#[set(everything)]
const constants: {
	dilate_radius: float;
	tex_size: float2;
};

#[set(everything)]
const sampler_linear: sampler;

#[set(everything)]
const tex: tex2d;

#[set(everything)]
const texdilate: tex2d;

// const offsets: float2[8] = {
// 	float2(-1.0,  0.0), float2( 1.0,  0.0), float2( 0.0,  1.0), float2( 0.0, -1.0),
// 	float2(-1.0,  1.0), float2( 1.0,  1.0), float2( 1.0, -1.0), float2(-1.0, -1.0)
// };

struct vert_in {
	pos: float2;
}

struct vert_out {
	pos: float4;
	tex: float2;
}

fun get_offset(i: int): float2 {
	if (i == 0) {
		return float2(-1.0,  0.0);
	}
	if (i == 1) {
		return float2( 1.0,  0.0);
	}
	if (i == 2) {
		return float2( 0.0,  1.0);
	}
	if (i == 3) {
		return float2( 0.0, -1.0);
	}
	if (i == 4) {
		return float2(-1.0,  1.0);
	}
	if (i == 5) {
		return float2( 1.0,  1.0);
	}
	if (i == 6) {
		return float2( 1.0, -1.0);
	}
	return float2(-1.0, -1.0);
}

fun dilate_pass_vert(input: vert_in): vert_out {
	var output: vert_out;
	output.tex = input.pos.xy * 0.5 + 0.5;
	output.tex.y = 1.0 - output.tex.y;
	output.pos = float4(input.pos.xy, 0.0, 1.0);
	return output;
}

fun dilate_pass_frag(input: vert_out): float4 {
	// Based on https://shaderbits.com/blog/uv-dilation by Ryan Brucks
	var texel_size: float2 = float2(1.0, 1.0) / constants.tex_size;
	var min_dist: float = 10000000.0;
	//var coord: uint2 = uint2(input.tex * constants.tex_size);
	var coordf: float2 = float2(input.tex.x * constants.tex_size.x, input.tex.y * constants.tex_size.y);
	var coord: uint2 = uint2(uint(coordf.x), uint(coordf.y));
	//var mask: float = texdilate[coord].r;
	var mask4: float4 = texdilate[coord];
	var mask: float = mask4.r;
	if (mask > 0.0) {
		discard;
	}

	var color: float4 = tex[coord];

	var i: int = 0;
	while (i < int(constants.dilate_radius)) {
		i += 1;
		var j: int = 0;
		while (j < 8) {
			var cur_uv: float2 = input.tex + get_offset(j) * texel_size * float2(float(i), float(i));
			coordf = cur_uv * constants.tex_size;
			coord = uint2(uint(coordf.x), uint(coordf.y));
			var offset_mask4: float4 = texdilate[coord];
			var offset_mask: float = offset_mask4.r;
			var offset_col: float4 = tex[coord];

			if (offset_mask != 0.0) {
				var cur_dist: float = length(input.tex - cur_uv);
				if (cur_dist < min_dist) {
					var project_uv: float2 = cur_uv + get_offset(j) * texel_size * float2(float(i), float(i)) * float2(0.25, 0.25);
					var direction: float4 = sample_lod(tex, sampler_linear, project_uv, 0.0);
					min_dist = cur_dist;
					if (direction.x != 0.0 || direction.y != 0.0 || direction.z != 0.0) {
						var delta: float4 = offset_col - direction;
						color = offset_col + delta * float4(4.0, 4.0, 4.0, 4.0);
					}
					else {
						color = offset_col;
					}
				}
			}
			j += 1;
		}
	}

	return color;
}

#[pipe]
struct pipe {
	vertex = dilate_pass_vert;
	fragment = dilate_pass_frag;
}