source: GTP/trunk/Lib/Vis/OnlineCullingCHC/OGRE/src/OgreItemBufferQueryManager.cpp @ 171

#include "OgreItemBufferQueryManager.h"
#include <OgreLogManager.h>
#include <OgreStringConverter.h>
#include <vector>
#include <OgreSubEntity.h>

namespace Ogre {

//----------------------------------------------------------------------- 
ItemBufferQueryManager::ItemBufferQueryManager(PlatformHierarchyInterface *hierarchyInterface, 
                                                                                           Viewport *vp,
                                                                                           const bool renderPatches):
PlatformQueryManager(hierarchyInterface, vp), mRenderPatchesForItemBuffer(renderPatches)
{
}
//-----------------------------------------------------------------------
void ItemBufferQueryManager::ComputeCameraVisibility(const Camera &camera,
                            InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
                            InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry,
                                InfoContainer<GtpVisibility::PatchInfo> *visiblePatches,
                            bool relativeVisibility)
{
        // we need access to the scene manager and the rendersystem
        PlatformHierarchyInterface *pfHierarchyInterface = 
                dynamic_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);


        //-- 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);
        sm->_renderScene(pCam, mViewport, false); // render item buffer
   

        //-- collect results
        
        // initialise item buffer (if not already initialised)
        InitItemBuffer(visibleNodes, visibleGeometry, visiblePatches);

        int dimx = 0;
        int dimy = 0;

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

        int n = mRenderPatchesForItemBuffer ? 
                (int)visiblePatches->size() : (int)visibleGeometry->size();

        //std::stringstream d; d << "dimx: " << dimx << ", dimy: " << dimy; LogManager::getSingleton().logMessage(d.str());

        // 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];

                //std::stringstream d; d << "myid: " << (int)buf[idx] << " " << (int)buf[idx + 1] << " " << (int)buf[idx + 2]; LogManager::getSingleton().logMessage(d.str());

                // if valid id <= add visibility (id values start at 1)
                if ((id > 0) && (id < n))
                {
                        if (mRenderPatchesForItemBuffer)
                        {
                                ((*visiblePatches)[id]).AddVisibility(1, 1);
                        }
                        else
                        {
                                ((*visibleGeometry)[id]).AddVisibility(1, 1);
                        }
                }
        }


        //-- reset options

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

        mWasInitialised = false; // reset initialised - flag
        mViewport->setOverlaysEnabled(overlayEnabled); // reset old overlay status
        mViewport->setBackgroundColour(bg); // reset background color

        delete [] buf;  // delete copy of the frame buffer
}
//-----------------------------------------------------------------------
void ItemBufferQueryManager::InitItemBuffer(
                                InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
                            InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry,
                                InfoContainer<GtpVisibility::PatchInfo> *visiblePatches)
{
        if (mWasInitialised)
                return;

        mWasInitialised = true;

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

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

        // TODO: make this more efficient
        visibleGeometry->clear();
        visibleNodes->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 (mRenderPatchesForItemBuffer)
                        {
                                ++ id;
                                visiblePatches->push_back(GtpVisibility::PatchInfo(subEnt, 0, 0));
                        }
                                
                        subEnt->setId(id);
                        //subEnt->setId((41 << 16) + (4 << 8) + 60);
                        //subEnt->setId((2 << 16) + (4 << 8) + 60);
                }
                        
                if (!mRenderPatchesForItemBuffer)
                {
                        visibleGeometry->push_back(GtpVisibility::MeshInfo(ent, 0, 0));
                        ++ id;
                }
        }
}

/*
//-----------------------------------------------------------------------
Entity* VisibilityOctreeSceneManager::createEntity(const String& entityName, 
                                                                                                        const String& meshName)
{
        Entity *ent = SceneManager::createEntity(entityName, meshName);

        for (int i = 0; i < (int)ent->getNumSubEntities(); ++i)
        {
                ent->getSubEntity(i)->setId(mCurrentEntityId);
        }

        // increase counter of entity id values
        ++ mCurrentEntityId;

        return ent;
}
*/
} // namespace Ogre