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    Open CASCADE Technology Reference Manual 8.0.1
    OpenGl_IndexBuffer Class Reference

    Index buffer is just a VBO with special target (GL_ELEMENT_ARRAY_BUFFER). More...

    #include <OpenGl_IndexBuffer.hxx>

    Inheritance diagram for OpenGl_IndexBuffer:

    Public Member Functions

     OpenGl_IndexBuffer ()
     Empty constructor.
    unsigned int GetTarget () const override
     Return buffer object target (GL_ELEMENT_ARRAY_BUFFER).
    void DumpJson (Standard_OStream &theOStream, int theDepth=-1) const override
     Dumps the content of me into the stream.
    Public Member Functions inherited from OpenGl_Buffer
     OpenGl_Buffer ()
     Create uninitialized buffer.
     ~OpenGl_Buffer () override
     Destroy object.
    virtual bool IsVirtual () const
     Return TRUE if this is a virtual (for backward compatibility) VBO object.
    bool IsValid () const
    unsigned int GetComponentsNb () const
    int GetElemsNb () const
    void SetElemsNb (int theNbElems)
     Overrides the number of vertex attributes / number of vertexes. It is up to user specifying this number correct (e.g. below initial value)!
    unsigned int GetDataType () const
    uint8_t * GetDataOffset () const
    virtual bool Create (const occ::handle< OpenGl_Context > &theGlCtx)
     Creates buffer object name (id) if not yet generated. Data should be initialized by another method.
    void Release (OpenGl_Context *theGlCtx) override
     Destroy object - will release GPU memory if any.
    virtual void Bind (const occ::handle< OpenGl_Context > &theGlCtx) const
     Bind this buffer object.
    virtual void Unbind (const occ::handle< OpenGl_Context > &theGlCtx) const
     Unbind this buffer object.
    bool Init (const occ::handle< OpenGl_Context > &theGlCtx, const unsigned int theComponentsNb, const int theElemsNb, const float *theData)
     Notice that buffer object will be unbound after this call.
    bool Init (const occ::handle< OpenGl_Context > &theGlCtx, const unsigned int theComponentsNb, const int theElemsNb, const unsigned int *theData)
     Notice that buffer object will be unbound after this call.
    bool Init (const occ::handle< OpenGl_Context > &theGlCtx, const unsigned int theComponentsNb, const int theElemsNb, const unsigned short *theData)
     Notice that buffer object will be unbound after this call.
    bool Init (const occ::handle< OpenGl_Context > &theGlCtx, const unsigned int theComponentsNb, const int theElemsNb, const uint8_t *theData)
     Notice that buffer object will be unbound after this call.
    bool SubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, const float *theData)
     Notice that buffer object will be unbound after this call. Function replaces portion of data within this buffer object using glBufferSubData(). The buffer object should be initialized before call.
    bool GetSubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, float *theData)
     Read back buffer sub-range. Notice that buffer object will be unbound after this call. Function reads portion of data from this buffer object using glGetBufferSubData().
    bool SubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, const unsigned int *theData)
     Notice that buffer object will be unbound after this call. Function replaces portion of data within this buffer object using glBufferSubData(). The buffer object should be initialized before call.
    bool GetSubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, unsigned int *theData)
     Read back buffer sub-range. Notice that buffer object will be unbound after this call. Function reads portion of data from this buffer object using glGetBufferSubData().
    bool SubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, const unsigned short *theData)
     Notice that buffer object will be unbound after this call. Function replaces portion of data within this buffer object using glBufferSubData(). The buffer object should be initialized before call.
    bool GetSubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, unsigned short *theData)
     Read back buffer sub-range. Notice that buffer object will be unbound after this call. Function reads portion of data from this buffer object using glGetBufferSubData().
    bool SubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, const uint8_t *theData)
     Notice that buffer object will be unbound after this call. Function replaces portion of data within this buffer object using glBufferSubData(). The buffer object should be initialized before call.
    bool GetSubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, uint8_t *theData)
     Read back buffer sub-range. Notice that buffer object will be unbound after this call. Function reads portion of data from this buffer object using glGetBufferSubData().
    size_t EstimatedDataSize () const override
     offset to data
    virtual bool init (const occ::handle< OpenGl_Context > &theGlCtx, const unsigned int theComponentsNb, const int theElemsNb, const void *theData, const unsigned int theDataType, const int theStride)
     Initialize buffer with new data.
    bool init (const occ::handle< OpenGl_Context > &theGlCtx, const unsigned int theComponentsNb, const int theElemsNb, const void *theData, const unsigned int theDataType)
     Initialize buffer with new data.
    virtual bool subData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, const void *theData, const unsigned int theDataType)
     Update part of the buffer with new data.
    virtual bool getSubData (const occ::handle< OpenGl_Context > &theGlCtx, const int theElemFrom, const int theElemsNb, void *theData, const unsigned int theDataType)
     Read back buffer sub-range.
    Public Member Functions inherited from OpenGl_Resource
     OpenGl_Resource ()
     Empty constructor.
     ~OpenGl_Resource () override
     Destructor. Inheritors should call Clean (NULL) within it.
    Public Member Functions inherited from Standard_Transient
     Standard_Transient ()
     Empty constructor.
     Standard_Transient (const Standard_Transient &)
     Copy constructor – does nothing.
    Standard_Transientoperator= (const Standard_Transient &)
     Assignment operator, needed to avoid copying reference counter.
    virtual ~Standard_Transient ()=default
     Destructor must be virtual.
    virtual const opencascade::handle< Standard_Type > & DynamicType () const
     Returns a type descriptor about this object.
    bool IsInstance (const opencascade::handle< Standard_Type > &theType) const
     Returns a true value if this is an instance of Type.
    bool IsInstance (const char *const theTypeName) const
     Returns a true value if this is an instance of TypeName.
    bool IsKind (const opencascade::handle< Standard_Type > &theType) const
     Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
    bool IsKind (const char *const theTypeName) const
     Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
    Standard_TransientThis () const
     Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero.
    int GetRefCount () const noexcept
     Get the reference counter of this object.
    void IncrementRefCounter () noexcept
     Increments the reference counter of this object. Uses relaxed memory ordering since incrementing only requires atomicity, not synchronization with other memory operations.
    int DecrementRefCounter () noexcept
     Decrements the reference counter of this object; returns the decremented value. Uses release ordering for the decrement to ensure all writes to the object are visible before the count reaches zero. An acquire fence is added only when the count reaches zero, ensuring proper synchronization before deletion. This is more efficient than using acq_rel for every decrement.
    virtual void Delete () const
     Memory deallocator for transient classes.

    Additional Inherited Members

    typedef void base_type
     Returns a type descriptor about this object.
    Static Public Member Functions inherited from OpenGl_Buffer
    static TCollection_AsciiString FormatTarget (unsigned int theTarget)
     Format VBO target enumeration value.
    static size_t sizeOfGlType (unsigned int theType)
    static constexpr const char * get_type_name ()
     Returns a type descriptor about this object.
    static const opencascade::handle< Standard_Type > & get_type_descriptor ()
     Returns type descriptor of Standard_Transient class.
    Static Public Attributes inherited from OpenGl_Buffer
    static const unsigned int NO_BUFFER = 0
     Helpful constants.
    void BindBufferBase (const occ::handle< OpenGl_Context > &theGlCtx, unsigned int theIndex)
     Binds a buffer object to an indexed buffer target. Wrapper for glBindBufferBase().
    void UnbindBufferBase (const occ::handle< OpenGl_Context > &theGlCtx, unsigned int theIndex)
     Unbinds a buffer object from an indexed buffer target. Wrapper for glBindBufferBase().
    void BindBufferRange (const occ::handle< OpenGl_Context > &theGlCtx, unsigned int theIndex, const intptr_t theOffset, const size_t theSize)
     Binds a buffer object to an indexed buffer target with specified offset and size. Wrapper for glBindBufferRange().
    uint8_t * myOffset
     offset to data
    unsigned int myBufferId
     VBO name (index).
    unsigned int myComponentsNb
     Number of components per generic vertex attribute, must be 1, 2, 3, or 4.
    int myElemsNb
     Number of vertex attributes / number of vertices.
    unsigned int myDataType
     Data type (GL_FLOAT, GL_UNSIGNED_INT, GL_UNSIGNED_BYTE etc.).

    Detailed Description

    Index buffer is just a VBO with special target (GL_ELEMENT_ARRAY_BUFFER).

    Constructor & Destructor Documentation

    ◆ OpenGl_IndexBuffer()

    OpenGl_IndexBuffer::OpenGl_IndexBuffer ( )

    Empty constructor.

    Member Function Documentation

    ◆ DumpJson()

    void OpenGl_IndexBuffer::DumpJson ( Standard_OStream & theOStream,
    int theDepth = -1 ) const
    overridevirtual

    Dumps the content of me into the stream.

    Reimplemented from OpenGl_Buffer.

    ◆ GetTarget()

    unsigned int OpenGl_IndexBuffer::GetTarget ( ) const
    overridevirtual

    Return buffer object target (GL_ELEMENT_ARRAY_BUFFER).

    Implements OpenGl_Buffer.


    The documentation for this class was generated from the following file: