source: trunk/VUT/chcdemo/RenderTraverser.h @ 22

#ifndef NO_PRAGMA_ONCE
#pragma once
#endif

#ifndef RENDERTRAVERSER_H
#define RENDERTRAVERSER_H

#include "glInterface.h"
#include "HierarchyNode.h"
#include <queue>
//#include <priority_queue>
#include <stack>

using namespace std;

typedef stack<HierarchyNode *> TraversalStack;
typedef queue<HierarchyNode *> QueryQueue;
typedef priority_queue<HierarchyNode *, vector<HierarchyNode *>, myless<vector<HierarchyNode *>::value_type> > PriorityQueue;

class RenderTraverser
{
public:
        enum {RENDER_CULL_FRUSTUM, RENDER_STOP_AND_WAIT, RENDER_COHERENT, NUM_RENDERMODES};

        RenderTraverser();
        //! Renders the scene with the specified method
        /**
                The mode is one of
                RENDER_CULL_FRUSTUM: renders the scene with view frustum culling only
                RENDER_STOP_AND_WAIT: renders the scene with the hierarchical stop and wait algorithm
                RENDER_COHERENT: renders the scene with the coherent hierarchical algorithm
        */
        void Render(int mode=RENDER_CULL_FRUSTUM);
        //! sets the scene hierarchy.
        void SetHierarchy(HierarchyNode *sceneRoot);
        //! sets viewpoint
        void SetViewpoint(Vector3 const &viewpoint);
        //! sets view projection matrix
        void SetProjViewMatrix(Matrix4x4 const &projViewMatrix);
        //! returns root of hierarchy
        HierarchyNode *GetHierarchy();
        //! sets visible pixels threshold for visibility classification
        void SetVisibilityThreshold(int threshold);
        //! returns visibility threshold
        int GetVisibilityThreshold();

        // several statistics for a rendering pass
        long GetRenderTime();
        int GetNumTraversedNodes();
        int GetNumQueryCulledNodes();
        int GetNumFrustumCulledNodes();
        int GetNumRenderedGeometry();

        //! renders a visualization of the hierarchy
        void RenderVisualization();

        //! use optimization to take leaf nodes instead of bounding box for occlusion queries   
        void SetUseOptimization(bool useOptimization);

protected:

        //! renders the scene with view frustum culling only
        void RenderCullFrustum();
        //! renders the scene with the hierarchical stop and wait algorithm
        void RenderStopAndWait();
        //! renders the scene with the coherent hierarchical algorithm and the query queye
        void RenderCoherentWithQueue();
        //! does some importand initialisations
        void Preprocess();
        
        //! returns occlusion query result for specified node
        int GetOcclusionQueryResult(HierarchyNode *node);
        //! the node is traversed as usual
        void TraverseNode(HierarchyNode *node);
        //! visibility is pulled up from visibility of children 
        void PullUpVisibility(HierarchyNode *node);
        //! is result available from query queue?
        bool ResultAvailable(HierarchyNode *node);
        //! issues occlusion query for specified node
        void IssueOcclusionQuery(HierarchyNode *node, bool wasVisible);
        //! resets occlusion queries after a traversal
        void ResetQueries();
        //! does view frustum culling. returns intersect (if intersects view plane)
        bool InsideViewFrustum(HierarchyNode *node, bool &intersects);
        //! switches to normal render mode
        void Switch2GLRenderState();
        //! switches to occlusion query mode (geometry not rendered on the screen)
        void Switch2GLQueryState();

protected:

        // the current clip planes of the view frustum
        VecPlane mClipPlanes;
        // the indices of the np-vertices of the bounding box for view frustum culling
        int mNPVertexIndices[12];

        Vector3 mViewpoint;
        Matrix4x4 mProjViewMatrix;
        HierarchyNode *mHierarchyRoot;
        //TraversalStack mTraversalStack;
        PriorityQueue mDistanceQueue; // use a priority queue rather than a renderstack
        
        //priority_queue<vector<HierarchyNode *>, HierarchyNode *> mPriorityQueue;
        int mFrameID;
        int mVisibilityThreshold;
        unsigned int *mOcclusionQueries;
        int mCurrentTestIdx;
        bool mIsQueryMode;
        
        bool mIntersects;

        // statistics
        int mNumTraversedNodes;
        int mNumQueryCulledNodes;
        int mNumFrustumCulledNodes;
        int mNumRenderedGeometry;

        long mRenderTime;

        bool mUseOptimization;
};

#endif // RENDERTRAVERSER_H