three
Version:
JavaScript 3D library
76 lines (48 loc) • 2.04 kB
JavaScript
/**
* Based on Nvidia Cg tutorial
*/
var 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" )
};
export { FresnelShader };