Posterize.osl

/*
 * Posterise.osl by Charlie (c)2012
 * from https://github.com/sambler/osl-shaders
 *
 * license: public domain
 *
 * original script from -
 * http://blenderartists.org/forum/showthread.php?270332-OSL-Goodness/page5
 * Modified 1/4/2020 by Saul Espinosa for Redshift 3D
 */


shader posterise
[[  string help = "Posterize Filter Effect",
    string label = "Posterize" ]]
(
    int Range = 8
	[[
	int min = 0, int max = 50
	]],
    color Color = 1
	[[
	string label = "Input"
	]],
	
    output color Output = 0 )
{

    float posterise(float Value){
        if( Range > 1 ) {
        return floor(Value * Range) / (Range-1);
    }
    else if(Range == 1) {
         return 0;
    }
    else  {
        return Value;
        }

    }

    Output[0] = posterise(Color[0]);
    Output[1] = posterise(Color[1]);
    Output[2] = posterise(Color[2]);


}