Re: How to use transparent images In UE4
Posted: 20 Mar 2018, 14:52
Hi,
That PNG doesn't have the color channels premultiplied by the alpha channel. The topmost, leftmost texel is RGBA (255, 221, 93, 0). If it had alpha premultiplied it should be (0, 0, 0, 0). What this setting does is it fixes a problem that comes from the way Unreal handles PNGs when they are imported, but it doesn't do the premultiplication. This forum post has a tool you can add to your pipeline to do the premultiplication:
viewtopic.php?f=3&t=1036&p=5842
Perhaps the meaning of the setting wasn't very clear.
I guess I could maybe add another option to do the premultiplication, if enough people find it useful.
That PNG doesn't have the color channels premultiplied by the alpha channel. The topmost, leftmost texel is RGBA (255, 221, 93, 0). If it had alpha premultiplied it should be (0, 0, 0, 0). What this setting does is it fixes a problem that comes from the way Unreal handles PNGs when they are imported, but it doesn't do the premultiplication. This forum post has a tool you can add to your pipeline to do the premultiplication:
viewtopic.php?f=3&t=1036&p=5842
Perhaps the meaning of the setting wasn't very clear.
I guess I could maybe add another option to do the premultiplication, if enough people find it useful.