TAARenderPass.js

( function () {

	/**
 *
 * Temporal Anti-Aliasing Render Pass
 *
 * When there is no motion in the scene, the TAA render pass accumulates jittered camera samples across frames to create a high quality anti-aliased result.
 *
 * References:
 *
 * TODO: Add support for motion vector pas so that accumulation of samples across frames can occur on dynamics scenes.
 *
 */

	class TAARenderPass extends THREE.SSAARenderPass {

		constructor( scene, camera, clearColor, clearAlpha ) {

			super( scene, camera, clearColor, clearAlpha );
			this.sampleLevel = 0;
			this.accumulate = false;

		}

		render( renderer, writeBuffer, readBuffer, deltaTime ) {

			if ( this.accumulate === false ) {

				super.render( renderer, writeBuffer, readBuffer, deltaTime );
				this.accumulateIndex = - 1;
				return;

			}

			const jitterOffsets = _JitterVectors[ 5 ];

			if ( this.sampleRenderTarget === undefined ) {

				this.sampleRenderTarget = new THREE.WebGLRenderTarget( readBuffer.width, readBuffer.height, this.params );
				this.sampleRenderTarget.texture.name = 'TAARenderPass.sample';

			}

			if ( this.holdRenderTarget === undefined ) {

				this.holdRenderTarget = new THREE.WebGLRenderTarget( readBuffer.width, readBuffer.height, this.params );
				this.holdRenderTarget.texture.name = 'TAARenderPass.hold';

			}

			if ( this.accumulateIndex === - 1 ) {

				super.render( renderer, this.holdRenderTarget, readBuffer, deltaTime );
				this.accumulateIndex = 0;

			}

			const autoClear = renderer.autoClear;
			renderer.autoClear = false;
			const sampleWeight = 1.0 / jitterOffsets.length;

			if ( this.accumulateIndex >= 0 && this.accumulateIndex < jitterOffsets.length ) {

				this.copyUniforms[ 'opacity' ].value = sampleWeight;
				this.copyUniforms[ 'tDiffuse' ].value = writeBuffer.texture; // render the scene multiple times, each slightly jitter offset from the last and accumulate the results.

				const numSamplesPerFrame = Math.pow( 2, this.sampleLevel );

				for ( let i = 0; i < numSamplesPerFrame; i ++ ) {

					const j = this.accumulateIndex;
					const jitterOffset = jitterOffsets[ j ];

					if ( this.camera.setViewOffset ) {

						this.camera.setViewOffset( readBuffer.width, readBuffer.height, jitterOffset[ 0 ] * 0.0625, jitterOffset[ 1 ] * 0.0625, // 0.0625 = 1 / 16
							readBuffer.width, readBuffer.height );

					}

					renderer.setRenderTarget( writeBuffer );
					renderer.clear();
					renderer.render( this.scene, this.camera );
					renderer.setRenderTarget( this.sampleRenderTarget );
					if ( this.accumulateIndex === 0 ) renderer.clear();
					this.fsQuad.render( renderer );
					this.accumulateIndex ++;
					if ( this.accumulateIndex >= jitterOffsets.length ) break;

				}

				if ( this.camera.clearViewOffset ) this.camera.clearViewOffset();

			}

			const accumulationWeight = this.accumulateIndex * sampleWeight;

			if ( accumulationWeight > 0 ) {

				this.copyUniforms[ 'opacity' ].value = 1.0;
				this.copyUniforms[ 'tDiffuse' ].value = this.sampleRenderTarget.texture;
				renderer.setRenderTarget( writeBuffer );
				renderer.clear();
				this.fsQuad.render( renderer );

			}

			if ( accumulationWeight < 1.0 ) {

				this.copyUniforms[ 'opacity' ].value = 1.0 - accumulationWeight;
				this.copyUniforms[ 'tDiffuse' ].value = this.holdRenderTarget.texture;
				renderer.setRenderTarget( writeBuffer );
				if ( accumulationWeight === 0 ) renderer.clear();
				this.fsQuad.render( renderer );

			}

			renderer.autoClear = autoClear;

		}

	}

	const _JitterVectors = [[[ 0, 0 ]], [[ 4, 4 ], [ - 4, - 4 ]], [[ - 2, - 6 ], [ 6, - 2 ], [ - 6, 2 ], [ 2, 6 ]], [[ 1, - 3 ], [ - 1, 3 ], [ 5, 1 ], [ - 3, - 5 ], [ - 5, 5 ], [ - 7, - 1 ], [ 3, 7 ], [ 7, - 7 ]], [[ 1, 1 ], [ - 1, - 3 ], [ - 3, 2 ], [ 4, - 1 ], [ - 5, - 2 ], [ 2, 5 ], [ 5, 3 ], [ 3, - 5 ], [ - 2, 6 ], [ 0, - 7 ], [ - 4, - 6 ], [ - 6, 4 ], [ - 8, 0 ], [ 7, - 4 ], [ 6, 7 ], [ - 7, - 8 ]], [[ - 4, - 7 ], [ - 7, - 5 ], [ - 3, - 5 ], [ - 5, - 4 ], [ - 1, - 4 ], [ - 2, - 2 ], [ - 6, - 1 ], [ - 4, 0 ], [ - 7, 1 ], [ - 1, 2 ], [ - 6, 3 ], [ - 3, 3 ], [ - 7, 6 ], [ - 3, 6 ], [ - 5, 7 ], [ - 1, 7 ], [ 5, - 7 ], [ 1, - 6 ], [ 6, - 5 ], [ 4, - 4 ], [ 2, - 3 ], [ 7, - 2 ], [ 1, - 1 ], [ 4, - 1 ], [ 2, 1 ], [ 6, 2 ], [ 0, 4 ], [ 4, 4 ], [ 2, 5 ], [ 7, 5 ], [ 5, 6 ], [ 3, 7 ]]];

	THREE.TAARenderPass = TAARenderPass;

} )();