playcanvas/build/playcanvas.dbg/src/scene/shader-lib/glsl/chunks/lit/frag/fresnelSchlick.js

Open-source WebGL/WebGPU 3D engine for the web

var fresnelSchlick_default = (
  /* glsl */
  `
// pow(x, 5) implemented as multiplies to avoid the log2/exp2 pair pow compiles to
float pow5(float x) {
    float x2 = x * x;
    return x2 * x2 * x;
}

// Schlick's approximation
vec3 getFresnel(
        float cosTheta, 
        float gloss, 
        vec3 specularity
#if defined(LIT_IRIDESCENCE)
        , vec3 iridescenceFresnel, 
        float iridescenceIntensity
#endif
    ) {
    float fresnel = pow5(1.0 - saturate(cosTheta));
    float glossSq = gloss * gloss;

    // Scale gloss contribution by specularity intensity to ensure F90 approaches 0 when F0 is 0
    float specIntensity = max(specularity.r, max(specularity.g, specularity.b));
    vec3 ret = specularity + (max(vec3(glossSq * specIntensity), specularity) - specularity) * fresnel;

#if defined(LIT_IRIDESCENCE)
    return mix(ret, iridescenceFresnel, iridescenceIntensity);
#else
    return ret;
#endif    
}

float getFresnelCC(float cosTheta) {
    float fresnel = pow5(1.0 - saturate(cosTheta));
    return 0.04 + (1.0 - 0.04) * fresnel;
}
`
);
export {
  fresnelSchlick_default as default
};