I'm doing some gfx to be displayed in GP2X LCD. I draw the gfx on PC mainly in Photoshop but the colors are very different and some details are really lost in GP2X Screen. Does anyone knows how to choose compatible colors with GP2X LCD Screen.

P.S. : I use an MKII device.

Any help would be highly appreciated.

The Best,

A_r_k from yuan-works was mentioning about the same thing, he said something about putting info online about it in awhile here...

Not sure if this is the same question but I've been curious about this actually. Whether the gp2x supports 32bit colour or not, or if I have to stick with 16bit.

For something I read it automatically scales the colour down I think if it is higher than supported but I would prefer a definitive answer.

Also I'm just going to test it tomorrow so don't worry too much

It can display 16 bit, RGB565
Not sure if Photoshop can change to this mode (i doubt it, but maybe)
The only reasonable way to blit RGB888 graphics is to cast away the least significant bit's for each channel.
So basicly 0x123456 becomes 0x083256.

I wrote a small program that applied floyd steinberg dithering on RGB888->RGB565 which i think it really helped with displaying images with gradients. I think it was used for the first background in gmenu2x. Although i lost the source now, it isn't very hard to code (just tedious). Also you can probably find some program that pulls this off as well (but most seem to only do RGB->palette)

I use Photoshop as well, with the 5_6_5 plugin from this page.

Actually I'd appreciate if you can make such a program again to help all people interested in GP2X gfx.

I use Nvidia's dds plugin for Photoshop which can be found on their site. It's free and allows the output of various modes including rgb565 and has options for dithering the image.

http://developer.nvidia.com/object/photosh...ds_plugins.html

Thank you Alex and ruckage! This will help I think.

P.S. : Hey ruckage, Have I told you how fantastic your game (ruck-man) ?

The MKII's LCD is pretty bad colour wise, which is why I'll soon release a color corrector for the gp2x, and it might eventually be added in open2x if DJWillis is convinced of its efficiency.

Actually hardware supports 4 formats:
4bpp with palette (16 colors)
8bpp with palette (256 colors)
RGB565
RGB24
It's only the high level libs use mostly RGB565 for some reason.


Interesting. And how are you going to do this, by adjusting gamma tables?

While waiting a software to correct the Gp2X gfx you always can try to calibrate your PC screen (making a profile) by displaying a test pattern on it.

That interesting to know. I was having a small problem when blitting and it ended up being a problem with the order I was getting the colour values from the image. Getting them in the order RGBA worked fine in windows, but (using alpha blending) produced a coloured background where it should have been transparent.

I've since found out that the order to make it work is to store the values from the image in RABG, which seems very odd to me. The code is exactly the same as the windows build so I can't be shifting along a bit anywhere. But they are using different SDL libraries.

you knnow what would be sweet...
Photoshop CS3 has Device Central..which allows you preview your work in the device it is intended for, even simulating, cloudy days, direct sunlight etc etc etc.
There is pretty much every phone and mobile device available for preview..I have not played around with it much (as I work mostly in CMYK print), but I will give it a look...perhaps there is a way to create a GP2X profile for Device Central...?

In the meantime...what popular mobile device is closet to the gP2x lcd? b/c then you can just preview your work in that setting

anyone have this DDS plugin for Mac?

--
ketch

I was under the impression the screen only has pins for at most RGB565 connected, so even if you blit RGB888 it'll still lose the least significant bits.

Yup. Released yesterday for testing. http://www.gp32x.com/board/index.php?showt...=37790&st=0

@ mfk : If you want colors to look right on the gp2x, either user my colour daemon, or created a cruve in Photoshop with the following settings :

In : 64, Out : 97
In : 128, Out : 143
In : 192, Out : 177

and apply this to all your gfx. Then it'll all look pretty much right on your MKII.