shader_type canvas_item;

uniform float rows = 44.0;  // Really int but don't want to recast all the time
uniform float cols = 63.0;  // ^

uniform vec4 color_unmarked: hint_color = vec4(0.5, 0.5, 0.5, 1.0);
uniform vec4 color_marked: hint_color = vec4(0.0, 0.0, 1.0, 1.0);
uniform vec4 color_crossed: hint_color = vec4(1.0, 0.0, 0.0, 1.0);

uniform float line_thickness = 0.1;  // Cell scale
uniform float line_offset = 0.05;  // Should be half of thickness to be centered, but might need tweaking for small values

void fragment(){
	vec2 frag_pos = UV * vec2(cols, rows);
	bvec2 frag_marginal = lessThan(fract(frag_pos+line_offset), vec2(line_thickness));
	bvec2 frag_marginal_x = lessThan(fract(frag_pos-0.425), vec2(0.15));
//	vec2 grid_data = texture(TEXTURE, (frag_pos+line_offset)/vec2(cols+1.0, rows+1.0)).rg;
//	float grid_data_s = texture(TEXTURE, ((frag_pos+line_offset)/vec2(cols+1.0, rows+1.0)).yx).a*128.0; //*17.0;
//	COLOR = vec4(grid_data_s, grid_data_s, grid_data_s, 1.0);
	int grid_data_s = int(texture(TEXTURE, ((frag_pos+line_offset)/vec2(cols+1.0, rows+1.0)).yx).r*255.0);
	ivec2 grid_data = ivec2(grid_data_s%4, grid_data_s/4);
	COLOR = vec4(0.0);
	if (frag_marginal.x){
		if (grid_data.g >= 2){
			if (frag_marginal_x.y)
				COLOR = color_crossed;
		}else if (grid_data.g == 1){
			COLOR = color_marked;
		}else
			COLOR = color_unmarked;
	}
	if  (frag_marginal.y){
		if (grid_data.r >= 2){
			if (frag_marginal_x.x)
				COLOR = color_crossed;
		}else if (grid_data.r == 1){
			COLOR = color_marked;
		}else
			COLOR = color_unmarked;
	}
//	if (frag_marginal.x){
//		if (grid_data.g >= 0.99){
//			if (frag_marginal_x.y)
//				COLOR = color_crossed;
//		}else if (grid_data.g >= 0.49){
//			COLOR = color_marked;
//		}else
//			COLOR = color_unmarked;
//	}
//	if  (frag_marginal.y){
//		if (grid_data.r >= 0.99){
//			if (frag_marginal_x.x)
//				COLOR = color_crossed;
//		}else if (grid_data.r >= 0.49){
//			COLOR = color_marked;
//		}else
//			COLOR = color_unmarked;
//	}
}