shader_type canvas_item;
uniform int step_count = 168;
uniform int inner = 101;
uniform int pixel_size = 121;
uniform int highlight = 0;
uniform float grid_thickness = 0.125;
uniform float offset = 0.0;

float mask(float inner_radius, float outer_radius, vec2 p) {
	if (inner_radius < length(p) && length(p) < outer_radius) {
		return 1.0;
	} else {
		return 0.0;
	}
}

float f(vec2 uv, vec2 p) {
	
	float angle = atan(p.y, p.x) / PI / 2.0 + 0.5 + offset/float(step_count);
	float color = round(angle * float(step_count)) / float(step_count);


	return color;
}

float grid_mask(vec2 uv) {
	float x = mod(uv.x*float(pixel_size), 1.0);
	float y = mod(uv.y*float(pixel_size), 1.0);
	return step(grid_thickness, x)* step(grid_thickness, y);
}

void fragment() {
	vec2 p = UV - vec2(0.5, 0.5);
	p = round(p * float(pixel_size)) / float(pixel_size);
	
	float color = f(UV, p);
	//color *= edge_mask(UV, vec2(0.002, 0.002));
	vec3 chroma = vec3(color, color, color);
	int i = int(color * float(step_count));
	if (i == highlight) {
		chroma = vec3(0.0, 1.0, 0.0);
	} else if (i % 2 == 0) {
		chroma = vec3(0.3, 0.3, 0.3);
	} else if (i % 2 == 1) {
		chroma = vec3(0.6, 0.6, 0.6);
	}
	chroma *= grid_mask(UV);
	chroma *= mask(float(inner) / float(pixel_size * 2), 0.5, p);
	COLOR = vec4(chroma, 1.0);
	
}

//void light() {
//	// Called for every pixel for every light affecting the CanvasItem.
//	// Uncomment to replace the default light processing function with this one.
//}