texturity.js/src/shaders/chunks/color-models.js

WebGL based library for drawing textures

export default function () {
    
    return `
    vec3 hsl2rgb( in vec3 c )
    {
        vec3 rgb = clamp( abs(mod(c.x*6.0+vec3(0.0,4.0,2.0),6.0)-3.0)-1.0, 0.0, 1.0 );
        
        return c.z + c.y * (rgb-0.5)*(1.0-abs(2.0*c.z-1.0));
    }
        
    vec3 HueShift (in vec3 Color, in float Shift)
    {
        vec3 P = vec3(0.55735)*dot(vec3(0.55735),Color);
            
        vec3 U = Color-P;
            
        vec3 V = cross(vec3(0.55735),U);    
        
        Color = U*cos(Shift*6.2832) + V*sin(Shift*6.2832) + P;
            
        return vec3(Color);
    }
        
    vec3 rgb2hsl( in vec3 c ){
        float h = 0.0;
        float s = 0.0;
        float l = 0.0;
        float r = c.r;
        float g = c.g;
        float b = c.b;
        float cMin = min( r, min( g, b ) );
        float cMax = max( r, max( g, b ) );
        
        l = ( cMax + cMin ) / 2.0;
        if ( cMax > cMin ) {
            float cDelta = cMax - cMin;
                
            //s = l < .05 ? cDelta / ( cMax + cMin ) : cDelta / ( 2.0 - ( cMax + cMin ) ); Original
            s = l < .0 ? cDelta / ( cMax + cMin ) : cDelta / ( 2.0 - ( cMax + cMin ) );
           
            if ( r == cMax ) {
                h = ( g - b ) / cDelta;
            } else if ( g == cMax ) {
                h = 2.0 + ( b - r ) / cDelta;
            } else {
                h = 4.0 + ( r - g ) / cDelta;
            }
    
            if ( h < 0.0) {
                h += 6.0;
            }
            h = h / 6.0;
        }
        return vec3( h, s, l );
    }
        
    vec3 rgb2hsv(vec3 c)
    {
        vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
        vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
        vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
        
        float d = q.x - min(q.w, q.y);
        float e = 1.0e-10;
        return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
    }
        
    vec3 hsv2rgb(vec3 c)
    {
       vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
        vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
        return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
    }`
}