2600 / 7800 ports

[rdefabri]

There have been some excellent ports to the A8 line, notably Glurk’s 2600 ports.

 

Since there are some great 2600 and 7800 titles (Gorf Arcade for 2600, Popeye for 7800), I’m curious if any of these could be ported over.

 

I realize that some of these games use additional voice chips, or in the case of the 7800, the MARIA chip — which makes it difficult if not impossible, but with VBXE, could any of these games be ported over?

[Beeblebrox]

I'd love to see the prototype Sirius ported over as close as possible on stock A8 chipset, perhaps utilising 128k and above. The double ships and soundfx. 

 

 

Also same for Apple snaffle

 

Edited April 1, 2023 by Beeblebrox

[rdefabri]

Some great 7800 homebrews, I’m envious!

[pseudografx]

AFAIK, Sirius is not a homebrew, it should have been released commercially back in the day but was never finished.

[Beeblebrox]

Correct. Siruis was an unreleased prototype:

 

http://www.atariprotos.com/7800/software/sirius/sirius.htm

 

Really love the dual ship aspect to the gameplay and great soundfx. Some bosses thrown into the mix also. Nice backdrops.

[Rybags]

With VBXE problably all.

But 7800 graphics are done so differently to just about everything out there that it's a non-trivial job.

As examples I did Spectipede from the C= Plus/4.  The graphics are pretty similar to ours except bitmap which is cell based like C64 (this game uses MC text).  I had that game in a working state after about 2.5 hours.

I did Moon Cresta (partially) from the 7800.  It was multiple days work before any working program was had.  There's not too many moving objects besides the stars (which I did in legacy graphics with attribute for colours) so sprite conversion wasn't too hard.

 

The Maria chip is essentially a sprite engine with the limitation being based on how much can be read in at the memory speed (I think 7 MHz with 3 cycles for Rom read and 2 for Ram? )

 

The 2600 - we've seen multiple games from it but still the graphics are sufficiently different that ports are usually far from direct.  Although it only has 2 Players there is the replication mode which the computer can't easily replicate.  Also object positioning is done differently on both systems so conversion has to take place there.

[Eagle]

12 hours ago, Rybags said:

The Maria chip is essentially a sprite engine with the limitation being based on how much can be read in at the memory speed (I think 7 MHz with 3 cycles for Rom read and 2 for Ram? )

Yes, and it can make a lot of sprites.

Few examples.