Android DXT compatibility bug?

I just did a simple test packing a project with Android DXT setting. The project contained only one 2048 texture compressed into DXT1 format applied onto a cube mesh. The texture only connected to Emissive input of the material. The Project Target Hardware configuration had been set to Mobile/Tablet and Scalable 2D or 3D. On my Android phone, which integrated a Mali-450 MP GPU with 120MB VRAM, the texture was not properly rendered. The entire mesh appeared only a pure white color. But I’m sure my phone actually supports DXT format. However, when I switched the texture compression mode to R8G8B8A8 still using Android DXT package setting, it worked ! But it was an unacceptable fact that DXT1(and DXT5) didn’t work. And I also tested Unity3D engine with DXT packing mode, it worked perfectly with my phone. So it seems to be a bug of UE4. In fact, I’m more a UE4 user, so I really hope you can fix it soon.

Howdy Awesome_Junior_Miss,

Thank you for reporting this issue. I have attempted a simple repro and have been unsuccessful so far. Here are a couple of a photos to show my setup exactly:

Would there be any additional steps required to test this issue? Also, what version of UE4 would you be using when seeing this issue and is that version a binary build or a source build of the engine?

Any additional information would be greatly appreciated.

Thanks and have a great day!

Thanks for reply. Well, I found it was not an issue, I misunderstood one thing that my phone doesn’t exactly support DXT. However, Unity3D just made it looks like my phone supports DXT, actually it just automatically convert DXT to RGB format when building the package in order to be compatible with ETC devices. So UE4 did the right thing, it was not a bug. But as an advice, from a noob user, for the UE4 development team, if UE4 could tell me my device doesn’t support DXT when I accidentally choose Android DXT package mode, that would be much more user friendly. Thank you again.

Hey Awesome_Junior_Miss,

Glad to hear that you were able to figure out what was causing the error for you. We currently do not have a texture format list for mobile devices but there is an easy way to figure out what format your device will run off of. After you have deployed a project to your mobile device, you can bring up the console window by four finger tapping the screen of the device. From there, you will be able to see the available texture format that your device supports.

Thanks!