Enable OpenXR backend from the WebXR crate (#32817)

* Enable OpenXR backend from the WebXR crate

Signed-off-by: Daniel Adams <msub2official@gmail.com>

* Ensure openxr feature is only included on windows

Signed-off-by: Daniel Adams <msub2official@gmail.com>

* Add cfgs for OpenXR usages

Signed-off-by: Daniel Adams <msub2official@gmail.com>

---------

Signed-off-by: Daniel Adams <msub2official@gmail.com>

Cargo.lock

@@ -4449,6 +4449,27 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "openxr"
+version = "0.18.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a03958eb34719625119448d483ebd2fe008a2128b6286f2a7138b7e48072053"
+dependencies = [
+ "libc",
+ "libloading",
+ "ndk-context",
+ "openxr-sys",
+]
+
+[[package]]
+name = "openxr-sys"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1534b2c14b56564e58b91f5015817e1d87bd43ca12a188eda6a9ea3859b0ec25"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "option-operations"
 version = "0.5.0"
@@ -7354,11 +7375,14 @@ dependencies = [
  "gl_generator",
  "gvr-sys",
  "log",
+ "openxr",
  "serde",
  "sparkle",
  "surfman",
  "time 0.1.45",
  "webxr-api",
+ "winapi",
+ "wio",
 ]
 
 [[package]]

components/config/prefs.rs

@@ -400,6 +400,9 @@ mod gen {
                     layers: {
                         enabled: bool,
                     },
+                    openxr: {
+                        enabled: bool,
+                    },
                     sessionavailable: bool,
                     #[serde(rename = "dom.webxr.unsafe-assume-user-intent")]
                     unsafe_assume_user_intent: bool,

ports/servoshell/Cargo.toml

@@ -116,5 +116,6 @@ image = { workspace = true }
 sig = "1.0"
 
 [target.'cfg(target_os = "windows")'.dependencies]
+webxr = { git = "https://github.com/servo/webxr", features = ["ipc", "glwindow", "headless", "openxr-api"] }
 windows-sys = { workspace = true, features = ["Win32_Graphics_Gdi"] }
 libservo = { path = "../../components/servo", features = ["no-wgl"] }

ports/servoshell/desktop/app.rs

@@ -19,6 +19,8 @@ use servo::servo_config::pref;
 use servo::Servo;
 use surfman::GLApi;
 use webxr::glwindow::GlWindowDiscovery;
+#[cfg(target_os = "windows")]
+use webxr::openxr::OpenXrDiscovery;
 use winit::event::WindowEvent;
 use winit::event_loop::EventLoopWindowTarget;
 use winit::window::WindowId;
@@ -27,7 +29,7 @@ use super::events_loop::{EventsLoop, WakerEvent};
 use super::minibrowser::Minibrowser;
 use super::webview::WebViewManager;
 use super::{headed_window, headless_window};
-use crate::desktop::embedder::EmbedderCallbacks;
+use crate::desktop::embedder::{EmbedderCallbacks, XrDiscovery};
 use crate::desktop::tracing::trace_winit_event;
 use crate::desktop::window_trait::WindowPortsMethods;
 use crate::parser::get_default_url;
@@ -153,12 +155,19 @@ impl App {
                         >(w.unwrap())
                     };
                     let factory = Box::new(move || Ok(window.new_glwindow(w)));
-                    Some(GlWindowDiscovery::new(
+                    Some(XrDiscovery::GlWindow(GlWindowDiscovery::new(
                         surfman.connection(),
                         surfman.adapter(),
                         surfman.context_attributes(),
                         factory,
-                    ))
+                    )))
+                } else if pref!(dom.webxr.openxr.enabled) && !opts::get().headless {
+                    #[cfg(target_os = "windows")]
+                    let openxr = Some(XrDiscovery::OpenXr(OpenXrDiscovery::new(None)));
+                    #[cfg(not(target_os = "windows"))]
+                    let openxr = None;
+
+                    openxr
                 } else {
                     None
                 };

ports/servoshell/desktop/embedder.rs

@@ -8,16 +8,24 @@ use servo::compositing::windowing::EmbedderMethods;
 use servo::embedder_traits::{EmbedderProxy, EventLoopWaker};
 use servo::servo_config::pref;
 use webxr::glwindow::GlWindowDiscovery;
+#[cfg(target_os = "windows")]
+use webxr::openxr::OpenXrDiscovery;
+
+pub enum XrDiscovery {
+    GlWindow(GlWindowDiscovery),
+    #[cfg(target_os = "windows")]
+    OpenXr(OpenXrDiscovery),
+}
 
 pub struct EmbedderCallbacks {
     event_loop_waker: Box<dyn EventLoopWaker>,
-    xr_discovery: Option<GlWindowDiscovery>,
+    xr_discovery: Option<XrDiscovery>,
 }
 
 impl EmbedderCallbacks {
     pub fn new(
         event_loop_waker: Box<dyn EventLoopWaker>,
-        xr_discovery: Option<GlWindowDiscovery>,
+        xr_discovery: Option<XrDiscovery>,
     ) -> EmbedderCallbacks {
         EmbedderCallbacks {
             event_loop_waker,
@@ -39,7 +47,11 @@ impl EmbedderMethods for EmbedderCallbacks {
         if pref!(dom.webxr.test) {
             xr.register_mock(webxr::headless::HeadlessMockDiscovery::new());
         } else if let Some(xr_discovery) = self.xr_discovery.take() {
-            xr.register(xr_discovery);
+            match xr_discovery {
+                XrDiscovery::GlWindow(discovery) => xr.register(discovery),
+                #[cfg(target_os = "windows")]
+                XrDiscovery::OpenXr(discovery) => xr.register(discovery),
+            }
         }
     }
 }

resources/prefs.json

@@ -49,6 +49,7 @@
   "dom.webxr.glwindow.spherical": false,
   "dom.webxr.hands.enabled": false,
   "dom.webxr.layers.enabled": false,
+  "dom.webxr.openxr.enabled": false,
   "dom.webxr.sessionavailable": false,
   "dom.webxr.test": false,
   "dom.webxr.unsafe-assume-user-intent": false,