three-stdlib/shaders/FresnelShader.js

stand-alone library of threejs examples

const FresnelShader = {
  uniforms: {
    mRefractionRatio: { value: 1.02 },
    mFresnelBias: { value: 0.1 },
    mFresnelPower: { value: 2 },
    mFresnelScale: { value: 1 },
    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")
};
export {
  FresnelShader
};
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