Perceptual Color Blending

Blending linear RGB colors (left column) using Oklab color space (right column) to improve perceptual uniformity as well as hue and lightness prediction.

function vector oklab(vector clr_A, clr_B; float bias){
    
    matrix3 kCONEtoLMS = set(                
         0.4121656120,  0.2118591070,  0.0883097947,
         0.5362752080,  0.6807189584,  0.2818474174,
         0.0514575653,  0.1074065790,  0.6302613616);
         
    matrix3 kLMStoCONE = set(
         4.0767245293, -1.2681437731, -0.0041119885,
        -3.3072168827,  2.6093323231, -0.7034763098,
         0.2307590544, -0.3411344290,  1.7068625689);
    
    vector lms_A = pow(kCONEtoLMS * clr_A, set(1.0 / 3.0));
    vector lms_B = pow(kCONEtoLMS * clr_B, set(1.0 / 3.0));
    
    vector lms = lerp(lms_A, lms_B, bias);
    lms *= 1.0 + 0.2 * bias * (1.0 - bias); // optional
    
    vector cone = kLMStoCONE * (lms * lms * lms);
    return cone;
}

vector clr_0 = chv('color_0');
vector clr_1 = chv('color_1');

vector uv = vertex(0, 'uv', i@vtxnum);

v@Cd = oklab(clr_0, clr_1, uv[1]);