Bug: discolored mipmapped compressed textures

Development
1

Hi,

I have built a test case that shows a possible bug. On the screenshot you can see discolored mipmaps on compressed textures.

test case:

screenshot:
http://alrik-online.de/alrik/screens/MipmappingBug.jpg

regards

Alrik

2

I can confirm this issue on
linux 64bit with intel onboard using mesa driver.

What is your os, ect?

3

Windows 7 64Bit and AMD Radeon R9 290x using Catalyst 14.5 driver

4

Also happens on Win 8.1 64 bit with latest Nvidia drivers (347.88) on a GTX 780.

5

Wow… a bug in DXTFlipper. Who would have thought :wink:

There is a bug with how it flips images of size 2x2, i.e. the second to last mipmap level which is where the glitch appears in the screenshot.

For DXT1/3 images, the format for color and alpha blocks is the same, so the bug would not appear. For DXT5 images, the alpha block is formatted differently. The issue is that it flips the color block and then the alpha block for 2x2 images, but the correct order is alpha blocks first.

Fixed in GitHub master.

3 Likes
6

That is awesome. Thank you for the fix! :blush:

7

wow,

sounds like that was realy hard to pin down :wink:
Thanks