OpenCasCade是什么

Open CASCADE（简称OCC）平台是由法国Matra Datavision公司开发的CAD/CAE/CAM软件平台，可以说是世界上最重要的几何造型基础软件平台之一。开源OCC对象库是一个面向对象C++类库，用于快速开发设计领域的专业应用程序。

最近一直在利用OpenCasCade来进行空间几何的相关算法，于是有了这个教程让大家可以更直观的看到occ内部对象最终组装呈现的实际效果是什么。

利用OpenGL如何让occ做简单模型展示

1.依赖引用

预编译头stdafx.h中加入头文件引用与静态描述引用

#include <V3d_View.hxx>               //V3d_View
#include <WNT_Window.hxx>             //Handle_WNT_Window
#include <AIS_InteractiveContext.hxx> //AIS_InteractiveContext
#include <AIS_Shape.hxx>              //Handle_AIS_Shape
#include <Standard.hxx>
#include <Standard_PrimitiveTypes.hxx>
#include <AIS_InteractiveContext.hxx>
#include <AIS_Line.hxx>
#include <AIS_Shape.hxx>
#include <AIS_Point.hxx>
#include <AIS_TexturedShape.hxx>
#include <Aspect_Grid.hxx>
#include <Aspect_PolygonOffsetMode.hxx>
#include <Aspect_DisplayConnection.hxx>
#include <gp.hxx>
#include <gp_Ax1.hxx>
#include <gp_Ax2.hxx>
#include <gp_Ax2d.hxx>
#include <gp_Dir.hxx>
#include <gp_Dir2d.hxx>
#include <gp_Pnt.hxx>
#include <gp_Pnt2d.hxx>
#include <gp_Trsf.hxx>
#include <gp_Vec.hxx>
#include <gp_Lin2d.hxx>
#include <gp_Pln.hxx>
#include <gp.hxx>
#include <gp_Pnt2d.hxx>
#include <Geom_CylindricalSurface.hxx>
#include <Geom_Plane.hxx>
#include <Geom_Surface.hxx>
#include <Geom_TrimmedCurve.hxx>
#include <Geom2d_TrimmedCurve.hxx>
#include <GeomLib.hxx>
#include <Geom_Surface.hxx>
#include <Geom_Curve.hxx>
#include <Geom_CartesianPoint.hxx>
#include <Geom2d_Ellipse.hxx>
#include <Geom2d_TrimmedCurve.hxx>
#include <Geom2d_Circle.hxx>
#include <GeomAPI_ProjectPointOnCurve.hxx>
#include <GCPnts_QuasiUniformDeflection.hxx>
#include <Graphic3d_Group.hxx>
#include <Graphic3d_HorizontalTextAlignment.hxx>
#include <Graphic3d_VerticalTextAlignment.hxx>
#include <Graphic3d_ArrayOfPolylines.hxx>
#include <Graphic3d_ExportFormat.hxx>
#include <Graphic3d_ArrayOfPolylines.hxx>
#include <Graphic3d_AspectFillArea3d.hxx>
#include <Graphic3d_AspectText3d.hxx>
#include <Graphic3d_AspectLine3d.hxx>
#include <Graphic3d_AspectMarker3d.hxx>
#include <Graphic3d_Texture1Dsegment.hxx>
#include <OpenGl_GraphicDriver.hxx>
#include <Prs3d_Root.hxx>
#include <Prs3d_Drawer.hxx>
#include <Prs3d_IsoAspect.hxx>
#include <Prs3d_ShadingAspect.hxx>
#include <Prs3d_Presentation.hxx>
#include <PrsMgr_PresentationManager3d.hxx>
#include <Prs3d_TextAspect.hxx>
#include <Prs3d_Text.hxx>
#include <Select3D_SensitiveBox.hxx>
#include <Select3D_SensitiveCurve.hxx>
#include <Select3D_SensitiveGroup.hxx>
#include <SelectMgr_Selection.hxx>
#include <SelectMgr_SequenceOfOwner.hxx>
#include <SelectMgr_EntityOwner.hxx>
#include <ShapeBuild_Edge.hxx>
#include <StdSelect_ViewerSelector3d.hxx>
#include <StdPrs_ShadedShape.hxx>
#include <StdPrs_HLRPolyShape.hxx>
#include <StdSelect_BRepSelectionTool.hxx>
#include <StdPrs_WFShape.hxx>
#include <StdPrs_ToolRFace.hxx>
#include <StdSelect.hxx>
#include <StdSelect_BRepOwner.hxx>
#include <StdSelect_BRepSelectionTool.hxx>#include <TCollection_AsciiString.hxx>
#include "TopExp.hxx"
#include <TopExp_Explorer.hxx>
#include <TopoDS.hxx>
#include <TopoDS_Builder.hxx>
#include <TopoDS_Compound.hxx>
#include <TopoDS_ListOfShape.hxx>
#include <TopoDS_ListIteratorOfListOfShape.hxx>
#include <TopoDS_Iterator.hxx>
#include "TopoDS_Edge.hxx"
#include "TopoDS_Vertex.hxx"
#include <TopoDS_Wire.hxx>
#include <TopoDS_Shape.hxx>
#include <TopoDS_Compound.hxx>
#include <TopTools_HSequenceOfShape.hxx>
#include <TopTools_IndexedMapOfShape.hxx>
#include <V3d_Viewer.hxx>
#include <V3d_View.hxx>
#include <WNT_Window.hxx>
#include <BRepAlgoAPI_Fuse.hxx>
#include <BRepBuilderAPI_MakeVertex.hxx>
#include <BRepBuilderAPI_MakeEdge.hxx>
#include <BRepBuilderAPI_MakeFace.hxx>
#include <BRepBuilderAPI_MakeWire.hxx>
#include <BRepBuilderAPI_Transform.hxx>
#include <BRepBuilderAPI_MakePolygon.hxx>
#include <BRepFilletAPI_MakeFillet.hxx>
#include <BRepLib.hxx>
#include <BRepOffsetAPI_MakeThickSolid.hxx>
#include <BRepOffsetAPI_ThruSections.hxx>
#include <BRepPrimAPI_MakeCylinder.hxx>
#include <BRepPrimAPI_MakePrism.hxx>
#include <BRep_Tool.hxx>
#include <BRepTools.hxx>
#include <BRepBuilderAPI_NurbsConvert.hxx>
#include <BRepPrimAPI_MakeCylinder.hxx>
#include <BRepBndLib.hxx>
#include <BRepAdaptor_HArray1OfCurve.hxx>
#include <BRepAdaptor_Curve2d.hxx>
#include <GC_MakeArcOfCircle.hxx>
#include <GC_MakeSegment.hxx>
#include <TopTools_ListOfShape.hxx>
#include <GProp_PEquation.hxx>
#include <math_Matrix.hxx>
#include <gce_MakeCirc.hxx>
#include <geom2d_line.hxx>
#include <GCE2d_MakeSegment.hxx>
#include <TopExp_Explorer.hxx>#pragma comment(lib,"TKVCAF.lib")
#pragma comment(lib,"TKVrml.lib")
#pragma comment(lib,"TKStl.lib")
#pragma comment(lib,"TKBrep.lib")
#pragma comment(lib,"TKIGES.lib")
#pragma comment(lib,"TKShHealing.lib")
#pragma comment(lib,"TKStep.lib")
#pragma comment(lib,"TKXSBase.lib")
#pragma comment(lib,"TKBool.lib")
#pragma comment(lib,"TKCAF.lib")
#pragma comment(lib,"TKCDF.lib")
#pragma comment(lib,"TKernel.lib")
#pragma comment(lib,"TKFeat.lib")
#pragma comment(lib,"TKFillet.lib")
#pragma comment(lib,"TKG2d.lib")
#pragma comment(lib,"TKG3d.lib")
#pragma comment(lib,"TKGeomAlgo.lib")
#pragma comment(lib,"TKGeomBase.lib")
#pragma comment(lib,"TKHLR.lib")
#pragma comment(lib,"TKMath.lib")
#pragma comment(lib,"TKOffset.lib")
#pragma comment(lib,"TKPrim.lib")
#pragma comment(lib,"TKService.lib")
#pragma comment(lib,"TKTopAlgo.lib")
#pragma comment(lib,"TKV3d.lib")
#pragma comment(lib,"TKOpenGl.lib")
#pragma comment(lib,"TKMesh.lib")
#pragma comment(lib,"TKBO.lib")

2.设置驱动环境

在 App 类头文件中初始化一个驱动设备对象的实例 myGraphicDriver

 class CMFCApplication1App : public CWinAppEx
{
public:CMFCApplication1App() noexcept;Handle(Aspect_DisplayConnection) myDisplayConnection;Handle(OpenGl_GraphicDriver) aGraphicDriver = new OpenGl_GraphicDriver(myDisplayConnection);Handle(OpenGl_GraphicDriver) GetGraphicDriver() const { return aGraphicDriver; }//为C**App提供调用接口函数

3.设置View容器

在Doc类头文件中声明V3d_Viewer 和 AIS_InteractiveContext两个类
V3d_Viewer 是一个 V3d_View也就是视图的管理器（做一个承载）

public:Handle_V3d_Viewer myViewer;Handle_AIS_InteractiveContext myAISContext;Handle(V3d_Viewer) GetViewer() { return myViewer; }Handle(AIS_InteractiveContext)& GetAISContext() { return myAISContext; }

源文件构造中进行初始化

CMFCApplication1Doc::CMFCApplication1Doc() noexcept
{// TODO: 在此添加一次性构造代码Handle(Graphic3d_GraphicDriver) theGraphicDriver =((CMFCApplication1App*)AfxGetApp())->GetGraphicDriver();myViewer = new V3d_Viewer(theGraphicDriver);myViewer->SetDefaultLights();myViewer->SetLightOn();myAISContext = new AIS_InteractiveContext(myViewer);
}

4.在view绘制图形

做完了上边三步occ的view就已经基本配置完毕，接下来就是装在到窗口上，并且在上面绘制图形
下面是源文件内容

//将Occ的view绑到窗口的view上去
void CMFCApplication1View::OnInitialUpdate()
{myView = GetDocument()->GetViewer()->CreateView();bool myHlrModeIsOn = Standard_False;myView->SetComputedMode(myHlrModeIsOn);Handle(Graphic3d_GraphicDriver) theGraphicDriver = ((CMFCApplication1App*)AfxGetApp())->GetGraphicDriver();Handle(WNT_Window) aWNTWindow = new WNT_Window(GetSafeHwnd());//,Quantity_NOC_MATRAGRAY);myView->SetWindow(aWNTWindow);//if(!aWNTWindow->IsMapped()) aWNTWindow->Map();
}

绘制图形方法（这里我就画一个长方体）

//绘制图形修改这里
void CMFCApplication1View::OnDraw(CDC* /*pDC*/)
{CMFCApplication1Doc* pDoc = GetDocument();ASSERT_VALID(pDoc);if (!pDoc)return;// TODO: 在此处为本机数据添加绘制代码BRepBuilderAPI_MakePolygon MP;MP.Add(gp_Pnt(0, 0, 0));MP.Add(gp_Pnt(100, 0, 0));MP.Add(gp_Pnt(100, 100, 0));MP.Add(gp_Pnt(0, 100, 0));MP.Close();//完成构造 封闭空间TopoDS_Face F = BRepBuilderAPI_MakeFace(MP.Wire());gp_Vec aPrimVec(0, 0, 300);//拉伸 形成拉伸体TopoDS_Shape shape = BRepPrimAPI_MakePrism(F, aPrimVec);Handle(AIS_Shape) anAISShape = new AIS_Shape(shape);pDoc->myAISContext->Display(anAISShape);//绘制图形
}