nuclear@2: #ifndef BRDF_H_
nuclear@2: #define BRDF_H_
nuclear@2: 
nuclear@21: #include <vector>
nuclear@2: #include "texture.h"
nuclear@2: 
nuclear@2: class Reflectance {
nuclear@2: public:
nuclear@2: 	Reflectance();
nuclear@2: 	virtual ~Reflectance() = default;
nuclear@2: 
nuclear@2: 	virtual Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const = 0;
nuclear@2: 	virtual float sample(const Vector3 &norm, const Vector3 &outdir, Vector3 *indir) const;
nuclear@2: 	virtual float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const = 0;
nuclear@2: };
nuclear@2: 
nuclear@21: typedef float (*CompReflWeightFunc)(const Vector3 &norm, const Vector3 &outdir);
nuclear@21: 
nuclear@21: class CompositeRefl : public Reflectance {
nuclear@21: private:
nuclear@21: 	struct SubRefl {
nuclear@21: 		Reflectance *brdf;
nuclear@21: 		float weight;
nuclear@21: 		CompReflWeightFunc weight_func;	// if null, use static weight above
nuclear@21: 	};
nuclear@21: 	std::vector<SubRefl> sub_brdf;
nuclear@21: 	mutable bool valid_checked;
nuclear@21: 
nuclear@21: 	int pick_brdf(const Vector3 &norm, const Vector3 &outdir) const;
nuclear@21: 
nuclear@21: public:
nuclear@21: 	CompositeRefl();
nuclear@21: 
nuclear@21: 	virtual void add_brdf(Reflectance *brdf, float weight);
nuclear@21: 	virtual void add_brdf(Reflectance *brdf, CompReflWeightFunc weight_func);
nuclear@21: 
nuclear@21: 	bool check_valid() const;
nuclear@21: 
nuclear@21: 	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
nuclear@21: 	float sample(const Vector3 &norm, const Vector3 &outdir, Vector3 *indir) const override;
nuclear@21: 	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
nuclear@21: };
nuclear@21: 
nuclear@2: class LambertRefl : public Reflectance {
nuclear@2: public:
nuclear@2: 	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
nuclear@2: 	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
nuclear@2: };
nuclear@2: 
nuclear@21: class MirrorRefl : public Reflectance {
nuclear@21: public:
nuclear@21: 	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
nuclear@21: 	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
nuclear@21: };
nuclear@21: 
nuclear@28: class PhongRefl : public Reflectance {
nuclear@28: public:
nuclear@28: 	float shininess;
nuclear@28: 
nuclear@28: 	PhongRefl();
nuclear@28: 
nuclear@28: 	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
nuclear@28: 	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
nuclear@28: };
nuclear@28: 
nuclear@2: #endif	// BRDF_H_