IsoSurfaceBuilder.h

#pragma once

#include "DataGrid.h"
#include <vector>

namespace ParaEngine
{
    class IsoSurfaceBuilder
    {
    public:
        friend class IsoSurfaceRenderable;
        enum SurfaceFlags
        {
            GEN_NORMALS = 0x01,
            GEN_VERTEX_COLOURS = 0x02,
            GEN_TEX_COORDS = 0x04,
        };

        enum NormalType
        {
            NORMAL_WEIGHTED_AVERAGE,
            NORMAL_AVERAGE,
            NORMAL_GRADIENT
        };

        IsoSurfaceBuilder();
        virtual ~IsoSurfaceBuilder();
        virtual void initialize(DataGrid* dg, int flags);
        void update(IsoSurfaceRenderable * isr);
        DataGrid* getDataGrid() {return mDataGrid.get(); }
        float getIsoValue() const {return mIsoValue; }
        void setIsoValue(float isoValue) {mIsoValue = isoValue; }
        bool getFlipNormals() const {return mFlipNormals; }
        void setFlipNormals(bool flipNormals) {mFlipNormals = flipNormals; }
        NormalType getNormalType() const {return mNormalType; }
        void setNormalType(NormalType normalType) {mNormalType = normalType; }

        int mNumIsoVertices;    
        int isoVertexGroupOffsets[3];

        virtual int getNumIsoVertices();
        virtual void createGridCellIsoVertices();
        virtual void buildIsoSurface();

    protected:

        struct IsoTriangle
        {
            int vertices[3];
        };

        struct GridCell
        {
            GridCell():isoVertices(NULL){};
            int cornerIndices[8];
            int* isoVertices;
        };

        typedef std::vector<int> IsoVertexVector;
        typedef std::vector<IsoTriangle> IsoTriangleVector;

        DataGridPtr mDataGrid;
        int mSurfaceFlags;
        float mIsoValue;
        bool mFlipNormals;
        NormalType mNormalType;
        int* mIsoVertexIndices;
        Vector3* mIsoVertexPositions;
        Vector3* mIsoVertexNormals;
        Color* mIsoVertexColours;
        Vector2* mIsoVertexTexCoords;
        GridCell* mGridCells;
        IsoVertexVector mIsoVertices;
        IsoTriangleVector mIsoTriangles;

        static const int msEdgeTable[256];
        static const int msTriangleTable[256][16];
    //#include "IsoSurfaceBuilderTables.h"

        void createIsoVertices();
        void createGridCells();
        void destroyGridCells();
        int useIsoVertex(int isoVertex, int corner0, int corner1);
        void addIsoTriangle(const IsoTriangle& isoTriangle);
    };
}