erebus

diff liberebus/src/brdf.h @ 31:53a98c148bf8

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- introduced SurfaceGeometry to carry all the geometric information input to BRDF sampling and evaluation functions. - made Reflectance keep an (optional) pointer to its material - simplified PhongRefl::sample_dir, with the help of SurfaceGeometry - worked around microsoft's broken std::thread implementation's deadlock on join
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 07 Jun 2014 09:14:17 +0300
parents 4a0a288ffb27
children c4d48a21bc4a
line diff
     1.1 --- a/liberebus/src/brdf.h	Sat Jun 07 06:10:21 2014 +0300
     1.2 +++ b/liberebus/src/brdf.h	Sat Jun 07 09:14:17 2014 +0300
     1.3 @@ -4,18 +4,56 @@
     1.4  #include <vector>
     1.5  #include "texture.h"
     1.6  
     1.7 +class Material;
     1.8 +
     1.9 +class SurfaceGeometry {
    1.10 +public:
    1.11 +	Vector3 normal, tangent;
    1.12 +	Vector2 uv;
    1.13 +
    1.14 +	enum VecLength { unit, unknown };
    1.15 +
    1.16 +	explicit SurfaceGeometry(const Vector3 &norm, VecLength st = unknown);
    1.17 +	SurfaceGeometry(const Vector3 &norm, const Vector2 &uv, VecLength st = unknown);
    1.18 +	SurfaceGeometry(const Vector3 &norm, const Vector3 &tang, VecLength st = unknown);
    1.19 +	SurfaceGeometry(const Vector3 &norm, const Vector3 &tang, const Vector2 &uv, VecLength st = unknown);
    1.20 +
    1.21 +	/** create a cartesian direction vector in sample space (zenith = +Z) and
    1.22 +	 * transform it to world space.
    1.23 +	 * \param theta the horizontal angle (azimuth, in radians) around the Z axis [0, 2pi]
    1.24 +	 * \param phi the vertical angle (elevation, in radians) away from the Z axis [0, pi]
    1.25 +	 */
    1.26 +	Vector3 spherical_to_world(float theta, float phi) const;
    1.27 +	/// transforms a direction vector from sample space (centered around Z) to world space
    1.28 +	Vector3 sample_to_world(const Vector3 &v) const;
    1.29 +	/// transforms a direction vector from world space to sample space (centered around Z)
    1.30 +	Vector3 world_to_sample(const Vector3 &v) const;
    1.31 +};
    1.32 +
    1.33 +/// abstract bidirection reflectance distribution function base class
    1.34  class Reflectance {
    1.35 +protected:
    1.36 +	const Material *mtl;	// pointer to the material we belong to
    1.37 +
    1.38  public:
    1.39  	Reflectance();
    1.40 +	explicit Reflectance(const Material *mtl);
    1.41  	virtual ~Reflectance() = default;
    1.42  
    1.43 -	virtual Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const = 0;
    1.44 -	virtual float sample(const Vector3 &norm, const Vector3 &outdir, Vector3 *indir) const;
    1.45 -	virtual float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const = 0;
    1.46 +	void set_material(const Material *mtl);
    1.47 +	const Material *get_material() const;
    1.48 +
    1.49 +	/// given an outgoing light direction generate an incidence direction to sample the BRDF
    1.50 +	virtual Vector3 sample_dir(const SurfaceGeometry &geom, const Vector3 &outdir) const = 0;
    1.51 +	/// given an outgoing direction, generate an incidence direction, and evaluate its probability
    1.52 +	virtual float sample(const SurfaceGeometry &geom, const Vector3 &outdir, Vector3 *indir) const;
    1.53 +	/// given an outgoing direction and an incidence direction, evaluate the probability of this path
    1.54 +	virtual float eval(const SurfaceGeometry &geom, const Vector3 &outdir, const Vector3 &indir) const = 0;
    1.55  };
    1.56  
    1.57 -typedef float (*CompReflWeightFunc)(const Vector3 &norm, const Vector3 &outdir);
    1.58 +typedef float (*CompReflWeightFunc)(const SurfaceGeometry &geom, const Vector3 &outdir);
    1.59  
    1.60 +/// composite BRDF, with multiple weighted sub-reflectances.
    1.61  class CompositeRefl : public Reflectance {
    1.62  private:
    1.63  	struct SubRefl {
    1.64 @@ -26,41 +64,41 @@
    1.65  	std::vector<SubRefl> sub_brdf;
    1.66  	mutable bool valid_checked;
    1.67  
    1.68 -	int pick_brdf(const Vector3 &norm, const Vector3 &outdir) const;
    1.69 +	int pick_brdf(const SurfaceGeometry &geom, const Vector3 &outdir) const;
    1.70  
    1.71  public:
    1.72  	CompositeRefl();
    1.73 +	explicit CompositeRefl(const Material *mtl);
    1.74  
    1.75  	virtual void add_brdf(Reflectance *brdf, float weight);
    1.76  	virtual void add_brdf(Reflectance *brdf, CompReflWeightFunc weight_func);
    1.77  
    1.78  	bool check_valid() const;
    1.79  
    1.80 -	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
    1.81 -	float sample(const Vector3 &norm, const Vector3 &outdir, Vector3 *indir) const override;
    1.82 -	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
    1.83 +	Vector3 sample_dir(const SurfaceGeometry &geom, const Vector3 &outdir) const override;
    1.84 +	float sample(const SurfaceGeometry &geom, const Vector3 &outdir, Vector3 *indir) const override;
    1.85 +	float eval(const SurfaceGeometry &geom, const Vector3 &outdir, const Vector3 &indir) const override;
    1.86  };
    1.87  
    1.88 +/// lambertian perfect diffuse reflectance
    1.89  class LambertRefl : public Reflectance {
    1.90  public:
    1.91 -	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
    1.92 -	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
    1.93 +	Vector3 sample_dir(const SurfaceGeometry &geom, const Vector3 &outdir) const override;
    1.94 +	float eval(const SurfaceGeometry &geom, const Vector3 &outdir, const Vector3 &indir) const override;
    1.95  };
    1.96  
    1.97 +/// perfect specular reflectance
    1.98  class MirrorRefl : public Reflectance {
    1.99  public:
   1.100 -	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
   1.101 -	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
   1.102 +	Vector3 sample_dir(const SurfaceGeometry &geom, const Vector3 &outdir) const override;
   1.103 +	float eval(const SurfaceGeometry &geom, const Vector3 &outdir, const Vector3 &indir) const override;
   1.104  };
   1.105  
   1.106 +/// glossy phong reflectance with lafortune sampling
   1.107  class PhongRefl : public Reflectance {
   1.108  public:
   1.109 -	float shininess;
   1.110 -
   1.111 -	PhongRefl();
   1.112 -
   1.113 -	Vector3 sample_dir(const Vector3 &norm, const Vector3 &outdir) const override;
   1.114 -	float eval(const Vector3 &norm, const Vector3 &outdir, const Vector3 &indir) const override;
   1.115 +	Vector3 sample_dir(const SurfaceGeometry &geom, const Vector3 &outdir) const override;
   1.116 +	float eval(const SurfaceGeometry &geom, const Vector3 &outdir, const Vector3 &indir) const override;
   1.117  };
   1.118  
   1.119  #endif	// BRDF_H_