My First Kernel

[ClausB]

I've been lurking around these 2600 forums for nearly 2 years, learning what I can about VCS programming. I've been an Atari 8-bit programmer since 1980, but never tried the 2600, mainly because the TIA documentation wasn't available to me back then. But in these excellent forums you can find almost anything you need!

 

I've been working on my first kernel all this year, and I hope it will become the basis for a game I'm designing. It's been developed and tested only on the PC, using Stella 2.6.1 and some other tools, but not DASM. Stella, with its nice debugger, makes it so easy.

 

It's almost ready for posting, though it's still far from a complete game.

[GroovyBee]

Post away! Don't forget to include some screenshots of your work in progress. Although I'm not a 2600 guy I like to see what other people are doing on the machine.

[ClausB]

Here it is.

 

 

I had hoped to have it by July for the 40th anniversary of Apollo 11, but now it will have to be for Apollo 12.

 

The joystick trigger is the only active control right now.

APOLLO12.BIN

[yuppicide]

Looks great so far! Love the sprite!

[MausGames]

It's a great start! You should consider adding a reset.

[ClausB]

Thanks!

 

Sorry about the reset. I got spoiled by Stella's easy restart.

 

Anyone tried it on a real 2600?

[Zach]

Anyone tried it on a real 2600?

Yep, and unfortunately one of the bugs that emulators don't show appears. There is a small gap between the player objects. Chances are this is due to writing to the HM registers too early in the scanline. The Stella Programmer's Guide has more information. It's an easy mistake to make, and others have done so before, so think of it as a programming rite of passage. Otherwise the work so far is looking great!

[+Nathan Strum]

Yep, and unfortunately one of the bugs that emulators don't show appears. There is a small gap between the player objects.

Actually, the gap does appear in Stella 3.0.

[ClausB]

There is a small gap between the player objects. Chances are this is due to writing to the HM registers too early in the scanline. The Stella Programmer's Guide has more information.

Thanks for trying it. You're right, I set the HMPx regs too soon after the HMOVE. I see now that warning in the Guide. Here's a fix:

 

APOLLO12.BIN

 

Guess I should upgrade Stella, or maybe even get a 2600!

[Keatah]

Love this! Any change of it getting turned into a full-featured game? The sprite looks good, really good. And the ballistics seem just about right.

 

 

I had hoped to have it by July for the 40th anniversary of Apollo 11, but now it will have to be for Apollo 12.

 

Get this game back on track and we can go to the moon ourselves. No need to worry about NASA or anniversaries. Perhaps make the source available and someone else'd pick it up. I would, but I ain't no VCS programmer..

Edited November 4, 2017 by Keatah

[ClausB]

Thanks.

 

Well, we have two years until the 50th anniversary!

[djmips]

172 days