source: trunk/VUT/Ogre/src/OgreOcclusionQueriesQueryManager.cpp @ 155

#include "OgreOcclusionQueriesQueryManager.h"
#include <OgreLogManager.h>
#include <OgreStringConverter.h>
#include <vector>


namespace Ogre {
//----------------------------------------------------------------------- 
OcclusionQueriesQueryManager::OcclusionQueriesQueryManager(PlatformHierarchyInterface *hierarchyInterface, Viewport *vp):
PlatformQueryManager(hierarchyInterface, vp)
{
}
//-----------------------------------------------------------------------
bool OcclusionQueriesQueryManager::ShootRay(const Ray &ray, std::vector<Mesh *> *visibleMeshes, bool isGlobalLine)
{
    // run OGRE ray shooting query
    return false;
}
//-----------------------------------------------------------------------
void OcclusionQueriesQueryManager::ComputeCameraVisibility(const Camera &camera,
                            InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
                            InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry,
                            bool relativeVisibility)
{
        // we need access to the scene manager and the rendersystem
        PlatformHierarchyInterface *pfHierarchyInterface = 
                dynamic_cast<PlatformHierarchyInterface *>(mHierarchyInterface);

        //-- Render scene to get conservative visibility and fill depth buffer 

        // 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);

        //-- render the scene once to update depth buffer
        pfHierarchyInterface->GetSceneManager()->_renderScene(pCam, mViewport, false);

        /* 
                Two query lists for projected pixels and for visibile pixels:
                We test queries after a rendering pass 
                to get exact visibility with regard to the current camera.
                We issue all queries at once to avoid starvation & stalls.
        */
        GtpVisibility::QueryList queryList[2];
        
        // get rendered hierarchy nodes
        GtpVisibility::HierarchyNodeList *nodeList = mHierarchyInterface->GetRenderedNodes();
        // vector for storing entities of meshes
        GtpVisibility::GeometryList geometryList;
        
        GtpVisibility::HierarchyNodeList::iterator nodeIt, nodeIt_end = nodeList->end();
        // geometry list has still do be built
        GtpVisibility::GeometryList::iterator geometryIt, geometryIt_end;

        // to obtain the correct number of projected pixels, depth write must be disabled
        bool enableDepthWrite = false;

        // this option must be provided by the scene manager
        pfHierarchyInterface->GetSceneManager()->setOption("DepthWrite", &enableDepthWrite);

        /* relative visiblity:
                1) get visible pixels count of objects
                2) clear frame buffer
                3) get projected visible pixels count:
                   test all objects again without depth write (set as option in scene manager)
                4) calculate ratio between visible vs. projected pixels
        */
        // for relative visibility we need 2 rendering passes
        int n = relativeVisibility ? 2 : 1;
        
        for (int i=0; i<n; ++i)
        {
                //-- queries for hierarchy nodes
                for (nodeIt = nodeList->begin(); nodeIt != nodeIt_end; ++nodeIt)                
                {
                        // TODO: DELETE QUERIES FROM PREVIOUS RENDER
                        queryList[i].push_back(mHierarchyInterface->IssueOcclusionQuery(*nodeIt, false));
                        
                        // store geometry of the hierarchy node in a geometry list (only once!)
                        if (i == 0)
                        {
                                mHierarchyInterface->GetNodeGeometryList(*nodeIt, &geometryList, false);
                        }
                }

                geometryIt_end = geometryList.end();

                //-- add queries for geometry
                for (geometryIt = geometryList.begin(); geometryIt != geometryIt_end; ++geometryIt)
                {
                        queryList[i].push_back(mHierarchyInterface->IssueOcclusionQuery(*geometryIt));
                }

        
                pfHierarchyInterface->GetRenderSystem()->clearFrameBuffer(FBT_DEPTH);
        }

        enableDepthWrite = true;
        // this option must be provided by the scene manager
        pfHierarchyInterface->GetSceneManager()->setOption("DepthWrite", &enableDepthWrite);
        // reset old overlay status
        mViewport->setOverlaysEnabled(overlayEnabled);

        // ---- collect results
        GtpVisibility::QueryList::iterator visQueryIt, projQueryIt;

        visQueryIt = queryList[0].begin();
        projQueryIt = queryList[1].begin();

        
        for (nodeIt = nodeList->begin(); nodeIt != nodeIt_end; ++nodeIt)
        {
                unsigned int visiblePixels = 0;
                (*visQueryIt)->GetQueryResult(visiblePixels, true);
        
                unsigned int projectedPixels = 0;

                if (relativeVisibility)
                {
                        (*projQueryIt)->GetQueryResult(projectedPixels, true);
                
                        ++projQueryIt;
                }

                ++visQueryIt;
                
                // node with visibilty 0 in queue (e.g., if node is intersected by near plane)
                if (visiblePixels > 0)
                {
                        visibleNodes->push_back(GtpVisibility::NodeInfo(*nodeIt, visiblePixels, projectedPixels));
                }
        }

        // ---- queries for geometry
        geometryIt_end = geometryList.end();
        
        for (geometryIt = geometryList.begin(); geometryIt != geometryIt_end; ++geometryIt)
        {
                unsigned int visiblePixels = 0;
                (*visQueryIt)->GetQueryResult(visiblePixels, true);
                
                unsigned int projectedPixels = 0;

                if (relativeVisibility)
                {
                        (*projQueryIt)->GetQueryResult(projectedPixels, true);

                        ++projQueryIt;
                }

                ++visQueryIt;

                // WARNING: approximate depth ordering during rendering => 
                // geometry maybe occluded
                if (visiblePixels > 0)
                {                        
                        visibleGeometry->push_back(GtpVisibility::MeshInfo(*geometryIt, visiblePixels, 
                                projectedPixels));
                }
        }

}
//-----------------------------------------------------------------------
inline bool nodeinfo_eq(const GtpVisibility::NodeInfo &info1, const GtpVisibility::NodeInfo &info2) 
{ 
        return info1.GetNode() == info2.GetNode(); 
}
//-----------------------------------------------------------------------
inline bool meshinfo_eq(const GtpVisibility::MeshInfo &info1, const GtpVisibility::MeshInfo &info2) 
{ 
        return info1.GetMesh() == info2.GetMesh(); 
}
//-----------------------------------------------------------------------
inline bool nodeinfo_lower(const GtpVisibility::NodeInfo &info1, const GtpVisibility::NodeInfo &info2) 
{ 
        return info1.GetNode() < info2.GetNode(); 
}
//-----------------------------------------------------------------------
inline bool meshinfo_lower(const GtpVisibility::MeshInfo &info1, const GtpVisibility::MeshInfo &info2) 
{ 
        return info1.GetMesh() < info2.GetMesh(); 
}
//-----------------------------------------------------------------------
void OcclusionQueriesQueryManager::ComputeFromPointVisibility(const Vector3 &point,
                               InfoContainer<GtpVisibility::NodeInfo> *visibleNodes,
                               InfoContainer<GtpVisibility::MeshInfo> *visibleGeometry,
                               bool relativeVisibility)
{
        PlatformQueryManager::ComputeFromPointVisibility(point, visibleNodes, visibleGeometry, relativeVisibility);

        // --- remove duplicates (duplicates occur if an object is on the edge of the viewport)

        // before duplicates can be deleted we have to add up their visibility

        // --- visible nodes
        sort(visibleNodes->begin(), visibleNodes->end(), nodeinfo_lower);
        InfoContainer<GtpVisibility::NodeInfo>::iterator visibleNodesIt,
                visibleNodesIt_end = visibleNodes->end();
        
        GtpVisibility::NodeInfo *nodeInfo = NULL;

        for (visibleNodesIt = visibleNodes->begin(); visibleNodesIt != visibleNodesIt_end; 
                ++visibleNodesIt)
        {
                if (!nodeInfo || (nodeInfo->GetNode() != (*visibleNodesIt).GetNode()))
                {
                        nodeInfo = &(*visibleNodesIt);
                }
                else // add visibility
                {                       
                        nodeInfo->AddVisibility(*visibleNodesIt);
                }

        }
        
        // physically delete duplicates
        visibleNodes->erase( std::unique(visibleNodes->begin(), 
                visibleNodes->end(), nodeinfo_eq), visibleNodes->end());

        // --- visible geometry
        sort(visibleGeometry->begin(), visibleGeometry->end(), meshinfo_lower);
        InfoContainer<GtpVisibility::MeshInfo>::iterator visibleGeomIt,
                visibleGeomIt_end = visibleGeometry->end();

        GtpVisibility::MeshInfo *geomInfo = NULL;

        int i=0;
        for (visibleGeomIt = visibleGeometry->begin(); visibleGeomIt != visibleGeomIt_end; 
                ++visibleGeomIt)
        {
                if (!geomInfo || (geomInfo->GetMesh() != (*visibleGeomIt).GetMesh()))
                {
                        geomInfo = &(*visibleGeomIt);
                }
                else // info points to same mesh, just add visibility
                {
                        geomInfo->AddVisibility(*visibleGeomIt);
                }
        }

        // physically delete duplicates
        visibleGeometry->erase(std::unique(visibleGeometry->begin(), visibleGeometry->end(), 
                meshinfo_eq), visibleGeometry->end());
}

} // namespace Ogre