struct LightSourceParameters
{
	vec4 position;
	vec3 color;
	int type;
	vec3 attenuation;
};

const int max_lights = 6;
layout(set=0) uniform Lighting
{
	LightSourceParameters light_sources[max_lights];
	vec4 ambient_color;
	vec4 fog_color;
	//float fog_start_distance;
	float fog_density;
};

#pragma MSP stage(fragment)
struct IncomingLight
{
	vec3 direction;
	vec3 color;
};

virtual IncomingLight get_incoming_light(int index, vec3 world_pos)
{
	vec4 light_pos = light_sources[index].position;
	vec3 rel_pos = light_pos.xyz-world_pos*light_pos.w;
	float d = length(rel_pos);
	float attenuation = 1.0/dot(vec3(1.0, d, d*d), light_sources[index].attenuation);
	return IncomingLight(rel_pos/d, light_sources[index].color*attenuation);
}