vtkFrustumSource来理解视锥体

本是古典何须时尚 2022-12-24 05:58 113阅读 0赞

#include <vtkAutoInit.h>
    VTK_MODULE_INIT(vtkRenderingOpenGL)
    VTK_MODULE_INIT(vtkInteractionStyle)
    VTK_MODULE_INIT(vtkRenderingFreeType)
    
    #include <vtkActor.h>
    #include <vtkCamera.h>
    #include <vtkFrustumSource.h>
    #include <vtkMapper.h>
    #include <vtkNamedColors.h>
    #include <vtkPlanes.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkShrinkPolyData.h>
    #include <vtkSmartPointer.h>
    
    int main(int, char *[])
    {
    	// 通过该类得到指定物体的颜色
    	vtkSmartPointer<vtkNamedColors> colors =
    		vtkSmartPointer<vtkNamedColors>::New();
    
    	vtkSmartPointer<vtkCamera> camera =
    		vtkSmartPointer<vtkCamera>::New();
    	camera->SetClippingRange(.1, .4);
    	double planesArray[24];
    	// 获取当前视锥体的6个平面
    	camera->GetFrustumPlanes(1.0, planesArray);
    
    	vtkSmartPointer<vtkPlanes> planes =
    		vtkSmartPointer<vtkPlanes>::New();
    	planes->SetFrustumPlanes(planesArray);
    
    	// 创建视锥体
    	vtkSmartPointer<vtkFrustumSource> frustumSource =
    		vtkSmartPointer<vtkFrustumSource>::New();
    	frustumSource->ShowLinesOff();
    	frustumSource->SetPlanes(planes);
    
    	// 缩放
    	vtkSmartPointer<vtkShrinkPolyData> shrink =
    		vtkSmartPointer<vtkShrinkPolyData>::New();
    	shrink->SetInputConnection(frustumSource->GetOutputPort());
    	shrink->SetShrinkFactor(.9);
    
    	vtkSmartPointer<vtkPolyDataMapper> mapper =
    		vtkSmartPointer<vtkPolyDataMapper>::New();
    	mapper->SetInputConnection(shrink->GetOutputPort());
    
    	vtkSmartPointer<vtkProperty> back =
    		vtkSmartPointer<vtkProperty>::New();
    	back->SetColor(colors->GetColor3d("Tomato").GetData());
    
    	vtkSmartPointer<vtkActor> actor =
    		vtkSmartPointer<vtkActor>::New();
    	actor->SetMapper(mapper);
    	actor->GetProperty()->EdgeVisibilityOn();
    	actor->GetProperty()->SetColor(colors->GetColor3d("Banana").GetData());
    	// 设置反面颜色
    	actor->SetBackfaceProperty(back);
    
    	// a renderer and render window
    	vtkSmartPointer<vtkRenderer> renderer =
    		vtkSmartPointer<vtkRenderer>::New();
    	vtkSmartPointer<vtkRenderWindow> renderWindow =
    		vtkSmartPointer<vtkRenderWindow>::New();
    	renderWindow->SetWindowName("Frustum");
    	renderWindow->AddRenderer(renderer);
    
    	// an interactor
    	vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
    		vtkSmartPointer<vtkRenderWindowInteractor>::New();
    	renderWindowInteractor->SetRenderWindow(renderWindow);
    
    	// add the actors to the scene
    	renderer->AddActor(actor);
    	renderer->SetBackground(colors->GetColor3d("Silver").GetData());
    
    	// Position the camera so that we can see the frustum
    	renderer->GetActiveCamera()->SetPosition(1, 0, 0);
    	renderer->GetActiveCamera()->SetFocalPoint(0, 0, 0);
    	renderer->GetActiveCamera()->SetViewUp(0, 1, 0);
    	renderer->GetActiveCamera()->Azimuth(30);
    	renderer->GetActiveCamera()->Elevation(30);
    	renderer->ResetCamera();
    
    	// render an image (lights and cameras are created automatically)
    	renderWindow->Render();
    
    	// begin mouse interaction
    	renderWindowInteractor->Start();
    	return EXIT_SUCCESS;
    }

在透视投影中，三维模型中的视锥体，由相机位置，相机焦点，裁剪平面（近平面和远平面，屏幕与相机角度形成的裁剪？），相机的视角方向viewUp，

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