import postprocess;
import ambientocclusion;

////// fragment
void main()
{
	mat2 transform = mat2(texture(rotate, texcoord*screen_size/4.0)*2.0-1.0)
 		*mat2(screen_size.y/screen_size.x, 0.0, 0.0, 1.0)*3.0/screen_size.y;
	float sample = depth_ratio.x/(texture(depth, texcoord).r-depth_ratio.y);
	float sum = 0.0;
	for(int i=0; i<=3; ++i)
		for(int j=0; j<=3; ++j)
		{
			vec2 offs = transform*vec2(float(i)-1.5, float(j)-1.5);
			float dxy = length(offs)*-sample;
			float dz = depth_ratio.x/(texture(depth, texcoord+offs).r-depth_ratio.y)-sample;
			if(abs(dz)<3.0*dxy)
				sum += atan(dz/dxy)/1.570796;
			else if(dz<0.0)
				sum -= 0.8;
		}
	frag_color = vec4(min(1.0-sum*darkness/16.0, 1.0), 0.0, 0.0, 1.0);
}