GDIRegion.h

#pragma once
#include <vector>
#include <list>
using namespace std;
namespace ParaEngine
{
    struct GDISimpleEdge {
    public:
        GDISimpleEdge(const Vector3 &p1,const Vector3 &p2);
        friend class CGDIRegion;
    protected:
        GDISimpleEdge();
        Vector3 point1,point2;
        float slope;//=tgA=(point2.y-point1.y)/(point2.x-point1.x)
        float intersect;//=point1.y-slope*point1.x
        float GetY(float x)const{return intersect+slope*x;}
        int vertical;//if ==0 the edge is not vertical, if >0 the edge is upwards vertical, if <0 the edge is downwards vertical
    };
    struct GDIClipNode {
        Vector3 point;
        //-1 for inside-outside , 0 for none, 1 for outside-inside point
        int nodetype;
        //link to other place
        list<GDIClipNode>::const_iterator link;
    };
    class CGDIRegion
    {
    public:
        CGDIRegion();
        CGDIRegion(const RECT &rect);
        bool operator ==(const CGDIRegion &region);
        bool operator ==(const RECT &rect);
        operator RECT();
        void Translate(float dx,float dy,float dz=0);
        void Translate(const Vector3 &v);

        bool IsEmpty()const;
        bool IsInfinite()const{return m_points.size()==0;}
        void MakeEmpty();
        void MakeInifinite();
        CGDIRegion *Clone();
        bool LineIntersect(const Vector3 &point1,const Vector3 &point2, Vector3 &outpoint)const;
        bool LineIntersect(const GDISimpleEdge &edge,vector<Vector3> &outpoint,vector<int> &outedge)const;
        bool InsideTest(const Vector3 &point)const;

        int PolygonClip(const CGDIRegion &region,vector<CGDIRegion> &outregions);

        int RectClip(const CGDIRegion &region,CGDIRegion &outregion);
        static bool EdgeIntersect(const GDISimpleEdge &edge1,const GDISimpleEdge &edge2,Vector3 &point);

        Vector3 GetPoint(int index)const;
        int PointCount()const{return (int)m_points.size();}
        GDISimpleEdge GetEdge(int index)const;
    protected:
        bool IsPoint1Closer(const Vector3 &point,const Vector3 &point1, const Vector3 &point2,int relation=0);
        bool CalculateClipX(const GDISimpleEdge &edge1,const GDISimpleEdge &edge2,float &pointx)const;
        void GenerateEdge();
        void Preprocessing();
        vector<Vector3> m_points;
        vector<GDISimpleEdge> m_edges;
        list<GDIClipNode> m_nodes;
        int m_shape;
    };
}