#ifndef __MATERIALS_H__
#define __MATERIALS_H__

__device__ float min_wavelength;
__device__ float max_wavelength;
__device__ float wavelength_step;
__device__ unsigned int wavelength_size;

enum
{
	INIT = -1,
	MAX_DEPTH_REACHED,
	NO_HIT,
	BULK_ABSORB,
	SURFACE_ABSORB
};

struct Material
{
	float *refractive_index;
	float *absorption_length;
	float *scattering_length;
};

struct Surface
{
	float *absorption;
	float *reflection_diffuse;
	float *reflection_specular;
};

__device__ Material materials[100];
__device__ Surface surfaces[100];

__device__ float interp_property(const float &x, const float *fp)
{
	if (x < min_wavelength)
		return fp[0];

	if (x > max_wavelength)
		return fp[wavelength_size-1];

	unsigned int jl = (x-min_wavelength)/wavelength_step;
	float xl = min_wavelength + jl*wavelength_step;

	return xl + (x-xl)*(fp[jl+1]-fp[jl])/wavelength_step;
}

extern "C"
{

__global__ void set_wavelength_range(float _min_wavelength, float _max_wavelength, float _wavelength_step, unsigned int _wavelength_size)
{
	min_wavelength = _min_wavelength;
	max_wavelength = _max_wavelength;
	wavelength_step = _wavelength_step;
	wavelength_size = _wavelength_size;
}

__global__ void set_material(int material_index, float *refractive_index, float *absorption_length, float *scattering_length)
{
	materials[material_index].refractive_index = refractive_index;
	materials[material_index].absorption_length = absorption_length;
	materials[material_index].scattering_length = scattering_length;
}

__global__ void set_surface(int surface_index, float *absorption, float *reflection_diffuse, float *reflection_specular)
{
	surfaces[surface_index].absorption = absorption;
	surfaces[surface_index].reflection_diffuse = reflection_diffuse;
	surfaces[surface_index].reflection_specular = reflection_specular;
}

} // extern "c"

#endif