第一部分 VTK程序一般流程.ppt

1、报告人：邹水中 日 期：2010.4.2,VTK使用总结,内容简介,一、VTK程序一般流程 二、VTK的数据对象接口 三、 VTK的面绘制、体绘制、多平面显示 四、视点变换与相机控制 五、 VTK事件交互、VTK与MFC混合编程 六、VTK视窗控制与文本标注 七、VTK在测量中应用与VTK数据切割,第一部分 VTK程序一般流程,Visualization Toolkit 的机制Visualization Toolkit 是一个用于可视化应用程序构造与运行的支撑环境，它是在三维函数库OpenGL 的基础上采用面向对象的设计方法发展起来的。 它将在可视化开发过程中会经常遇到的细节屏蔽起来，并将一些

2、常用的算法封装起来。比如Visualization Toolkit 将在表面重建中比较常见的Marching Cubes 算法封装起来，以类的形式给以支持， 这样在对三维规则点阵数据进行表面重建时就不必再重复编写Marching Cubes 算法的代码而直接使用Visualization Toolkit 中已经提供的vtkMarchingCubes 类。,Visualization Toolkit 的框架结构,图形流水线：将几何数据转换为图像；可视化流水线：将信息转换为几何数据.另一种看法是:可视化流水线:负责构建几何表示;图形流水线:负责绘制. vtk使用一种lazy评价机制. 对于lazy

3、评价机制，通常无需人工地调用Update()，因为filters连接着可视化流水线，当actor接收到绘制本身的要求会将方法回馈到他的mapper，然后Update方法自动发送至可视化流水线。Render方法通常开始数据要求，数据被通过流水线向下投递。依赖于流水线的哪个端口过时，流水线中的filters可能重新执行，将数据送至更新的流水线末端，通过actor绘制.,可视化模型,VTK 图形模型由以下核心对象组成 vtkActor,vtkActor2D,vtkVolume vtkProp 和/或vtpProp3D 的子类 vtkLight vtkCamera vtkProperty,vtkPro

4、perty2D vtkMaper,vtkMapper2D vtkAbstractMapper 的子类 vtkTransform vtkLookupTable,vtkColorTransferFunction- vtkScalarsToColors 的子类 /for objects that convert scalars to colors vtkRender vtkRenderWindow vtkRenderWindowInteractor,图形模型,vtkLight 用来展示和操控场景中的灯光，只在3D中用到. VtkCamera 控制3D几何投影到2D。定位：定点、方向，还控制视角投影和

5、立体视图. vtkMapper 与查找表vtkLookupTable联合使用，用于转换和绘制几何体。Mapper提供可视化流水线和图形模型. vtkLookupTable 是vtkScalarsToColors和vtkColorTransferFunction的子类.,vtkRenderer和vtkRenderWindow 用来管理图形机与电脑窗口系统的接口.可以生成多个render windows,每个render windows中有多个renderer去绘制.一个render window中可以有多个区域(视窗). vtkRenderWindowInteractor 用于与场景交互,操纵c

6、amera,选择对象. vtkWin32OpenGLRenderWindow和vtkWin32RenderWindowInteractor vtkWin32OpenGLRenderWindow is a concrete implementation of the abstract class vtkRenderWindow. vtkWin32OpenGLRenderer interfaces to the standard OpenGL graphics library in the Windows/NT environment. implements Win32 specific func

7、tions required by vtkRenderWindowInteractor.,vtkActor的子类 vtkAssembly,vtkFollower,vtkLODActor等. vtkAssembly允许actors分层，在层级平移、旋转、缩放时合理转换. vtkLODActor在改变几何表示时保持交互帧速率,示例代码1 演示VTK一般流程及常用类的使用,vtkVolume16Reader *v16 = vtkVolume16Reader:New(); v16-SetDataDimensions(64,64); v16-SetDataByteOrderToLittleEndian(

8、); v16-SetFilePrefix (D:/VTK 5.4/VTKData/Data/headsq/quarter); v16-SetImageRange(1, 93); v16-SetDataSpacing (3.2, 3.2, 1.5); vtkContourFilter *skinExtractor = vtkContourFilter:New(); skinExtractor-SetInputConnection( v16-GetOutputPort(); skinExtractor-SetValue(0, 500); vtkPolyDataNormals *skinNormal

9、s = vtkPolyDataNormals:New(); skinNormals-SetInputConnection(skinExtractor-GetOutputPort(); skinNormals-SetFeatureAngle(60.0); /if the surface normal between two adjacent triangles is = FeatureAngle, an edge exists vtkStripper *skinStripper = vtkStripper:New(); skinStripper-SetInputConnection(skinNo

10、rmals-GetOutputPort(); vtkPolyDataMapper *skinMapper = vtkPolyDataMapper:New(); skinMapper-SetInputConnection(skinStripper-GetOutputPort(); skinMapper-ScalarVisibilityOff();,示例代码1,vtkActor *skin = vtkActor:New(); skin-SetMapper(skinMapper); skin-GetProperty()-SetDiffuseColor(1, .49, .25); skin-GetPr

11、operty()-SetSpecular(.3); skin-GetProperty()-SetSpecularPower(20); vtkLookupTable *bwLut = vtkLookupTable:New(); bwLut-SetTableRange (0, 2000); bwLut-SetSaturationRange(0, 1); bwLut-SetHueRange (0, 1); bwLut-SetValueRange (0.5, 1); bwLut-Build(); /effective built / The result is an image of type VTK

12、_UNSIGNED_CHAR vtkImageMapToColors *saggitalColors = vtkImageMapToColors:New(); saggitalColors-SetInputConnection(v16-GetOutputPort(); saggitalColors-SetLookupTable(bwLut); vtkImageActor *saggital = vtkImageActor:New(); saggital-SetInput(saggitalColors-GetOutput(); saggital-SetDisplayExtent(32,32, 0

13、,63, 0,92);,vtkRenderer *aRenderer = vtkRenderer:New(); vtkRenderWindow *renWin = vtkRenderWindow:New(); renWin-AddRenderer(aRenderer); vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor:New(); iren-SetRenderWindow(renWin); vtkCamera *aCamera = vtkCamera:New(); aCamera-SetViewUp (0, 0, -1);

14、 aCamera-SetPosition (0, 1, 0); aCamera-SetFocalPoint (0, 0, 0); aCamera-ComputeViewPlaneNormal(); aRenderer-AddActor(saggital); skin-GetProperty()-SetOpacity(0.5); aRenderer-SetActiveCamera(aCamera); aRenderer-Render(); aRenderer-ResetCamera (); aCamera-Dolly(1.5); aRenderer-SetBackground(1,1,1); a

15、Renderer-ResetCameraClippingRange (); renWin-SetSize(640, 480); iren-Initialize(); iren-Start();,示例代码3 演示视窗显示控制、相机控制,class vtkWidgetWindowLevelCallback : public vtkCommand public: static vtkWidgetWindowLevelCallback *New() return new vtkWidgetWindowLevelCallback; void Execute( vtkObject *caller, uns

16、igned long vtkNotUsed( event ), void *callData ) vtkImagePlaneWidget* self = reinterpret_cast( caller ); if(!self) return; double* wl = static_cast( callData );,if ( self = this-WidgetX ) this-WidgetY-SetWindowLevel(wl0,wl1); this-WidgetZ-SetWindowLevel(wl0,wl1); else if( self = this-WidgetY ) this-

17、WidgetX-SetWindowLevel(wl0,wl1); this-WidgetZ-SetWindowLevel(wl0,wl1); else if (self = this-WidgetZ) this-WidgetX-SetWindowLevel(wl0,wl1); this-WidgetY-SetWindowLevel(wl0,wl1); ,vtkWidgetWindowLevelCallback():WidgetX( 0 ), WidgetY( 0 ), WidgetZ ( 0 ) vtkImagePlaneWidget* WidgetX; vtkImagePlaneWidget

18、* WidgetY; vtkImagePlaneWidget* WidgetZ; ; int main( int argc, char *argv ) vtkRenderer* ren1 = vtkRenderer:New(); vtkRenderer* ren2 = vtkRenderer:New(); vtkRenderer* ren3 = vtkRenderer:New(); vtkRenderer* ren = vtkRenderer:New(); vtkRenderWindow* renWin = vtkRenderWindow:New(); vtkRenderWindowInter

19、actor* iren = vtkRenderWindowInteractor:New(); iren-SetRenderWindow(renWin); renWin-AddRenderer(ren1); renWin-AddRenderer(ren2); renWin-AddRenderer(ren3); renWin-AddRenderer(ren);,vtkDICOMImageReader *v16 = vtkDICOMImageReader:New(); v16-SetDataByteOrderToLittleEndian(); v16-SetDirectoryName(E:/MedI

20、mageData/336); v16-Update(); vtkOutlineFilter* outline = vtkOutlineFilter:New(); outline-SetInputConnection(v16-GetOutputPort(); vtkPolyDataMapper* outlineMapper = vtkPolyDataMapper:New(); outlineMapper-SetInputConnection(outline-GetOutputPort(); vtkActor* outlineActor = vtkActor:New(); outlineActor

21、-SetMapper( outlineMapper);,vtkWidgetWindowLevelCallback* cbk = vtkWidgetWindowLevelCallback:New(); cbk-WidgetX = planeWidgetX; cbk-WidgetY = planeWidgetY; cbk-WidgetZ = planeWidgetZ; / planeWidgetX-AddObserver( vtkCommand:EndWindowLevelEvent, cbk ); /planeWidgetY-AddObserver( vtkCommand:EndWindowLe

22、velEvent, cbk ); /planeWidgetZ-AddObserver( vtkCommand:EndWindowLevelEvent, cbk ); cbk-Delete();,vtkImageMapToColors* colorMap1 = vtkImageMapToColors:New(); colorMap1-PassAlphaToOutputOff(); colorMap1-SetActiveComponent(0); colorMap1-SetOutputFormatToLuminance(); colorMap1-SetInput(planeWidgetX-GetR

23、esliceOutput(); colorMap1-SetLookupTable(planeWidgetX-GetLookupTable(); vtkImageActor* imageActor1 = vtkImageActor:New(); imageActor1-PickableOff(); imageActor1-SetInput(colorMap1-GetOutput();,ren-AddActor( outlineActor); ren1-AddActor( imageActor1); ren2-AddActor( imageActor2); ren3-AddActor( image

24、Actor3); ren-SetBackground( 0.1, 0.1, 0.2); ren1-SetBackground( 0.1, 0.2, 0.1); ren2-SetBackground( 0.2, 0.1, 0.2); ren3-SetBackground( 0.2, 0.2, 0.2); renWin-SetSize( 600, 400); ren-SetViewport(0,0.5,0.5,1); ren1-SetViewport(0.5,0.5,1,1); ren2-SetViewport(0,0,0.5,0.5); ren3-SetViewport(0.5,0,1,0.5)

25、; renWin-Render();,ren-GetActiveCamera()-Elevation(110); ren-GetActiveCamera()-SetViewUp(0, 0, -1); ren-GetActiveCamera()-Azimuth(45); ren-GetActiveCamera()-Dolly(1.15); ren-ResetCameraClippingRange(); iren-Initialize(); iren-Start(); renWin-Render(); iren-SetKeyCode(z); iren-InvokeEvent(vtkCommand:CharEvent,NULL); iren-SetKeyCode(z); iren-InvokeEvent(vtkCommand:CharEvent,