OgreGL3PlusHardwareOcclusionQuery.h

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/*
The nVidia occlusion query extension is defined in glext.h so you don't 
need anything else. You do need to look up the function, we provide a 
GL3PlusSupport class to do this, which has platform implementations for 
getProcAddress. Check the way that extensions like glActiveTextureARB are 
initialised and used in glRenderSystem and copy what is done there.

  To do: fix so dx7 and DX9 checks and flags if HW Occlusion is supported
  See the openGl dito for ideas what to do.
*/

#ifndef __GL3PlusHARDWAREOCCLUSIONQUERY_H__
#define __GL3PlusHARDWAREOCCLUSIONQUERY_H__

#include "OgreGL3PlusPrerequisites.h"
#include "OgreHardwareOcclusionQuery.h"


namespace Ogre { 


// If you use multiple rendering passes you can test only the first pass and all other passes don't have to be rendered 
// if the first pass result has too few pixels visible.

// Be sure to render all occluder first and whats out so the RenderQue don't switch places on 
// the occluding objects and the tested objects because it thinks it's more effective..


class _OgreGL3PlusExport GL3PlusHardwareOcclusionQuery : public HardwareOcclusionQuery
{
//----------------------------------------------------------------------
// Public methods
//--
public:
    GL3PlusHardwareOcclusionQuery();
    ~GL3PlusHardwareOcclusionQuery();

    //------------------------------------------------------------------
    // Occlusion query functions (see base class documentation for this)
    //--
    void beginOcclusionQuery();
    void endOcclusionQuery();
    bool pullOcclusionQuery(unsigned int* NumOfFragments);
    bool isStillOutstanding(void);

    private:
        GLuint mQueryID;
};

}

#endif