Color bug with screen128

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Sid_Som
Posts: 15
Joined: Tue May 19, 2020 11:24 pm

Color bug with screen128

Post by Sid_Som »

I tried it on the web emulator also, it does the same.

But this is the bug, when you go to screen mode 128 it does not show the text for the black color.
Not sure if this issue has been brought up before or not (I checked the other topics and did not see it). I noticed it when going back to finish a program.

Is this an issue in the actual hardware or just the emulator?
DragWx
Posts: 309
Joined: Tue Mar 07, 2023 9:07 pm

Re: Color bug with screen128

Post by DragWx »

Color 0 is always the transparent color. If you did "COLOR 0,1" and printed some text, you'd see an effect that looks like the letters are cut out from white blocks, through which you see the graphics layer.

Try color 16 instead; it's also black but not transparent.
kelli217
Posts: 513
Joined: Sun Jul 05, 2020 11:27 pm

Re: Color bug with screen128

Post by kelli217 »

DragWx wrote: Mon Jul 03, 2023 2:56 pm Color 0 is always the transparent color. If you did "COLOR 0,1" and printed some text, you'd see an effect that looks like the letters are cut out from white blocks, through which you see the graphics layer.

Try color 16 instead; it's also black but not transparent.
A little tricky to do that. The COLOR command doesn't support values higher than 15, no matter what mode the text screen is in.

Layer 1's config has to have its T256C bit set, in addition to being in tile mode and 1bpp color depth.

And only then can you do it, by putting the low nybble of the color index in the 'foreground' value for the COLOR command, and the high nybble in the 'background' value. For color 16, then, that's COLOR 0,1.
DragWx
Posts: 309
Joined: Tue Mar 07, 2023 9:07 pm

Re: Color bug with screen128

Post by DragWx »

Oops, you're right. :P

Having bitmap + 256 color text mode could be a potential screen mode candidate; I know in DOS, you can toggle between being able to have blinking text or being able to use all 16 colors for text background colors. This would end up being similar.
Sid_Som
Posts: 15
Joined: Tue May 19, 2020 11:24 pm

Re: Color bug with screen128

Post by Sid_Som »

So using the color black for text is out of the question for screen mode 128? Wasn't sure if that was intentional or not.
Oh well; guess there will be no black option then (for people to use in this game). :)
Guybrush
Posts: 63
Joined: Fri Jul 10, 2020 10:38 pm

Re: Color bug with screen128

Post by Guybrush »

There's nothing stopping you from defining any of the colors #1-#15 as black.
Sid_Som
Posts: 15
Joined: Tue May 19, 2020 11:24 pm

Re: Color bug with screen128

Post by Sid_Som »

You mean I can change one of the other colors to black? I do not know how to do that.
Sid_Som
Posts: 15
Joined: Tue May 19, 2020 11:24 pm

Re: Color bug with screen128

Post by Sid_Som »

There's a COLOR command? Was unaware of that. Either way, the COLOR command is irrelevant to my program. But thank you all for the reply.
Guybrush
Posts: 63
Joined: Fri Jul 10, 2020 10:38 pm

Re: Color bug with screen128

Post by Guybrush »

Sid_Som wrote: Sun Jul 09, 2023 12:23 am You mean I can change one of the other colors to black? I do not know how to do that.
The color palette is in VERA's memory at $1FA00-$1FBFF, two bytes (12 bits, actually) for each entry.

So, to set the color #N to black, simply set $1FA00 + (N * 2) and $1FA00 + (N * 2 + 1) to 0

In BASIC, that would be
VPOKE 1,$FA00+N*2,0
VPOKE 1,$FA00+N*2+1,0
User avatar
ahenry3068
Posts: 996
Joined: Tue Apr 04, 2023 9:57 pm

Re: Color bug with screen128

Post by ahenry3068 »

I've been trying out various techniques even if they aren't quite necessary.

I was using transparent text, just making sure there was a black graphics screen behind it.

I just used this vpoke to use color 6 as black text, works perfectly.

Used it in my Game of Life, not quite posted yet for this function... Will post whatever I have done
before bedtime tonight. (1 or 2 hrs from now....lol)

Playing with visual stuff now... Hope to implement Mouse input
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