import msp_interface;

struct ShadowParameters
{
	int enabled;
	float darkness;
	mat4 shd_world_matrix;
	vec4 region;
};

uniform ShadowMap
{
	ShadowParameters shadows[max_lights];
};

uniform sampler2DShadow shadow_map;

layout(constant_id=auto) const bool use_shadow_map = false;

#pragma MSP stage(fragment)
virtual float get_shadow_factor(int index, vec4 world_pos)
{
	if(use_shadow_map)
	{
		if(shadows[index].enabled==0)
			return 1.0;

		vec3 shadow_coord = (shadows[index].shd_world_matrix*world_pos).xyz;
		if(shadow_coord.x<0 || shadow_coord.x>1 || shadow_coord.y<0 || shadow_coord.y>1)
			return 1.0;

		vec4 region = shadows[index].region;
		float shadow_sample = texture(shadow_map, shadow_coord*vec3(region.zw, 1.0)+vec3(region.xy, 0.0));
		return mix(1.0, shadow_sample, shadows[index].darkness);
	}
	else
		return 1.0;
}