AF Manager class for dynamic animation frame request/cancel

src/core/renderer/utilities/FrameScheduler.js

@@ -0,0 +1,124 @@
+class FrameScheduler {
+
+	constructor() {
+
+		// XR session
+		this.xrsession = null;
+
+		// Pending AFs
+		this.pending = new Map();
+
+	}
+
+	// Set active XR session
+	// To be called when entering XR
+	setXRSession( xrsession ) {
+
+		this.xrsession = xrsession;
+
+		this.flushPending();
+
+	}
+
+	// Remove XR session (exit)
+	// To be called when exiting XR
+	removeXRSession() {
+
+		this.xrsession = null;
+
+		this.flushPending();
+
+	}
+
+	// Request animation frame (defer to XR session if active)
+	requestAnimationFrame( cb ) {
+
+		let handle;
+
+		// Standard AF
+		if ( ! this.xrsession ) {
+
+			handle = window.requestAnimationFrame( ()=>{
+
+				this.pending.delete( handle );
+
+				cb();
+
+			} );
+
+			this.pending.set( handle, cb );
+
+			return handle;
+
+		} else { // XR session
+
+			handle = this.xrsession.requestAnimationFrame( ()=>{
+
+				this.pending.delete( handle );
+
+				cb();
+
+			} );
+
+			this.pending.set( handle, cb );
+
+			return handle;
+
+		}
+
+	}
+
+	// Cancel animation frame via handle (defer to XR session if active)
+	cancelAnimationFrame( handle ) {
+
+		this.pending.delete( handle );
+
+		if ( ! this.xrsession ) {
+
+			window.cancelAnimationFrame( handle );
+
+		} else {
+
+			this.xrsession.cancelAnimationFrame( handle );
+
+		}
+
+	}
+
+	// Cancel all pending AFs
+	cancelAllPending() {
+
+		this.pending.forEach( ( cb, handle )=>{
+
+			this.cancelAnimationFrame( handle );
+
+		} );
+
+	}
+
+	// Flush and complete pending AFs (defer to XR session if active)
+	flushPending() {
+
+		this.pending.forEach( ( cb, handle )=>{
+
+			if ( this.xrsession ) {
+
+				this.xrsession.cancelAnimationFrame( handle );
+
+				cb();
+
+			} else {
+
+				window.cancelAnimationFrame( handle );
+
+				cb();
+
+			}
+
+		} );
+
+	}
+
+}
+
+export { FrameScheduler };