Cartesian Coordinate Shader Graph Node

Documentation for the Cartesian Coordinate node available in the Unity Asset Store.  This implementation is based on the example in how to create a custom shader graph node. 

Description

This node for the Unity Shader Graph converts a 2D coordinates from Polar Coordinate form into standard UV Cartesian Coordinates.  It is the reverse of the Unity-provided Polar Coordinate node.

Cartesian coordinates, also known as rectangular coordinates, involve representing a two dimensional point by an x and y offset. UV coordinates used for texture sampling are in this form.  In Polar form, this point is instead represented as a distance from the center, and angle of rotation. 

Ports

Name	Direction	Type	Description
Polar Coordinates	Input	Vector2	Input coordinates in Polar form
Center	Input	Vector2	Center reference point
Radial Scale	Input	Vector1	Scale of distance value
Length Scale	Input	Vector1	Scale of angle value
Out	Output	Vector2	Output coordinates in Cartesian (or Rectangular) form

Full Code

#ifndef CARTESIAN_INCLUDE
#define CARTESIAN_INCLUDE

//Code to reverse the effects of Unity's Polar Coordinate node
void CartesianCoords_float(
    float2 PolarCoords, 
    float2 Center, 
    float RadialScale, 
    float LengthScale, 
    out float2 UV)
{
	// reverse the magic number division that occurs inside Unity's node
	float2 adjustedCoord = PolarCoords * float2(0.5, 6.28);
	
	// reverse the scaling factors (why is one called "LengthScale"?
        //  Just copying Unity's name, not sure why they called it that)
	adjustedCoord = adjustedCoord / float2(RadialScale, LengthScale);
	
	// standard polar to cartesian math
	float2 result;
	result.x = sin(adjustedCoord.y) * adjustedCoord.x;
	result.y = cos(adjustedCoord.y) * adjustedCoord.x;
	
	//our polar coords had set 0,0 to be at "Center", and we need it to be at the corner instead. 
	UV = result + Center;
}

#endif //CARTESIAN_INCLUDE