#ifndef GGX_MULTI_SCATTER_H
#define GGX_MULTI_SCATTER_H

#include "Common.h"
#include "cglm/struct/vec3.h"

// Initialize the tiny LUT. Safe to call multiple times.
void ggx_ms_init_lut_once(void);

// Heitz-style multiple-scattering GGX approximation (Smith model).
// Returns a broad lobe (Lambertian-shaped in shading space).
vec3s ggx_multi_scatter_lambert(vec3s f0, float NoV, float NoL, float roughness);

// Expose E(NoV, roughness) for lobe mixing / pdfs.
float ggx_ms_E(float NoV, float roughness);

#endif // GGX_MULTI_SCATTER_H