src/Graphic3d/Graphic3d_BSDF.hxx

   1 // Created on: 2015-01-15
   2 // Created by: Danila ULYANOV
   3 // Copyright (c) 2014 OPEN CASCADE SAS
   4 //
   5 // This file is part of Open CASCADE Technology software library.
   6 //
   7 // This library is free software; you can redistribute it and/or modify it under
   8 // the terms of the GNU Lesser General Public License version 2.1 as published
   9 // by the Free Software Foundation, with special exception defined in the file
  10 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
  11 // distribution for complete text of the license and disclaimer of any warranty.
  12 //
  13 // Alternatively, this file may be used under the terms of Open CASCADE
  14 // commercial license or contractual agreement.
  15
  16 #ifndef _Graphic3d_BSDF_HeaderFile
  17 #define _Graphic3d_BSDF_HeaderFile
  18
  19 #include <Graphic3d_Vec3.hxx>
  20 #include <Graphic3d_Vec4.hxx>
  21
  22 //! Type of the Fresnel model.
  23 enum Graphic3d_FresnelModel
  24 {
  25   Graphic3d_FM_SCHLICK    = 0,
  26   Graphic3d_FM_CONSTANT   = 1,
  27   Graphic3d_FM_CONDUCTOR  = 2,
  28   Graphic3d_FM_DIELECTRIC = 3
  29 };
  30
  31 //! Describes Fresnel reflectance parameters.
  32 class Graphic3d_Fresnel
  33 {
  34 public:
  35
  36   //! Creates uninitialized Fresnel factor.
  37   Graphic3d_Fresnel()
  38   : myFresnelType (Graphic3d_FM_CONSTANT)
  39   {
  40     // ideal specular reflector
  41     myFresnelData = Graphic3d_Vec3 (0.f, 1.f, 0.f);
  42   }
  43
  44   //! Creates Schlick's approximation of Fresnel factor.
  45   static Graphic3d_Fresnel CreateSchlick (const Graphic3d_Vec3& theSpecularColor)
  46   {
  47     return Graphic3d_Fresnel (Graphic3d_FM_SCHLICK, theSpecularColor);
  48   }
  49
  50   //! Creates Fresnel factor for constant reflection.
  51   static Graphic3d_Fresnel CreateConstant (const Standard_ShortReal theReflection)
  52   {
  53     return Graphic3d_Fresnel (Graphic3d_FM_CONSTANT, Graphic3d_Vec3 (0.f, 1.f, theReflection));
  54   }
  55
  56   //! Creates Fresnel factor for physical-based dielectric model.
  57   static Graphic3d_Fresnel CreateDielectric (Standard_ShortReal theRefractionIndex)
  58   {
  59     return Graphic3d_Fresnel (Graphic3d_FM_DIELECTRIC, Graphic3d_Vec3 (0.f, theRefractionIndex, 0.f));
  60   }
  61
  62   //! Creates Fresnel factor for physical-based conductor model.
  63   static Graphic3d_Fresnel CreateConductor (Standard_ShortReal theRefractionIndex,
  64                                             Standard_ShortReal theAbsorptionIndex)
  65   {
  66     return Graphic3d_Fresnel (Graphic3d_FM_CONDUCTOR, Graphic3d_Vec3 (0.f, theRefractionIndex, theAbsorptionIndex));
  67   }
  68
  69   //! Creates Fresnel factor for physical-based conductor model (spectral version).
  70   Standard_EXPORT static Graphic3d_Fresnel CreateConductor (const Graphic3d_Vec3& theRefractionIndex,
  71                                                             const Graphic3d_Vec3& theAbsorptionIndex);
  72
  73 public:
  74
  75   //! Returns serialized representation of Fresnel factor.
  76   Standard_EXPORT Graphic3d_Vec4 Serialize() const;
  77
  78   //! Performs comparison of two objects describing Fresnel factor.
  79   bool operator== (const Graphic3d_Fresnel& theOther) const
  80   {
  81     return myFresnelType == theOther.myFresnelType
  82         && myFresnelData == theOther.myFresnelData;
  83   }
  84
  85   //! Returns type of Fresnel.
  86   Graphic3d_FresnelModel FresnelType() const
  87   {
  88     return myFresnelType;
  89   }
  90
  91 protected:
  92
  93   //! Creates new Fresnel reflectance factor.
  94   Graphic3d_Fresnel (Graphic3d_FresnelModel theType, const Graphic3d_Vec3& theData)
  95   : myFresnelType (theType),
  96     myFresnelData (theData)
  97   {
  98     //
  99   }
 100
 101 private:
 102
 103   //! Type of Fresnel approximation.
 104   Graphic3d_FresnelModel myFresnelType;
 105
 106   //! Serialized parameters of specific approximation.
 107   Graphic3d_Vec3 myFresnelData;
 108 };
 109
 110 //! Describes material's BSDF (Bidirectional Scattering Distribution Function) used
 111 //! for physically-based rendering (in path tracing engine). BSDF is represented as
 112 //! weighted mixture of basic BRDFs/BTDFs (Bidirectional Reflectance (Transmittance)
 113 //! Distribution Functions).
 114 class Graphic3d_BSDF
 115 {
 116 public:
 117
 118   //! Weight of the Lambertian BRDF.
 119   Graphic3d_Vec3 Kd;
 120
 121   //! Weight of the reflection BRDF.
 122   Graphic3d_Vec3 Kr;
 123
 124   //! Weight of the transmission BTDF.
 125   Graphic3d_Vec3 Kt;
 126
 127   //! Weight of the Blinn's glossy BRDF.
 128   Graphic3d_Vec3 Ks;
 129
 130   //! Self-emitted radiance.
 131   Graphic3d_Vec3 Le;
 132
 133   //! Parameters of Fresnel reflectance.
 134   Graphic3d_Fresnel Fresnel;
 135
 136   //! Roughness (exponent) of Blinn's BRDF.
 137   Standard_ShortReal Roughness;
 138
 139   //! Absorption color of transparent media.
 140   Graphic3d_Vec3 AbsorptionColor;
 141
 142   //! Absorption intensity of transparent media.
 143   Standard_ShortReal AbsorptionCoeff;
 144
 145 public:
 146
 147   //! Creates BSDF describing diffuse (Lambertian) surface.
 148   static Standard_EXPORT Graphic3d_BSDF CreateDiffuse (const Graphic3d_Vec3& theWeight);
 149
 150   //! Creates BSDF describing polished metallic-like surface.
 151   static Standard_EXPORT Graphic3d_BSDF CreateMetallic (const Graphic3d_Vec3&    theWeight,
 152                                                         const Graphic3d_Fresnel& theFresnel,
 153                                                         const Standard_ShortReal theRoughness);
 154
 155   //! Creates BSDF describing transparent object.
 156   //! Transparent BSDF models simple transparency without
 157   //! refraction (the ray passes straight through the surface).
 158   static Standard_EXPORT Graphic3d_BSDF CreateTransparent (const Graphic3d_Vec3&    theWeight,
 159                                                            const Graphic3d_Vec3&    theAbsorptionColor,
 160                                                            const Standard_ShortReal theAbsorptionCoeff);
 161
 162   //! Creates BSDF describing glass-like object.
 163   //! Glass-like BSDF mixes refraction and reflection effects at
 164   //! grazing angles using physically-based Fresnel dielectric model.
 165   static Standard_EXPORT Graphic3d_BSDF CreateGlass (const Graphic3d_Vec3&    theWeight,
 166                                                      const Graphic3d_Vec3&    theAbsorptionColor,
 167                                                      const Standard_ShortReal theAbsorptionCoeff,
 168                                                      const Standard_ShortReal theRefractionIndex);
 169
 170 public:
 171
 172   //! Creates uninitialized BSDF.
 173   Graphic3d_BSDF() : Roughness (1.f), AbsorptionCoeff (0.f)
 174   {
 175     Fresnel = Graphic3d_Fresnel::CreateConstant (1.f);
 176   }
 177
 178   //! Normalizes BSDF components.
 179   Standard_EXPORT void Normalize();
 180
 181   //! Performs mixing of two BSDFs.
 182   Graphic3d_BSDF& operator+ (const Graphic3d_BSDF& theOther)
 183   {
 184     Kd += theOther.Kd;
 185     Kr += theOther.Kr;
 186     Kt += theOther.Kt;
 187     Ks += theOther.Ks;
 188     Le += theOther.Le;
 189
 190     return *this;
 191   }
 192
 193   //! Performs comparison of two BSDFs.
 194   bool operator== (const Graphic3d_BSDF& theOther) const
 195   {
 196     return Kd              == theOther.Kd
 197         && Kr              == theOther.Kr
 198         && Kt              == theOther.Kt
 199         && Ks              == theOther.Ks
 200         && Le              == theOther.Le
 201         && Fresnel         == theOther.Fresnel
 202         && Roughness       == theOther.Roughness
 203         && AbsorptionCoeff == theOther.AbsorptionCoeff
 204         && AbsorptionColor == theOther.AbsorptionColor;
 205   }
 206
 207 };
 208
 209 #endif // _Graphic3d_BSDF_HeaderFile