Switching graphic pages

Hardware Hacking, Programming and Game Solutions/Cheats
pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 12:30 pm

Hello,

I am making tests trying to mix two PMODE3 images that are one at page1-4 ($C00-$23FF) and the other at page 5-8 ($2400-$3BFF)
What I want to get is the illusion of mixing the colors of both screens' pixels so that it seems that there are 10 colors instead of 4 (4 simple and 6 combinations)

I have used the approach that Steve Evans gave to me in the thread about showing two different PMODEs on screen at the same time
Anyway, I end up with a lot of flickering

Does anybody know what is the best practice to get this fast page change without flickering?
The image is static, no move allowed, so it seemed easy at first sight, but probably I have taken the wrong way to solve it ...

Any advice will be welcome
regards
Pere

Pd. I attach here the asm code used to switch pages, it works but ... heavy flicker is present
Attachments
PAGESMIX-ASM.ZIP
ASM listing
(592 Bytes) Downloaded 86 times

pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 1:46 pm

hello,
I forgot to add the basic program that creates the two screens, loads the routne and starts it ...

regards
pere
Attachments
TEST-PAGESMIX-BAS.ZIP
Bas to test asm routine
(395 Bytes) Downloaded 88 times

sorchard
Posts: 413
Joined: Sat Jun 07, 2014 9:43 pm
Location: Norwich UK

Re: Switching graphic pages

Post by sorchard » Wed Oct 08, 2014 3:24 pm

Have you tried it on a real Dragon? I think it may look a lot better.

I think the problem is because the emulated frame rate will be close to 50Hz, but your laptop or PC is likely to have a refresh rate around 60Hz. Even if you could change the refresh rate to 50Hz, it wouldn't be exactly right and there would still be the occasional flicker.

The difference in frame rates also causes scrolling to appear slightly jerky.

I believe things would look better on an emulated coco because the frame rate is 60Hz but I haven't tried.
Stew

pser1
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Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 4:35 pm

hello sorchard,

you are right, I have copied the VDK to a floppy on my D64 and tested it there.
It runs with no flicker at all!
I was getting crazy about that flickering.

I must get the very same on the XRoar emulator on a Dragon64 ...
It looks great on the real thing ... some 10 colors (two of them with noticeable horizontal darker bars)
But this is because I apply them to very big surfaces. For sure when used on little areas it will be even better!
Maybe I try to mix a PMODE3 with a SG24 and let surprises arise :lol:

thanks a lot one more time.

cheers
pere

pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 4:46 pm

I have tried the other color palette and this one gives better results on the D64
There are vertical bars in some colors (Instead of horizontal), but I am sure they will not be notiicable on small surfaces

cheers
pere

pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
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Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 4:52 pm

I have to leave right now,
as soon as I come back, will upload some images of both color palettes

cheers
pere

pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
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Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 6:28 pm

back sooner than targeted!

These are two images that show the result of mixing colors 1,2,3,4 with themself and with each other.
This results in the four original colors plus 6 combinations (repeated, for instance, 2 with 3 gives the same than 3 with 2) set into 16 colored rectangles.

cheers
pere

PMODE3-Colorset0.jpg
PMODE3-Colorset0.jpg (36.52 KiB) Viewed 1891 times
PMODE3-Colorset1.jpg
PMODE3-Colorset1.jpg (36.98 KiB) Viewed 1891 times

pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
Location: Barcelona (SPAIN)

Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 7:00 pm

hello,

no matter what I do, it seems that it is not possible to change that frame rate on XRoar emulating Dragon, is it?

@sixxie
Do you know of any hidden XRoar parameter that could be tweaked to get rid of the unbearable flickering while switching pages
with the program I uploaded inside an VDK image?
In a real Dragon64 works flawlessly, its nice to see 10 colors on a PMODE3 image (no movement at all)

cheers
pere

sorchard
Posts: 413
Joined: Sat Jun 07, 2014 9:43 pm
Location: Norwich UK

Re: Switching graphic pages

Post by sorchard » Wed Oct 08, 2014 7:56 pm

The extra colours are great! Nice work :)

Have you tried mixing the two pmode3 colour sets?
Stew

pser1
Posts: 1338
Joined: Sun Mar 25, 2012 7:32 pm
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Re: Switching graphic pages

Post by pser1 » Wed Oct 08, 2014 8:40 pm

this was my next targeted move, this will give theoretically 16 different combinations, none of them the 8 originals!!

And another try will be done with three screens, two with colorset 1 and one with colorset 2. Using the actual mixed one (with 10 dif. colors) and mixing the 16 rectangles
with 4 rectangles of 4 different colors each, there should appear ... 40 colors, I need to see it to believe.

Anyway, trying to use this paging method will be painful, because we will need to convert the desired BMP image into three different files
that when mixed together will show in 40 colours something aproximate.

cheers
pere

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