Hi everybody !

I'm trying to make my own texture format for lwjgl. Basically, it's very simple : the image is in raw format, and I gzip the image to reduce its size.

My goal was to reduce the loading time (because using awt image loader is not very fast...). But i've made some benchmarks and here are the results :

- When using the awt loader : 1530 ms
- When using raw format without gzip compression : 450 ms (3 times faster !!!)
- When using raw format with gzip compression : 3560 ms

So I deduce that using a GZIPInputStream is very very slow...
Does someone know where to find a faster "ungziper" or how could I do to make the decompression faster ?

Thanks for your help
++
Chman

EDIT: Oh, and forget about my english

Hum... There are not so many gzip nor zip decoders for java on the web... The ones I've found were very slow, like in the JDK...

Any advices for my image loader ?

http://www.jcraft.com/jzlib/index.html this is the one other java compression lib I know of.

Ant knows how to do bzip2 but that is more CPU intensive than gzip http://ant.apache.org/manual/CoreTasks/pack.html

Hmm princec beat me to it.

Well keep your images gzip in your distribution. Then you can unzip all the files the first time the game is launched or when it is installed. HDD storage is cheap and most people have to much of it. I prefer a fast loading game over some 10-50mbs of HDD space anytime.

Disk space is hugely plentiful and abundant, and bandwidth ain't. So who cares if it's half a meg when it's unzipped? I only care that it takes 10 seconds to download!

You ought to be more worried about squeezing it into graphics card memory than the speed it unzips at! Look into S3TC texture compression to shrink your textures a bit.


Cas

No, only modern ones. You'll have to check for the extension.

If I recall, it doesn't save on disk space, but when you upload the texture to the card, the drivers convert it to the compressed format of your choice (in glTexImage2d)

Cas

Actually the best thing about the extension is the ability to _ignore_ specific formats. I can upload a texture with the GL_COMPRESSED_RGB(A) format and it will simply choose an appropriate format. That's the real spirit of OpenGL and comes as core in version 1.3 or 1.4 (don't remember exaclty). You will only need the more specific S3TC extension if you need to update your textures on the fly.

- elias

But we're talking compression as an internal texture format, so the texture will take up less of the precious video memory. The extension has nothing to do with disk format (even though you can retrieve the texture in the driver specific compressed format).

- elias