// - Use render(), or as in render(...), transfer the vertices once, not in a loop over all triangles (vertices are getting transformed multiple times)
// - We transform them later (below) a second time. Only do it once.
v0=Mat(mvp_matrix*Mat(v0_3d));
v1=Mat(mvp_matrix*Mat(v1_3d));
v2=Mat(mvp_matrix*Mat(v2_3d));
v0=Mat(affine_camera_matrix*Mat(v0_3d));
v1=Mat(affine_camera_matrix*Mat(v1_3d));
v2=Mat(affine_camera_matrix*Mat(v2_3d));
// Well, in in principle, we'd have to do the whole stuff as in render(), like