three.js/examples/js/postprocessing/RenderPass.js

( function () {

	class RenderPass extends THREE.Pass {

		constructor( scene, camera, overrideMaterial, clearColor, clearAlpha ) {

			super();
			this.scene = scene;
			this.camera = camera;
			this.overrideMaterial = overrideMaterial;
			this.clearColor = clearColor;
			this.clearAlpha = clearAlpha !== undefined ? clearAlpha : 0;
			this.clear = true;
			this.clearDepth = false;
			this.needsSwap = false;
			this._oldClearColor = new THREE.Color();

		}
		render( renderer, writeBuffer, readBuffer /*, deltaTime, maskActive */ ) {

			const oldAutoClear = renderer.autoClear;
			renderer.autoClear = false;
			let oldClearAlpha, oldOverrideMaterial;
			if ( this.overrideMaterial !== undefined ) {

				oldOverrideMaterial = this.scene.overrideMaterial;
				this.scene.overrideMaterial = this.overrideMaterial;

			}

			if ( this.clearColor ) {

				renderer.getClearColor( this._oldClearColor );
				oldClearAlpha = renderer.getClearAlpha();
				renderer.setClearColor( this.clearColor, this.clearAlpha );

			}

			if ( this.clearDepth ) {

				renderer.clearDepth();

			}

			renderer.setRenderTarget( this.renderToScreen ? null : readBuffer );

			// TODO: Avoid using autoClear properties, see https://github.com/mrdoob/three.js/pull/15571#issuecomment-465669600
			if ( this.clear ) renderer.clear( renderer.autoClearColor, renderer.autoClearDepth, renderer.autoClearStencil );
			renderer.render( this.scene, this.camera );
			if ( this.clearColor ) {

				renderer.setClearColor( this._oldClearColor, oldClearAlpha );

			}

			if ( this.overrideMaterial !== undefined ) {

				this.scene.overrideMaterial = oldOverrideMaterial;

			}

			renderer.autoClear = oldAutoClear;

		}

	}

	THREE.RenderPass = RenderPass;

} )();