LYGIA Shader Library

Use:

xyz2rgb(<vec3|vec4> color)

Check it on Github

#ifndef FNC_XYZ2LAB
#define FNC_XYZ2LAB
vec3 xyz2lab(const in vec3 c) {
    vec3 n = c / vec3(95.047, 100.0, 108.883);
    vec3 c0 = pow(n, vec3(1.0 / 3.0));
    vec3 c1 = (7.787 * n) + (16.0 / 116.0);
    vec3 v = mix(c0, c1, step(n, vec3(0.008856)));
    return vec3((116.0 * v.y) - 16.0,
                500.0 * (v.x - v.y),
                200.0 * (v.y - v.z));
}

vec4 xyz2lab(const in vec4 c) { return vec4(xyz2lab(c.xyz), c.w); }
#endif

Use:

xyz2rgb(<float3|float4> color)

Check it on Github

#ifndef FNC_XYZ2LAB
#define FNC_XYZ2LAB
float3 xyz2lab(in float3 c) {
    float3 n = c / float3(95.047, 100.0, 108.883);
    float3 c0 = pow(n, float3(1.0 / 3.0));
    float3 c1 = (7.787 * n) + (16.0 / 116.0);
    float3 v = lerp(c0, c1, step(n, float3(0.008856)));
    return float3((116.0 * v.y) - 16.0,
                500.0 * (v.x - v.y),
                200.0 * (v.y - v.z));
}

float4 xyz2lab(in float4 c) { return float4(xyz2lab(c.xyz), c.w); }
#endif

Check it on Github

fn xyz2lab(c: vec3f) -> vec3f {
    let n = c / vec3f(95.047, 100.0, 108.883);
    let c0 = pow(n, vec3f(1.0 / 3.0));
    let c1 = (7.787 * n) + (16.0 / 116.0);
    let v = mix(c0, c1, step(n, vec3f(0.008856)));
    return vec3f(   (116.0 * v.y) - 16.0,
                        500.0 * (v.x - v.y),
                        200.0 * (v.y - v.z));
}