MarbleVeinNoise

// Created by Saul Espinosa for Redshift 3D
// Based on  * LGVeinedMarble.osl by Shane Ambler
// Modified 01.11.2022
shader MarbleVeinNoise 
[[  string help = "Marble Vein Noise Generator",
    string label = "Marble Vein Noise" ]]
(
// Input Paramaters
        color diffuse_color = 0.0
        [[
            string label = "Base Color", 
            string page = "Base"
        ]],
        color VeinColor = 1.0
        [[
            string label = "Vein Color",
            string page = "Marble Vein"
        ]],
        float VeinFreq = 1.0
        [[
            string label = "Vein Frequency" ,
            string page = "Marble Vein",
            float min = 0, float max = 10
        ]],
        float VeinLevels = 2.0
        [[
            string label = "Vein Levels" ,
            string page = "Marble Vein",
            float min = 0, float max = 25
        ]],
        float WarpFreq = 1.0
        [[
            string label = "Warp Frequency" ,
            string page = "Marble Vein",
            float min = 0, float max = 25
        ]],
        float Warping = 0.5
        [[
            string label = "Vein Warping" ,
            string page = "Marble Vein",
            float min = 0, float max = 25
        ]],
        float Sharpness = 8.0
        [[
            string label = "Vein Sharpness" ,
            string page = "Marble Vein",
            float min = 0, float max = 25
        ]],
        int Space = 1
        [[
            string page = "Co-ordinates",
            string widget = "mapper",
            string options = "World:0|Object:1|Fixed:2",
            int connectable = 0
        ]],
        vector Origin = 0
        [[
            string page = "Co-ordinates",
        ]],
// Output Noise
    output color outColor = 1
)
{
// Define Noise
#define snoise(x) (2*noise(x)-1)
    color Ct;
    point Nf;
    point PP, offset;
    float i, turb, freq, j;
    float turbsum;
    if (Space == 0)
        PP = P + Origin;
    else if (Space == 1)
        PP = transform("object", P) + Origin;
    else
        PP = Origin;
    /* perturb the lookup */
    freq = 1;
    offset = 0;
    for (i = 0;  i < 6;  i += 1) {
        offset += 2 * Warping * ( noise (WarpFreq * freq * PP) - 0.5)  / freq;
        freq *= 2;
    }
    PP += offset;
    /* Now calculate the veining function for the lookup area */
    turbsum = 0;  freq = 1;
    PP *= VeinFreq;
    for (i = 0;  i < VeinLevels;  i += 1) {
        turb = abs (snoise (PP));
        turb = pow (smoothstep (0.8, 1, 1 - turb), Sharpness) / freq;
        turbsum += (1-turbsum) * turb;
        freq *= 3;
        PP *= 3;
    }
// Output
    outColor = mix (diffuse_color, VeinColor, turbsum);
}