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# OgreGLHardwareOcclusionQuery.h

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    00001 /*
    00002 -----------------------------------------------------------------------------
    00003 This source file is part of OGRE
    00004     (Object-oriented Graphics Rendering Engine)
    00005 For the latest info, see http://ogre.sourceforge.net/
    00006
    00007 Copyright © 2000-2003 The OGRE Team
    00008 Also see acknowledgements in Readme.html
    00009
    00010 This program is free software; you can redistribute it and/or modify it under
    00011 the terms of the GNU Lesser General Public License as published by the Free Software
    00012 Foundation; either version 2 of the License, or (at your option) any later
    00013 version.
    00014
    00015 This program is distributed in the hope that it will be useful, but WITHOUT
    00016 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    00017 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
    00018
    00019 You should have received a copy of the GNU Lesser General Public License along with
    00020 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
    00021 Place - Suite 330, Boston, MA 02111-1307, USA, or go to
    00022 http://www.gnu.org/copyleft/lesser.txt.
    00023 -----------------------------------------------------------------------------
    00024 */
    00025
    00026 /*
    00027 The nVidia occlusion query extension is defined in glext.h so you don't
    00028 need anything else. You do need to look up the function, we provide a
    00029 GLSupport class to do this, which has platform implementations for
    00030 getProcAddress. Check the way that extensions like glActiveTextureARB are
    00031 initialised and used in glRenderSystem and copy what is done there.
    00032
    00033
    00034
    00035   To do: fix so dx7 and DX9 checks and flags if HW Occlusion is supported
    00036   See the openGl dito for ideas what to do.
    00037
    00038 */
    00039
    00040
    00041
    00042 //GL_ActiveTextureARB_Func* glActiveTextureARB_ptr = (GL_ActiveTextureARB_Func)mGLSupport->getProcAddress("glActiveTextureARB");
    00043
    00044 #ifndef __GLHARDWAREOCCLUSIONQUERY_H__
    00045 #define __GLHARDWAREOCCLUSIONQUERY_H__
    00046
    00047 #include "OgreGLPrerequisites.h"
    00048 #include "OgreHardwareOcclusionQuery.h"
    00049
    00050
    00051 namespace Ogre {
    00052
    00053
    00054 // If you use multiple rendering passes you can test only the first pass and all other passes don't have to be rendered
    00055 // if the first pass resultet has too few pixels visable.
    00056
    00057 // Be sure to render all occlluder first and whats out so the RenderQue don't switch places on
    00058 // the occluding objects and the tested objects because it thinks it's more effective..
    00059
    00060
    00068 class GLHardwareOcclusionQuery : public HardwareOcclusionQuery
    00069 {
    00070 //----------------------------------------------------------------------
    00071 // Public methods
    00072 //--
    00073 public:
    00078     GLHardwareOcclusionQuery();
    00082     ~GLHardwareOcclusionQuery();
    00083
    00084     //------------------------------------------------------------------
    00085     // Occlusion query functions (see base class documentation for this)
    00086     //--
    00087
    00088     void beginOcclusionQuery();
    00089     void endOcclusionQuery();
    00090     bool pullOcclusionQuery( unsigned int* NumOfFragments);
    00091     bool pullOcclusionQuery( unsigned int* NumOfFragments, const HW_OCCLUSIONQUERY flag  );
    00092     unsigned int getLastQuerysPixelcount() { return m_uintPixelCount; }
    00093
    00094     // This functions are optional, it's a simple filter that simply skipps some hardware occlusion tests on visable objects only
    00095     // It's easy to use if you don't have to keep track on which objects are visable (can be skipped) and what objects arn't visable..
    00096     // (None visable objects and object you introduce for the first time have allways to be tested allthough the cheepest possible
    00097     // LOD (Level Of Detail) mesh and material wize).
    00098
    00109     void setSkipRate( int skip ) { m_Skip = skip; }     // Using 2 only 50 % of the tests are actully made and 3 results in only 33% of the tests. So on.
    00110     int  getSkipRate() { return m_Skip; }
    00111
    00112
    00113 //----------------------------------------------------------------------
    00114 // Protected members
    00115 //--
    00116 protected:
    00117
    00118     unsigned int    m_uintPixelCount;
    00119     unsigned int    m_uintQuery[1];
    00120     bool            m_bOcclusionQuery;
    00121     int             m_SkipCounter;      // m_SkipConter =  m_SkipConter % m_Skip; if ( m_SkipConter == 0 && m_uintPixelCount !=0 ) TestHWOcclusion else just return
    00122     static int      m_Skip;             // This is shared by all instancies
    00123     bool            m_bHWOcclusionSupport;
    00124 };
    00125
    00126
    00127 }
    00128
    00129 #endif
    00130

Copyright © 2002-2003 by The OGRE Team
Last modified Sun Nov 28 19:48:25 2004