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The Latest

Posted by vdub_bobby, 14 February 2008 · 264 views

2600 Game Development SuperCharger
HERE'S what I've been working on, slowly, over the last few weeks. Well, besides the tile demos I've posted in the homebrew forum, which are mostly just a sideline - for now, anyway. :ponder:

Attached File  Demo120080209.bin (4KB)
downloads: 287
Attached Image

Attached File  Demo220080214.bin (8.25KB)
downloads: 266
Attached Image

Both are very rough and likely will roll on a real TV.




Uihja. They both look interesting. Are they supposed to be two different parts of the same game?

What's the secret of the hidden black planet? ;)
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Uihja. They both look interesting. Are they supposed to be two different parts of the same game?

Yes. ;)

What's the secret of the hidden black planet? ;)

Ahhh...you discovered my little secr-

Oh wait. That's just an uninitialized pointer. ;)
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By the way, anyone have any comments on the star field in the first demo? Like the way it looks, or not?
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Hm... why does it flicker?
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It shouldn't...I must have posted a buggy version or something. Let me see if I can fix it or find a better binary.

EDIT: Welllllll. It works fine in Stella but doesn't in z26. Considering which one is more accurate, looks like I need to tweak it a bit. ;)

EDIT II: Which is annoying since I can't pause or single-frame-advance z26 and I can't really tell what the problem is...grrr ;)
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EDIT II: Which is annoying since I can't pause or single-frame-advance z26 and I can't really tell what the problem is...grrr ;)


If your computer is no deadly weapon >1GHz, then you can slow Z26 significantly down with enabling the log.

It seems 3/4 of the stars are just jumping left/right for one pixel on their way down, while 1/4 is fed with different NUSIZ values every other line, which is making them alternate between 1-2 pixels width.
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EDIT: Welllllll. It works fine in Stella but doesn't in z26. Considering which one is more accurate, looks like I need to tweak it a bit. ;)

EDIT II: Which is annoying since I can't pause or single-frame-advance z26 and I can't really tell what the problem is...grrr ;)

You can pause z26 by pressing the backspace key (press the enter key to resume). But for your purpose it might be better to slow the emulator down a bit. The command line option -r1 would make z26 run at one frame per second.

The problem seems to be with the pattern of the Cosmic Ark starfield effect. More specificly it's a problem with which scanlines get the double width pixels. We probably don't handle that properly in z26. I'm not sure how accurate Stella is with this.

On a real VCS the line with the double width pixels is always the one where the pixel would be displayed right before a new playfield block would start, IIRC. This is independent from where or how you trigger the starfield effect. I think the emulators might start the pattern always in the same way when you trigger the starfield effect, so the lines with the double width pixels might shift when you start the effect in a different scanline or the missile is in a different starting position.


Ciao, Eckhard Stolberg
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EDIT: Welllllll. It works fine in Stella but doesn't in z26. Considering which one is more accurate, looks like I need to tweak it a bit. ;)

EDIT II: Which is annoying since I can't pause or single-frame-advance z26 and I can't really tell what the problem is...grrr ;)

You can pause z26 by pressing the backspace key (press the enter key to resume). But for your purpose it might be better to slow the emulator down a bit. The command line option -r1 would make z26 run at one frame per second.

The problem seems to be with the pattern of the Cosmic Ark starfield effect. More specificly it's a problem with which scanlines get the double width pixels. We probably don't handle that properly in z26. I'm not sure how accurate Stella is with this.

On a real VCS the line with the double width pixels is always the one where the pixel would be displayed right before a new playfield block would start, IIRC. This is independent from where or how you trigger the starfield effect. I think the emulators might start the pattern always in the same way when you trigger the starfield effect, so the lines with the double width pixels might shift when you start the effect in a different scanline or the missile is in a different starting position.

Thanks! So...since the stars aren't moving left or right (just up/down) then actually my binary should be ok on hardware. I'll have to test it sometime to verify.

And thanks for the reminder of the -r1 option; I did activate the logging and, yes, it did slow it significantly, but it's kind of a clunky method! ;)
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Thanks! So...since the stars aren't moving left or right (just up/down) then actually my binary should be ok on hardware. I'll have to test it sometime to verify.

The sooner, the better - on MESS almost nothing of the binary is working:

Posted Image

And thanks for the reminder of the -r1 option; I did activate the logging and, yes, it did slow it significantly, but it's kind of a clunky method! :D

I agree, but it usually does the trick. And I always start with the log enabled anyways. (My hand is automatically pressing F12 when when launching a binary in Z26 after all these years :lolblue:)
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