i made something with opengl a few years ago, maybe you get examples from there.
ThreeD.xojo_binary_project
https://drive.google.com/file/d/1ZTtH1pERNenkHPksg7sdhMEHGXH4JxVO/view?usp=share_link
i remember this xojo opengl was very very out of date … (not for deploy an 3d app with)
https://www.khronos.org/opengl/wiki/History_of_OpenGL