Game Development Community

Experiments with pngcrush & texturetool

by Ronald Ian Bantayan · in iTorque 2D · 04/02/2009 (4:37 pm) · 1 replies

Just found out that using pngcrush with the -iphone option changes your source PNG into something that's only readable by the iPhone/iTouch hardware itself. It rearranges the header and some of the chunks so that a regular picture viewer can't load it, and TGB crashes if you try to import a PNG file processed with pngcrush. Same with texturetool. texturetool is supposed to convert an imagefile into PVR format, useable by the PowerVR MBX chip residing in your iPhoneOS device. But importation into iTGB nets the same results. A crash.

Right now, the only utility that works for me is PNGCrusher, which is a GUI of OptiPNG. Simply drag a file onto the program icon. It optimized my splash screen PNG by around 75% (~110KB --> 24KB.)

#1
04/02/2009 (11:47 pm)
I use pngout, which seems to beat all of the others, for my PNGs. As you'll find from the rest of this subforum, there are issues with PVR. Apple's format doesn't load in iTGB, and the supported format is only possible to create in Windows or Linux! Hope they have that in 1.2, but they probably rely on PowerVR giving them code.

PVRs will remain the same size in memory, so that is what we're hoping for. But since they are also using a reduced colourspace (only 16 bits for the whole pixel on iPhone/iPod touch), it would be beneficial to see the actual PVR data in iTGB's editor.