Does _MapTriangle work in a user defined Window?

[MasterGy]

i am using some old 3D rendering code from Stax who insists on Cartesian style coordinate system and build all vector routines around that so to use them I have to use Window call. Works fine for points and lines but I am having big problems with _MapTriangle ie nothing is getting drawn but no errors either.

if I can take a look to see if we can find the error