polygon_intersection.cpp

这是一个GPS相关的程序

			case 0:
				Add_Polygon(pShapes_AB, pShape_A, iShape_A + 1);
				break;

			case 1:
				Add_Polygon(pShapes_AB, pShape_A, iShape_A + 1, 0);
				break;

			case 2:
				Add_Polygon(pShapes_AB, pShape_A, 0, iShape_A + 1);
				break;
			}
		}
	}

	return( nResult > 0 );
}


///////////////////////////////////////////////////////////
//														 //
//														 //
//														 //
///////////////////////////////////////////////////////////

//---------------------------------------------------------
#define ADD_POLYGON(POLY)	if( (pShape_Add = pShapes->Add_Shape()) != NULL )\
	{\
		pShape_Add->Assign(POLY, false);\
		pShape_Add->Get_Record()->Set_Value(0, pShapes->Get_Count());\
		pShape_Add->Get_Record()->Set_Value(1, ID_A);\
		pShape_Add->Get_Record()->Set_Value(2, ID_B);\
	}

void CPolygon_Intersection::Add_Polygon(CSG_Shapes *pShapes, CSG_Shape *pShape, int ID_A, int ID_B)
{
	int		iPart, jPart, iPoint, nParts;
	CSG_Shape	*pShape_Add, *pShape_Part;
	CSG_Shapes	Shapes_Part;

	if( bSplitParts && pShape->Get_Part_Count() > 1 )
	{
		Shapes_Part.Create(SHAPE_TYPE_Polygon);
		pShape_Part	= Shapes_Part.Add_Shape();

		for(iPart=0; iPart<pShape->Get_Part_Count(); iPart++)
		{
			if( !((CSG_Shape_Polygon *)pShape)->is_Lake(iPart) )
			{
				pShape_Part->Del_Parts();
				nParts	= 0;

				for(iPoint=0; iPoint<pShape->Get_Point_Count(iPart); iPoint++)
				{
					pShape_Part->Add_Point(pShape->Get_Point(iPoint, iPart), nParts);
				}

				for(jPart=0; jPart<pShape->Get_Part_Count(); jPart++)
				{
					if(	((CSG_Shape_Polygon *)pShape)->is_Lake(jPart)
					&&	((CSG_Shape_Polygon *)pShape)->is_Containing(pShape->Get_Point(0, jPart), iPart) )
					{
						nParts++;

						for(iPoint=0; iPoint<pShape->Get_Point_Count(jPart); iPoint++)
						{
							pShape_Part->Add_Point(pShape->Get_Point(iPoint, jPart), nParts);
						}
					}
				}

				ADD_POLYGON(pShape_Part);
			}
		}
	}
	else
	{
		ADD_POLYGON(pShape);
	}
}

#undef ADD_POLYGON

//---------------------------------------------------------
#define ADD_POLYGON(POLY)	if( (pShape_Add = pShapes->Add_Shape()) != NULL )\
	{\
		pShape_Add->Assign(POLY, false);\
		pShape_Add->Get_Record()->Set_Value(0, pShapes->Get_Count());\
		pShape_Add->Get_Record()->Set_Value(1, ID);\
	}

void CPolygon_Intersection::Add_Polygon(CSG_Shapes *pShapes, CSG_Shape *pShape, int ID)
{
	int		iPart, jPart, iPoint, nParts;
	CSG_Shape	*pShape_Add, *pShape_Part;
	CSG_Shapes	Shapes_Part;

	if( bSplitParts && pShape->Get_Part_Count() > 1 )
	{
		Shapes_Part.Create(SHAPE_TYPE_Polygon);
		pShape_Part	= Shapes_Part.Add_Shape();

		for(iPart=0; iPart<pShape->Get_Part_Count(); iPart++)
		{
			if( !((CSG_Shape_Polygon *)pShape)->is_Lake(iPart) )
			{
				pShape_Part->Del_Parts();
				nParts	= 0;

				for(iPoint=0; iPoint<pShape->Get_Point_Count(iPart); iPoint++)
				{
					pShape_Part->Add_Point(pShape->Get_Point(iPoint, iPart), nParts);
				}

				for(jPart=0; jPart<pShape->Get_Part_Count(); jPart++)
				{
					if(	((CSG_Shape_Polygon *)pShape)->is_Lake(jPart)
					&&	((CSG_Shape_Polygon *)pShape)->is_Containing(pShape->Get_Point(0, jPart), iPart) )
					{
						nParts++;

						for(iPoint=0; iPoint<pShape->Get_Point_Count(jPart); iPoint++)
						{
							pShape_Part->Add_Point(pShape->Get_Point(iPoint, jPart), nParts);
						}
					}
				}

				ADD_POLYGON(pShape_Part);
			}
		}
	}
	else
	{
		ADD_POLYGON(pShape);
	}
}

#undef ADD_POLYGON


///////////////////////////////////////////////////////////
//														 //
//														 //
//														 //
///////////////////////////////////////////////////////////

//---------------------------------------------------------
bool CPolygon_Intersection::GPC_Polygon_Intersection(CSG_Shape *pShape_A, CSG_Shape *pShape_B, CSG_Shape *pShape_AB)
{
	bool		bResult;
	int			iPoint, nPoints, iPart;
	gpc_polygon	poly_A, poly_B, poly_AB;
	gpc_vertex	*Contour;

	bResult	= false;

	if(	GPC_Create_Polygon(pShape_A, &poly_A)
	&&	GPC_Create_Polygon(pShape_B, &poly_B) )
	{
		gpc_polygon_clip(GPC_INT, &poly_A, &poly_B, &poly_AB);

		if( poly_AB.num_contours > 0 )
		{
			pShape_AB->Del_Parts();

			for(iPart=0; iPart<poly_AB.num_contours; iPart++)
			{
				Contour	= poly_AB.contour[iPart].vertex;
				nPoints	= poly_AB.contour[iPart].num_vertices;

				for(iPoint=0; iPoint<nPoints; iPoint++)
				{
					pShape_AB->Add_Point(Contour[iPoint].x, Contour[iPoint].y, iPart);
				}
			}

			bResult	= true;
		}

		gpc_free_polygon(&poly_AB);
	}

	gpc_free_polygon(&poly_A);
	gpc_free_polygon(&poly_B);

	return( bResult );
}

//---------------------------------------------------------
bool CPolygon_Intersection::GPC_Difference(CSG_Shape *pShape_A, CSG_Shape *pShape_B, CSG_Shape *pShape_AB)
{
	bool		bResult;
	int			iPoint, nPoints, iPart;
	gpc_polygon	poly_A, poly_B, poly_AB;
	gpc_vertex	*Contour;

	bResult	= false;

	if(	GPC_Create_Polygon(pShape_A, &poly_A)
	&&	GPC_Create_Polygon(pShape_B, &poly_B) )
	{
		pShape_AB->Del_Parts();

		gpc_polygon_clip(GPC_DIFF, &poly_A, &poly_B, &poly_AB);

		if( poly_AB.num_contours > 0 )
		{
			for(iPart=0; iPart<poly_AB.num_contours; iPart++)
			{
				Contour	= poly_AB.contour[iPart].vertex;
				nPoints	= poly_AB.contour[iPart].num_vertices;

				for(iPoint=0; iPoint<nPoints; iPoint++)
				{
					pShape_AB->Add_Point(Contour[iPoint].x, Contour[iPoint].y, iPart);
				}
			}
		}

		gpc_free_polygon(&poly_AB);

		bResult	= true;
	}

	gpc_free_polygon(&poly_A);
	gpc_free_polygon(&poly_B);

	return( bResult );
}


///////////////////////////////////////////////////////////
//														 //
//														 //
//														 //
///////////////////////////////////////////////////////////

//---------------------------------------------------------
bool CPolygon_Intersection::GPC_Create_Polygon(CSG_Shape *pShape, gpc_polygon *pPolygon)
{
	int				iPoint, iPart;
	TSG_Point		Point;
	gpc_vertex		*Contour;
	gpc_vertex_list	vList;

	pPolygon->contour		= NULL;
	pPolygon->hole			= NULL;
	pPolygon->num_contours	= 0;

	//-----------------------------------------------------
	for(iPart=0; iPart<pShape->Get_Part_Count(); iPart++)
	{
		if( pShape->Get_Point_Count(iPart) > 0 )
		{
			Contour	= (gpc_vertex *)malloc(pShape->Get_Point_Count(iPart) * sizeof(gpc_vertex));

			for(iPoint=0; iPoint<pShape->Get_Point_Count(iPart); iPoint++)
			{
				Point	= pShape->Get_Point(iPoint, iPart);
				Contour[iPoint].x	= Point.x;
				Contour[iPoint].y	= Point.y;
			}

			vList.num_vertices	= pShape->Get_Point_Count(iPart);
			vList.vertex		= Contour;
			gpc_add_contour(pPolygon, &vList, ((CSG_Shape_Polygon *)pShape)->is_Lake(iPart) ? 1 : 0);

			free(Contour);
		}
	}

	return( pPolygon->num_contours > 0 );
}