Accueil / npm / three@0.186.1 / examples / jsm / postprocessing / SSAARenderPass.js
SSAARenderPass.js
import {
AdditiveBlending,
Color,
HalfFloatType,
ShaderMaterial,
UniformsUtils,
WebGLRenderTarget
} from 'three';
import { Pass, FullScreenQuad } from './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.
*
* ```js
* const ssaaRenderPass = new SSAARenderPass( scene, camera );
* ssaaRenderPass.sampleLevel = 3;
* composer.addPass( ssaaRenderPass );
* ```
*
* @augments Pass
* @three_import import { SSAARenderPass } from 'three/addons/postprocessing/SSAARenderPass.js';
*/
class SSAARenderPass extends Pass {
/**
* Constructs a new SSAA render pass.
*
* @param {Scene} scene - The scene to render.
* @param {Camera} camera - The camera.
* @param {?(number|Color|string)} [clearColor=0x000000] - The clear color of the render pass.
* @param {?number} [clearAlpha=0] - The clear alpha of the render pass.
*/
constructor( scene, camera, clearColor = 0x000000, clearAlpha = 0 ) {
super();
/**
* The scene to render.
*
* @type {Scene}
*/
this.scene = scene;
/**
* The camera.
*
* @type {Camera}
*/
this.camera = camera;
/**
* The sample level. Specified as n, where the number of
* samples is 2^n, so sampleLevel = 4, is 2^4 samples, 16.
*
* @type {number}
* @default 4
*/
this.sampleLevel = 4;
/**
* Whether the pass should be unbiased or not. This property has the most
* visible effect when rendering to a RGBA8 buffer because it mitigates
* rounding errors. By default RGBA16F is used.
*
* @type {boolean}
* @default true
*/
this.unbiased = true;
/**
* Whether to use a stencil buffer or not. This property can't
* be changed after the first render.
*
* @type {boolean}
* @default false
*/
this.stencilBuffer = false;
/**
* The clear color of the render pass.
*
* @type {?(number|Color|string)}
* @default 0x000000
*/
this.clearColor = clearColor;
/**
* The clear alpha of the render pass.
*
* @type {?number}
* @default 0
*/
this.clearAlpha = clearAlpha;
// internals
this._sampleRenderTarget = null;
this._oldClearColor = new Color();
this._copyUniforms = UniformsUtils.clone( CopyShader.uniforms );
this._copyMaterial = new ShaderMaterial( {
uniforms: this._copyUniforms,
vertexShader: CopyShader.vertexShader,
fragmentShader: CopyShader.fragmentShader,
transparent: true,
depthTest: false,
depthWrite: false,
premultipliedAlpha: true,
blending: AdditiveBlending
} );
this._fsQuad = new FullScreenQuad( this._copyMaterial );
}
/**
* Frees the GPU-related resources allocated by this instance. Call this
* method whenever the pass is no longer used in your app.
*/
dispose() {
if ( this._sampleRenderTarget ) {
this._sampleRenderTarget.dispose();
this._sampleRenderTarget = null;
}
this._copyMaterial.dispose();
this._fsQuad.dispose();
}
/**
* Sets the size of the pass.
*
* @param {number} width - The width to set.
* @param {number} height - The height to set.
*/
setSize( width, height ) {
if ( this._sampleRenderTarget ) this._sampleRenderTarget.setSize( width, height );
}
/**
* Performs the SSAA render pass.
*
* @param {WebGLRenderer} renderer - The renderer.
* @param {WebGLRenderTarget} writeBuffer - The write buffer. This buffer is intended as the rendering
* destination for the pass.
* @param {WebGLRenderTarget} readBuffer - The read buffer. The pass can access the result from the
* previous pass from this buffer.
* @param {number} deltaTime - The delta time in seconds.
* @param {boolean} maskActive - Whether masking is active or not.
*/
render( renderer, writeBuffer, readBuffer/*, deltaTime, maskActive */ ) {
if ( ! this._sampleRenderTarget ) {
this._sampleRenderTarget = new WebGLRenderTarget( readBuffer.width, readBuffer.height, { type: HalfFloatType, stencilBuffer: this.stencilBuffer } );
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 };