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PVRTexTool

by Hugo Munoz · in iTorque 2D · 09/19/2011 (8:26 pm) · 2 replies

Hi guys Im trying to compress some of my texture files using the PVRTexTool that comes with iTGB, my PNG's are in POW of 2 but when I compress them by using PVRTC2BPP and PRVTC4BPP options, they lost some quality, I guess this is a consequence of the compression, but surprisingly the files in pvr format are bigger than the original ones, is this normal ?? I have been playing with some of the parameters like mipMaps and PVR iterations, but almost always the result is the same, the compressed PVR file is bigger than the original PNG file, perhaps I'm miss-understanding something


Any thoughts ?
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Simon Almqvist Pettersson
Dohi Sweden
#1
09/20/2011 (12:07 am)
Yes, the PVR files can often become bigger than the .png version. But .pvr-files load faster and use much less memory when loaded on a device. Use them where you can and when maximum image quality is not of maximum importance.

Torque 3D Owner Ronny Bangsund
Torque Cheerleaders
#2
09/20/2011 (12:19 am)
The size of PVRs in memory will be the same as on disk (minus the header, if present). Nothing to worry about :)

It's unfortunately not easy to predict when to compress images with it since it can be affected by simple things. If you're compressing anything with a lot of wide colour transitions it often looks bad, while a sprite sheet with plenty of space between each sprite and very varied colours often compresses well. Sprites close up against each other definitely cause artifacts, and even low-colour background images get them.

A couple of examples of sprite sheets that turned out fine are the Kork and plant sheets from the Adventure Kit, and everything (tried most, anyway) in the 2D Fantasy Character Pack. I even used Apple's command line tool to compress them as 4-bit without them being visibly mangled.