potatohead's Blog

Hi PotatoHead.

 

That colored display is pretty much nearly exactly what I got from 1 of my many hacks in the Gime chip. By what I can workout. You lose access to the Palette Reg's after you run the mode change in the Fexx($FE00) area. But you could get different results if you set the Palettes to the colors you wanted before the Jump into the Fexx area.

How I think this worked is that all the Colors are already mapped into the Graphics screen. All Pixels are linked directly to the 16palette slots. So using a 16color mode 8Pixels/Byte I was getting a full 64 colors on the screen at the 1 time. No changing palettes mid scanline or timing tricks etc.

Also I found that to get this display you could not set any graphical pattern to the graphics screen. All data bits are to be left alone, other words on power up what ever is in the graphics screen is being used. How this could be of any use I have no idea.

But overall the display you got from a basic hack looks really impressive. Wonder what a full 16 color mode in 320x200 would yield.

When I get a chance I will upload a pic of what I got.

 

laters

 

Briza

Yeah, that's cool. Upload some screenies. I should have done this years ago. Didn't have capture hardware and Internet was new. The only reason I'm going down this road is a discussion here, triggered the memory.

 

IMHO, some retro ports done with this would be sweet! Have Rad Warrior for the CoCo? That's one game I thought would have been just excellent, had they thought of this. Way back when, I had that cart, and playing it, + seeing some artifacts, led me to tinker with a proggy not to different from the one I captured here.

 

The 320 mode yields a lot of different colors, but only 256 at any one time.

 

If you have time to tinker, build a palette with the 3 intensities (2 greys and 1 white) at the top of the palette, say slots 15, 14, 13, with 15 being white, 14 being light grey, 13 being dark grey. Slot 0 is black, then choose a bright red, dim red, bright blue, dim blue, yellow, green, etc...

 

Run this proggy and see the result. I've not played with the 320 mode yet, but I seem to remember the best overall color sets being something like that.

 

Anyway, the lowly CoCo 3 has a great CPU and a pretty killer 256 color graphics mode. Now it's on the net, documented at least.

 

You should upload code too. Had I done at least that, the last 15 years or so would have seen this used...

I don't think you can put pictures in blog attachments.

 

You have an AA blog. Post it there, and link it here!