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70 lines
1.9 KiB
70 lines
1.9 KiB
/**
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* Based on Nvidia Cg tutorial
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*/
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const FresnelShader = {
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uniforms: {
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'mRefractionRatio': { value: 1.02 },
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'mFresnelBias': { value: 0.1 },
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'mFresnelPower': { value: 2.0 },
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'mFresnelScale': { value: 1.0 },
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'tCube': { value: null }
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},
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vertexShader: /* glsl */`
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uniform float mRefractionRatio;
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uniform float mFresnelBias;
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uniform float mFresnelScale;
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uniform float mFresnelPower;
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varying vec3 vReflect;
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varying vec3 vRefract[3];
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varying float vReflectionFactor;
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void main() {
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vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );
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vec4 worldPosition = modelMatrix * vec4( position, 1.0 );
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vec3 worldNormal = normalize( mat3( modelMatrix[0].xyz, modelMatrix[1].xyz, modelMatrix[2].xyz ) * normal );
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vec3 I = worldPosition.xyz - cameraPosition;
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vReflect = reflect( I, worldNormal );
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vRefract[0] = refract( normalize( I ), worldNormal, mRefractionRatio );
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vRefract[1] = refract( normalize( I ), worldNormal, mRefractionRatio * 0.99 );
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vRefract[2] = refract( normalize( I ), worldNormal, mRefractionRatio * 0.98 );
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vReflectionFactor = mFresnelBias + mFresnelScale * pow( 1.0 + dot( normalize( I ), worldNormal ), mFresnelPower );
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gl_Position = projectionMatrix * mvPosition;
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}`,
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fragmentShader: /* glsl */`
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uniform samplerCube tCube;
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varying vec3 vReflect;
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varying vec3 vRefract[3];
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varying float vReflectionFactor;
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void main() {
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vec4 reflectedColor = textureCube( tCube, vec3( -vReflect.x, vReflect.yz ) );
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vec4 refractedColor = vec4( 1.0 );
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refractedColor.r = textureCube( tCube, vec3( -vRefract[0].x, vRefract[0].yz ) ).r;
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refractedColor.g = textureCube( tCube, vec3( -vRefract[1].x, vRefract[1].yz ) ).g;
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refractedColor.b = textureCube( tCube, vec3( -vRefract[2].x, vRefract[2].yz ) ).b;
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gl_FragColor = mix( refractedColor, reflectedColor, clamp( vReflectionFactor, 0.0, 1.0 ) );
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}`
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};
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export { FresnelShader };
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