Give inline sessions the correct projection matrices

components/script/dom/bindings/trace.rs

@@ -61,7 +61,7 @@ use cssparser::RGBA;
 use devtools_traits::{CSSError, TimelineMarkerType, WorkerId};
 use embedder_traits::{EventLoopWaker, MediaMetadata};
 use encoding_rs::{Decoder, Encoding};
-use euclid::default::{Point2D, Rect, Rotation3D, Transform2D, Transform3D};
+use euclid::default::{Point2D, Rect, Rotation3D, Transform2D};
 use euclid::Length as EuclidLength;
 use html5ever::buffer_queue::BufferQueue;
 use html5ever::{LocalName, Namespace, Prefix, QualName};
@@ -534,7 +534,7 @@ unsafe_no_jsmanaged_fields!(Mutex<MediaFrameRenderer>);
 unsafe_no_jsmanaged_fields!(ResourceFetchTiming);
 unsafe_no_jsmanaged_fields!(Timespec);
 unsafe_no_jsmanaged_fields!(HTMLMediaElementFetchContext);
-unsafe_no_jsmanaged_fields!(Rotation3D<f64>, Transform2D<f32>, Transform3D<f64>);
+unsafe_no_jsmanaged_fields!(Rotation3D<f64>, Transform2D<f32>);
 unsafe_no_jsmanaged_fields!(Point2D<f32>, Rect<Au>);
 unsafe_no_jsmanaged_fields!(Rect<f32>);
 unsafe_no_jsmanaged_fields!(CascadeData);
@@ -665,6 +665,20 @@ unsafe impl<T, U> JSTraceable for euclid::RigidTransform3D<f64, T, U> {
     }
 }
 
+unsafe impl<T, U> JSTraceable for euclid::Transform3D<f32, T, U> {
+    #[inline]
+    unsafe fn trace(&self, _trc: *mut JSTracer) {
+        // Do nothing
+    }
+}
+
+unsafe impl<T, U> JSTraceable for euclid::Transform3D<f64, T, U> {
+    #[inline]
+    unsafe fn trace(&self, _trc: *mut JSTracer) {
+        // Do nothing
+    }
+}
+
 unsafe impl<T> JSTraceable for EuclidLength<u64, T> {
     #[inline]
     unsafe fn trace(&self, _trc: *mut JSTracer) {

components/script/dom/xrsession.rs

@@ -40,7 +40,7 @@ use crate::dom::xrspace::XRSpace;
 use crate::dom::xrwebgllayer::XRWebGLLayer;
 use crate::task_source::TaskSource;
 use dom_struct::dom_struct;
-use euclid::RigidTransform3D;
+use euclid::{Rect, RigidTransform3D, Transform3D};
 use ipc_channel::ipc::IpcSender;
 use ipc_channel::router::ROUTER;
 use profile_traits::ipc;
@@ -48,8 +48,8 @@ use std::cell::Cell;
 use std::mem;
 use std::rc::Rc;
 use webxr_api::{
-    self, EnvironmentBlendMode, Event as XREvent, Frame, SelectEvent, SelectKind, Session,
-    Visibility,
+    self, util, Display, EnvironmentBlendMode, Event as XREvent, Frame, SelectEvent, SelectKind,
+    Session, View, Viewer, Visibility,
 };
 
 #[dom_struct]
@@ -65,6 +65,8 @@ pub struct XRSession {
     frame_requested: Cell<bool>,
     pending_render_state: MutNullableDom<XRRenderState>,
     active_render_state: MutDom<XRRenderState>,
+    /// Cached projection matrix for inline sessions
+    inline_projection_matrix: DomRefCell<Transform3D<f32, Viewer, Display>>,
 
     next_raf_id: Cell<i32>,
     #[ignore_malloc_size_of = "closures are hard"]
@@ -100,6 +102,7 @@ impl XRSession {
             frame_requested: Cell::new(false),
             pending_render_state: MutNullableDom::new(None),
             active_render_state: MutDom::new(render_state),
+            inline_projection_matrix: Default::default(),
 
             next_raf_id: Cell::new(0),
             raf_callback_list: DomRefCell::new(vec![]),
@@ -140,6 +143,10 @@ impl XRSession {
         self.ended.get()
     }
 
+    pub fn is_immersive(&self) -> bool {
+        self.mode != XRSessionMode::Inline
+    }
+
     fn setup_raf_loop(&self) {
         assert!(
             self.raf_sender.borrow().is_none(),
@@ -304,9 +311,12 @@ impl XRSession {
             self.active_render_state.set(&pending);
             // Step 6-7: XXXManishearth handle inlineVerticalFieldOfView
 
-            // XXXManishearth handle inline sessions and composition disabled flag
-            let swap_chain_id = pending.GetBaseLayer().map(|layer| layer.swap_chain_id());
-            self.session.borrow_mut().set_swap_chain(swap_chain_id);
+            if self.is_immersive() {
+                let swap_chain_id = pending.GetBaseLayer().map(|layer| layer.swap_chain_id());
+                self.session.borrow_mut().set_swap_chain(swap_chain_id);
+            } else {
+                self.update_inline_projection_matrix()
+            }
         }
 
         for event in frame.events.drain(..) {
@@ -339,8 +349,10 @@ impl XRSession {
         self.outside_raf.set(true);
 
         frame.set_active(false);
-        base_layer.swap_buffers();
-        self.session.borrow_mut().render_animation_frame();
+        if self.is_immersive() {
+            base_layer.swap_buffers();
+            self.session.borrow_mut().render_animation_frame();
+        }
         self.request_new_xr_frame();
 
         // If the canvas element is attached to the DOM, it is now dirty,
@@ -351,6 +363,44 @@ impl XRSession {
             .upcast::<Node>()
             .dirty(NodeDamage::OtherNodeDamage);
     }
+
+    fn update_inline_projection_matrix(&self) {
+        debug_assert!(!self.is_immersive());
+        let render_state = self.active_render_state.get();
+        let size = if let Some(base) = render_state.GetBaseLayer() {
+            base.size()
+        } else {
+            return;
+        };
+        let mut clip_planes = util::ClipPlanes::default();
+        let near = *render_state.DepthNear() as f32;
+        let far = *render_state.DepthFar() as f32;
+        clip_planes.update(near, far);
+        let top = *render_state.InlineVerticalFieldOfView() / 2.;
+        let top = near * top.tan() as f32;
+        let bottom = top;
+        let left = top * size.width as f32 / size.height as f32;
+        let right = left;
+        let matrix = util::frustum_to_projection_matrix(left, right, top, bottom, clip_planes);
+        *self.inline_projection_matrix.borrow_mut() = matrix;
+    }
+
+    /// Constructs a View suitable for inline sessions using the inlineVerticalFieldOfView and canvas size
+    pub fn inline_view(&self) -> View<Viewer> {
+        debug_assert!(!self.is_immersive());
+        let size = self
+            .active_render_state
+            .get()
+            .GetBaseLayer()
+            .expect("Must never construct views when base layer is not set")
+            .size();
+        View {
+            // Inline views have no offset
+            transform: RigidTransform3D::identity(),
+            projection: *self.inline_projection_matrix.borrow(),
+            viewport: Rect::from_size(size.to_i32()),
+        }
+    }
 }
 
 impl XRSessionMethods for XRSession {

components/script/dom/xrviewerpose.rs

@@ -42,7 +42,13 @@ impl XRViewerPose {
     ) -> DomRoot<XRViewerPose> {
         rooted_vec!(let mut views);
         session.with_session(|s| match s.views() {
-            Views::Inline => unimplemented!(),
+            Views::Inline => views.push(XRView::new(
+                global,
+                session,
+                &session.inline_view(),
+                XREye::None,
+                &pose,
+            )),
             Views::Mono(view) => {
                 views.push(XRView::new(global, session, &view, XREye::None, &pose))
             },

components/script/dom/xrwebgllayer.rs

@@ -20,10 +20,10 @@ use crate::dom::xrview::XRView;
 use crate::dom::xrviewport::XRViewport;
 use canvas_traits::webgl::WebGLFramebufferId;
 use dom_struct::dom_struct;
-use euclid::default::Size2D;
+use euclid::Size2D;
 use std::convert::TryInto;
 use webxr_api::SwapChainId as WebXRSwapChainId;
-use webxr_api::Views;
+use webxr_api::{Viewport, Views};
 
 #[dom_struct]
 pub struct XRWebGLLayer {
@@ -33,7 +33,7 @@ pub struct XRWebGLLayer {
     stencil: bool,
     alpha: bool,
     #[ignore_malloc_size_of = "ids don't malloc"]
-    swap_chain_id: WebXRSwapChainId,
+    swap_chain_id: Option<WebXRSwapChainId>,
     context: Dom<WebGLRenderingContext>,
     session: Dom<XRSession>,
     /// If none, this is an inline session (the composition disabled flag is true)
@@ -42,7 +42,7 @@ pub struct XRWebGLLayer {
 
 impl XRWebGLLayer {
     pub fn new_inherited(
-        swap_chain_id: WebXRSwapChainId,
+        swap_chain_id: Option<WebXRSwapChainId>,
         session: &XRSession,
         context: &WebGLRenderingContext,
         init: &XRWebGLLayerInit,
@@ -63,7 +63,7 @@ impl XRWebGLLayer {
 
     pub fn new(
         global: &GlobalScope,
-        swap_chain_id: WebXRSwapChainId,
+        swap_chain_id: Option<WebXRSwapChainId>,
         session: &XRSession,
         context: &WebGLRenderingContext,
         init: &XRWebGLLayerInit,
@@ -89,6 +89,7 @@ impl XRWebGLLayer {
         context: &WebGLRenderingContext,
         init: &XRWebGLLayerInit,
     ) -> Fallible<DomRoot<Self>> {
+        let framebuffer;
         // Step 2
         if session.is_ended() {
             return Err(Error::InvalidState);
@@ -97,9 +98,15 @@ impl XRWebGLLayer {
         // XXXManishearth step 4: check XR compat flag for immersive sessions
 
         // Step 9.2. "Initialize layer’s framebuffer to a new opaque framebuffer created with context."
-        let size = session.with_session(|session| session.recommended_framebuffer_resolution());
-        let (swap_chain_id, framebuffer) =
-            WebGLFramebuffer::maybe_new_webxr(session, context, size).ok_or(Error::Operation)?;
+        let (swap_chain_id, framebuffer) = if session.is_immersive() {
+            let size = session.with_session(|session| session.recommended_framebuffer_resolution());
+            let (swap_chain_id, fb) = WebGLFramebuffer::maybe_new_webxr(session, context, size)
+                .ok_or(Error::Operation)?;
+            framebuffer = fb;
+            (Some(swap_chain_id), Some(&*framebuffer))
+        } else {
+            (None, None)
+        };
 
         // Step 9.3. "Allocate and initialize resources compatible with session’s XR device,
         // including GPU accessible memory buffers, as required to support the compositing of layer."
@@ -117,12 +124,13 @@ impl XRWebGLLayer {
             session,
             context,
             init,
-            Some(&framebuffer),
+            framebuffer,
         ))
     }
 
     pub fn swap_chain_id(&self) -> WebXRSwapChainId {
         self.swap_chain_id
+            .expect("swap_chain_id must not be called for inline sessions")
     }
 
     pub fn session(&self) -> &XRSession {
@@ -133,19 +141,22 @@ impl XRWebGLLayer {
         if let WebGLFramebufferId::Opaque(id) = self
             .framebuffer
             .as_ref()
-            .expect("Must have framebuffer")
+            .expect("swap_buffers must not be called for inline sessions")
             .id()
         {
             self.context.swap_buffers(Some(id));
         }
     }
 
-    fn size(&self) -> Size2D<i32> {
-        if let Some(framebuffer) = self.framebuffer {
+    pub fn size(&self) -> Size2D<u32, Viewport> {
+        if let Some(framebuffer) = self.framebuffer.as_ref() {
             let size = framebuffer.size().unwrap_or((0, 0));
-            Size2D::new(size.0, size.1)
+            Size2D::new(
+                size.0.try_into().unwrap_or(0),
+                size.1.try_into().unwrap_or(0),
+            )
         } else {
-            self.context.Canvas().get_size()
+            Size2D::from_untyped(self.context.Canvas().get_size())
         }
     }
 }
@@ -183,12 +194,12 @@ impl XRWebGLLayerMethods for XRWebGLLayer {
 
     /// https://immersive-web.github.io/webxr/#dom-xrwebgllayer-framebufferwidth
     fn FramebufferWidth(&self) -> u32 {
-        self.size().width.try_into().unwrap_or(0)
+        self.size().width
     }
 
     /// https://immersive-web.github.io/webxr/#dom-xrwebgllayer-framebufferheight
     fn FramebufferHeight(&self) -> u32 {
-        self.size().height.try_into().unwrap_or(0)
+        self.size().height
     }
 
     /// https://immersive-web.github.io/webxr/#dom-xrwebgllayer-getviewport