jiPMask.osl

#include <stdosl.h>

shader jiPMask(
    string Mapping = "PWorld"
    	[[ string widget = "popup",
    		string options = "PWorld|PRef" ]],
    color Pos = color(0.0),
    color Radius = color(1.0),
    float whitepoint = 1.0
    	[[ float min = 0, float max = 1 ]],
    float blackpoint = 0.0
    	[[ float min = 0, float max = 1 ]],
    float gamma = 1.0,
    output float Mask = 0.0,
	output color PRef = color(0.0),
	output color PWorld = color(0.0)
)

{
 	//Pworld & Pref
 	point PosRef = transform("object", P);
   	point PosWorld = transform("world", P);
   	PRef = PosRef;
   	PWorld = PosWorld;

   	color Position; //Declaring the position variable that will eventually be used
  	if (Mapping == "PRef")
  		Position = PosRef;
    else
        Position = PosWorld;

    float XPos = (Position[0]-Pos[0])/(Radius[0]+0.0001);
   	float YPos = (Position[1]-Pos[1])/(Radius[1]+0.0001);
   	float ZPos = (Position[2]-Pos[2])/(Radius[2]+0.0001);

   	float mult = 1/whitepoint;
   	float invMult = pow(1/sqrt(1-blackpoint),2);

	Mask = pow(clamp(mult*(1-(invMult*(sqrt(pow(XPos,2)+pow(YPos,2)+pow(ZPos,2))))),0,1),1/gamma);
}