vtk 深度圖

WriteDepthMap（）函數
https://stackoverrun.com/cn/q/13036969
https://stackoverrun.com/cn/q/4808791
https://www.vtk.org/Wiki/VTK/Examples/Cxx/Utilities/ZBuffer

• ZBuffer

    可以通過使用Z緩衝區中的值並在0-255之間縮放來實現可視化，但是這不提供真實的深度信息。
  

• 真實的深度
  https://stackoverflow.com/questions/17654545/render-rgb-d-image-from-mesh

double z = render_win->GetZbufferDataAtPoint(x,y);
worldPicker->Pick(x, y, z, renderer);
worldPicker->GetPickPosition(coords);
double euclidean_distance = sqrt(pow((coords[0] - cam_pos[0]), 2) + pow(coords[1] - cam_pos[1], 2) + pow(coords[2] - cam_pos[2], 2));

http://vtk.1045678.n5.nabble.com/Build-depth-map-of-a-3D-model-td5689116.html