// Author: Ilya Khramov // Copyright (c) 2019 OPEN CASCADE SAS // // This file is part of Open CASCADE Technology software library. // // This library is free software; you can redistribute it and/or modify it under // the terms of the GNU Lesser General Public License version 2.1 as published // by the Free Software Foundation, with special exception defined in the file // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT // distribution for complete text of the license and disclaimer of any warranty. // // Alternatively, this file may be used under the terms of Open CASCADE // commercial license or contractual agreement. #ifndef _Graphic3d_PBRMaterial_HeaderFile #define _Graphic3d_PBRMaterial_HeaderFile #include #include #include #include #include //! Class implementing Metallic-Roughness physically based material definition class Graphic3d_PBRMaterial { public: //! Creates new physically based material in Metallic-Roughness system. //! 'metallic' parameter is 0 by default. //! 'roughness' parameter is 1 by default. //! 'color' parameter is (0, 0, 0) by default. //! 'alpha' parameter is 1 by default. //! 'IOR' parameter is 1.5 by default. //! 'emission' parameter is (0, 0, 0) by default. Standard_EXPORT Graphic3d_PBRMaterial(); //! Creates new physically based material in Metallic-Roughness system from Graphic3d_BSDF. Standard_EXPORT Graphic3d_PBRMaterial (const Graphic3d_BSDF& theBSDF); //! Returns material's metallic coefficient in [0, 1] range. //! 1 for metals and 0 for dielectrics. //! It is preferable to be exactly 0 or 1. Average values are needed for textures mixing in shader. Standard_ShortReal Metallic() const { return myMetallic; } //! Modifies metallic coefficient of material in [0, 1] range. Standard_EXPORT void SetMetallic (Standard_ShortReal theMetallic); //! Maps roughness from [0, 1] to [MinRoughness, 1] for calculations. Standard_EXPORT static Standard_ShortReal Roughness(Standard_ShortReal theNormalizedRoughness); //! Returns real value of roughness in [MinRoughness, 1] range for calculations. Standard_ShortReal Roughness() const { return Roughness(myRoughness); } //! Returns roughness mapping parameter in [0, 1] range. //! Roughness is defined in [0, 1] for handful material settings //! and is mapped to [MinRoughness, 1] for calculations. Standard_ShortReal NormalizedRoughness() const { return myRoughness; } //! Modifies roughness coefficient of material in [0, 1] range. Standard_EXPORT void SetRoughness (Standard_ShortReal theRoughness); //! Returns index of refraction in [1, 3] range. Standard_ShortReal IOR() const { return myIOR; } //! Modifies index of refraction in [1, 3] range. //! In practice affects only on non-metal materials reflection possibilities. Standard_EXPORT void SetIOR (Standard_ShortReal theIOR); //! Returns albedo color with alpha component of material. const Quantity_ColorRGBA& Color() const { return myColor; } //! Modifies albedo color with alpha component. Standard_EXPORT void SetColor (const Quantity_ColorRGBA& theColor); //! Modifies only albedo color. Standard_EXPORT void SetColor (const Quantity_Color& theColor); //! Returns alpha component in range [0, 1]. Standard_ShortReal Alpha() const { return myColor.Alpha(); }; //! Modifies alpha component. Standard_EXPORT void SetAlpha (Standard_ShortReal theAlpha); //! Returns light intensity emitted by material. //! Values are greater or equal 0. Graphic3d_Vec3 Emission() const { return myEmission; } //! Modifies light intensity emitted by material. Standard_EXPORT void SetEmission (const Graphic3d_Vec3& theEmission); //! Generates material in Metallic-Roughness system from Graphic3d_BSDF. Standard_EXPORT void SetBSDF (const Graphic3d_BSDF& theBSDF); public: //! PBR materials comparison operator. Standard_Boolean operator== (const Graphic3d_PBRMaterial& theOther) const { return (myMetallic == theOther.myMetallic) && (myRoughness == theOther.myRoughness) && (myIOR == theOther.myIOR) && (myColor == theOther.myColor) && (myEmission == theOther.myEmission); } public: //! Generates 2D look up table of scale and bias for fresnell zero coefficient. //! It is needed for calculation reflectance part of environment lighting. //! @param [out] theLUT table storage (must be Image_Format_RGF). //! @param [in] theNbIntegralSamples number of importance samples in hemisphere integral calculation for every table item. Standard_EXPORT static void GenerateEnvLUT (const Handle(Image_PixMap)& theLUT, unsigned int theNbIntegralSamples = 1024); //! Compute material roughness from common material (specular color + shininess). //! @param theSpecular [in] specular color //! @param theShiness [in] normalized shininess coefficient within [0..1] range //! @return roughness within [0..1] range Standard_EXPORT static Standard_ShortReal RoughnessFromSpecular (const Quantity_Color& theSpecular, const Standard_Real theShiness); //! Compute material metallicity from common material (specular color). //! @param theSpecular [in] specular color //! @return metallicity within [0..1] range static Standard_ShortReal MetallicFromSpecular (const Quantity_Color& theSpecular) { return ((Graphic3d_Vec3 )theSpecular).maxComp(); } public: //! Roughness cannot be 0 in real calculations, so it returns minimal achievable level of roughness in practice static Standard_ShortReal MinRoughness() { return 0.01f; } public: //! Shows how much times less samples can be used in certain roughness value specular IBL map generation //! in compare with samples number for map with roughness of 1. //! Specular IBL maps with less roughness values have higher resolution but require less samples for the same quality of baking. //! So that reducing samples number is good strategy to improve performance of baking. //! The samples number for specular IBL map with roughness of 1 (the maximum possible samples number) is expected to be defined as baking parameter. //! Samples number for other roughness values can be calculated by multiplication origin samples number by this factor. //! @param theProbability value from 0 to 1 controlling strength of samples reducing. //! Bigger values result in slower reduction to provide better quality but worse performance. //! Value of 1 doesn't affect at all so that 1 will be returned (it can be used to disable reduction strategy). //! @param theRoughness roughness value of current generated specular IBL map (from 0 to 1). //! @return factor to calculate number of samples for current specular IBL map baking. //! Be aware! It has no obligation to return 1 in case of roughness of 1. //! Be aware! It produces poor quality with small number of origin samples. In that case it is recommended to be disabled. Standard_EXPORT static Standard_ShortReal SpecIBLMapSamplesFactor (Standard_ShortReal theProbability, Standard_ShortReal theRoughness); //! Dumps the content of me into the stream Standard_EXPORT void DumpJson (Standard_OStream& theOStream, Standard_Integer theDepth = -1) const; private: //! Calculates geometry factor of Cook-Torrance BRDF using Smith formula. static Standard_ShortReal lutGenGeometryFactor (Standard_ShortReal theCosL, Standard_ShortReal theCosV, Standard_ShortReal theRoughness); //! Generates quasi-random point from Hammersley set. //! @param theNumber number of point //! @param theCount size of Hammersley set static Graphic3d_Vec2 lutGenHammersley (unsigned int theNumber, unsigned int theCount); //! Generates only cosine theta of direction in spherical coordinates system //! according to micro facet distribution function from Cook-Torrance BRDF. static Standard_ShortReal lutGenImportanceSampleCosTheta (Standard_ShortReal theHammerslayPointComponent, Standard_ShortReal theRoughness); //! Generates direction using point from Hammersley set //! according to micro facet distribution function from Cook-Torrance BRDF. static Graphic3d_Vec3 lutGenImportanceSample (const Graphic3d_Vec2 &theHammerslayPoint, Standard_ShortReal theRoughness); //! Generates vector using cosine of angle between up vector (normal in hemisphere) //! and desired vector. //! x component for resulting vector will be zero. static Graphic3d_Vec3 lutGenView (Standard_ShortReal theCosV); //! Returns reflected vector according axis. //! @param theVector vector is needed to be reflected. //! @param theAxis axis of reflection. static Graphic3d_Vec3 lutGenReflect (const Graphic3d_Vec3 &theVector, const Graphic3d_Vec3 &theAxis); private: Quantity_ColorRGBA myColor; //!< albedo color with alpha component [0, 1] Standard_ShortReal myMetallic; //!< metallic coefficient of material [0, 1] Standard_ShortReal myRoughness; //!< roughness coefficient of material [0, 1] Graphic3d_Vec3 myEmission; //!< light intensity emitted by material [>= 0] Standard_ShortReal myIOR; //!< index of refraction [1, 3] }; #endif // _Graphic3d_PBRMaterial_HeaderFile