i remember the opengl comes with xojo was very outdated.
glGenTextures should exists starting with 2.0
https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGenTextures.xhtml
https://documentation.xojo.com/api/graphics/opengl.html#opengl
long ago i had a project called ThreeD
https://forum.xojo.com/t/opengl-and-makecurrent/79557
https://forum.xojo.com/t/xojo3d-not-working/75646/3