From d146303f1d7e2247cfa768a6caf2b4deb5e5bf11 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Thu, 9 Apr 2020 20:27:24 -0700
Subject: [PATCH] Dirty canvas when exiting immersive sessions

---
 components/script/dom/webglrenderingcontext.rs |  2 +-
 components/script/dom/xrsystem.rs              | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/components/script/dom/webglrenderingcontext.rs b/components/script/dom/webglrenderingcontext.rs
index f23ca9f1415..53dff84c6ec 100644
--- a/components/script/dom/webglrenderingcontext.rs
+++ b/components/script/dom/webglrenderingcontext.rs
@@ -503,7 +503,7 @@ impl WebGLRenderingContext {
         }
     }
 
-    fn mark_as_dirty(&self) {
+    pub fn mark_as_dirty(&self) {
         // If we have a bound framebuffer, then don't mark the canvas as dirty.
         if self.bound_draw_framebuffer.get().is_some() {
             return;
diff --git a/components/script/dom/xrsystem.rs b/components/script/dom/xrsystem.rs
index 0e2a44f09cb..7bd7f72e8fe 100644
--- a/components/script/dom/xrsystem.rs
+++ b/components/script/dom/xrsystem.rs
@@ -3,8 +3,13 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use crate::dom::bindings::cell::DomRefCell;
+use crate::dom::bindings::codegen::Bindings::XRRenderStateBinding::XRRenderStateMethods;
+use crate::dom::bindings::codegen::Bindings::XRSessionBinding::XRSessionMethods;
 use crate::dom::bindings::codegen::Bindings::XRSystemBinding::XRSessionInit;
 use crate::dom::bindings::codegen::Bindings::XRSystemBinding::{XRSessionMode, XRSystemMethods};
+use crate::dom::bindings::codegen::Bindings::XRWebGLLayerBinding::{
+    XRWebGLLayerMethods, XRWebGLRenderingContext,
+};
 use crate::dom::bindings::conversions::{ConversionResult, FromJSValConvertible};
 use crate::dom::bindings::error::Error;
 use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
@@ -81,6 +86,17 @@ impl XRSystem {
         if let Some(active) = self.active_immersive_session.get() {
             if Dom::from_ref(&*active) == Dom::from_ref(session) {
                 self.active_immersive_session.set(None);
+
+                // Dirty the canvas, since it has been skipping this step whilst in immersive
+                // mode
+                if let Some(layer) = session.RenderState().GetBaseLayer() {
+                    match layer.Context() {
+                        XRWebGLRenderingContext::WebGLRenderingContext(c) => c.mark_as_dirty(),
+                        XRWebGLRenderingContext::WebGL2RenderingContext(c) => {
+                            c.base_context().mark_as_dirty()
+                        },
+                    }
+                }
             }
         }
         self.active_inline_sessions