/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org

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Permission is hereby granted, free of charge, to any person obtaining a copy
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in the Software without restriction, including without limitation the rights
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The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

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THE SOFTWARE.
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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 
GLSupport 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.

*/



//GL_ActiveTextureARB_Func* glActiveTextureARB_ptr = (GL_ActiveTextureARB_Func)mGLSupport->getProcAddress("glActiveTextureARB");

#ifndef __GLHARDWAREOCCLUSIONQUERY_H__
#define __GLHARDWAREOCCLUSIONQUERY_H__

#include "OgreGLPrerequisites.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..


/**
  * This is a class that is the base class of the query class for 
  * hardware occlusion.
  *
  * @author Lee Sandberg email: lee@abcmedia.se
  * Updated on 13/9/2005 by Tuan Kuranes email: tuan.kuranes@free.fr
  */

class _OgreGLExport GLHardwareOcclusionQuery : public HardwareOcclusionQuery
{
//----------------------------------------------------------------------
// Public methods
//--
public:
	/**
	  * Default object constructor
	  * 
	  */
	GLHardwareOcclusionQuery();
	/**
	  * Object destructor
	  */
	~GLHardwareOcclusionQuery();

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


    //----------------------------------------------------------------------
    // private members
    //--
    private:

	    GLuint			mQueryID;
};

}

#endif 

