1 #ifndef BRDF_H_

2 #define BRDF_H_

3

4 #include <vector>

5 #include "texture.h"

6

7 class Reflectance {

8 public:

9 Reflectance();

10 virtual ~Reflectance() = default;

11

12 virtual Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const = 0;

13 virtual float sample(const Vector3 &norm, const Vector3 &outdir, Vector3 *indir) const;

14 virtual float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const = 0;

15 };

16

17 typedef float (*CompReflWeightFunc)(const Vector3 &norm, const Vector3 &outdir);

18

19 class CompositeRefl : public Reflectance {

20 private:

21 struct SubRefl {

22 Reflectance *brdf;

23 float weight;

24 CompReflWeightFunc weight_func; // if null, use static weight above

25 };

26 std::vector<SubRefl> sub_brdf;

27 mutable bool valid_checked;

28

29 int pick_brdf(const Vector3 &norm, const Vector3 &outdir) const;

30

31 public:

32 CompositeRefl();

33

34 virtual void add_brdf(Reflectance *brdf, float weight);

35 virtual void add_brdf(Reflectance *brdf, CompReflWeightFunc weight_func);

36

37 bool check_valid() const;

38

39 Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;

40 float sample(const Vector3 &norm, const Vector3 &outdir, Vector3 *indir) const override;

41 float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;

42 };

43

44 class LambertRefl : public Reflectance {

45 public:

46 Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;

47 float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;

48 };

49

50 class MirrorRefl : public Reflectance {

51 public:

52 Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;

53 float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;

54 };

55

56 #endif // BRDF_H_