source: trunk/VUT/OcclusionCullingSceneManager/src/OgreOcclusionCullingTerrainSceneTraverser.cpp @ 44

#include "OgreOcclusionCullingTerrainSceneTraverser.h"
#include "OgreOcclusionCullingTerrainSceneManager.h"
#include "OgreHardwareOcclusionQuery.h"

#include <windows.h>

namespace Ogre {
        //-----------------------------------------------------------------------
        OcclusionCullingTerrainSceneTraverser::OcclusionCullingTerrainSceneTraverser(SceneManager *sm, RenderSystem *rsys): 
        OcclusionCullingSceneTraverser(sm, rsys), mOctreeSceneRoot(0), mOctreeDistanceQueue(0)
        {
        }
        //-----------------------------------------------------------------------
        OcclusionCullingTerrainSceneTraverser::~OcclusionCullingTerrainSceneTraverser()
        {               
                if(mOctreeDistanceQueue)
                        delete mOctreeDistanceQueue;
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::traverseOctant(Camera *cam, Octree *octant )
        {
                mNumTraversedNodes ++;
        
                // if we come across some renderable geometry => render it
                renderOctant(cam, octant);
                
                for(int i=0; i<8; i++)
                {
                        Octree *nextChild = octant->mChildren[(i & 4) >> 2][(i & 2) >> 1][i & 1];
                
                        if(nextChild)
                                mOctreeDistanceQueue->push(nextChild);
                }
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::renderCullFrustum(Camera *cam)
        {
                AxisAlignedBox box;

                while(!mOctreeDistanceQueue->empty())
                {
                        Octree *octant = mOctreeDistanceQueue->top();
                        mOctreeDistanceQueue->pop();
        
                        // interesting for visualization purpose
                        //TODO: octree->setNodeVisible(false);
                        octant->_getCullBounds(&box);
                        
                        //if(static_cast<OctreeCamera *>(cam)->getVisibility(box) == OctreeCamera::NONE)
                        if(!cam->isVisible(box))
                        {
                                mNumFrustumCulledNodes ++;
                                continue;
                        }

                        // update node's visited flag 
                        octant->setLastVisited(mFrameId);
                        octant->setOctreeVisible(true);
                
                        traverseOctant(cam, octant);
                }
        }       
        //-----------------------------------------------------------------------
        /** Renders the scene with the hierarchical stop and wait algorithm. */
        void OcclusionCullingTerrainSceneTraverser::renderStopAndWait( Camera *cam )
        {
                AxisAlignedBox box;

                while(!mOctreeDistanceQueue->empty())
                {
                        Octree *octant = mOctreeDistanceQueue->top();
                        mOctreeDistanceQueue->pop();
                
                        // interesting for visualization purpose
                        octant->setOctreeVisible(false);
                        octant->setLastVisited(mFrameId);

                        //TODO: Isvisible also checked inside scenenode::findvisibleobjects
                        octant->_getCullBounds(&box);

                        bool intersects = false;

                        //if(vis == OctreeCamera::NONE)
                        if(!cam->isVisible(box, intersects))
                        {
                                mNumFrustumCulledNodes ++;
                                continue;
                        }
                        //if intersects near plane => skip occlusion query because wrong results possible
                        if(intersects)
                        {
                                octant->setOctreeVisible(true);
                                traverseOctant(cam, octant);
                                continue;
                        }

                        HardwareOcclusionQuery *query = issueOcclusionQuery(&box, false);
                                
                        unsigned int visiblePixels;
                        // wait if result not available
                        query->pullOcclusionQuery(&visiblePixels);
                        
                        // node visible
                        if(visiblePixels > mVisibilityThreshold)
                        {
                                traverseOctant(cam, octant);
                        }
                        else
                        {
                                mNumQueryCulledNodes ++;
                        }
                }
        }
        //-----------------------------------------------------------------------
        /** Renders the scene with the coherent hierarchical algorithm and the query queye. */
        void OcclusionCullingTerrainSceneTraverser::renderCoherentWithQueue( Camera *cam )
        {
                OctreeQueryQueue queryQueue;
                AxisAlignedBox box;

                //-- PART 1: process finished occlusion queries
                while(!mOctreeDistanceQueue->empty() || !queryQueue.empty())
                {
                        while(!queryQueue.empty() && 
                                  ((queryQueue.front().second)->resultAvailable() || mOctreeDistanceQueue->empty()))
                        {
                                Octree *octant = queryQueue.front().first;
                                HardwareOcclusionQuery *query = queryQueue.front().second;

                                queryQueue.pop();
                        
                                // wait until result available
                                unsigned int visiblePixels;
                                query->pullOcclusionQuery(&visiblePixels);

                                if(visiblePixels > mVisibilityThreshold)
                                {
                                        pullUpVisibility(cam, octant);
                                        traverseOctant(cam, octant);
                                }
                                else
                                {
                                        mNumQueryCulledNodes ++;
                                }
                        }       

                        //-- PART 2: hierarchical traversal
                        if(!mOctreeDistanceQueue->empty())
                        {
                                Octree *octant = mOctreeDistanceQueue->top();
                                mOctreeDistanceQueue->pop();
                                        
                                octant->_getCullBounds(&box);

                                bool intersects = false;
                                //TODO: Isvisible also checked inside scenenode::findvisibleobjects
                                if(!cam->isVisible(box, intersects))
                                {
                    mNumFrustumCulledNodes ++;
                                        continue;
                                }

                                // if intersects near plane => skip occlusion query because wrong results possible
                                if(intersects)
                                {
                                        // update node's visited flag
                                        octant->setLastVisited(mFrameId);
                                        pullUpVisibility(cam, octant);                  
                                        traverseOctant(cam, octant);

                                        continue;
                                }

                                // identify previously visible nodes
                                bool wasVisible = octant->isOctreeVisible() && (octant->lastVisited() == mFrameId - 1);
                                        
                                // identify nodes that we cannot skip queries for
                                bool leafOrWasInvisible = !wasVisible || isLeaf(octant);

                                // reset node's visibility classification 
                                octant->setOctreeVisible(false);

                                // update node's visited flag
                                octant->setLastVisited(mFrameId);
                        
                                // skip testing previously visible interior nodes
                                if(leafOrWasInvisible)
                                {
                                        HardwareOcclusionQuery *query = issueOcclusionQuery(&box, wasVisible);
                                        queryQueue.push(OctreeQueryPair(octant, query));
                                }
                                        
                                // always traverse a node if it was visible
                                if(wasVisible)
                                {
                                        traverseOctant(cam, octant);
                                }
                                else
                                {
                                        mNumFrustumCulledNodes ++;
                                }
                        }
                }
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::pullUpVisibility( Camera *cam, Octree *octant )
        {
                while(octant && !octant->isOctreeVisible())
                {
                        // if we come across some renderable geometry => render it
                        renderOctant(cam, octant);
                        
                        octant->setOctreeVisible(true);
                        octant = octant->getParent();
                }
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::renderOctant( Camera *cam, Octree *octant )
        {
                //if(octant->numNodes() > 0)
                if(octant->lastVisited() != octant->lastRendered())
                {
                        //setRenderingMode(MODE_RENDER);

                        octant->setLastRendered(octant->lastVisited());
                        ((OcclusionCullingTerrainSceneManager *)mSceneManager)->_renderOctant(cam, octant);
                }
                else OutputDebugString("already rendered");
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::setSceneRoot(Octree *root)
        {
                mOctreeSceneRoot = root;
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::initDistanceQueue(Camera *cam)
        {
                if(mOctreeDistanceQueue)
                        delete mOctreeDistanceQueue;

                mOctreeDistanceQueue = new OctreePriorityQueue(octreeless<Octree *>(cam));
                mOctreeDistanceQueue->push(mOctreeSceneRoot);
        }
        //-----------------------------------------------------------------------
        bool OcclusionCullingTerrainSceneTraverser::isLeaf(Octree *octant)
        {
                for(int i=0; i<8; i++)
                {
                        if(octant->mChildren[(i & 4) >> 2][(i & 2) >> 1][i & 1])
                                return false;
                }

                return true;
        }
        //-----------------------------------------------------------------------
        void OcclusionCullingTerrainSceneTraverser::setNumOctreeNodes(unsigned int num)
        {
                mNumOctreeNodes = num;
        }
        //-----------------------------------------------------------------------
        bool OcclusionCullingTerrainSceneTraverser::getOption( const String & key, void *val )
        {
                if ( key == "NumOctreeNodes" )
                {
                        * static_cast < unsigned int * > ( val ) = mNumOctreeNodes;
                        return true;
                }

                return OcclusionCullingSceneTraverser::getOption(key, val);
        }
        //-----------------------------------------------------------------------
        bool OcclusionCullingTerrainSceneTraverser::getOptionKeys( StringVector & refKeys )
        {
                refKeys.push_back( "NumOctreeNodes" );
                
                return OcclusionCullingSceneTraverser::getOptionKeys(refKeys);          
        }
}