Imagination PowerVR SDK Blog

Mip Map Filtering Quality Issue



This discussion was created from comments split from: PVRTexTool mipmap quality issue.


Hi Tobias,

we have an issue with the quality of the mipmaps filtering too.

Perhaps this is related to your problem…

We use the latest version PVRTexTool 4.04 (SDK build 3.1@2308999).

I have a RGBA8888 PVR Texture converted from a png file.

(I’ve tried it also with the command line tool, every combination possible, still the same problems with the Quality)

It seem’s that the Mipmap Filters doesn’t make any difference and why is the quality so bad?

Check out the fine borders of the icons… if I resize it in Photoshop it looks much better.

And I think cubic filtering should look much smoother.

Please view the image in 100% size:


Hi Phellman,

This issue is unrelated to the first and going to require a separate investigation - so I’ve split it off into another topic. I can investigate in parallel whilst I’m there though. I’ll attempt to use the images you’ve used to debug this, but I will probably need the original images to see the effect. Would you be able to provide them, or at least the affected portion of the image?




Thank you! I sent it to you personally.


Hi Phellman,

So just thought I’d update you on this, I’ve got something looking a lot nicer for Cubic filtering now, and should be able to get that out sometime in the lifecycle of our 3.2 release. The quality improvement is quite noticeable. It probably won’t be in the first 3.2 release because I’ve managed to uncover a whole boatload of things that need changing with the Resizing methods before I’m going to be comfortable releasing it. In particular, the issue in the previous topic is causing some problems, though I believe I will be able to work around them successfully soon.

There are also a some other issues with the way the cubic resize is implemented which I need to address, and a number of quality issues with linear resizing. Hopefully I’ll be able to get these squared away in the next few weeks however, and may be able to release something shortly after the initial release. I have to admit, I had no idea how involved image resizing was before this…




Hi Tobias,

great to hear and thank you for updating me!

Is there any chance to make better mipmaps by hand?

Because we are using this on bitmapfonts and for smaller resolutions and therefore smaller mipmaps this is really not working…

Thanks and we hope for a quick release!

Thank you!


Yes that’s something I want to add back in, I just haven’t managed to do it yet. Something you can do if you want this functionality, is download one of our legacy SDKs (2.10 will do it - here) and use the old version of PVRTexTool to generate your textures. This feature was unfortunately lost when moving to Qt, but I think I can add it back now that the GUI is more stable.




Hi Phellman,

I took a little bit of time and added the Surface loading back into PVRTexTool, it’s now back in (albeit in a simplistic form for now) and it will be available in the 3.2 SDK.