vtk 怎么通过鼠标获取点云坐标

VTK是一个强大的可视化工具库，可以用于三维图形渲染和处理。如果要在VTK中通过鼠标获取点云坐标，我们可以使用 vtkRenderWindowInteractor 类中的特定事件来捕获鼠标的位置信息：

1. 首先，创建一个 vtkRenderWindowInteractor 实例，并注册一个鼠标事件处理函数。

2. 在鼠标事件处理函数中，使用 GetMousePosition 方法获取鼠标当前的位置坐标。

3. 使用 vtkPicker 类获取鼠标所处位置的三维点坐标。

以下是示例代码：

#include <vtkRenderWindowInteractor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkGenericRenderWindowInteractor.h>
#include <vtkPointPicker.h>
#include <vtkSmartPointer.h>

void MouseCallbackFunction(vtkObject* caller, long unsigned int vtkNotUsed(event),
                           void* vtkNotUsed(clientData), void* vtkNotUsed(callData))
{
  vtkSmartPointer<vtkRenderWindowInteractor> iren =
    static_cast<vtkRenderWindowInteractor*>(caller);

  int* pos = iren->GetEventPosition();
  vtkSmartPointer<vtkPointPicker> picker =
    vtkSmartPointer<vtkPointPicker>::New();
  picker->Pick(pos[0], pos[1], 0, iren->GetRenderWindow()->GetRenderers()->GetFirstRenderer());

  double* worldPosition = picker->GetPickPosition();
  std::cout << "Picked world position (x,y,z) is: (" << worldPosition[0] << ", "
                                                     << worldPosition[1] << ", "
                                                     << worldPosition[2] << ")" << std::endl;
}

int main()
{
  vtkSmartPointer<vtkGenericRenderWindowInteractor> renderWindowInteractor =
    vtkSmartPointer<vtkGenericRenderWindowInteractor>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->SetWindowName("VTK Mouse Position Example");
  renderWindow->SetSize(500, 500);
  renderWindowInteractor->SetRenderWindow(renderWindow);

  vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(renderer);

  // create some simple 3D data (a single point in space)
  vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
  double p[3] = { 1.0, 2.0, 3.0 };
  points->InsertNextPoint(p);
  vtkSmartPointer<vtkPolyData> pointPolyData = vtkSmartPointer<vtkPolyData>::New();
  pointPolyData->SetPoints(points);
  vtkSmartPointer<vtkVertexGlyphFilter> vertexFilter = vtkSmartPointer<vtkVertexGlyphFilter>::New();
  vertexFilter->SetInputData(pointPolyData);
  vertexFilter->Update();

  vtkSmartPointer<vtkPolyDataMapper> pointMapper = vtkSmartPointer<vtkPolyDataMapper>::New();
  pointMapper->SetInputConnection(vertexFilter->GetOutputPort());
  vtkSmartPointer<vtkActor> pointActor = vtkSmartPointer<vtkActor>::New();
  pointActor->SetMapper(pointMapper);
  renderer->AddActor(pointActor);

  renderWindowInteractor->AddObserver(vtkCommand::MouseMoveEvent, MouseCallbackFunction);

  renderWindowInteractor->Initialize();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

这个例子创建一个简单的单点三维数据，并在界面上显示该点，然后用鼠标在该点附近移动并输出当前鼠标位置的三维坐标。可以通过修改示例代码，将点云数据替换为自己的实际数据来实现获取鼠标位置对应的点云坐标。