int gen_plane_mesh(struct g3d_mesh *mesh, float width, float height, int usub, int vsub);
int gen_cube_mesh(struct g3d_mesh *mesh, float sz, int sub);
int gen_torus_mesh(struct g3d_mesh *mesh, float rad, float ringrad, int usub, int vsub);
int gen_plane_mesh(struct g3d_mesh *mesh, float width, float height, int usub, int vsub);
int gen_cube_mesh(struct g3d_mesh *mesh, float sz, int sub);
int gen_torus_mesh(struct g3d_mesh *mesh, float rad, float ringrad, int usub, int vsub);