OpenImageIO/oiio — pull request #342 by lgritz (2012-04-24 19:13:15+00:00)
Title: Review: In IBA::resize, use divide rather than multiply-by-inverse to improve precision

In IBA::resize, use divide rather than multiply-by-inverse to improve precision for filter normalization.

There are numbers for which x*(1.0f/x) != 1.0, wowee, and that throws off our filtering,
for example we can filter a flat 1.0 image and get result values that aren't exactly 1.0.

I did verify that even when resizing big images, this makes no measurable difference in speed.

(This was the original source of the roundoff error for the review I sent out yesterday regarding float-to-int quantization.)