Ticking "Alpha is transparent" would corrupt the color value of texture in the transparent region

Unity Engine
1

I found that if we tick the “Alpha is transparent” option in the texture’s importer, it would corrupt the RGB value in the region where alpha is 0.

This wouldn’t be a problem for normal AlphaBlended shaders, but it’s undesirable for premultiplied alpha shaders which need to extract the RGB value at the transparent region.

The only workaround I found now is to explicitly add an alpha channel in PSD or TGA, and leave the option unchecked when imported into Unity.

Not sure if this is expected behaviour, but not quite desireable.

2618684--183812--upload_2016-5-2_18-6-54.png

2618684--183813--upload_2016-5-2_18-8-11.png

2

This is working as intended … apart from showing alpha in the preview that “corruption” is the only thing that check box is for. The corruption, as you noted, is good for regular alpha blend as it helps fix the fringing that can happen. It’s kind of there to fix the fact that photoshop and other graphics editors like to strip the color data in the 100% clear areas which for real time you actually want to keep.