three 基础库
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import {
Mesh,
ShaderMaterial,
SphereGeometry
} from '../../../build/three.module.js';
class LightProbeHelper extends Mesh {
constructor( lightProbe, size ) {
const material = new ShaderMaterial( {
type: 'LightProbeHelperMaterial',
uniforms: {
sh: { value: lightProbe.sh.coefficients }, // by reference
intensity: { value: lightProbe.intensity }
},
vertexShader: [
'varying vec3 vNormal;',
'void main() {',
' vNormal = normalize( normalMatrix * normal );',
' gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );',
'}',
].join( '\n' ),
fragmentShader: [
'#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 ) );',
'}'
].join( '\n' )
} );
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 };