24-bit texture swizzling?

gotmilk065 · Post by **gotmilk065** » Sat Nov 28, 2009 11:01 am

Is it even possible to swizzle a 24-bit image?

I think I'm misunderstanding the concept entirely.. In all the examples I see, it's only being done to paletted images.

If you can, does it yield a performance increase?

a_noob · Post by **a_noob** » Sun Nov 29, 2009 4:04 am

The psp's gpu does not support 24 bit images. You will need to upsample it to to 32bit or down sample it to 16 or palletted. And yes you can swizzle 32 and 16bit unpalletted.

gotmilk065 · Post by **gotmilk065** » Sun Nov 29, 2009 3:28 pm

a_noob wrote:The psp's gpu does not support 24 bit images. You will need to upsample it to to 32bit or down sample it to 16 or palletted. And yes you can swizzle 32 and 16bit unpalletted.

Right, 32-bit images.

Do I use the same function I use for an 8-bit paletted image (GU_PSM_T8) for swizzling it? It doesn't work correctly.. Show's up with weird artifacts all over it, can't even be recognized as the same image.

gotmilk065 · Post by **gotmilk065** » Tue Dec 01, 2009 12:47 pm

Sorry for any bump, but I'd really like to understand why swizzling works and how to do it with a 32-bit image being rendered with GU_PSM_8888..

jojojoris · Post by **jojojoris** » Wed Dec 02, 2009 2:13 am

http://wiki.ps2dev.org/psp:ge_faq

gotmilk065 · Post by **gotmilk065** » Wed Dec 02, 2009 11:43 am

From what I gather, I should swizzle it with the width parameter multiplied by four, since it's a 32-bit image..?

Please correct me if I'm wrong; I'm trying to understand this to my fullest.

a_noob · Post by **a_noob** » Wed Dec 02, 2009 2:37 pm

That should do the trick, also don't forget to tell the GPU that the texture is swizzled when binding it.

Raphael · Post by **Raphael** » Fri Dec 04, 2009 7:58 pm

To add up on a_noobs reply (hi there btw :):
the swizzle function doesn't know, nor care about pixelformats. It only works on raw bytes and "swizzles" them around, hence it needs a byte-width as parameter, rather than pixel-width... everything else is cared for by the GU when unswizzling for rendering.

gotmilk065 · Post by **gotmilk065** » Tue Dec 08, 2009 8:59 am

Raphael wrote:To add up on a_noobs reply (hi there btw :):
the swizzle function doesn't know, nor care about pixelformats. It only works on raw bytes and "swizzles" them around, hence it needs a byte-width as parameter, rather than pixel-width... everything else is cared for by the GU when unswizzling for rendering.

Thanks, guys! Everything's working out, now :D

anmabagima · Post by **anmabagima** » Thu Dec 10, 2009 1:46 am

Hi there,

I would like to have swizzled textures as well. How do I do this ? Is there code part of the SDK i was unable to locate or do someone have the code this thread is referring to ?

Thanks for the help.
AnMaBaGiMa

Raphael · Post by **Raphael** » Thu Dec 10, 2009 6:41 am

Basically every available graphics engine (OSL, triEngine, JGE, ...) and even a lot of graphics sample codes have a swizzling function included. Doing a search on the forum would have helped too.

anmabagima · Post by **anmabagima** » Thu Dec 10, 2009 7:13 am

Hi,

thanks. I've found what I need ;o)