source: GTP/trunk/Lib/Vis/OnlineCullingCHC/OGRE/src/OgrePlatformQueryManager.cpp @ 2455

#include "OgrePlatformQueryManager.h"
#include "OcclusionQuery.h"
#include <OgreSceneManager.h>
#include <OgreLogManager.h>
#include <OgreStringConverter.h>
#include <vector>
#include <OgreSubEntity.h>
#include "OgrePlatformHierarchyInterface.h"



namespace Ogre {


//-----------------------------------------------------------------------
void PlatformQueryManager::ComputeFromPointVisibility(
                                                                                        const Vector3 &point,
                                                                                        NodeInfoContainer *visibleNodes,
                                                                                        MeshInfoContainer *visibleGeometry,
                                                                                        PatchInfoContainer *visiblePatches,
                                                                                        const bool relativeVisibility,
                                                                                        const bool approximateVisibility)
{
        SceneManager *sm = static_cast<PlatformHierarchyInterface *>
                                                                (mHierarchyInterface)->GetSceneManager();

        // create a camera for the point query
        Camera *cam = sm->createCamera("PointQueryCam");        

        //save old camera
        Camera *savedCam = mViewport->getCamera();
        
        
        //////////////
        //-- initialise new camera

        mViewport->setCamera(cam);
        cam->setPosition(point);

        cam->setNearClipDistance(savedCam->getNearClipDistance());
        cam->setFarClipDistance(savedCam->getFarClipDistance());

        // set frustum to 45 degrees so all the scene can be captured with 6 shots
        cam->setAspectRatio(1.0);
        cam->setFOVy(Radian(Math::HALF_PI));

        int sign = -1;
        
        ///////////////
        //-- capture visibility from all 6 directions

        for (int dir=0; dir < 6; dir++) 
        {
                sign *= -1;
                
                // Print camera details
        if (0)
                {
                        std::stringstream d;
                        d << "Point query camera: " + StringConverter::toString(cam->getDerivedPosition()) + 
                                " " + "O: " + StringConverter::toString(cam->getDerivedOrientation());
                        LogManager::getSingleton().logMessage(d.str());
                }

                // prevent from initialising geometry / node array again
                if (dir > 0)
                {
                        mWasInitialised = true;
                }

                ComputeCameraVisibility(*cam, 
                                                                visibleNodes, 
                                                                visibleGeometry, 
                                                                visiblePatches, 
                                            relativeVisibility,
                                                                approximateVisibility);

                // permute directions
                Vector3 direction(0,0,0);
                direction[dir / 2] = sign;

                cam->setDirection(direction);
        }
        
        // reset camera
        mViewport->setCamera(savedCam);
}
//-----------------------------------------------------------------------
void PlatformQueryManager::ComputeCameraVisibility(
                                                                        const Camera &camera,
                                                                        NodeInfoContainer *visibleNodes,
                                                                        MeshInfoContainer *visibleGeometry,
                                                                        PatchInfoContainer *visiblePatches,
                                                                        const bool relativeVisibility,
                                                                        const bool approximateVisibility)
{
        // we need access to the scene manager and the rendersystem
        PlatformHierarchyInterface *pfHierarchyInterface = 
                static_cast<PlatformHierarchyInterface *>(mHierarchyInterface);

        SceneManager *sm = pfHierarchyInterface->GetSceneManager();


        // const_cast allowed because camera is not changed in renderScene
        Camera *pCam = const_cast<Camera *>(&camera); 

        // disable overlays, reset them later
        bool overlayEnabled = mViewport->getOverlaysEnabled();
        mViewport->setOverlaysEnabled(false);
        
        // clear background with black (i.e., not a valid item id)
        ColourValue bg = mViewport->getBackgroundColour();
        mViewport->setBackgroundColour(ColourValue(0, 0, 0, 0));
        //pfHierarchyInterface->GetRenderSystem()->clearFrameBuffer(FBT_COLOUR | FBT_DEPTH);

#ifdef ITEM_BUFFER
        // initialise item buffer (if not already initialised)
        InitItemBuffer(visibleGeometry, visiblePatches);

        //////////
        //-- render scene with item buffer (i.e., objects with their id as color codes)

        // enable item buffer (must be provided by scene manager)
        bool useItemBuffer = true;
        sm->setOption("UseItemBuffer", &useItemBuffer);
#endif // ITEM_BUFFER

        sm->_renderScene(pCam, mViewport, false); // render item buffer
   
#ifdef ITEM_BUFFER
        /////////
        //-- collect results
        CollectItemBufferResults(visibleGeometry, visiblePatches);

        /////////
        //-- reset state
        useItemBuffer = false; // don't need item buffer anymore
        sm->setOption("UseItemBuffer", &useItemBuffer);
#endif // ITEM_BUFFER

        mWasInitialised = false; // reset initialised - flag
        mViewport->setOverlaysEnabled(overlayEnabled); // reset old overlay status
        mViewport->setBackgroundColour(bg); // reset background color
}
#ifdef ITEM_BUFFER
//-----------------------------------------------------------------------
void PlatformQueryManager::CollectItemBufferResults(
                                MeshInfoContainer *visibleGeometry,
                                PatchInfoContainer *visiblePatches)
{
        int dimx = 0;
        int dimy = 0;

        // copy frame buffer 
        uchar *buf = mViewport->getTarget()->getBufferContents(dimx, dimy);

        // loop through frame buffer and collect visible pixels
        for (int idx = 0; idx < dimy * dimx * 3; idx += 3)
        {
                //-- decode color code to receive id
                int id = buf[idx] << 16;
                id += buf[idx + 1] << 8;
                id += buf[idx + 2];

                // if valid id <= add visibility (id values start at 1)
                if (mQueryModes == PATCH_VISIBILITY)
                {       
                        if ((id > 0) && (id < (int)visiblePatches->size()))
                        {
                                ((*visiblePatches)[id]).AddVisibility(1, 0);
                        }
                }
                else if (mQueryModes == GEOMETRY_VISIBILITY)
                {
                        if ((id > 0) && (id < (int)visibleGeometry->size()))
                        {
                                ((*visibleGeometry)[id]).AddVisibility(1, 0);
                        }
                }
        }

        delete [] buf;
}

//-----------------------------------------------------------------------
void PlatformQueryManager::InitItemBuffer(
                                MeshInfoContainer *visibleGeometry,
                                PatchInfoContainer *visiblePatches)
{
        if (mWasInitialised)
                return;

        mWasInitialised = true;

        SceneManager *sm = 
                //static_cast<PlatformHierarchyInterface *>(mHierarchyInterface)->GetSceneManager();
                static_cast<PlatformHierarchyInterface *>(mHierarchyInterface)->GetSceneManager();

        SceneManager::EntityIterator it = sm->getEntityIterator();

        // TODO: make the function more efficient

        visibleGeometry->clear();
        visiblePatches->clear();

        int id = 0;

        /* We can either use patches or meshes. If patches are used, an unique id must
           be given each patch. Otherwise the same id must be given to all patches belonging
           to the same mesh.
    */
        while (it.hasMoreElements())
        {
                Entity *ent = it.getNext();

                for (int i = 0; i < (int)ent->getNumSubEntities(); ++i)
                {
                        SubEntity *subEnt = ent->getSubEntity(i);

                        if (mQueryModes == PATCH_VISIBILITY)
                        {
                                ++ id;
                                visiblePatches->push_back(GtpVisibility::PatchInfo(subEnt, 0, 0));
                        }
                                
                        subEnt->setId(id);
                        //subEnt->setId((41 << 16) + (4 << 8) + 60);
                }
                        
                if (mQueryModes == GEOMETRY_VISIBILITY)
                {
                        visibleGeometry->push_back(GtpVisibility::MeshInfo(ent, 0, 0));
                        ++ id;
                }
        }
}
#endif // ITEM_BUFFER
//-----------------------------------------------------------------------
void PlatformQueryManager::SetViewport(Viewport *vp)
{
        mViewport = vp;
}
} // namespace Ogre