#[set(everything)]
const constants: {
	dir_inv: float2;
};

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

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

#[set(everything)]
const gbuffer0: tex2d;

// const blur_weights: float[] = {
// 	0.132572, 0.125472, 0.106373, 0.08078, 0.05495, 0.033482, 0.018275, 0.008934, 0.003912, 0.001535
// };

const discard_threshold: float = 0.95;

struct vert_in {
	pos: float2;
}

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

fun ssao_blur_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 octahedron_wrap(v: float2): float2 {
	var a: float2;
	if (v.x >= 0.0) {
		a.x = 1.0;
	}
	else {
		a.x = -1.0;
	}

	if (v.y >= 0.0) {
		a.y = 1.0;
	}
	else {
		a.y = -1.0;
	}

	var r: float2;
	r.x = abs(v.y);
	r.y = abs(v.x);
	r.x = 1.0 - r.x;
	r.y = 1.0 - r.y;
	return r * a;

	// return (1.0 - abs(v.yx)) * (float2(v.x >= 0.0 ? 1.0 : -1.0, v.y >= 0.0 ? 1.0 : -1.0));
}

fun get_nor(enc: float2): float3 {
	var n: float3;
	n.z = 1.0 - abs(enc.x) - abs(enc.y);
	if (n.z >= 0.0) {
		n.xy = enc.xy;
	}
	else {
		n.xy = octahedron_wrap(enc.xy);
	}
	n = normalize(n);
	return n;
}

fun ssao_blur_pass_frag(input: vert_out): float {

	var nor: float3 = get_nor(sample_lod(gbuffer0, sampler_linear, input.tex, 0.0).rg);
	// var weight: float = blur_weights[0];
	var weight: float = 0.132572;
	var color: float = sample_lod(tex, sampler_linear, input.tex, 0.0).r * weight;

	for (var i: int = 1; i < 8; i += 1) {
		var blur_weight_i: float; // = blur_weights[i];
		if (i == 1) {
			blur_weight_i = 0.125472;
		}
		if (i == 2) {
			blur_weight_i = 0.106373;
		}
		if (i == 3) {
			blur_weight_i = 0.08078;
		}
		if (i == 4) {
			blur_weight_i = 0.05495;
		}
		if (i == 5) {
			blur_weight_i = 0.033482;
		}
		if (i == 6) {
			blur_weight_i = 0.018275;
		}
		if (i == 7) {
			blur_weight_i = 0.008934;
		}

		var posadd: float = float(i);

		var nor2: float3 = get_nor(sample_lod(gbuffer0, sampler_linear, input.tex + posadd * constants.dir_inv, 0.0).rg);
		var influence_factor: float = step(discard_threshold, dot(nor2, nor));
		var col: float = sample_lod(tex, sampler_linear, input.tex + posadd * constants.dir_inv, 0.0).r;

		var w: float = blur_weight_i * influence_factor;
		color += col * w;
		weight += w;

		nor2 = get_nor(sample_lod(gbuffer0, sampler_linear, input.tex - posadd * constants.dir_inv, 0.0).rg);
		influence_factor = step(discard_threshold, dot(nor2, nor));
		col = sample_lod(tex, sampler_linear, input.tex - posadd * constants.dir_inv, 0.0).r;
		w = blur_weight_i * influence_factor;
		color += col * w;
		weight += w;
	}

	color = color / weight;
	return color;
}

#[pipe]
struct pipe {
	vertex = ssao_blur_pass_vert;
	fragment = ssao_blur_pass_frag;
}