source: trunk/VUT/Ogre/src/OgreItemBufferQueryManager.cpp @ 159

#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)
{
}
//-----------------------------------------------------------------------
bool ItemBufferQueryManager::ShootRay(const Ray &ray, std::vector<Mesh *> *visibleMeshes, bool isGlobalLine)
{
    // run OGRE ray shooting query
    return false;
}
//-----------------------------------------------------------------------
void ItemBufferQueryManager::ComputeCameraVisibility(const Camera &camera,
                            InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
                            InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry,
                                InfoContainer<GtpVisibility::PatchInfo> *visiblePatches,
                            bool relativeVisibility)
{
        // initialise item buffer (if not already initialised)
        InitItemBuffer(visibleNodes, visibleGeometry, visiblePatches);

        // we need access to the scene manager and the rendersystem
        PlatformHierarchyInterface *pfHierarchyInterface = 
                dynamic_cast<PlatformHierarchyInterface *>(mHierarchyInterface);

        SceneManager *sm = pfHierarchyInterface->GetSceneManager();

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

        // 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);

        // set item buffer (must be provided by scene manager)
        bool useItemBuffer = true;
        sm->setOption("UseItemBuffer", &useItemBuffer);
        
        // clear background with black (i.e., not a valid item id)
        ColourValue bg = mViewport->getBackgroundColour();
        mViewport->setBackgroundColour(ColourValue(0, 0, 0, 0));


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


        //---- collect results
        int dimx = 0;
        int dimy = 0;

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

        int n = mRenderPatchesForItemBuffer ? (int)visiblePatches->size() : (int)visibleGeometry->size();
        
        // loop through frame buffer & 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 ((id > 0) && (id < n))
                {
                        if (mRenderPatchesForItemBuffer)
                        {
                                ((*visiblePatches)[id]).AddVisibility(1, 1);
                        }
                        else
                        {
                                ((*visibleGeometry)[id]).AddVisibility(1, 1);
                        }
                }
        }

        //-- reset options

        // don't need item buffer anymore
        useItemBuffer = false;
        sm->setOption("UseItemBuffer", &useItemBuffer);
        // reset initialised - flag
        mWasInitialised = false;
        // reset old overlay status
        mViewport->setOverlaysEnabled(overlayEnabled);
        // reset background color
        mViewport->setBackgroundColour(bg);

        // delete array storing the frame buffer
        delete [] buf;
}
//-----------------------------------------------------------------------
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);
                }
                        
                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