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- import {
- Mesh,
- ShaderMaterial,
- SphereGeometry
- } from 'three';
- class LightProbeHelper extends Mesh {
- constructor( lightProbe, size = 1 ) {
- const material = new ShaderMaterial( {
- type: 'LightProbeHelperMaterial',
- uniforms: {
- sh: { value: lightProbe.sh.coefficients }, // by reference
- intensity: { value: lightProbe.intensity }
- },
- vertexShader: /* glsl */`
- varying vec3 vNormal;
- void main() {
- vNormal = normalize( normalMatrix * normal );
- gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
- }
- `,
- fragmentShader: /* glsl */`
- #define RECIPROCAL_PI 0.318309886
- vec3 inverseTransformDirection( in vec3 normal, in mat4 matrix ) {
- // matrix is assumed to be orthogonal
- return normalize( ( vec4( normal, 0.0 ) * matrix ).xyz );
- }
- // source: https://graphics.stanford.edu/papers/envmap/envmap.pdf,
- vec3 shGetIrradianceAt( in vec3 normal, in vec3 shCoefficients[ 9 ] ) {
- // normal is assumed to have unit length,
- float x = normal.x, y = normal.y, z = normal.z;
- // band 0,
- vec3 result = shCoefficients[ 0 ] * 0.886227;
- // band 1,
- result += shCoefficients[ 1 ] * 2.0 * 0.511664 * y;
- result += shCoefficients[ 2 ] * 2.0 * 0.511664 * z;
- result += shCoefficients[ 3 ] * 2.0 * 0.511664 * x;
- // band 2,
- result += shCoefficients[ 4 ] * 2.0 * 0.429043 * x * y;
- result += shCoefficients[ 5 ] * 2.0 * 0.429043 * y * z;
- result += shCoefficients[ 6 ] * ( 0.743125 * z * z - 0.247708 );
- result += shCoefficients[ 7 ] * 2.0 * 0.429043 * x * z;
- result += shCoefficients[ 8 ] * 0.429043 * ( x * x - y * y );
- return result;
- }
- uniform vec3 sh[ 9 ]; // sh coefficients
- uniform float intensity; // light probe intensity
- varying vec3 vNormal;
- void main() {
- vec3 normal = normalize( vNormal );
- vec3 worldNormal = inverseTransformDirection( normal, viewMatrix );
- vec3 irradiance = shGetIrradianceAt( worldNormal, sh );
- vec3 outgoingLight = RECIPROCAL_PI * irradiance * intensity;
- gl_FragColor = linearToOutputTexel( vec4( outgoingLight, 1.0 ) );
- }
- `,
- } );
- const geometry = new SphereGeometry( 1, 32, 16 );
- super( geometry, material );
- this.lightProbe = lightProbe;
- this.size = size;
- this.type = 'LightProbeHelper';
- this.onBeforeRender();
- }
- dispose() {
- this.geometry.dispose();
- this.material.dispose();
- }
- onBeforeRender() {
- this.position.copy( this.lightProbe.position );
- this.scale.set( 1, 1, 1 ).multiplyScalar( this.size );
- this.material.uniforms.intensity.value = this.lightProbe.intensity;
- }
- }
- export { LightProbeHelper };
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