Cartesian to polar coordinate shader

// cartesian to polar CG screen shader

CGPROGRAM

uniform float _CenterX;
uniform float _CenterY;
uniform float _Angle;
uniform float _AngleOffset;
uniform sampler2D _MainTex;

float4 frag (v2f i) : COLOR
{
    // normalised screen-space pixel coords are taken from the input struct v2f
    float2 uv = i.uvOrig;
    // the angle between the centre point and the pixel coordinate is calculated
    float angle = atan2(uv.x - _CenterX, uv.y + _CenterY);
    // the distance between the centre point and the pixel coordinate is calculated
    float radius = sqrt(pow(uv.x - _CenterX, 2) + pow(uv.y + _CenterY, 2));
    // the pixel coordinates are reassigned
    uv.x = angle / _Angle + _AngleOffset;
    uv.y = radius - _CenterY;

    return tex2D(_MainTex, uv);
}

ENDCG