// 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 _OpenGl_PBREnvironment_HeaderFile #define _OpenGl_PBREnvironment_HeaderFile #include #include //! This class contains specular and diffuse maps required for Image Base Lighting (IBL) in PBR shading model with it's generation methods. class OpenGl_PBREnvironment : public OpenGl_NamedResource { DEFINE_STANDARD_RTTIEXT(OpenGl_PBREnvironment, OpenGl_NamedResource) public: //! Creates and initializes new PBR environment. It is the only way to create OpenGl_PBREnvironment. //! @param theCtx OpenGL context where environment will be created //! @param thePow2Size final size of texture's sides can be calculated as 2^thePow2Size; //! if thePow2Size less than 1 it will be set to 1 //! @param theSpecMapLevelsNum number of mipmap levels used in specular IBL map; //! if theSpecMapLevelsNum less than 2 or less than Pow2Size + 1 it will be set to the corresponding values. //! @param theId OpenGl_Resource name //! @return handle to created PBR environment or NULL handle in case of fail Standard_EXPORT static Handle(OpenGl_PBREnvironment) Create (const Handle(OpenGl_Context)& theCtx, unsigned int thePow2Size = 9, unsigned int theSpecMapLevelsNum = 6, const TCollection_AsciiString& theId = "PBREnvironment"); public: //! Binds diffuse and specular IBL maps to the corresponding texture units. Standard_EXPORT void Bind (const Handle(OpenGl_Context)& theCtx); //! Unbinds diffuse and specular IBL maps. Standard_EXPORT void Unbind (const Handle(OpenGl_Context)& theCtx); //! Fills all mipmaps of specular IBL map and diffuse IBL map with one color. //! So that environment illumination will be constant. Standard_EXPORT void Clear (const Handle(OpenGl_Context)& theCtx, const Graphic3d_Vec3& theColor = Graphic3d_Vec3 (1.f)); //! Generates specular and diffuse (irradiance) IBL maps. //! @param theCtx OpenGL context //! @param theEnvMap source environment map //! @param theZIsInverted flags indicates whether environment cubemap has inverted Z axis or not //! @param theIsTopDown flags indicates whether environment cubemap has top-down memory layout or not //! @param theDiffMapNbSamples number of samples in Monte-Carlo integration for diffuse IBL spherical harmonics calculation //! @param theSpecMapNbSamples number of samples in Monte-Carlo integration for specular IBL map generation //! @param theProbability controls strength of samples number reducing strategy during specular IBL map baking (see 'SpecIBLMapSamplesFactor' for details) //! theZIsInverted and theIsTopDown can be taken from Graphic3d_CubeMap source of environment cubemap. //! theDiffMapNbSamples and theSpecMapNbSamples is the main parameter directly affected to performance. Standard_EXPORT void Bake (const Handle(OpenGl_Context)& theCtx, const Handle(OpenGl_Texture)& theEnvMap, Standard_Boolean theZIsInverted = Standard_False, Standard_Boolean theIsTopDown = Standard_True, Standard_Size theDiffMapNbSamples = 1024, Standard_Size theSpecMapNbSamples = 256, Standard_ShortReal theProbability = 0.99f); //! Returns number of mipmap levels used in specular IBL map. //! It can be different from value passed to creation method. unsigned int SpecMapLevelsNumber() const { return mySpecMapLevelsNumber; } //! Returns size of IBL maps sides as power of 2. //! So that the real size can be calculated as 2^Pow2Size() unsigned int Pow2Size() const { return myPow2Size; } //! Checks whether the given sizes affects to the current ones. //! It can be imagined as creation of new PBR environment. //! If creation method with this values returns the PBR environment having real sizes which are equals to current ones //! then this method will return false. //! It is handful when sizes are required to be changed. //! If this method returns false there is no reason to recreate PBR environment in order to change sizes. Standard_EXPORT bool SizesAreDifferent (unsigned int thePow2Size, unsigned int theSpecMapLevelsNumber) const; //! Indicates whether IBL map's textures have to be bound or it is not obligate. bool IsNeededToBeBound() const { return myIsNeededToBeBound; } //! Releases all OpenGL resources. //! It must be called before destruction. Standard_EXPORT virtual void Release (OpenGl_Context* theCtx) Standard_OVERRIDE; //! Returns estimated GPU memory usage for holding data without considering overheads and allocation alignment rules. virtual Standard_Size EstimatedDataSize() const Standard_OVERRIDE { unsigned int aDiffIBLMapSidePixelsCount = 1 << myPow2Size; aDiffIBLMapSidePixelsCount *= aDiffIBLMapSidePixelsCount; Standard_Size anEstimatedDataSize = aDiffIBLMapSidePixelsCount; for (unsigned int i = 0; i < mySpecMapLevelsNumber; ++i) { anEstimatedDataSize += aDiffIBLMapSidePixelsCount >> (2 * i); } anEstimatedDataSize *= 6; // cubemap sides anEstimatedDataSize *= 3; // channels return anEstimatedDataSize; } //! Checks completeness of PBR environment. //! Creation method returns only completed objects or null handles otherwise. Standard_Boolean IsComplete() const { return myIsComplete; } //! Destructor. //! Warning! 'Release' method must be called before destruction. //! Otherwise unhandled critical error will be generated. Standard_EXPORT virtual ~OpenGl_PBREnvironment(); private: //! Creates new PBR environment. //! Parameters and logic are described in 'Create' method documentation. Standard_EXPORT OpenGl_PBREnvironment (const Handle(OpenGl_Context)& theCtx, unsigned int thePowOf2Size = 9, unsigned int theSpecMapLevelsNumber = 6, const TCollection_AsciiString& theId = "PBREnvironment"); private: //! Enum classified the type of IBL map enum OpenGl_TypeOfIBLMap { OpenGl_TypeOfIBLMap_DiffuseSH, OpenGl_TypeOfIBLMap_Specular, OpenGl_TypeOfIBLMap_DiffuseFallback, }; //! Parameters for baking IBL. struct BakingParams { Standard_Size NbSpecSamples; Standard_Size NbDiffSamples; Standard_Integer EnvMapSize; Standard_ShortReal Probability; Standard_Boolean IsZInverted; Standard_Boolean IsTopDown; BakingParams() : NbSpecSamples (0), NbDiffSamples (0), EnvMapSize (1024), Probability (1.0f), IsZInverted (false), IsTopDown (false) {} }; //! Initializes all textures. //! @return false in case of failed texture initialization //! Warning! Requires using of OpenGl_PBREnvironmentSentry. bool initTextures (const Handle(OpenGl_Context)& theCtx); //! Creates frame buffer object for IBL maps generation. //! @return false in case of failed FBO initialization //! Warning! Requires using of OpenGl_PBREnvironmentSentry. bool initFBO (const Handle(OpenGl_Context)& theCtx); //! Initializes vertex buffer object of screen rectangle. //! @return false in case of failed creation //! Warning! Requires using of OpenGl_PBREnvironmentSentry. bool initVAO (const Handle(OpenGl_Context)& theCtx); //! Responses for diffuse (irradiance) IBL map processing. //! @return false in case of failed baking or clearing //! Warning! Requires using of OpenGl_PBREnvironmentSentry. bool processDiffIBLMap (const Handle(OpenGl_Context)& theCtx, const BakingParams* theDrawParams); //! Responses for specular IBL map processing. //! @return false in case of failed baking or clearing //! Warning! Requires using of OpenGl_PBREnvironmentSentry. bool processSpecIBLMap (const Handle(OpenGl_Context)& theCtx, const BakingParams* theDrawParams); //! Checks completeness of frame buffer object for all targets //! (all cube map sides and levels of IBL maps). //! @return false in case of uncompleted frame buffer object. //! Warning! Requires using of OpenGl_PBREnvironmentSentry. bool checkFBOComplentess (const Handle(OpenGl_Context)& theCtx); //! Version of 'Bake' without OpenGl_PBREnvironmentSetnry. //! Warning! Requires using of OpenGl_PBREnvironmentSentry. void bake (const Handle(OpenGl_Context)& theCtx, const Handle(OpenGl_Texture)& theEnvMap, Standard_Boolean theZIsInverted = Standard_False, Standard_Boolean theIsTopDown = Standard_True, Standard_Size theDiffMapNbSamples = 1024, Standard_Size theSpecMapNbSamples = 256, Standard_ShortReal theProbability = 1.f); //! Version of 'Clear' without OpenGl_PBREnvironmentSetnry. //! Warning! Requires using of OpenGl_PBREnvironmentSentry. void clear (const Handle(OpenGl_Context)& theCtx, const Graphic3d_Vec3& theColor = Graphic3d_Vec3 (1.f)); private: unsigned int myPow2Size; //!< size of IBL maps sides (real size can be calculated as 2^myPow2Size) unsigned int mySpecMapLevelsNumber; //!< number of mipmap levels used in specular IBL map OpenGl_Texture myIBLMaps[3]; //!< IBL maps OpenGl_VertexBuffer myVBO; //!< vertex buffer object of screen rectangular GLuint myFBO; //!< frame buffer object to generate or clear IBL maps Standard_Boolean myIsComplete; //!< completeness of PBR environment Standard_Boolean myIsNeededToBeBound; //!< indicates whether IBL map's textures have to be bound or it is not obligate Standard_Boolean myCanRenderFloat; //!< indicates whether driver supports rendering into floating point texture or not }; #endif // _OpenGl_PBREnvironment_HeaderFile