7800basic Smasteroids flickers badly (video included)

[Coopdevil]

Hi all, first time caller etc. etc.

 

I've downloaded 7800basic to have a play with it but hit a problem straight away. The .78 file here - 

 - works beautifully and everything moves ssssooo smoothly. But when I attempt to compile the .bas on my install of 7800 basic, it runs terribly - the bottom half of all the falling sprites flickers like 2600 Pacman and swops between the bottom half and top half of the sprite. I uploaded a brief video to Youtube to show this

 

 

The player 1 sprites move fine although I forgot to plug in my joypad when taking the video like an idiot.

 

Have I overlooked something obvious? This occurs on both v0.15 and v0.16 Win 64 bit with that .bas file from that link, and the .bas from the downloaded binaries. 

 

Coop

Edited December 2, 2020 by Coopdevil

[+SmittyB]

I'm not at my computer to have a proper look right now, but I will say you shouldn't use ProSystem as it's quite out of date and not very accurate compared to other emulators.

BupSystem is the closest in terms of how it's used but is far more accurate. I'd also recommend A7800 and JS7800.

 

See if you get the same results with one of those and if you don't it'll be down to the lesser emulation of ProSystem.

 

 

Also, welcome to the  AtariAge forums.

[Coopdevil]

Cheers SmittyB, it ran OK under BupSystem. Just very weird that the earlier build of Smasteroids works OK on ProSystem but not mine!

 

Coop

[+SmittyB]

7800basic has improved a lot over the years so it's probably just down to those changes in the compiled code confusing ProSystem by throwing off its (rather inaccurate) timings.

[Mord]

Looks like the source started behaving like the above video as far back as compiled on win64-0.11.

 

When I compile it on 0.10 it works properly, but compiled on 0.11, 0.13, 0.14 and 0.16 you get the glitchy sprites. (didn't try 0.12 or 0.15, but would expect them to behave similarly)

 

0.11 is where the canary was added and some minor efficiency changes were done for plotsprite, among a few other things.

[RevEng]

It was the plotsprite tuning. One of the changes I introduced in the code broke prosystem. Between a choice of better performance vs. keeping an outdated and incomplete emulator happy, I picked better performance.