Merge pull request #5305 from TrevorDev/customAnimationFrameReq

customAnimationFrameRequester

dist/preview release/what's new.md

@@ -5,6 +5,8 @@
 - Added support for [parallel shader compilation](https://www.khronos.org/registry/webgl/extensions/KHR_parallel_shader_compile/) ([Deltakosh](https://github.com/deltakosh))
 - Added FlyCamera for free navigation in 3D space, with a limited set of settings ([Phuein](https://github.com/phuein))
 - Added Object Based Motion Blur post-process ([julien-moreau](https://github.com/julien-moreau))
+- WebXR ([TrevorDev](https://github.com/TrevorDev))
+  - Add customAnimationFrameRequester to allow sessions to hook into engine's render loop ([TrevorDev](https://github.com/TrevorDev))
 
 ## Updates
 

src/Engine/babylon.engine.ts

@@ -625,6 +625,11 @@ module BABYLON {
         public onBeginFrameObservable = new Observable<Engine>();
 
         /**
+         * If set, will be used to request the next animation frame for the render loop
+         */
+        public customAnimationFrameRequester: Nullable<ICustomAnimationFrameRequester> = null;
+
+        /**
          * Observable raised when the engine ends the current frame
          */
         public onEndFrameObservable = new Observable<Engine>();
@@ -1894,11 +1899,14 @@ module BABYLON {
 
             if (this._activeRenderLoops.length > 0) {
                 // Register new frame
-                var requester = null;
-                if (this._vrDisplay && this._vrDisplay.isPresenting) {
-                    requester = this._vrDisplay;
+                if (this.customAnimationFrameRequester) {
+                    this.customAnimationFrameRequester.requestID = Tools.QueueNewFrame(this.customAnimationFrameRequester.renderFunction || this._bindedRenderFunction, this.customAnimationFrameRequester);
+                    this._frameHandler = this.customAnimationFrameRequester.requestID;
+                } else if (this._vrDisplay && this._vrDisplay.isPresenting) {
+                    this._frameHandler = Tools.QueueNewFrame(this._bindedRenderFunction, this._vrDisplay);
+                } else {
+                    this._frameHandler = Tools.QueueNewFrame(this._bindedRenderFunction);
                 }
-                this._frameHandler = Tools.QueueNewFrame(this._bindedRenderFunction, requester);
             } else {
                 this._renderingQueueLaunched = false;
             }

src/Tools/babylon.tools.ts

@@ -1,5 +1,25 @@
 module BABYLON {
     /**
+     * Interface for any object that can request an animation frame
+     */
+    export interface ICustomAnimationFrameRequester {
+        /**
+         * This function will be called when the render loop is ready. If this is not populated, the engine's renderloop function will be called
+         */
+        renderFunction?: Function;
+        /**
+         * Called to request the next frame to render to
+         * @see https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame
+         */
+        requestAnimationFrame: Function;
+        /**
+         * You can pass this value to cancelAnimationFrame() to cancel the refresh callback request
+         * @see https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame#Return_value
+         */
+        requestID?: number;
+    }
+
+    /**
      * Interface containing an array of animations
      */
     export interface IAnimatable {