three
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JavaScript 3D library
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JavaScript
import SpotLightNode from './SpotLightNode.js';
import { float, Fn, If, vec2 } from '../tsl/TSLCore.js';
import { length, min, max, saturate, acos } from '../math/MathNode.js';
import { div, sub } from '../math/OperatorNode.js';
import { lightShadowMatrix } from '../accessors/Lights.js';
import { positionWorld } from '../accessors/Position.js';
const sdBox = /*@__PURE__*/ Fn( ( [ p, b ] ) => {
const d = p.abs().sub( b );
return length( max( d, 0.0 ) ).add( min( max( d.x, d.y ), 0.0 ) );
} );
/**
* An implementation of a projector light node.
*
* @augments SpotLightNode
*/
class ProjectorLightNode extends SpotLightNode {
static get type() {
return 'ProjectorLightNode';
}
update( frame ) {
super.update( frame );
const light = this.light;
this.penumbraCosNode.value = Math.min( Math.cos( light.angle * ( 1 - light.penumbra ) ), .99999 );
if ( light.aspect === null ) {
let aspect = 1;
if ( light.map !== null ) {
aspect = light.map.width / light.map.height;
}
light.shadow.aspect = aspect;
} else {
light.shadow.aspect = light.aspect;
}
}
/**
* Overwrites the default implementation to compute projection attenuation.
*
* @param {NodeBuilder} builder - The node builder.
* @return {Node<float>} The spot attenuation.
*/
getSpotAttenuation( builder ) {
const attenuation = float( 0 );
const penumbraCos = this.penumbraCosNode;
// compute the fragment's position in the light's clip space
const spotLightCoord = lightShadowMatrix( this.light ).mul( builder.context.positionWorld || positionWorld );
// the sign of w determines whether the current fragment is in front or behind the light.
// to avoid a back-projection, it's important to only compute an attenuation if w is positive
If( spotLightCoord.w.greaterThan( 0 ), () => {
const projectionUV = spotLightCoord.xyz.div( spotLightCoord.w );
const boxDist = sdBox( projectionUV.xy.sub( vec2( 0.5 ) ), vec2( 0.5 ) );
const angleFactor = div( - 1.0, sub( 1.0, acos( penumbraCos ) ).sub( 1.0 ) );
attenuation.assign( saturate( boxDist.mul( - 2.0 ).mul( angleFactor ) ) );
} );
return attenuation;
}
}
export default ProjectorLightNode;