Texture Atlases

SyaPed

Unity Texture atlases for mobile games...Combine regular and alpha'd textures into one atlas or seperate into two atlases? Or put all diffuse texture in one atlas and all alpha info in another atlas?

hakankaraduman

As far as I know, you can put both rgb and alpha channels in one image. Just paint black the areas which don't have alpha value in alpha channel.

SanderDL

It's better to seperate the two. You don't want to have a big atlast with an expensive shader just because you have some part that need an alpha.

DLoud

Sander is right. It's better to separate the two. Objects using alpha transparency will be rendered as a transparent object even though the whole mesh may be using the white portion of the alpha. Overdraw could be an issue depending on your scene complexity.

There are some perf gains to be had by keeping them separate.

SyaPed

Thanks guys

DLoud

You betcha!

rafastrip

hakankaraduman said:

As far as I know, you can put both rgb and alpha channels in one image. Just paint black the areas which don't have alpha value in alpha channel.

hey , bro ,how can I separate the channels? in unity ? or with another software ? to optimize the result of the atlases.

Mehran Khan

maybe try using texture arrays, I have been using them on mobile-VR and they work like a breeze, not to mention they allow you to skip the dreaded atlassing step.
you will need amplify shader editor to make custom shaders with array support.

rafastrip

Mehran Khan said:

maybe try using texture arrays, I have been using them on mobile-VR and they work like a breeze, not to mention they allow you to skip the dreaded atlassing step.
you will need amplify shader editor to make custom shaders with array support.

what do you mean about textura array? a collection of cartoony and well sized texture one by one put together like a texture atlasing? is the same technique as texture atlasing or similar? use  photoshop for example to create the collection of these ? thx for the info.

jStins

https://docs.unity3d.com/Manual/SL-TextureArrays.html

RyanB

Another issue with mixing RGB and RGBA is that some compression formats sacrifice RGB quality to add the A channel.  An RGBA texture will look worse than an RGB texture using PVRTC. 

Previous thread: https://polycount.com/discussion/161034/ios-pvrtc-compression-terribly-for-rgba