I am trying to export Blender's model data for DirectX.
The tangent is need to compute.
The Algorithm is from http://www.terathon.com/code/tangent.html
But in this step: float r = 1.0F / (s1 * t2 - s2 * t1);
It appears an error: float division by zero
I found the reason is one triangle face has two same uv. （
the uv mapping in DirectX is seems OK）
Is it regular?
How can I get the tangent In this case?
Update: Perhaps uv mapping is wrong, I am not familiar with the principles of uv mapping.
Edited by endrollex, 10 August 2014 - 10:33 PM.