import { AdditiveBlending, Color, LinearFilter, RGBAFormat, ShaderMaterial, UniformsUtils, WebGLRenderTarget } from '../../../build/three.module.js'; import { Pass, FullScreenQuad } from '../postprocessing/Pass.js'; import { CopyShader } from '../shaders/CopyShader.js'; /** * * Supersample Anti-Aliasing Render Pass * * This manual approach to SSAA re-renders the scene ones for each sample with camera jitter and accumulates the results. * * References: https://en.wikipedia.org/wiki/Supersampling * */ class SSAARenderPass extends Pass { constructor( scene, camera, clearColor, clearAlpha ) { super(); this.scene = scene; this.camera = camera; this.sampleLevel = 4; // specified as n, where the number of samples is 2^n, so sampleLevel = 4, is 2^4 samples, 16. this.unbiased = true; // as we need to clear the buffer in this pass, clearColor must be set to something, defaults to black. this.clearColor = ( clearColor !== undefined ) ? clearColor : 0x000000; this.clearAlpha = ( clearAlpha !== undefined ) ? clearAlpha : 0; this._oldClearColor = new Color(); if ( CopyShader === undefined ) console.error( 'THREE.SSAARenderPass relies on CopyShader' ); const copyShader = CopyShader; this.copyUniforms = UniformsUtils.clone( copyShader.uniforms ); this.copyMaterial = new ShaderMaterial( { uniforms: this.copyUniforms, vertexShader: copyShader.vertexShader, fragmentShader: copyShader.fragmentShader, premultipliedAlpha: true, transparent: true, blending: AdditiveBlending, depthTest: false, depthWrite: false } ); this.fsQuad = new FullScreenQuad( this.copyMaterial ); } dispose() { if ( this.sampleRenderTarget ) { this.sampleRenderTarget.dispose(); this.sampleRenderTarget = null; } } setSize( width, height ) { if ( this.sampleRenderTarget ) this.sampleRenderTarget.setSize( width, height ); } render( renderer, writeBuffer, readBuffer ) { if ( ! this.sampleRenderTarget ) { this.sampleRenderTarget = new WebGLRenderTarget( readBuffer.width, readBuffer.height, { minFilter: LinearFilter, magFilter: LinearFilter, format: RGBAFormat } ); this.sampleRenderTarget.texture.name = 'SSAARenderPass.sample'; } const jitterOffsets = _JitterVectors[ Math.max( 0, Math.min( this.sampleLevel, 5 ) ) ]; const autoClear = renderer.autoClear; renderer.autoClear = false; renderer.getClearColor( this._oldClearColor ); const oldClearAlpha = renderer.getClearAlpha(); const baseSampleWeight = 1.0 / jitterOffsets.length; const roundingRange = 1 / 32; this.copyUniforms[ 'tDiffuse' ].value = this.sampleRenderTarget.texture; const viewOffset = { fullWidth: readBuffer.width, fullHeight: readBuffer.height, offsetX: 0, offsetY: 0, width: readBuffer.width, height: readBuffer.height }; const originalViewOffset = Object.assign( {}, this.camera.view ); if ( originalViewOffset.enabled ) Object.assign( viewOffset, originalViewOffset ); // render the scene multiple times, each slightly jitter offset from the last and accumulate the results. for ( let i = 0; i < jitterOffsets.length; i ++ ) { const jitterOffset = jitterOffsets[ i ]; if ( this.camera.setViewOffset ) { this.camera.setViewOffset( viewOffset.fullWidth, viewOffset.fullHeight, viewOffset.offsetX + jitterOffset[ 0 ] * 0.0625, viewOffset.offsetY + jitterOffset[ 1 ] * 0.0625, // 0.0625 = 1 / 16 viewOffset.width, viewOffset.height ); } let sampleWeight = baseSampleWeight; if ( this.unbiased ) { // the theory is that equal weights for each sample lead to an accumulation of rounding errors. // The following equation varies the sampleWeight per sample so that it is uniformly distributed // across a range of values whose rounding errors cancel each other out. const uniformCenteredDistribution = ( - 0.5 + ( i + 0.5 ) / jitterOffsets.length ); sampleWeight += roundingRange * uniformCenteredDistribution; } this.copyUniforms[ 'opacity' ].value = sampleWeight; renderer.setClearColor( this.clearColor, this.clearAlpha ); renderer.setRenderTarget( this.sampleRenderTarget ); renderer.clear(); renderer.render( this.scene, this.camera ); renderer.setRenderTarget( this.renderToScreen ? null : writeBuffer ); if ( i === 0 ) { renderer.setClearColor( 0x000000, 0.0 ); renderer.clear(); } this.fsQuad.render( renderer ); } if ( this.camera.setViewOffset && originalViewOffset.enabled ) { this.camera.setViewOffset( originalViewOffset.fullWidth, originalViewOffset.fullHeight, originalViewOffset.offsetX, originalViewOffset.offsetY, originalViewOffset.width, originalViewOffset.height ); } else if ( this.camera.clearViewOffset ) { this.camera.clearViewOffset(); } renderer.autoClear = autoClear; renderer.setClearColor( this._oldClearColor, oldClearAlpha ); } } // These jitter vectors are specified in integers because it is easier. // I am assuming a [-8,8) integer grid, but it needs to be mapped onto [-0.5,0.5) // before being used, thus these integers need to be scaled by 1/16. // // Sample patterns reference: https://msdn.microsoft.com/en-us/library/windows/desktop/ff476218%28v=vs.85%29.aspx?f=255&MSPPError=-2147217396 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 ] ] ]; export { SSAARenderPass };