Merge pull request BabylonJS#10913 from RaananW/xrFoveated

[XR] Foveated rendering and update framerate

dist/preview release/what's new.md

@@ -169,6 +169,8 @@
 - Initial support for WebXR camera parenting ([#10593](https://github.com/BabylonJS/Babylon.js/issues/10593)) ([RaananW](https://github.com/RaananW))
 - Fix ReflectionProbe for WebXR ([#10390](https://github.com/BabylonJS/Babylon.js/issues/10390)) ([RaananW](https://github.com/RaananW))
 - Fix error on XR dispose due to undefined sepectator camera ([Alex-MSFT](https://github.com/Alex-MSFT))
+- Support for WebXR Foveated rendering ([#8920](https://github.com/BabylonJS/Babylon.js/issues/8920)) ([RaananW](https://github.com/RaananW))
+- Support WebXR framerate update ([#10912](https://github.com/BabylonJS/Babylon.js/issues/10912)) ([RaananW](https://github.com/RaananW))
 
 ### Gizmos
 

src/LibDeclarations/webxr.d.ts

@@ -94,6 +94,7 @@ declare class XRWebGLLayer {
     readonly framebufferWidth: number;
     readonly framebufferHeight: number;
     readonly ignoreDepthValues: boolean;
+    fixedFoveation?: number | null;
     getViewport: (view: XRView) => XRViewport;
 }
 
@@ -258,6 +259,10 @@ interface XRSession {
      * Provided when the optional 'dom-overlay' feature is requested.
      */
     readonly domOverlayState?: XRDOMOverlayState;
+
+    readonly frameRate?: number;
+    readonly supportedFrameRates?: Float32Array;
+    updateTargetFrameRate(rate: number): Promise<void>;
 }
 
 interface XRViewerPose extends XRPose {

src/XR/webXRSessionManager.ts

@@ -376,6 +376,55 @@ export class WebXRSessionManager implements IDisposable {
         return this._xrNavigator.xr.native ?? false;
     }
 
+    /**
+     * The current frame rate as reported by the device
+     */
+    public get currentFrameRate(): number | undefined {
+        return this.session?.frameRate;
+    }
+
+    /**
+     * A list of supported frame rates (only available in-session!
+     */
+    public get supportedFrameRates(): Float32Array | undefined {
+        return this.session?.supportedFrameRates;
+    }
+
+    /**
+     * Set the framerate of the session.
+     * @param rate the new framerate. This value needs to be in the supportedFrameRates array
+     * @returns a promise that resolves once the framerate has been set
+     */
+    public updateTargetFrameRate(rate: number): Promise<void> {
+        return this.session.updateTargetFrameRate(rate);
+    }
+
+    /**
+     * Check if fixed foveation is supported on this device
+     */
+    public get isFixedFoveationSupported(): boolean {
+        return !!this._baseLayer?.fixedFoveation !== null;
+    }
+
+    /**
+     * Get the fixed foveation currently set, as specified by the webxr specs
+     * If this returns null, then fixed foveation is not supported
+     */
+    public get fixedFoveation(): Nullable<number> {
+        return this._baseLayer?.fixedFoveation !== undefined ? this._baseLayer.fixedFoveation : null;
+    }
+
+    /**
+     * Set the fixed foveation to the specified value, as specified by the webxr specs
+     * This value will be normalized to be between 0 and 1, 1 being max foveation, 0 being no foveation
+     */
+    public set fixedFoveation(value: Nullable<number>) {
+        const val = Math.max(0, Math.min(1, value || 0));
+        if (this._baseLayer?.fixedFoveation !== undefined) {
+            this._baseLayer.fixedFoveation = val;
+        }
+    }
+
     private _createRenderTargetTexture(width: number, height: number, framebuffer: WebGLFramebuffer): RenderTargetTexture {
         if (!this._engine) {
             throw new Error("Engine is disposed");