Enable post-processing in VR (#20)

* Update WebXRManager.js

* Update WebGLRenderer.js

* Update WebGLRenderer.js

deleted useless blank lines

* Update WebXRManager.js

- Deleted useless code and blank lines
- refectored _getRenderTarget to getRenderTarget

* Update WebGLRenderer.js

Reflect the refactoring of getRenderTarget function

Improve compatibility of Post-Processing with VR (#23)

* Update EffectComposer.js for better compatibility with VR

* Update Pass.js for better compatibility with VR

Author: enzofrancescaHM

examples/jsm/postprocessing/EffectComposer.js

@@ -39,6 +39,8 @@ import { ClearMaskPass, MaskPass } from './MaskPass.js';
  *
  * @three_import import { EffectComposer } from 'three/addons/postprocessing/EffectComposer.js';
  */
+const size = /* @__PURE__ */ new Vector2();
+
 class EffectComposer {
 
 	/**
@@ -62,7 +64,7 @@ class EffectComposer {
 
 		if ( renderTarget === undefined ) {
 
-			const size = renderer.getSize( new Vector2() );
+			renderer.getSize( size );
 			this._width = size.width;
 			this._height = size.height;
 
@@ -128,6 +130,22 @@ class EffectComposer {
 		 */
 		this.clock = new Clock();
 
+		this.onSessionStateChange = this.onSessionStateChange.bind( this );
+		this.renderer.xr.addEventListener( 'sessionstart', this.onSessionStateChange );
+		this.renderer.xr.addEventListener( 'sessionend', this.onSessionStateChange );
+
+	}
+
+	onSessionStateChange() {
+
+		this.renderer.getSize( size );
+		this._width = size.width;
+		this._height = size.height;
+
+		this._pixelRatio = this.renderer.xr.isPresenting ? 1 : this.renderer.getPixelRatio();
+
+		this.setSize( this._width, this._height );
+
 	}
 
 	/**
@@ -285,7 +303,7 @@ class EffectComposer {
 
 		if ( renderTarget === undefined ) {
 
-			const size = this.renderer.getSize( new Vector2() );
+			this.renderer.getSize( size );
 			this._pixelRatio = this.renderer.getPixelRatio();
 			this._width = size.width;
 			this._height = size.height;
@@ -356,6 +374,9 @@ class EffectComposer {
 
 		this.copyPass.dispose();
 
+		this.renderer.xr.removeEventListener( 'sessionstart', this.onSessionStateChange );
+		this.renderer.xr.removeEventListener( 'sessionend', this.onSessionStateChange );
+
 	}
 
 }

examples/jsm/postprocessing/Pass.js

@@ -165,8 +165,13 @@ class FullScreenQuad {
 	 */
 	render( renderer ) {
 
-		renderer.render( this._mesh, _camera );
+		// Disable XR projection for fullscreen effects
+		// https://github.com/mrdoob/three.js/pull/18846
+		const xrEnabled = renderer.xr.enabled;
 
+		renderer.xr.enabled = false;
+		renderer.render( this._mesh, _camera );
+		renderer.xr.enabled = xrEnabled;
 	}
 
 	/**

src/renderers/WebGLRenderer.js

@@ -2761,6 +2761,13 @@ class WebGLRenderer {
 		 */
 		this.setRenderTarget = function ( renderTarget, activeCubeFace = 0, activeMipmapLevel = 0 ) {
 
+			// Render to base layer instead of canvas in WebXR
+			if ( renderTarget === null && this.xr.isPresenting ) {
+
+				renderTarget = this.xr.getRenderTarget();
+
+			}
+
 			_currentRenderTarget = renderTarget;
 			_currentActiveCubeFace = activeCubeFace;
 			_currentActiveMipmapLevel = activeMipmapLevel;

src/renderers/webxr/WebXRManager.js

@@ -256,6 +256,8 @@ class WebXRManager extends EventDispatcher {
 
 			// restore framebuffer/rendering state
 
+			scope.isPresenting = false;
+
 			renderer.setRenderTarget( initialRenderTarget );
 
 			glBaseLayer = null;
@@ -268,8 +270,6 @@ class WebXRManager extends EventDispatcher {
 
 			animation.stop();
 
-			scope.isPresenting = false;
-
 			renderer.setPixelRatio( currentPixelRatio );
 			renderer.setSize( currentSize.width, currentSize.height, false );
 
@@ -385,6 +385,12 @@ class WebXRManager extends EventDispatcher {
 
 		};
 
+		this.getRenderTarget = function () {
+
+			return newRenderTarget;
+
+		};
+
 		/**
 		 * Returns the current XR session.
 		 *