in bug #58956 we have a discussion about Octave's OpenGl renderer. In order to understand the limitations, I would like to reverse engineer the code in "axis::properties::update_camera ()", which can be found in the "graphics.cc" file. In this method, the model- and view - matrices are calculated. From the update_camera .c code, I created a .m prototyping code in order to visualize an arbitrary plot setup and Octave's 4x4 OpenGl transformation matrices. In the attachment you can see, for example, a visualization of Octave's x_gl_mat1 transformation for a 2D- and a 3D-view including the clipping planes.
My question is: If anyone knows if there is already a documentation about this code section, please let me know.