I am trying to implement clipping in my simple renderer, but i have a trouble with setting the boundaries. I used the same projection matrix that is in OpenGL. The problem is, the vertices that are behind the camera(z<near) when mapped to NDC are bigger than 1(but they should be less than -1), so i can't use vertex.z > w. enter image description here

  • $\begingroup$ This is the expected behavior of a perspective transformation. Anything beyond the far plane is mapped to the range (1, 2f/(f-n)) and anything behind the camera gets mapped to (2f/(f-n), infinity). If you want test for "behind the camera", you can check to see if the value is greater then 2f/f-n. Once an object has been transformed into clip space it is usually not examined further. Are you implementing a software pipeline? $\endgroup$
    – pmw1234
    Jul 29, 2020 at 12:43
  • $\begingroup$ I decided to clip near plane in world space and for other planes in NDC. Works quite well. Thanks for reply, though! $\endgroup$ Jul 30, 2020 at 13:06


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