How to use Z-buffer in Matlab

19 次查看（过去 30 天）

MENGZHI DI 2018-10-9

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/422969-how-to-use-z-buffer-in-matlab

评论： yang zhang 2020-2-11

Now I have a 3D point cloud. And I want to convert it to 2D image that viewed from different directions. I think it may works following: (1) rotate the 3D model, (2) use Z-buffer to determine which points are visible, (2) project 3D model to 2D image. I have some problem with the second step, which is Z-buffer. Could someone give me some advice about how to do it?

9 个评论
显示 7更早的评论隐藏 7更早的评论

Walter Roberson 2020-2-10

Given a viewpoint and a viewing angle, you do a translation of the point coordinates to be relative to the viewpoint, and then you do a rotation of the points to align viewpoint. Then any point that has a negative (local) Z coordinate is "behind your head" and cannot be seen, and every other point can be seen provided that it is not co-linear along that axes (if it is, then it projects to exactly the same local x and local y).

It is, however, not common to bother to compute these things yourself, as MATLAB does the computation automatically when you plot.

There is a closely related question having to do with how far an object is away from the viewpoint, in order to know how much detail to render the object at. However when doing that kind of calculation, you always have perspective, which the original question does not deal with. The computations to determine how much "Level of Detail" (LOD) for 3D scenes in virtual reality are typically handled by functions provided by the VR environment.

yang zhang 2020-2-11