Shannon's Blog - color blind, 3 steps forward 1 step back, epiphany

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[Colorblind]

 

I was tinkering around with some code that was posted up on the A800 sourceforge cvs that now provides seperate NTSC and PAL palette support. When I implemented the code (assuming I didn't foobar something) I noticed that the PAL palette's black level seemed kinda off. See below pictures.

 

Now this guy took pictures. See links below. Now the guy said this..

Atari PAL and NTSC colors are actually a little bit different. As you might know, PAL stands for "phase alternating line" - the color phase is shifted by 180° every other line. But Atari didn't manage to build a perfect 180° phase shift into the PAL GTIA. As a result (the TV set reverses the phase shift and averages the color vectors) the color saturation is reduced - the colors look a little bit 'washed out' (especially red doesn't look too great IMHO).

But the thing is he said that the picture was taken from an S-video modded Atari.

 

His pictures look closer to NTSC than the ones produced by the new NTSC palette.

 

Another odd thing is if I apply the default saturation of 100 and color shift of 30 that earlier versions of colours.c would apply to the PAL palette it almost appears to be exactly the same as the NTSC palette.

 

So I made a post over in the atari 8-bit forum for some input.

 

 

new NTSC

 

 

 

 

 

 

 

 

 

 

 

//

new PAL

 

 

 

 

 

 

 

 

 

 

 

//

Svideo PAL

 

 

 

 

 

 

 

 

 

 

 

//

 

 

I actually dragged out my 5200 and took a look at a few games and for the most part the new NTSC palette seems ok but unfortunately who knows how bad the tint is off on the tv I was hooked up to. So I'll have to try it on a couple other TV's.

 

[3 steps forward, 1 step back]

While working on my little "project" it's amazing how much progress can be made but then some little "quirk" pops up. Well seems the 5200 version of Beef Drop doesn't respond to the Start, *, and # keys anymore although other 5200 titles seem unaffected.

 

[epiphanies]

It's pretty funny digging thru code trying to figure something out only to find out it was right in front of you. For some reason I could not figure out how X-port's code was producing sound. He pretty much cleaned out the sound.c code. Well seems he moved it somewhere else. Doh!

 

Just realized that the code changes I made to SIO.c to only do four drives can probably be switched back to 8 since the code automagically ignores "empty" drives anyways. Same thing with the disk rotate option.

 

Apparently the front end does not "unload" a cartridge when switching games thus creating weird behavior. (like atari basic being unusable). Fixed that.

 

X-port set up an A800 directory for configuration uploads so I'll start upping stuff there once I know the conguration file is stable.

 

http://www.atariage.com/forums/index.php?a...;showentry=4369