India/cocos2d-x/cocos/renderer/CCVertexIndexBuffer.h

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 Copyright (c) 2013-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#ifndef __CC_VERTEX_INDEX_BUFFER_H__
#define __CC_VERTEX_INDEX_BUFFER_H__

#include <vector>
#include "base/CCRef.h"
#include "platform/CCGL.h"

/**
 * @addtogroup renderer
 * @{
 */

NS_CC_BEGIN

class EventListenerCustom;

/**
VertexBuffer is an abstraction of low level openGL Vertex Buffer Object.
It is used to save an array of vertices.
*@js NA
*/
class CC_DLL VertexBuffer : public Ref
{
public:
    /**
    Create an instance of VertexBuffer.
    @param sizePerVertex Size in bytes of one vertex.
    @param vertexNumber The number of vertex.
    @param usage A hint to indicate whether the vertexBuffer are updated frequently or not to let GL optimise it.
    */
    static VertexBuffer* create(int sizePerVertex, int vertexNumber, GLenum usage = GL_STATIC_DRAW);
    /**Get the size in bytes of one vertex.*/
    int getSizePerVertex() const;
    /**Get the number of vertices.*/
    int getVertexNumber() const;
    /**
    Update all or part of vertices data, if the range specified exceeds the vertex buffer, it will be clipped.
    @param verts The pointer of the vertex data.
    @param count The number of vertices to update.
    @param begin The first vertex to update.
    */
    bool updateVertices(const void* verts, int count, int begin);

    /**
    Get the size of the vertex array in bytes, equals getSizePerVertex() * getVertexNumber().
    */
    int getSize() const;
    /**
    Get the internal openGL handle.
    */
    GLuint getVBO() const;
    
protected:
    /**
    Constructor.
    */
    VertexBuffer();
    /**
    Destructor.
    */
    virtual ~VertexBuffer();
    /**
    Init the storage of vertex buffer.
    @param sizePerVertex Size in bytes of one vertex.
    @param vertexNumber The number of vertex.
    @param usage A hint to indicate whether the vertexBuffer are updated frequently or not to let GL optimise it.
    */
    bool init(int sizePerVertex, int vertexNumber, GLenum usage = GL_STATIC_DRAW);
protected:
    /**
    Event handler for foreground.
    */
    void recreateVBO() const;
    /**
    Event listener for foreground.
    */
    EventListenerCustom* _recreateVBOEventListener;
protected:
    /**
    Internal handle for openGL.
    */
    mutable GLuint _vbo;
    /**
    Size in bytes for one vertex.
    */
    int _sizePerVertex;
    /**
    Number of vertices.
    */
    int _vertexNumber;
    /**
    Buffer used for shadow copy.
    */
    std::vector<unsigned char> _shadowCopy;
    /**
    Hint for optimisation in GL.
    */
    GLenum _usage;
protected:
    /**
    Static member to indicate that use _shadowCopy or not. 
    */
    static bool _enableShadowCopy;
public:
    /**
    Static getter for shadowCopy.
    */
    static bool isShadowCopyEnabled() { return _enableShadowCopy; }
    /**
     Static setter for shadowCopy.
     */
    static void enableShadowCopy(bool enabled) { _enableShadowCopy = enabled; }
};

/**
IndexBuffer is an abstraction of low level openGL Buffer Object.
It used to save an array of indices.
@js NA
*/
class CC_DLL IndexBuffer : public Ref
{
public:
    /**
    Enum for the type of index, short indices and int indices could be used.
    */
    enum class IndexType
    {
        /**Short index will be used.*/
        INDEX_TYPE_SHORT_16,
        /**Int index will be used.*/
        INDEX_TYPE_UINT_32
    };
    
public:
    /**
    Create an instance of IndexBuffer.
    @param type type of index.
    @param number The number of indices.
    @param usage A hint to indicate whether the vertexBuffer are updated frequently or not to let GL optimise it.
    */
    static IndexBuffer* create(IndexType type, int number, GLenum usage = GL_STATIC_DRAW);
    /**
    Getter for type of indices.
    */
    IndexType getType() const;
    /**
    Get the size in bytes for one index, will be 2 for INDEX_TYPE_SHORT_16 and 4 for INDEX_TYPE_UINT_32.
    */
    int getSizePerIndex() const;
    /**
    Get the number of indices.
    */
    int getIndexNumber() const;
    /**
    Update all or part of indices data, if the range specified exceeds the vertex buffer, it will be clipped.
    @param indices The pointer of the index data.
    @param count The number of indices to update.
    @param begin The start index to update.
    */
    bool updateIndices(const void* indices, int count, int begin);
    /**
    Get the size in bytes of the array of indices.
    */
    int getSize() const;
    /**
    Get the openGL handle for index buffer.
    */
    GLuint getVBO() const;

protected:
    /**
    Constructor.
    */
    IndexBuffer();
    /**
    Destructor.
    */
    virtual ~IndexBuffer();
    /**
    Init the storageof IndexBuffer.
    @param type type of index.
    @param number The number of indices.
    @param usage A hint to indicate whether the vertexBuffer are updated frequently or not to let GL optimise it.
    */
    bool init(IndexType type, int number, GLenum usage = GL_STATIC_DRAW);
    
protected:
    /**
    Handle for openGL.
    */
    mutable GLuint _vbo;
    /**
    Type for index.
    */
    IndexType _type;
    /**
    Number of indices.
    */
    int _indexNumber;
    
protected:
    /**
    Event handler for foreground.
    */
    void recreateVBO() const;
    /**
    Event listener for foreground.
    */
    EventListenerCustom* _recreateVBOEventListener;
    /**
    Buffer used for shadow copy.
    */
    std::vector<unsigned char> _shadowCopy;
    /**
    Hint for optimisation in GL.
    */
    GLenum _usage;
protected:
    /**
    Static member to indicate that use _shadowCopy or not.
    */
    static bool _enableShadowCopy;
public:
    /**
    Static getter for shadowCopy.
    */
    static bool isShadowCopyEnabled() { return _enableShadowCopy; }
    /**
     Static setter for shadowCopy.
     */
    static void enableShadowCopy(bool enabled) { _enableShadowCopy = enabled; }
};


NS_CC_END

/**
 end of support group
 @}
 */
#endif /* __CC_VERTEX_INDEX_BUFFER_H__*/