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Zeviouz (2600)

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One thing I really like about VCS games, old or new, is that the controls are as close to zero-lag as can be. By virtue of the simplistic steam-punk like components in the console itself, everything seems fast-acting.

 

For starters the main microprocessor has something like 3,500 parts - and the video output of the console isn't but a few hundred more transistors away.

 

It was fun and rewarding snaking and weaving through Bacura. Big figure-eights and grand swooping curves.

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30 minutes ago, Keatah said:

One thing I really like about VCS games, old or new, is that the controls are as close to zero-lag as can be. By virtue of the simplistic steam-punk like components in the console itself, everything seems fast-acting.

 

For starters the main microprocessor has something like 3,500 parts - and the video output of the console isn't but a few hundred more transistors away.

 

It was fun and rewarding snaking and weaving through Bacura. Big figure-eights and grand swooping curves.

you mean on playstation and stuff theres lag?

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3 hours ago, Synthpopalooza said:

I might have a go at improving the music, if you want.  Been messing with TIA tracker and I'm sure I can improve it.

Sure, go for it!

 

Chris

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14 hours ago, cd-w said:

Here is a screenshot of the game - note the 4 color Playfield and awesome sprites by Nathan.

 

Chris

zeviouz_screen.png

Ah, from this picture and some debugging in Stella, I think I understand how this background is created with 2 colors per scanline, as you mentioned during the Zeropage Homebrew stream: It looks like you change both the BGCOLOR and PFCOLOR for each scanline, and then use some clever PF-interleaving to create very colorful backgrounds, right?

 

Is this similar to the ChronoColour technique used in Boulder Dash? (I think in Boulder Dash the BGCOLOR is always black, but I might be wrong there?)

 

O, and by the way: excellent game! 🙂

 

Edited by Dionoid

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6 minutes ago, Dionoid said:

Is this the similar to the ChronoColour technique used in BoulderDash (in which I think the BGCOLOR is always black, but I might be wrong there)?

Yes, it is similar. Boulder Dash uses three PF colors and a fixed black background color, Zeviouz uses two PF and two background colors for the mix. In both games the colors used are fixed per area/cave (Boulder Dash changes them for each cave). And they do not flicker.

Edited by Thomas Jentzsch
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boulder dash doesnt work on harmony regular- will this work on harmony regular- i havent put it on yet

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Yes, this one will work. Completely different tech used here.

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One of my favorite arcade and 7800 titles.  I was blown away at how smooth and beautiful it is!

 

I always enjoy simultaneous two player games, it might be interesting to add an option where player 2 is responsible for bombs or rotate control like Demon Attack does.

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9 hours ago, Thomas Jentzsch said:

Yes, it is similar. Boulder Dash uses three PF colors and a fixed black background color, Zeviouz uses two PF and two background colors for the mix. In both games the colors used are fixed per area/cave (Boulder Dash changes them for each cave). And they do not flicker.

 

I didn't consider the similarity to Boubder Dash until now, but it is essentially the same technique.   I got the original idea from this thread, though it isn't actually necessary to flicker the colors - the scrolling also helps to blend the colors together.

 

Chris

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is tigervision "Espial" supposed to be a variation of Xevious too i think? cause it plays like xevious more than the orig vcs xevious prototype....

Edited by chewy

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Wow - 200 downloads already - thanks everyone!

 

Chris

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Finally a good Xevious on the VCS !
I have the previous game on an "undressed" cart since almost 20 years and I thought it was a good point from starting a "complete" Xevious, but this one has a completely new engine that makes spectacular use of the characteristics of the VCS !

The various "programming tricks" that have been seen for more than a decade now are part of all realizations of a certain depth, so EXCELLENT job, Chris, Nathan !!

If I can (I'm a coin-op fan and a decent player with a few hundred thousand points), the Solvalou is a tad too fast on the move (and that's something that would have been nice in the arcade ;) ) and so is enemies' bullets. It may be that it is my impression also due to the fact that I'm used to playing it in vertical development but obviously VCS can't do it on a TV screen...

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On 8/19/2020 at 9:50 PM, cd-w said:

...though it isn't actually necessary to flicker the colors - the scrolling also helps to blend the colors together.

I did some tests with flicker, but at least in my slow LCD it doesn't look any better.

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Game is amazing - sound is great, graphics are beyond believe (on an Atari 2600) and most of it - it plays like a charm (fast and has a „good feeling“). It‘s not complete but yet has a great attention to detail - i can confirm that there are also hidden secrets on board like the little white flag earning an extra life (found it only once today and managed to collect it). Only wish for the future is a PAL 60 version, please!

Edited by Bomberman94
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The basic idea of Zeviouz (PF color mixing) could be used for other vertical scrollers too. I have no game in mind, but I am sure others can come up with a lot of them. E.g. games which are extending the gameplay with power-ups. Or maybe add some horizontal scrolling.

 

And then I wondered how far one could get with 6507 assembly only and did some math (assuming the kernel is in RAM):

  • The asymmetric playfield alone requires 6 read/writes per scanline plus 2 color read/writes. Each playfield r/w requires 7 cycles. And each color r/w 5 cycles. So that's already 42 + 10 = 52 cycles per scanline used. 
  • Displaying a sprite using e.g. MaskedDraw requires 11 cycles, that results into 22 cycles for both sprites.
  • And then you have a minimal loop overhead of 5 cycles every 2nd line (it makes sense to unroll the kernel at least once).

So in total that's 52 + 22 + 2.5 = 76.5 cycles. Which is already too much. And then you still have no sprite repositioning (and hiding the HMOVE blanks) or multicolored sprites covered. 


One could omit PF0 (which would look pretty odd then with the striped background) and save 14 cycles/scanline. And/or use two-line sprites and save 11 cycles/scanline. Maybe then it becomes feasible. But the overall conclusion is that you cannot replicate the Zeviouz kernel even theoretically using pure 6507 assembler.

Edited by Thomas Jentzsch
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