameters;
use dom::vrframedata::VRFrameData;
use dom::vrpose::VRPose;
use dom::vrstageparameters::VRStageParameters;
use dom::webglrenderingcontext::WebGLRenderingContext;
use dom_struct::dom_struct;
use ipc_channel::ipc;
use ipc_channel::ipc::{IpcSender, IpcReceiver};
use js::jsapi::JSContext;
use script_runtime::CommonScriptMsg;
use script_runtime::ScriptThreadEventCategory::WebVREvent;
use script_thread::Runnable;
use std::cell::Cell;
use std::mem;
use std::rc::Rc;
use std::sync::mpsc;
use std::thread;
use webrender_traits::VRCompositorCommand;
use webvr_traits::{WebVRDisplayData, WebVRDisplayEvent, WebVRFrameData, WebVRLayer, WebVRMsg};
#[dom_struct]
pub struct VRDisplay {
eventtarget: EventTarget,
#[ignore_heap_size_of = "Defined in rust-webvr"]
display: DOMRefCell<WebVRDisplayData>,
depth_near: Cell<f64>,
depth_far: Cell<f64>,
presenting: Cell<bool>,
left_eye_params: MutJS<VREyeParameters>,
right_eye_params: MutJS<VREyeParameters>,
capabilities: MutJS<VRDisplayCapabilities>,
stage_params: MutNullableJS<VRStageParameters>,
#[ignore_heap_size_of = "Defined in rust-webvr"]
frame_data: DOMRefCell<WebVRFrameData>,
#[ignore_heap_size_of = "Defined in rust-webvr"]
layer: DOMRefCell<WebVRLayer>,
layer_ctx: MutNullableJS<WebGLRenderingContext>,
#[ignore_heap_size_of = "Defined in rust-webvr"]
next_raf_id: Cell<u32>,
/// List of request animation frame callbacks
#[ignore_heap_size_of = "closures are hard"]
raf_callback_list: DOMRefCell<Vec<(u32, Option<Rc<FrameRequestCallback>>)>>,
// Compositor VRFrameData synchonization
frame_data_status: Cell<VRFrameDataStatus>,
#[ignore_heap_size_of = "channels are hard"]
frame_data_receiver: DOMRefCell<Option<IpcReceiver<Result<Vec<u8>, ()>>>>,
running_display_raf: Cell<bool>,
paused: Cell<bool>,
stopped_on_pause: Cell<bool>,
}
unsafe_no_jsmanaged_fields!(WebVRDisplayData);
unsafe_no_jsmanaged_fields!(WebVRFrameData);
unsafe_no_jsmanaged_fields!(WebVRLayer);
#[derive(Clone, Copy, PartialEq, Eq, HeapSizeOf)]
enum VRFrameDataStatus {
Waiting,
Synced,
Exit
}
unsafe_no_jsmanaged_fields!(VRFrameDataStatus);
impl VRDisplay {
fn new_inherited(global: &GlobalScope, display: WebVRDisplayData) -> VRDisplay {
let stage = match display.stage_parameters {
Some(ref params) => Some(VRStageParameters::new(params.clone(), &global)),
None => None
};
VRDisplay {
eventtarget: EventTarget::new_inherited(),
display: DOMRefCell::new(display.clone()),
depth_near: Cell::new(0.01),
depth_far: Cell::new(10000.0),
presenting: Cell::new(false),
left_eye_params: MutJS::new(&*VREyeParameters::new(display.left_eye_parameters.clone(), &global)),
right_eye_params: MutJS::new(&*VREyeParameters::new(display.right_eye_parameters.clone(), &global)),
capabilities: MutJS::new(&*VRDisplayCapabilities::new(display.capabilities.clone(), &global)),
stage_params: MutNullableJS::new(stage.as_ref().map(|v| v.deref())),
frame_data: DOMRefCell::new(Default::default()),
layer: DOMRefCell::new(Default::default()),
layer_ctx: MutNullableJS::default(),
next_raf_id: Cell::new(1),
raf_callback_list: DOMRefCell::new(vec![]),
frame_data_status: Cell::new(VRFrameDataStatus::Waiting),
frame_data_receiver: DOMRefCell::new(None),
running_display_raf: Cell::new(false),
// Some VR implementations (e.g. Daydream) can be paused in some life cycle situations
// such as showing and hiding the controller pairing screen.
paused: Cell::new(false),
// This flag is set when the Display was presenting when it received a VR Pause event.
// When the VR Resume event is received and the flag is set, VR presentation automatically restarts.
stopped_on_pause: Cell::new(false)
}
}
pub fn new(global: &GlobalScope, display: WebVRDisplayData) -> Root<VRDisplay> {
reflect_dom_object(box VRDisplay::new_inherited(&global, display),
global,
VRDisplayBinding::Wrap)
}
}
impl Drop for VRDisplay {
fn drop(&mut self) {
if self.presenting.get() {
self.force_stop_present();
}
}
}
impl VRDisplayMethods for VRDisplay {
// https://w3c.github.io/webvr/#dom-vrdisplay-isconnected
fn IsConnected(&self) -> bool {
self.display.borrow().connected
}
// https://w3c.github.io/webvr/#dom-vrdisplay-ispresenting
fn IsPresenting(&self) -> bool {
self.presenting.get()
}
// https://w3c.github.io/webvr/#dom-vrdisplay-capabilities
fn Capabilities(&self) -> Root<VRDisplayCapabilities> {
Root::from_ref(&*self.capabilities.get())
}
// https://w3c.github.io/webvr/#dom-vrdisplay-stageparameters
fn GetStageParameters(&self) -> Option<Root<VRStageParameters>> {
self.stage_params.get().map(|s| Root::from_ref(&*s))
}
// https://w3c.github.io/webvr/#dom-vrdisplay-geteyeparameters
fn GetEyeParameters(&self, eye: VREye) -> Root<VREyeParameters> {
match eye {
VREye::Left => Root::from_ref(&*self.left_eye_params.get()),
VREye::Right => Root::from_ref(&*self.right_eye_params.get())
}
}
// https://w3c.github.io/webvr/#dom-vrdisplay-displayid
fn DisplayId(&self) -> u32 {
self.display.borrow().display_id
}
// https://w3c.github.io/webvr/#dom-vrdisplay-displayname
fn DisplayName(&self) -> DOMString {
DOMString::from(self.display.borrow().display_name.clone())
}
// https://w3c.github.io/webvr/#dom-vrdisplay-getframedata-framedata-framedata
fn GetFrameData(&self, frameData: &VRFrameData) -> bool {
// If presenting we use a synced data with compositor for the whole frame.
// Frame data is only synced with compositor when GetFrameData is called from
// inside the VRDisplay.requestAnimationFrame. This is checked using the running_display_raf property.
// This check avoids data race conditions when calling GetFrameData from outside of the
// VRDisplay.requestAnimationFrame callbacks and fixes a possible deadlock during the interval
// when the requestAnimationFrame is moved from window to VRDisplay.
if self.presenting.get() && self.running_display_raf.get() {
if self.frame_data_status.get() == VRFrameDataStatus::Waiting {
self.sync_frame_data();
}
frameData.update(& self.frame_data.borrow());
return true;
}
// If not presenting we fetch inmediante VRFrameData
let (sender, receiver) = ipc::channel().unwrap();
self.webvr_thread().send(WebVRMsg::GetFrameData(self.global().pipeline_id(),
self.DisplayId(),
self.depth_near.get(),
self.depth_far.get(),
sender)).unwrap();
return match receiver.recv().unwrap() {
Ok(data) => {
frameData.update(&data);
true
},
Err(e) => {
error!("WebVR::GetFrameData: {:?}", e);
false
}
};
}
// https://w3c.github.io/webvr/#dom-vrdisplay-getpose
fn GetPose(&self) -> Root<VRPose> {
VRPose::new(&self.global(), &self.frame_data.borrow().pose)
}
// https://w3c.github.io/webvr/#dom-vrdisplay-resetpose
fn ResetPose(&self) {
let (sender, receiver) = ipc::channel().unwrap();
self.webvr_thread().send(WebVRMsg::ResetPose(self.global().pipeline_id(),
self.DisplayId(),
sender)).unwrap();
if let Ok(data) = receiver.recv().unwrap() {
// Some VRDisplay data might change after calling ResetPose()
*self.display.borrow_mut() = data;
}
}
// https://w3c.github.io/webvr/#dom-vrdisplay-depthnear
fn DepthNear(&self) -> Finite<f64> {
Finite::wrap(self.depth_near.get())
}
// https://w3c.github.io/webvr/#dom-vrdisplay-depthnear
fn SetDepthNear(&self, value: Finite<f64>) {
self.depth_near.set(*value.deref());
}
// https://w3c.github.io/webvr/#dom-vrdisplay-depthfar
fn DepthFar(&self) -> Finite<f64> {
Finite::wrap(self.depth_far.get())
}
// https://w3c.github.io/webvr/#dom-vrdisplay-depthfar
fn SetDepthFar(&self, value: Finite<f64>) {
self.depth_far.set(*value.deref());
}
// https://w3c.github.io/webvr/#dom-vrdisplay-requestanimationframe
fn RequestAnimationFrame(&self, callback: Rc<FrameRequestCallback>) -> u32 {
if self.presenting.get() {
let raf_id = self.next_raf_id.get();
self.next_raf_id.set(raf_id + 1);
self.raf_callback_list.borrow_mut().push((raf_id, Some(callback)));
raf_id
} else {
// WebVR spec: When a VRDisplay is not presenting it should
// fallback to window.requestAnimationFrame.
self.global().as_window().RequestAnimationFrame(callback)
}
}
// https://w3c.github.io/webvr/#dom-vrdisplay-cancelanimationframe
fn CancelAnimationFrame(&self, handle: u32) {
if self.presenting.get() {
let mut list = self.raf_callback_list.borrow_mut();
if let Some(mut pair) = list.iter_mut().find(|pair| pair.0 == handle) {
pair.1 = None;
}
} else {
// WebVR spec: When a VRDisplay is not presenting it should
// fallback to window.cancelAnimationFrame.
self.global().as_window().CancelAnimationFrame(handle);
}
}
#[allow(unrooted_must_root)]
// https://w3c.github.io/webvr/#dom-vrdisplay-requestpresent
fn RequestPresent(&self, layers: Vec<VRLayer>) -> Rc<Promise> {
let promise = Promise::new(&self.global());
// TODO: WebVR spec: this method must be called in response to a user gesture
// WebVR spec: If canPresent is false the promise MUST be rejected
if !self.display.borrow().capabilities.can_present {
let msg = "VRDisplay canPresent is false".to_string();
promise.reject_native(promise.global().get_cx(), &msg);
return promise;
}
// Current WebVRSpec only allows 1 VRLayer if the VRDevice can present.
// Future revisions of this spec may allow multiple layers to enable more complex rendering effects
// such as compositing WebGL and DOM elements together.
// That functionality is not allowed by this revision of the spec.
if layers.len() != 1 {
let msg = "The number of layers must be 1".to_string();
promise.reject_native(promise.global().get_cx(), &msg);
return promise;
}
// Parse and validate received VRLayer
let layer = validate_layer(self.global().get_cx(), &layers[0]);
let layer_bounds;
let layer_ctx;
match layer {
Ok((bounds, ctx)) => {
layer_bounds = bounds;
layer_ctx = ctx;
},
Err(msg) => {
let msg = msg.to_string();
promise.reject_native(promise.global().get_cx(), &msg);
return promise;
}
};
// WebVR spec: Repeat calls while already presenting will update the VRLayers being displayed.
if self.presenting.get() {
*self.layer.borrow_mut() = layer_bounds;
self.layer_ctx.set(Some(&layer_ctx));
promise.resolve_native(promise.global().get_cx(), &());
return promise;
}
// Request Present
let (sender, receiver) = ipc::channel().unwrap();
self.webvr_thread().send(WebVRMsg::RequestPresent(self.global().pipeline_id(),
self.display.borrow().display_id,
sender))
.unwrap();
match receiver.recv().unwrap() {
Ok(()) => {
*self.layer.borrow_mut() = layer_bounds;
self.layer_ctx.set(Some(&layer_ctx));
self.init_present();
promise.resolve_native(promise.global().get_cx(), &());
},
Err(e) => {
promise.reject_native(promise.global().get_cx(), &e);
}
}
promise
}
#[allow(unrooted_must_root)]
// https://w3c.github.io/webvr/#dom-vrdisplay-exitpresent
fn ExitPresent(&self) -> Rc<Promise> {
let promise = Promise::new(&self.global());
// WebVR spec: If the VRDisplay is not presenting the promise MUST be rejected.
if !self.presenting.get() {
let msg = "VRDisplay is not presenting".to_string();
promise.reject_native(promise.global().get_cx(), &msg);
return promise;
}
// Exit present
let (sender, receiver) = ipc::channel().unwrap();
self.webvr_thread().send(WebVRMsg::ExitPresent(self.global().pipeline_id(),
self.display.borrow().display_id,
Some(sender)))
.unwrap();
match receiver.recv().unwrap() {
Ok(()) => {
self.stop_present();
promise.resolve_native(promise.global().get_cx(), &());
},
Err(e) => {
promise.reject_native(promise.global().get_cx(), &e);
}
}
promise
}
// https://w3c.github.io/webvr/#dom-vrdisplay-submitframe
fn SubmitFrame(&self) {
if !self.presenting.get() {
warn!("VRDisplay not presenting");
return;
}
let api_sender = self.layer_ctx.get().unwrap().ipc_renderer();
let display_id = self.display.borrow().display_id as u64;
let layer = self.layer.borrow();
let msg = VRCompositorCommand::SubmitFrame(display_id, layer.left_bounds, layer.right_bounds);
api_sender.send(CanvasMsg::WebVR(msg)).unwrap();
}
}
impl VRDisplay {
fn webvr_thread(&self) -> IpcSender<WebVRMsg> {
self.global().as_window().webvr_thread().expect("Shouldn't arrive here with WebVR disabled")
}
pub fn update_display(&self, display: &WebVRDisplayData) {
*self.display.borrow_mut() = display.clone();
if let Some(ref stage) = display.stage_parameters {
if self.stage_params.get().is_none() {
let params = Some(VRStageParameters::new(stage.clone(), &self.global()));
self.stage_params.set(params.as_ref().map(|v| v.deref()));
} else {
self.stage_params.get().unwrap().update(&stage);
}
} else {
self.stage_params.set(None);
}
}
pub fn handle_webvr_event(&self, event: &WebVRDisplayEvent) {
match *event {
WebVRDisplayEvent::Connect(ref display) => {
self.update_display(&display);
},
WebVRDisplayEvent::Disconnect(_id) => {
self.display.borrow_mut().connected = false;
},
WebVRDisplayEvent::Activate(ref display, _) |
WebVRDisplayEvent::Deactivate(ref display, _) |
WebVRDisplayEvent::Blur(ref display) |
WebVRDisplayEvent::Focus(ref display) => {
self.update_display(&display);
self.notify_event(&event);
},
WebVRDisplayEvent::PresentChange(ref display, presenting) => {
self.update_display(&display);
self.presenting.set(presenting);
self.notify_event(&event);
},
WebVRDisplayEvent::Change(ref display) => {
// Change event doesn't exist in WebVR spec.
// So we update display data but don't notify JS.
self.update_display(&display);
},
WebVRDisplayEvent::Pause(_) => {
if self.paused.get() {
return;
}
self.paused.set(true);
if self.presenting.get() {
self.stop_present();
self.stopped_on_pause.set(true);
}
},
WebVRDisplayEvent::Resume(_) => {
self.paused.set(false);
if self.stopped_on_pause.get() {
self.stopped_on_pause.set(false);
self.init_present();
}
},
WebVRDisplayEvent::Exit(_) => {
self.stopped_on_pause.set(false);
if self.presenting.get() {
self.stop_present();
}
}
};
}
fn notify_event(&self, event: &WebVRDisplayEvent) {
let root = Root::from_ref(&*self);
let event = VRDisplayEvent::new_from_webvr(&self.global(), &root, &event);
event.upcast::<Event>().fire(self.upcast());
}
fn init_present(&self) {
self.presenting.set(true);
let (sync_sender, sync_receiver) = ipc::channel().unwrap();
*self.frame_data_receiver.borrow_mut() = Some(sync_receiver);
let display_id = self.display.borrow().display_id as u64;
let api_sender = self.layer_ctx.get().unwrap().ipc_renderer();
let js_sender = self.global().script_chan();
let address = Trusted::new(&*self);
let near_init = self.depth_near.get();
let far_init = self.depth_far.get();
// The render loop at native headset frame rate is implemented using a dedicated thread.
// Every loop iteration syncs pose data with the HMD, submits the pixels to the display and waits for Vsync.
// Both the requestAnimationFrame call of a VRDisplay in the JavaScript thread and the VRSyncPoses call
// in the Webrender thread are executed in parallel. This allows to get some JavaScript code executed ahead.
// while the render thread is syncing the VRFrameData to be used for the current frame.
// This thread runs until the user calls ExitPresent, the tab is closed or some unexpected error happened.
thread::Builder::new().name("WebVR_RAF".into()).spawn(move || {
let (raf_sender, raf_receiver) = mpsc::channel();
let mut near = near_init;
let mut far = far_init;
// Initialize compositor
api_sender.send(CanvasMsg::WebVR(VRCompositorCommand::Create(display_id))).unwrap();
loop {
// Run RAF callbacks on JavaScript thread
let msg = box NotifyDisplayRAF {
address: address.clone(),
sender: raf_sender.clone()
};
js_sender.send(CommonScriptMsg::RunnableMsg(WebVREvent, msg)).unwrap();
// Run Sync Poses in parallell on Render thread
let msg = VRCompositorCommand::SyncPoses(display_id, near, far, sync_sender.clone());
api_sender.send(CanvasMsg::WebVR(msg)).unwrap();
// Wait until both SyncPoses & RAF ends
if let Ok(depth) = raf_receiver.recv().unwrap() {
near = depth.0;
far = depth.1;
} else {
// Stop thread
// ExitPresent called or some error happened
return;
}
}
}).expect("Thread spawning failed");
}
fn stop_present(&self) {
self.presenting.set(false);
*self.frame_data_receiver.borrow_mut() = None;
let api_sender = self.layer_ctx.get().unwrap().ipc_renderer();
let display_id = self.display.borrow().display_id as u64;
let msg = VRCompositorCommand::Release(display_id);
api_sender.send(CanvasMsg::WebVR(msg)).unwrap();
}
// Only called when the JSContext is destroyed while presenting.
// In this case we don't want to wait for WebVR Thread response.
fn force_stop_present(&self) {
self.webvr_thread().send(WebVRMsg::ExitPresent(self.global().pipeline_id(),
self.display.borrow().display_id,
None))
.unwrap();
self.stop_present();
}
fn sync_frame_data(&self) {
let status = if let Some(receiver) = self.frame_data_receiver.borrow().as_ref() {
match receiver.recv().unwrap() {
Ok(bytes) => {
*self.frame_data.borrow_mut() = WebVRFrameData::from_bytes(&bytes[..]);
VRFrameDataStatus::Synced
},
Err(()) => {
VRFrameDataStatus::Exit
}
}
} else {
VRFrameDataStatus::Exit
};
self.frame_data_status.set(status);
}
fn handle_raf(&self, end_sender: &mpsc::Sender<Result<(f64, f64), ()>>) {
self.frame_data_status.set(VRFrameDataStatus::Waiting);
self.running_display_raf.set(true);
let mut callbacks = mem::replace(&mut *self.raf_callback_list.borrow_mut(), vec![]);
let now = self.global().as_window().Performance().Now();
// Call registered VRDisplay.requestAnimationFrame callbacks.
for (_, callback) in callbacks.drain(..) {
if let Some(callback) = callback {
let _ = callback.Call__(Finite::wrap(*now), ExceptionHandling::Report);
}
}
self.running_display_raf.set(false);
if self.frame_data_status.get() == VRFrameDataStatus::Waiting {
// User didn't call getFrameData while presenting.
// We automatically reads the pending VRFrameData to avoid overflowing the IPC-Channel buffers.
// Show a warning as the WebVR Spec recommends.
warn!("WebVR: You should call GetFrameData while presenting");
self.sync_frame_data();
}
match self.frame_data_status.get() {
VRFrameDataStatus::Synced => {
// Sync succeeded. Notify RAF thread.
end_sender.send(Ok((self.depth_near.get(), self.depth_far.get()))).unwrap();
},
VRFrameDataStatus::Exit | VRFrameDataStatus::Waiting => {
// ExitPresent called or some error ocurred.
// Notify VRDisplay RAF thread to stop.
end_sender.send(Err(())).unwrap();
}
}
}
}
struct NotifyDisplayRAF {
address: Trusted<VRDisplay>,
sender: mpsc::Sender<Result<(f64, f64), ()>>
}
impl Runnable for NotifyDisplayRAF {
fn name(&self) -> &'static str { "NotifyDisplayRAF" }
fn handler(self: Box<Self>) {
let display = self.address.root();
display.handle_raf(&self.sender);
}
}
// WebVR Spect: If the number of values in the leftBounds/rightBounds arrays
// is not 0 or 4 for any of the passed layers the promise is rejected
fn parse_bounds(src: &Option<Vec<Finite<f32>>>, dst: &mut [f32; 4]) -> Result<(), &'static str> {
match *src {
Some(ref values) => {
if values.len() == 0 {
return Ok(())
}
if values.len() != 4 {
return Err("The number of values in the leftBounds/rightBounds arrays must be 0 or 4")
}
for i in 0..4 {
dst[i] = *values[i].deref();
}
Ok(())
},
None => Ok(())
}
}
fn validate_layer(cx: *mut JSContext,
layer: &VRLayer)
-> Result<(WebVRLayer, Root<WebGLRenderingContext>), &'static str> {
let ctx = layer.source.as_ref().map(|ref s| s.get_or_init_webgl_context(cx, None)).unwrap_or(None);
if let Some(ctx) = ctx {
let mut data = WebVRLayer::default();
parse_bounds(&layer.leftBounds, &mut data.left_bounds)?;
parse_bounds(&layer.rightBounds, &mut data.right_bounds)?;
Ok((data, ctx))
} else {
Err("VRLayer source must be a WebGL Context")
}
}