After thinking about it some, it looks like my tangent space matrix switched handedness on me. Jumped to right-handed but I’m working in left.

I reversed my wind order and cross-product calculation and both t and b are positive now. Is this correct?

I read a paper on deriving the tangent space matrix and was wondering what if any effect does handedness(left vs right) and vertex winding order have on the outcome of tangent and binormal.

I’m in a left-handed system and for a quad with normal (0, 0, -1), my tangent comes out to (-1, 0, 0), and my binormal is (0, -1, 0). The UVs are mapped to the four corresponding corners of the texture, not inverted or anything like that.

Seems like tangent and binormal should be positive in this case, so I’m fishing around for hints to try and understand.

Thx,

Unfadable