VTK实现STL模型的三视图显示及交互
最近收到需求，要实现多视图显示同一个STL模型，并且控制主窗口要其他试图窗口也跟着交互，花了点时间去尝试一下，把这个效果给实现出来了，而且实现也挺简单。
效果演示
要点
- 用同一个vtkRenderer传三次给vtkRenderWindow是不行的，要创建三个vtkRenderer来显示用一个vtkActor，分别传给vtkRenderWindow才行。
- 用同一个vtkCamera同时控制三个vtkRenderer是不行的，因为vtkCamera的参数发生改变，会同步影响，要实现不同的视角，还是需要准备三个vtkCamera分别传给三个vtkRenderer。
- 既然要实现控制一个主vtkCamera，影响另外两个辅vtkCamera也要同步更新，那最直接的方法就是用回调函数。
代码实现
#include <iostream>
#include <vtkAutoInit.h>
#include <vtkSTLReader.h>
#include <vtkPLYReader.h>
#include <vtkPolyDataMapper.h>
#include <vtkSmartPointer.h>
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkTransform.h>#include <vtkGenericOpenGLRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkCommand.h>
VTK_MODULE_INIT(vtkRenderingOpenGL2)
VTK_MODULE_INIT(vtkInteractionStyle);
VTK_MODULE_INIT(vtkRenderingFreeType);class vtkUpdateCamera : public vtkCommand
{
public:static vtkUpdateCamera* New(){return new vtkUpdateCamera;}void Execute(vtkObject* caller, unsigned long vtkNotUsed(event), void* callData){//获取主cameravtkRenderer* renderer = dynamic_cast<vtkRenderer*>(caller);auto camera = renderer->GetActiveCamera();//更新两个辅助camera的参数camera1->SetPosition(camera->GetPosition());camera1->SetFocalPoint(camera->GetFocalPoint());camera1->SetViewUp(camera->GetViewUp());camera1->Azimuth(90);camera1->Modified();//通过调整摄像头的viewup的旋转角度，为辅助摄像头实现上试图，左视图的朝向camera2->SetPosition(camera->GetPosition());camera2->SetFocalPoint(camera->GetFocalPoint());double* viewUp = camera->GetViewUp();double* direction = camera->GetDirectionOfProjection();double view[3];vtkMath::Cross(direction, viewUp, view);camera2->SetViewUp(view);camera2->Azimuth(-90);camera2->Modified();}void SetCamera1(vtkCamera* c){camera1 = c;}void SetCamera2(vtkCamera* c){camera2 = c;}private:vtkCamera* camera1;vtkCamera* camera2;
};int main()
{vtkSmartPointer<vtkSTLReader> reader = vtkSmartPointer<vtkSTLReader>::New();reader->SetFileName("D://Bunny.stl");reader->Update();vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();mapper->SetInputData(reader->GetOutput());vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();actor->SetMapper(mapper);double* bounds = reader->GetOutput()->GetBounds();vtkSmartPointer<vtkCamera> camera = vtkSmartPointer<vtkCamera>::New();camera->SetPosition(0, bounds[2]- 200, 0);camera->SetFocalPoint(reader->GetOutput()->GetCenter());camera->SetViewUp(0, 0, 1);vtkSmartPointer<vtkCamera> camera1 = vtkSmartPointer<vtkCamera>::New();vtkSmartPointer<vtkCamera> camera2 = vtkSmartPointer<vtkCamera>::New();//为主渲染器准备更新摄像头的回调函数vtkSmartPointer<vtkUpdateCamera> callback = vtkSmartPointer<vtkUpdateCamera>::New();callback->SetCamera1(camera1);callback->SetCamera2(camera2);//---------设置主渲染器----------vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();renderer->AddActor(actor);renderer->SetActiveCamera(camera);renderer->SetBackground(1, 1, 1);renderer->SetViewport(0, 0, 0.33, 1);//为主渲染器绑定回调函数，使用AnyEvent为了使任何交互都影响两个辅助摄像头renderer->AddObserver(vtkCommand::AnyEvent, callback);//---------设置第一个辅助渲染器----------vtkSmartPointer<vtkRenderer> renderer1 = vtkSmartPointer<vtkRenderer>::New();auto actors = renderer->GetActors();actors->InitTraversal();for (int i = 0; i < actors->GetNumberOfItems(); i++){renderer1->AddActor(actors->GetNextActor());}renderer1->SetActiveCamera(camera1);renderer1->SetViewport(0.33, 0, 0.66, 1);renderer1->SetBackground(1, 1, 1);//---------设置第二个辅助渲染器----------vtkSmartPointer<vtkRenderer> renderer2 = vtkSmartPointer<vtkRenderer>::New();renderer2->SetActiveCamera(camera2);renderer2->SetViewport(0.66, 0, 1, 1);renderer2->SetBackground(1, 1, 1);actors->InitTraversal();for (int i = 0; i < actors->GetNumberOfItems(); i++){renderer2->AddActor(actors->GetNextActor());}vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();renderWindow->AddRenderer(renderer);renderWindow->AddRenderer(renderer1);renderWindow->AddRenderer(renderer2);renderWindow->SetSize(1200, 400);vtkSmartPointer<vtkInteractorStyleTrackballCamera> style = vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();vtkSmartPointer<vtkRenderWindowInteractor> rwi = vtkSmartPointer<vtkRenderWindowInteractor>::New();rwi->SetRenderWindow(renderWindow);rwi->SetInteractorStyle(style);rwi->Start();
}
