Fix UE's alpha handling

[anonymous_user_fbe2d247]

@Antidamage

Yeah after thinking about it for a few days doing it during mipmap generation would be a strange place to fix it.

I’ve lost the issue tracker link but it turns out Epic became aware of it in April finally and are going to do exactly what we’re discussing, I can only assume that they’ll handle bleed as an import step or something. Obviously it’d be an option in the texture.

Are mipmaps really generated on the GPU? That doesn’t seem right but I’ve never gone beyond a high level with it.

Mipmaps are generated on CPU. But bilinear filtering happen when you sample texture at rendering time.