Bounder graphics corruption mystery

By Manuel

Ascended (15113)

Manuel's picture

10-01-2019, 23:27

Someone commented on my Bounder YouTube video that it showed a bit of graphics corruption at the top side of the question mark tiles. I never noticed that, but indeed: it seems a bit corrupted.
Even more so when he told me this doesn't occur in openMSX on the National CF-3300! I tried it, and he's right. But I couldn't quickly find why it works fine on that machine. I tried several other machines (with the same VDP, with the same BIOS) but the corruption occurred on all other machines I tried.

Does someone know more about this? What's causing the corruption? Can you find a pattern in this?

See also: https://www.youtube.com/watch?v=ARpSDe4W3Hw in the comment thread from Miguel Colom.

Login or register to post comments

By mars2000you

Enlighted (5431)

mars2000you's picture

11-01-2019, 00:04

Maybe RAM in slot 3-0 on CF-3300 is the 'explanation' ....

By Manuel

Ascended (15113)

Manuel's picture

12-01-2019, 21:29

Miguel wrote:

Quote:

Well, after some debugging I know what is going on. A part of the pattern of the question mark is stored at 0xF093, which is overwritten by the BASIC stack before the game is started. A CLEAR 100, &HF000 before loading fixes it.

As I know that address is probably also used by the diskROM, I could indeed make the graphics look OK when adding a diskdrive to the machine I was using. The CF-3300 has a diskdrive, so that explains that as well Smile

By CASDuino

Expert (87)

CASDuino's picture

13-01-2019, 20:26

Interesting that I'd never noticed it before. Just tried both CAS files and they have the corruption on a HX-10.

EDIT:Tested the TSX files as well to see if it's possible that it was just bad versions but that too had the graphics glitch.

By Manuel

Ascended (15113)

Manuel's picture

13-01-2019, 22:06

Now, if you have one, try to connect a disk interface and try again Smile

By CASDuino

Expert (87)

CASDuino's picture

15-01-2019, 21:17

Unfortunately I don't have a disk drive interface. I can confirm that the Clear 100,&HF000 works though.

EDIT just added a Panasonic FS-FD1A to a HX-10 on OpenMSX and loaded the TSX and the corruption was gone.

By gdx

Prophet (2561)

gdx's picture

16-01-2019, 01:50

I have this game on the file "BOUNDER.COM" that works well.

By mars2000you

Enlighted (5431)

mars2000you's picture

16-01-2019, 02:19

Probably MSX-DOS initialisation fixes the problem!

By gdx

Prophet (2561)

gdx's picture

16-01-2019, 12:55

In fact BOUNDER.COM also has a graphic bug. Presentation screen is shifted down to the right, but I found another DSK that seems to really work well. This is a disk version by MSX Enhancers that works nice. The ball has been colored in orange like basketball.

By CASDuino

Expert (87)

CASDuino's picture

16-01-2019, 14:27

gdx wrote:

The ball has been colored in orange like basketball.

Yeah. Gremlin always made some slight changes to make sure they were not straight Spectrum ports. A nice bit of added extra. Also made it a lot better than the speccy version too.

My MSX profile