#version 460

#extension GL_GOOGLE_include_directive : require

#include "structures.layout"

layout (location = 0) in struct FragDataIn {
	vec3 normal;
	vec2 uv;
} FragData;

layout (location = 0, index = 0) out vec4 FragColor;

vec4 CalculateDirectionalLight(vec4 diff_col, vec4 diff_samp, vec4 light_col, vec3 dir, vec3 normal)
{
	float diffuse_factor = max(dot(normal, -dir), 0.0);

	vec4 ambient = vec4(vec3(G.ambient_color * diff_col), diff_samp.a);
	vec4 diffuse = vec4(vec3(light_col * diffuse_factor), diff_samp.a);

	diffuse *= diff_samp;
	ambient *= diff_samp;

	return (ambient + diffuse);
}

float UnPreMultLinearToSRGB(float col)
{
	return col < 0.0031308f ? col * 12.92f : (pow(col, 1.0f / 2.4f) * 1.055f) - 0.055f;
}

vec4 UnPreMultLinearToSRGB(vec4 col)
{
	col.r = UnPreMultLinearToSRGB(col.x);
	col.g = UnPreMultLinearToSRGB(col.x);
	col.b = UnPreMultLinearToSRGB(col.x);
	return col;
}

void main()
{
	ivec2 coord = ivec2(gl_FragCoord.xy);
	int store_mask = 0;
	int view_size = int(G.res.x) * int(G.res.y);
	int sample_id = 0;
	int list_pos = view_size * OIT_LAYERS  * sample_id + coord.y * int(G.res.x) + coord.x; 

	vec4 col = ModelDiffuse;
	vec4 tex_col = texture(sampler2D(AlbedoTex, SamplerNearest), FragData.uv);

	vec4 out_col = CalculateDirectionalLight(col, tex_col, G.light_color, G.light_direction, FragData.normal);
	out_col.a = 1.0;// Materials[nonuniformEXT(PC.mat_id)].alpha;

	if(ALPHA_TEX)
	{
		vec4 alpha_col = texture(sampler2D(AlphaTex, SamplerNearest), FragData.uv);
		out_col.a = alpha_col.a;
	}

	//FragColor = out_col;

	//TODO: set up OIT again
	vec4 srgb_col = out_col;// UnPreMultLinearToSRGB(out_col);

	uvec4 store_value = uvec4(packUnorm4x8(srgb_col), floatBitsToUint(gl_FragCoord.z), store_mask, 0);

	uint old_counter = imageAtomicAdd(ImageAux, coord, 1u);
	if (old_counter < OIT_LAYERS)
	{
		imageStore(ImageABuffer, list_pos + int(old_counter) * view_size, store_value);

		FragColor = vec4(0.0);
	}
	else
	{
		FragColor = vec4(0.0); //vec4(out_col.rgb * out_col.a, out_col.a); // Change to vec4(0.0) to disable tail blending
	}
}