[Quesa-develop] TriMesh colours going to the wrong face

[Tom S. <to...@as...>]

Hi,

I am rendering 8-vertex cuboid shaped TriMeshes, with
an individual diffuseColor attribute specified for each triangle.

I am using an Orthographic camera with BackfacingStyleRemove.

When the view orientation is such that some faces of a cube lie
in a plane exactly perpendicular to the window plane, Quesa
seems to have trouble matching the correct colour specified to the face.

For example, I might have a red cube and a yellow cube, and
then some faces of the yellow cube turn red or vice versa.

As far as I can tell, this is a Quesa problem - I have tried the
same app compiled for Mac OS 9 / QD3D and all works fine.

I am using the release Quesa 1.6d18, on Windows XP.

The best work-around I have found is to set to BackfacingStyleFlip which
completely cures the problem but the speed reduction is too costly.

Is there another way?

Grateful for any suggestions,

Tom