#version 330 core

#include <globals.glsl>
#include <random.glsl>

in vec3 f_pos;
flat in uint f_pos_norm;
in vec3 f_col;
in float f_light;

layout (std140)
uniform u_locals {
    vec3 model_offs;
	float load_time;
};

uniform sampler2D t_waves;

out vec4 tgt_color;

#include <sky.glsl>
#include <light.glsl>

void main() {
	// First 3 normals are negative, next 3 are positive
	vec3 normals[6] = vec3[]( vec3(-1,0,0), vec3(0,-1,0), vec3(0,0,-1), vec3(1,0,0), vec3(0,1,0), vec3(0,0,1) );

	// TODO: last 3 bits in v_pos_norm should be a number between 0 and 5, rather than 0-2 and a direction.
	uint norm_axis = (f_pos_norm >> 30) & 0x3u;
	// Increase array access by 3 to access positive values
	uint norm_dir = ((f_pos_norm >> 29) & 0x1u) * 3u;
	// Use an array to avoid conditional branching
	vec3 f_norm = normals[norm_axis + norm_dir];

	vec3 cam_to_frag = normalize(f_pos - cam_pos.xyz);

	/*
	// Round the position to the nearest triangular grid cell
	vec3 hex_pos = f_pos * 2.0;
	hex_pos = hex_pos + vec3(hex_pos.y * 1.4 / 3.0, hex_pos.y * 0.1, 0);
	if (fract(hex_pos.x) > fract(hex_pos.y)) {
		hex_pos += vec3(1.0, 1.0, 0);
	}
	hex_pos = floor(hex_pos);
	*/

	vec3 light, diffuse_light, ambient_light;
	get_sun_diffuse(f_norm, time_of_day.x, light, diffuse_light, ambient_light, 0.0);
	float point_shadow = shadow_at(f_pos,f_norm);
	diffuse_light *= f_light * point_shadow;
	ambient_light *= f_light, point_shadow;
	vec3 point_light = light_at(f_pos, f_norm);
	light += point_light;
	diffuse_light += point_light;
	vec3 surf_color = illuminate(srgb_to_linear(vec3(0.2, 0.2, 1.0)), light, diffuse_light, ambient_light);

	float fog_level = fog(f_pos.xyz, focus_pos.xyz, medium.x);
	vec4 clouds;
    vec3 fog_color = get_sky_color(normalize(f_pos - cam_pos.xyz), time_of_day.x, cam_pos.xyz, f_pos, 0.25, true, clouds);

	float passthrough = pow(dot(faceforward(f_norm, f_norm, cam_to_frag), -cam_to_frag), 0.5);

	vec4 color = mix(vec4(surf_color, 1.0), vec4(surf_color, 1.0 / (1.0 + diffuse_light * 0.25)), passthrough);

    tgt_color = mix(mix(color, vec4(fog_color, 0.0), fog_level), vec4(clouds.rgb, 0.0), clouds.a);
}