Amiga 1200 - graphics corruption

[solarmon]

Hi

Can somebody explain why I have such a graphics corruption when loading up Buggy Boy from disk (via .adf image on a Gotek/Flashfloppy):

[img=300x300]https://i.imgur.com/KtIHPha.jpg[/img]
[img=300x300]https://i.imgur.com/gMAq5Jh.jpg[/img]


EDIT: I don't know why image resize is not working. Here are the links:

https://i.imgur.com/KtIHPha.jpg
https://i.imgur.com/gMAq5Jh.jpg


You can see with the first image that it is just about to start at the top of the screen.

Is this a hardware fault on the custom chips, or memory chips. Or maybe due to faulty caps that need replacing?

I see such corruption/glitches on other games. It doesn't seem to occur for static graphics, only moving/changing graphics.

Cheers!

EDIT: Forgot to say, the A1200 has a Commodore 2B motherboard, 2MB chip ram only, if that helps.

[fryguy]

Buggy boy is an old game. Have tried changing to OCS in Early Startup menu and disable CPU caches? But even that might not help.

[lesta_smsc]

I saw similar artefacts in some cracktros but game worked fine... Or using the KS 1.3 helped.

[solarmon]

For Buggy Boy, using the early boot menu to disable CPU caches and using the Original Chip Type did not help. This corruption only seem to appear in the crack intro. In game, there is no corruption.

Turrican has the following horizontal type corruption. You see that the character can overlay the corruption, which actually stays in the position it appears in the playing field:

https://i.imgur.com/0q0RyP9.jpg
https://i.imgur.com/w6ykXSB.jpg

Again, disabling CPU caches and setting to use Original Chip Type did not seem to help.

For Hybris, the corruption is even more severe:

https://i.imgur.com/KW9iQP8.jpg
https://i.imgur.com/NYwC0Ki.jpg
https://i.imgur.com/5RzdBjS.jpg

However, disabling CPU caches and setting to use the Original Chip Type did actually resolve the corruption.

I tried Buggy Boy and Hybris using WHDLoad (through TinyLauncher on startup) and I don't get the same corruption. Probably because for Buggy Boy since there is no crack intro. And for Hybris probably because WHDLoad chooses the right kickstart/chipset.

I didn't yet get a chance to test Turrican using WHDLoad.

[Venom]

For anyone in the future with similar issues, as it seems that corrupt/glitchy graphics seems to extremely poorly documented online or I couldn't find any mention except this thread.

The issue is software incompatibility with your kickstart version. The one I've had issues with the most is Deluxe Galaga and could perfectly recreate the issues shown by Solarmon. Sometimes changing to OCS works but sometimes it doesn't. WHDLoad solves the issue if you have the the correct kickstart version loaded in your WHDLoad "devs/kickstarts" folder. Games from floppy also load fine if you load them with loading workbench on boot (with WHDLoad installed at least, haven't tried without). However loading them straight from floppy doesn't work.

This is basically a floppy/gotek loading only issue. If you can you could check in the readme/guide of the game you want to load if there is a compatibility patch you can run if you boot without a startup sequence (2 mouse buttons down on boot). For example in my case Deluxe Galaga ran fine if I booted without a startup sequence, types "setpatch30" and than ran the game from floppy.

Or the TL;DR:
Booting some games straight from floppy has compatibility issues. This can be solved with WHDLoad or a startup patch if the game has one.

Sorry for the necropost, but this way the wheel doesn't have to be reinvented.