backface culling inaccuracy

[glitchered]

State your operating system:

windows 10

DesMuME version

0.9.13 release

Issue

backface culling on flat floor or ceiling polygons is not emulated correctly. shows the wireframe instead of faces. ran it on device too.

basic dual screen 3d template with culling enabled and properly oriented faces.

[zeromus]

Seems like you have a test rom. Can you send a test rom?