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Space Invaders - WIP

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My idea - use the original samples or at least some of them.

The 4 note marching song could probably be done at an economically low playback rate.

 

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7 minutes ago, Synthpopalooza said:

Has there been any sound designed yet?  I got a few ideas ... 

I haven't done sound and have no idea about it other than some basic beeps with the BASIC sound command - this was something I was going to ask about, either to learn or get someone to do the job for me :)

 

I need an accurate copy of the aracade version at 60hz for NTSC.  Although the PAL version will run at 50hz and the invaders will therefore move slower (unless I can figure out a decent way to move them faster) I'd like the music and effects to sound the same as the 60hz version.

 

As for the optional versions of the game, you can play around with the sound effects/music as much as you like.

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If you like I can try to cook up something in the next couple of days.  I'm pretty confident that I can get it very close to the arcade version.

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Just now, Synthpopalooza said:

If you like I can try to cook up something in the next couple of days.  I'm pretty confident that I can get it very close to the arcade version.

Sent you a PM, thanks.

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I don't think the arcade version was frame-locked though I don't recall seeing tearing that you'd associate with mid-frame updates.

Possibly a page-flipping technique at VBlank could be used and the game could just run at "CPU speed" with delay loops ?

 

Even though NTSC is "faster" in raw CPU terms PAL usually is because NTSC suffers more screen DMA losses.

 

Of course a problem with CPU delay based timing is that the whole thing breaks if you're using a faster CPU, though methods could be employed to overcome that problem.

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Space Invaders was my one video game addiction.  OK, maybe Donkey Kong as well.  However, I was pretty good at Space Invaders but not the latter.

 

I don't know if it had a hacked ROM or there was a feature of the game's settings or if there's a bug in software, but the machine I played would post 99 credits when I rolled the score past 9999.  

 

I routinely rolled the score 5 times.  Rarely 6 times.  There was one player who was better.  Together we played all morning before afternoon classes on 50 cents. 

 

These tricks and "easter egg" made my score possible.   The latter is a cheat but you need to develop a skill in order to make use of it.

 

When an invader one row above the bottom  (or just above your gun) you are safe from being shot. You move to the far right then move back to the left shooting every invader  along the.   You must be 100% every time a row reaches that region.  It's possible to recover from a miss but it takes a lot of fast shooting and mostly luck.  

 

I hope your port will play on NTSC machines because I truly love this game.

 

Looks great so far!  Thanks for revisiting this classic!

 

-SteveS

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I got tired of it years ago but was always bothered that we missed an authentic version.

 

It's one of those rare games where accuracy is more desirable even if it means sacrificing quality or gameplay elements.

 

My interest was renewed a bit with Space Invaders Frenzy, the arcade game.  It adds a whole new dimension, and I've already mentioned here it'd be a cool game to have although of course it's pretty demanding in terms of hardware grunt.

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2 hours ago, Stephen said:

How is the logo so white?  On PAL, the output looks like:
2025765078_AtariPower.thumb.png.414b8114760ad93d5d110093166369a2.png

 

On NTSC, it's the same green I'm talking about above that tends towards blue and ends up having a more whitish appearance in the lighter luminances.

 

Here it is for PAL.

 

665836285_AtariPower(PAL).thumb.png.70a13084512367673dbeb9595ba6f557.png

 

Atari Power (PAL).xex

 

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Thanks - I will say that I am quite severely colour-blind so I can never be sure of what I am seeing on stuff like this.

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1 hour ago, Stephen said:

Thanks - I will say that I am quite severely colour-blind so I can never be sure of what I am seeing on stuff like this.

Ah, yeah, you mentioned that before (color blind).

 

No problem; I don't mind explaining the stuff.

 

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5 hours ago, a8isa1 said:

These tricks and "easter egg" made my score possible.   The latter is a cheat but you need to develop a skill in order to make use of it.

 

-SteveS

I forgot to make that a link.

 

p.s. That's not my site.  I played the tactics mentioned.

 

 

Edited by a8isa1

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2 hours ago, Stephen said:

Thanks - I will say that I am quite severely colour-blind so I can never be sure of what I am seeing on stuff like this.

Me too. It makes the whole art/design/electronics stuff a challenge doesn't it! Fun times with photographing in a known light temperature and an RGB color picker.

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Hoping for authenticity you add the 'counting' system, can't remember it 100%, think it was fire 23 shots and then hit the saucer for 300 points and then fire 15 (or was it 13) shots and the saucer will always be worth 300 if you keep firing x shots and then kill the saucer.. 

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17 minutes ago, Mclaneinc said:

Hoping for authenticity you add the 'counting' system, can't remember it 100%, think it was fire 23 shots and then hit the saucer for 300 points and then fire 15 (or was it 13) shots and the saucer will always be worth 300 if you keep firing x shots and then kill the saucer.. 

Yes, I'm following the arcade specs laid out here https://computerarcheology.com/Arcade/SpaceInvaders/

 

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2 hours ago, Mr Robot said:

Me too. It makes the whole art/design/electronics stuff a challenge doesn't it! Fun times with photographing in a known light temperature and an RGB color picker.

The sweetest thing my (now) wife did, was highlight EVERY dot in the infamous "fuck the colour blind" t-shirt so I could read what everyone was laughing at.

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This is looking great, PacManPlus did a great version for the 7800, not sure if you could get any nuggets from his conversion?

 

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30 minutes ago, mimo said:

This is looking great, PacManPlus did a great version for the 7800, not sure if you could get any nuggets from his conversion?

 

He made the source code available for it too.

 

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1 minute ago, MrFish said:

 

He made the source code available for it too.

 

I thought he had, I just couldn't find it 

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4 minutes ago, MrFish said:

 

He made the source code available for it too.

 

Well, that's no fun :)

 

I've seen the 7800 version on youtube, and I'm sure I'll grab a couple of ideas from it, but the main reason I'm doing this is to teach myself assembler.

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