bytev-charts/lib/plugin/three.js/examples/js/shaders/FresnelShader.js

基于echarts和JavaScript及ES6封装的一个可以直接调用的图表组件库，内置主题设计，简单快捷，且支持用户自定义配置； npm 安装方式: npm install bytev-charts 若启动提示还需额外install插件,则运行 npm install @babel/runtime-corejs2 即可;

import "core-js/modules/es.array.join.js";
console.warn("THREE.FresnelShader: As part of the transition to ES6 Modules, the files in 'examples/js' were deprecated in May 2020 (r117) and will be deleted in December 2020 (r124). You can find more information about developing using ES6 Modules in https://threejs.org/docs/#manual/en/introduction/Installation.");
/**
 * Based on Nvidia Cg tutorial
 */

THREE.FresnelShader = {
  uniforms: {
    "mRefractionRatio": {
      value: 1.02
    },
    "mFresnelBias": {
      value: 0.1
    },
    "mFresnelPower": {
      value: 2.0
    },
    "mFresnelScale": {
      value: 1.0
    },
    "tCube": {
      value: null
    }
  },
  vertexShader: ["uniform float mRefractionRatio;", "uniform float mFresnelBias;", "uniform float mFresnelScale;", "uniform float mFresnelPower;", "varying vec3 vReflect;", "varying vec3 vRefract[3];", "varying float vReflectionFactor;", "void main() {", "	vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );", "	vec4 worldPosition = modelMatrix * vec4( position, 1.0 );", "	vec3 worldNormal = normalize( mat3( modelMatrix[0].xyz, modelMatrix[1].xyz, modelMatrix[2].xyz ) * normal );", "	vec3 I = worldPosition.xyz - cameraPosition;", "	vReflect = reflect( I, worldNormal );", "	vRefract[0] = refract( normalize( I ), worldNormal, mRefractionRatio );", "	vRefract[1] = refract( normalize( I ), worldNormal, mRefractionRatio * 0.99 );", "	vRefract[2] = refract( normalize( I ), worldNormal, mRefractionRatio * 0.98 );", "	vReflectionFactor = mFresnelBias + mFresnelScale * pow( 1.0 + dot( normalize( I ), worldNormal ), mFresnelPower );", "	gl_Position = projectionMatrix * mvPosition;", "}"].join("\n"),
  fragmentShader: ["uniform samplerCube tCube;", "varying vec3 vReflect;", "varying vec3 vRefract[3];", "varying float vReflectionFactor;", "void main() {", "	vec4 reflectedColor = textureCube( tCube, vec3( -vReflect.x, vReflect.yz ) );", "	vec4 refractedColor = vec4( 1.0 );", "	refractedColor.r = textureCube( tCube, vec3( -vRefract[0].x, vRefract[0].yz ) ).r;", "	refractedColor.g = textureCube( tCube, vec3( -vRefract[1].x, vRefract[1].yz ) ).g;", "	refractedColor.b = textureCube( tCube, vec3( -vRefract[2].x, vRefract[2].yz ) ).b;", "	gl_FragColor = mix( refractedColor, reflectedColor, clamp( vReflectionFactor, 0.0, 1.0 ) );", "}"].join("\n")
};