//Polar coordinates shader by Ben Hickling



#define PI 3.14159265359

uniform float texture_offset = 0.0;

uniform float rotation = 0.0;
uniform float scale = 1.0;



float4 mainImage(VertData v_in) : TARGET
{
	float2 tex_coord = v_in.uv;
	float2 uv = v_in.uv - float2(0.5, 0.5);
	
	float ang = atan2(uv.y, uv.x);
	float len = length(uv);
	
	tex_coord.x = len;
	tex_coord.y = ang * 0.5 / PI + 0.5 + rotation;
	
	return image.Sample(textureSampler, frac((tex_coord  + float2(texture_offset,0)) * scale));

}