import { Vector2, TempNode } from 'three/webgpu';
import { nodeObject, Fn, uniformArray, select, float, NodeUpdateType, uv, dot, clamp, uniform, convertToTexture, smoothstep, bool, vec2, vec3, If, Loop, max, min, Break, abs } from 'three/tsl';
/** @module FXAANode **/
/**
* Post processing node for applying FXAA. This node requires sRGB input
* so tone mapping and color space conversion must happen before the anti-aliasing.
*
* @augments TempNode
*/
class FXAANode extends TempNode {
static get type() {
return 'FXAANode';
}
/**
* Constructs a new FXAA node.
*
* @param {TextureNode} textureNode - The texture node that represents the input of the effect.
*/
constructor( textureNode ) {
super( 'vec4' );
/**
* The texture node that represents the input of the effect.
*
* @type {TextureNode}
*/
this.textureNode = textureNode;
/**
* The `updateBeforeType` is set to `NodeUpdateType.FRAME` since the node updates
* its internal uniforms once per frame in `updateBefore()`.
*
* @type {String}
* @default 'frame'
*/
this.updateBeforeType = NodeUpdateType.FRAME;
/**
* A uniform node holding the inverse resolution value.
*
* @private
* @type {UniformNode<vec2>}
*/
this._invSize = uniform( new Vector2() );
}
/**
* This method is used to update the effect's uniforms once per frame.
*
* @param {NodeFrame} frame - The current node frame.
*/
updateBefore( /* frame */ ) {
const map = this.textureNode.value;
this._invSize.value.set( 1 / map.image.width, 1 / map.image.height );
}
/**
* This method is used to setup the effect's TSL code.
*
* @param {NodeBuilder} builder - The current node builder.
* @return {ShaderCallNodeInternal}
*/
setup( /* builder */ ) {
const textureNode = this.textureNode.bias( - 100 );
const uvNode = textureNode.uvNode || uv();
const EDGE_STEP_COUNT = float( 6 );
const EDGE_GUESS = float( 8.0 );
const EDGE_STEPS = uniformArray( [ 1.0, 1.5, 2.0, 2.0, 2.0, 4.0 ] );
const _ContrastThreshold = float( 0.0312 );
const _RelativeThreshold = float( 0.063 );
const _SubpixelBlending = float( 1.0 );
const Sample = Fn( ( [ uv ] ) => {
return textureNode.sample( uv );
} );
const SampleLuminance = Fn( ( [ uv ] ) => {
return dot( Sample( uv ).rgb, vec3( 0.3, 0.59, 0.11 ) );
} );
const SampleLuminanceOffset = Fn( ( [ texSize, uv, uOffset, vOffset ] ) => {
const shiftedUv = uv.add( texSize.mul( vec2( uOffset, vOffset ) ) );
return SampleLuminance( shiftedUv );
} );
const ShouldSkipPixel = ( l ) => {
const threshold = max( _ContrastThreshold, _RelativeThreshold.mul( l.highest ) );
return l.contrast.lessThan( threshold );
};
const SampleLuminanceNeighborhood = ( texSize, uv ) => {
const m = SampleLuminance( uv );
const n = SampleLuminanceOffset( texSize, uv, 0.0, - 1.0 );
const e = SampleLuminanceOffset( texSize, uv, 1.0, 0.0 );
const s = SampleLuminanceOffset( texSize, uv, 0.0, 1.0 );
const w = SampleLuminanceOffset( texSize, uv, - 1.0, 0.0 );
const ne = SampleLuminanceOffset( texSize, uv, 1.0, - 1.0 );
const nw = SampleLuminanceOffset( texSize, uv, - 1.0, - 1.0 );
const se = SampleLuminanceOffset( texSize, uv, 1.0, 1.0 );
const sw = SampleLuminanceOffset( texSize, uv, - 1.0, 1.0 );
const highest = max( max( max( max( s, e ), n ), w ), m );
const lowest = min( min( min( min( s, e ), n ), w ), m );
const contrast = highest.sub( lowest );
return { m, n, e, s, w, ne, nw, se, sw, highest, lowest, contrast };
};
const DeterminePixelBlendFactor = ( l ) => {
let f = float( 2.0 ).mul( l.s.add( l.e ).add( l.n ).add( l.w ) );
f = f.add( l.se.add( l.sw ).add( l.ne ).add( l.nw ) );
f = f.mul( 1.0 / 12.0 );
f = abs( f.sub( l.m ) );
f = clamp( f.div( max( l.contrast, 0 ) ), 0.0, 1.0 );
const blendFactor = smoothstep( 0.0, 1.0, f );
return blendFactor.mul( blendFactor ).mul( _SubpixelBlending );
};
const DetermineEdge = ( texSize, l ) => {
const horizontal =
abs( l.s.add( l.n ).sub( l.m.mul( 2.0 ) ) ).mul( 2.0 ).add(
abs( l.se.add( l.ne ).sub( l.e.mul( 2.0 ) ) ).add(
abs( l.sw.add( l.nw ).sub( l.w.mul( 2.0 ) ) )
)
);
const vertical =
abs( l.e.add( l.w ).sub( l.m.mul( 2.0 ) ) ).mul( 2.0 ).add(
abs( l.se.add( l.sw ).sub( l.s.mul( 2.0 ) ) ).add(
abs( l.ne.add( l.nw ).sub( l.n.mul( 2.0 ) ) )
)
);
const isHorizontal = horizontal.greaterThanEqual( vertical );
const pLuminance = select( isHorizontal, l.s, l.e );
const nLuminance = select( isHorizontal, l.n, l.w );
const pGradient = abs( pLuminance.sub( l.m ) );
const nGradient = abs( nLuminance.sub( l.m ) );
const pixelStep = select( isHorizontal, texSize.y, texSize.x ).toVar();
const oppositeLuminance = float().toVar();
const gradient = float().toVar();
If( pGradient.lessThan( nGradient ), () => {
pixelStep.assign( pixelStep.negate() );
oppositeLuminance.assign( nLuminance );
gradient.assign( nGradient );
} ).Else( () => {
oppositeLuminance.assign( pLuminance );
gradient.assign( pGradient );
} );
return { isHorizontal, pixelStep, oppositeLuminance, gradient };
};
const DetermineEdgeBlendFactor = ( texSize, l, e, uv ) => {
const uvEdge = uv.toVar();
const edgeStep = vec2().toVar();
If( e.isHorizontal, () => {
uvEdge.y.addAssign( e.pixelStep.mul( 0.5 ) );
edgeStep.assign( vec2( texSize.x, 0.0 ) );
} ).Else( () => {
uvEdge.x.addAssign( e.pixelStep.mul( 0.5 ) );
edgeStep.assign( vec2( 0.0, texSize.y ) );
} );
const edgeLuminance = l.m.add( e.oppositeLuminance ).mul( 0.5 );
const gradientThreshold = e.gradient.mul( 0.25 );
const puv = uvEdge.add( edgeStep.mul( EDGE_STEPS.element( 0 ) ) ).toVar();
const pLuminanceDelta = SampleLuminance( puv ).sub( edgeLuminance ).toVar();
const pAtEnd = abs( pLuminanceDelta ).greaterThanEqual( gradientThreshold ).toVar();
Loop( { start: 1, end: EDGE_STEP_COUNT }, ( { i } ) => {
If( pAtEnd, () => {
Break();
} );
puv.addAssign( edgeStep.mul( EDGE_STEPS.element( i ) ) );
pLuminanceDelta.assign( SampleLuminance( puv ).sub( edgeLuminance ) );
pAtEnd.assign( abs( pLuminanceDelta ).greaterThanEqual( gradientThreshold ) );
} );
If( pAtEnd.not(), () => {
puv.addAssign( edgeStep.mul( EDGE_GUESS ) );
} );
const nuv = uvEdge.sub( edgeStep.mul( EDGE_STEPS.element( 0 ) ) ).toVar();
const nLuminanceDelta = SampleLuminance( nuv ).sub( edgeLuminance ).toVar();
const nAtEnd = abs( nLuminanceDelta ).greaterThanEqual( gradientThreshold ).toVar();
Loop( { start: 1, end: EDGE_STEP_COUNT }, ( { i } ) => {
If( nAtEnd, () => {
Break();
} );
nuv.subAssign( edgeStep.mul( EDGE_STEPS.element( i ) ) );
nLuminanceDelta.assign( SampleLuminance( nuv ).sub( edgeLuminance ) );
nAtEnd.assign( abs( nLuminanceDelta ).greaterThanEqual( gradientThreshold ) );
} );
If( nAtEnd.not(), () => {
nuv.subAssign( edgeStep.mul( EDGE_GUESS ) );
} );
const pDistance = float().toVar();
const nDistance = float().toVar();
If( e.isHorizontal, () => {
pDistance.assign( puv.x.sub( uv.x ) );
nDistance.assign( uv.x.sub( nuv.x ) );
} ).Else( () => {
pDistance.assign( puv.y.sub( uv.y ) );
nDistance.assign( uv.y.sub( nuv.y ) );
} );
const shortestDistance = float().toVar();
const deltaSign = bool().toVar();
If( pDistance.lessThanEqual( nDistance ), () => {
shortestDistance.assign( pDistance );
deltaSign.assign( pLuminanceDelta.greaterThanEqual( 0.0 ) );
} ).Else( () => {
shortestDistance.assign( nDistance );
deltaSign.assign( nLuminanceDelta.greaterThanEqual( 0.0 ) );
} );
const blendFactor = float().toVar();
If( deltaSign.equal( l.m.sub( edgeLuminance ).greaterThanEqual( 0.0 ) ), () => {
blendFactor.assign( 0.0 );
} ).Else( () => {
blendFactor.assign( float( 0.5 ).sub( shortestDistance.div( pDistance.add( nDistance ) ) ) );
} );
return blendFactor;
};
const ApplyFXAA = Fn( ( [ uv, texSize ] ) => {
const luminance = SampleLuminanceNeighborhood( texSize, uv );
If( ShouldSkipPixel( luminance ), () => {
return Sample( uv );
} );
const pixelBlend = DeterminePixelBlendFactor( luminance );
const edge = DetermineEdge( texSize, luminance );
const edgeBlend = DetermineEdgeBlendFactor( texSize, luminance, edge, uv );
const finalBlend = max( pixelBlend, edgeBlend );
const finalUv = uv.toVar();
If( edge.isHorizontal, () => {
finalUv.y.addAssign( edge.pixelStep.mul( finalBlend ) );
} ).Else( () => {
finalUv.x.addAssign( edge.pixelStep.mul( finalBlend ) );
} );
return Sample( finalUv );
} ).setLayout( {
name: 'FxaaPixelShader',
type: 'vec4',
inputs: [
{ name: 'uv', type: 'vec2' },
{ name: 'texSize', type: 'vec2' },
]
} );
const fxaa = Fn( () => {
return ApplyFXAA( uvNode, this._invSize );
} );
const outputNode = fxaa();
return outputNode;
}
}
export default FXAANode;
/**
* TSL function for creating a FXAA node for anti-aliasing via post processing.
*
* @function
* @param {Node<vec4>} node - The node that represents the input of the effect.
* @returns {FXAANode}
*/
export const fxaa = ( node ) => nodeObject( new FXAANode( convertToTexture( node ) ) );