#ifndef BSDF_H
#define BSDF_H

#include "Algorithm/Sobol.h"
#include "cglm/struct/vec3.h"

float power_heuristic(float pdf_a, float pdf_b);
float roughness_to_blinn_phong_specular_exponent(float roughness);
vec3s fresnel_schlick_vec3(vec3s f0, float cos_theta);

// BSDF sampling functions
float pdf_cosine_weighted_hemisphere(vec3s normal, vec3s wi);
float pdf_blinn_phong_lobe(vec3s normal, vec3s wi, vec3s wo, float roughness);

vec3s sample_cosine_weighted_hemisphere_z_angular(float angular, uint32_t index, uint32_t d1, uint32_t d2);
vec3s sample_cosine_weighted_hemisphere_z(uint32_t index, uint32_t d1, uint32_t d2);
void create_orthonormal_basis(vec3s direction, vec3s* u, vec3s* v);
vec3s random_cosine_direction_angular(vec3s direction, float angular, uint32_t index, uint32_t d1, uint32_t d2);
vec3s random_cosine_direction(vec3s direction, uint32_t index, uint32_t d1, uint32_t d2);

vec3s random_uniform_cdf_direction(vec3s direction, uint32_t index, uint32_t d1, uint32_t d2);
vec3s random_uniform_cdf_direction_angular(vec3s direction, uint32_t index, float angular, uint32_t d1, uint32_t d2);

#endif // BSDF_H