Space Invaders 7800

[PacManPlus]

Thanks, Gorf (I always feel funny calling people by their screen name)

 

Maybe we can port 'Gorf' to the 7800 some day

[Lord Helmet]

Maybe we can port 'Gorf' to the 7800 some day

 

Maybe that should be your next game!!

 

 

[Underball]

I know this isn't a request thread, but Gorf and SI are so similar in gameplay, I'd rather see Bob dedicate his time to something entirely different, if he decides to hook us all up and code up another masterpiece for the 7800.

 

I'd love to see any one of the following(or really all of them ) ported to the 7800:

 

Crystal Castles

Spy Hunter

Donkey Kong with all levels and better sounds

Gyruss

Stargate/Defender

Time Pilot

Zaxxon (possible hack of Desert Falcon)

[ZylonBane]

@ZylonBane - I used your invader hit sound (I wish the TIA could produce higher pitches with that waveform!) It sounds good

Thanks! Some other things I noticed--

• No flashing "PLAY PLAYER 1" when you start a game.
  
• When you destroy a UFO, the point display isn't the same color as the UFO.
  
• There's a tiny explosion sprite that should appear when your shot hits the top of the screen, a shield, or an invader shot.
  
• Do invader shots always cancel out player shots in your version? If memory serves, in the arcade version it seems to be random whether one of the shots "wins", or they just destroy each other.
  

[PacManPlus]

@ZylonBane - I used your invader hit sound (I wish the TIA could produce higher pitches with that waveform!) It sounds good

Thanks! Some other things I noticed--

• No flashing "PLAY PLAYER 1" when you start a game.
  
• When you destroy a UFO, the point display isn't the same color as the UFO.
  
• There's a tiny explosion sprite that should appear when your shot hits the top of the screen, a shield, or an invader shot.
  
• Do invader shots always cancel out player shots in your version? If memory serves, in the arcade version it seems to be random whether one of the shots "wins", or they just destroy each other.
  

 

1 - I think the score itself flashes, no? (not the message)... Anyway, I should add that; it's not a big deal.

2 - Easy fix

3 - This one I knew about, but had to forego due to issues I was having with the sprites.

4 - I used a random number call and did an AND #$03 to yield 4 results. Two values cancel both shots, one cancels just the invader's shot, and one cancels just the player's shot.

 

Bob.

[PacManPlus]

Ok.

 

Sorry all, the 'ripple effect' is not happening. I started trying to implement it, and was having some screen issues, which I think happened because I ran out of CPU time. The way the invaders move now can't be that bad; it's like that on the 2600, 5200, and 8-bit. Also, even if I was able to get the 'line by line' version of he ripple effect, having two invaders left (for example) on the same line will move at a different speed than having two invaders left each on separate lines. This is because I only have a few values to work with for a delay between lines, as opposed to the delay moving the entire set at once. I am sorry.

 

That being said, I do have Release Candidate 3 here. The following things are changed here:

1) The Score flashes like the arcade when showing the 'Play Player 1' message.

2) The points color now matches the ufo

3) Used ZylonBane's Invader Kill sound.

4) Changed the colors to a compromise of the 4th picture of Trebor's post above (post #101), and readability.

5) The invaders at the beginning of the wave now come in one frame at a time, like the arcade.

 

Hope you enjoy what I've been able to do. I will try to make this available on cart (eventually) for those who want one.

I have to make sure PAL works first.

 

Thanks, everyone

Bob

Edited July 24, 2008 by PacManPlus

[gambler172]

Hi Bob

Count me in for a cart.

greetings Walter

[PacManPlus]

Thanks, Walter

[Trebor]

4) Changed the colors to a compromise of the 4th picture of Trebor's post above (post #101), and readability.

 

I will try to make this available on cart (eventually) for those who want one.

 

 

LOVE the new color scheme...nice blend of Arcade Deluxe Colors (Invaders themselves), classic colors (Greenish at the bottom), yet a unique flavor for the 7800.

 

Cart? YES, please!

 

-Trebor

Edited July 10, 2008 by Trebor

[ZylonBane]

Sorry all, the 'ripple effect' is not happening. I started trying to implement it, and was having some screen issues, which I think happened because I ran out of CPU time.

Now you've really got me curious. What sort of per-frame calculating are you doing that's eating so many cycles?

 

1) The Score flashes like the arcade when showing the 'Play Player 1' message.

What interval are you using? Under the Prosystem emulator, it seems really fast-- more flickery than an intentional blink effect. And the blinking goes on for a lot longer than the arcade.

 

4) Changed the colors to a compromise of the 4th picture of Trebor's post above (post #101), and readability.

Yikes. Yellow-orange invaders? I realize you're trying to maximize legibility for people on composite hookups, but that's not even close to the arcade. Really, I thought the first ROM you posted had the best color choices. Would it be practical to add a color mode to the main menu? Then you could offer the various B&W, B&W+green overlay, and other color combinations.

 

Also, the extra ships should be green instead of white. That's how the original overlay was set up.

 

Also also, when the invaders drop down into the shield area, they turn bright blue(?!).

 

Would it be practical to make the player shots white and the invader shots yellow? That's essentially how the colors are in Space Invaders Deluxe, and you're already in that territory anyway with the differently colored invaders.

 

5) The invaders at the beginning of the wave now come in one frame at a time, like the arcade.

This is really nice. Looks just like the arcade. It would be nice if the pause after they appear was a little shorter. I don't remember that delay in the arcade version.

 

The sound effect when you get a new life sounds like a harsh buzzing, when it's supposed to be more of a rapid beeping. I'll take a closer look at this effect tonight.

Edited July 10, 2008 by ZylonBane

[PacManPlus]

Now you've really got me curious. What sort of per-frame calculating are you doing that's eating so many cycles?

It might be easier if I show you. You have PM.

 

Score Flashing - What interval are you using? Under the Prosystem emulator, it seems really fast-- more flickery than an intentional blink effect. And the blinking goes on for a lot longer than the arcade.

Fixed both.

 

Colors - Yikes. Yellow-orange invaders? I realize you're trying to maximize legibility for people on composite hookups, but that's not even close to the arcade. Really, I thought the first ROM you posted had the best color choices. Would it be practical to add a color mode to the main menu? Then you could offer the various B&W, B&W+green overlay, and other color combinations.

I was trying to reproduce the overlay that Trebor posted that was red at the top, then as it goes down it is orange, yellow, green, and teal.

 

Also, the extra ships should be green instead of white. That's how the original overlay was set up.

Fixed.

 

Also, when the invaders drop down into the shield area, they turn bright blue(?!).

Yeah, that may have been a mistake. I was trying to keep them a different color so they didn't 'blend in' with the shields. Bad move.

 

Would it be practical to make the player shots white and the invader shots yellow? That's essentially how the colors are in Space Invaders Deluxe, and you're already in that territory anyway with the differently colored invaders.

Unfortunately, I don't have any color palettes left. When I set the 'Invisible Invader' option, I turn Palettes 2, 3, 4, and 5 to black. 0 and 1 are the score and UFO, respectively, and 6 and 7 are (the shields and player 1) and player 2, respectively. If I made them yellow, (palette 3) they would be invisible with the invaders, making for a *very* tough game

 

Invaders at the beginning of the wave coming in one at a time - This is really nice. Looks just like the arcade. It would be nice if the pause after they appear was a little shorter. I don't remember that delay in the arcade version.

Fixed.

 

The sound effect when you get a new life sounds like a harsh buzzing, when it's supposed to be more of a rapid beeping. I'll take a closer look at this effect tonight.

That's funny, because I though the arcade one sounded like a harsh buzzing (at least in MAME). I just tried to replicate that.

 

Bob

[ZylonBane]

Invaders at the beginning of the wave coming in one at a time - This is really nice. Looks just like the arcade. It would be nice if the pause after they appear was a little shorter. I don't remember that delay in the arcade version.

Fixed.

Cool. Now that I've had a chance to check it out in MAME, turns out I has only half-right. There's about a second delay before the player appears, but the invaders start moving (but not firing!) immediately after they appear. Well heck, you have MAME too so I don't have to tell ya that.

 

Another little thing I noticed is that "GAME OVER" comes in one letter at a time in the arcade. Also there's no double space between "GAME" and "OVER".

 

 

The sound effect when you get a new life sounds like a harsh buzzing, when it's supposed to be more of a rapid beeping. I'll take a closer look at this effect tonight.

That's funny, because I though the arcade one sounded like a harsh buzzing (at least in MAME). I just tried to replicate that.

I took another look at the page of that guy who's trying to simulate the sound circuitry, and it turns out this sound is basically just a 480Hz tone that's turned on and off at 100Hz or so. Since your sound driver only runs once per frame it can't quite replicate that, but it can get close in spirit. Here's the best I could manage:

 

Distoration = 12. Data is frequency, volume as before:

10,10

10,0

10,10

10,0

10,10

10,0

10,10

10,0

10,10

10,0

10,10

10,0

10,0

10,0

10,0

10,10

10,0

10,10

10,0

10,10

10,0

10,0

10,0

10,0

10,10

10,0

10,10

10,0

10,10

extra_life_arcade.wav

extra_life_2600.wav

[Trebor]

I was trying to reproduce the overlay that Trebor posted that was red at the top, then as it goes down it is orange, yellow, green, and teal.

 

Yep...That overlay comes directly from Space Invaders Deluxe and seen and supported in MAME.

 

See an image of all the artwork in action here:

http://www.mameworld.net/mrdo/mame_artwork/invaddlx.png

 

Grab the file(s) for yourself here:

http://www.mameworld.net/mrdo/mame_artwork....html?p=10#here

 

EDIT:

AND...Interestingly enough, if you look at these screen captures from the cocktail version(s):

 

http://www.mameworld.net/mrdo/mame_artwork/invaders0002.png

http://www.mameworld.net/mrdo/mame_artwork/invaders0003.png

http://www.mameworld.net/mrdo/mame_artwork/invaders0004.png

 

Some come close in matching Bob's second choice of colors (Which most don't recall/experience or/and don't like).

 

 

-Trebor

Edited July 11, 2008 by Trebor

[Trebor]

For the sake of convenience, and in the event the links should break or come down, I’m posting all the shots here:

 

SPACE INVADERS (Upright and Cocktail version(s)):

 

 

 

 

SPACE INVADERS DELUXE:

 

 

 

 

SPACE INVADERS II [MIDWAY]:

 

 

 

 

SPACE INVADERS PART II:

 

 

 

 

It's pretty varied on the color scheme you can imitate depending on which machine/version you're basing it upon.

 

-Trebor

[Rybags]

Looking real good.

 

Just a couple of things.

- in the real thing, a shot that misses hits the top and there's a small null explosion animation. It's not vital, but the time penalty to the player is important as it means that little extra time that you're not able to get a shot off. Also, similar deal if one of your shots hits an enemy shot.

- IMO the most impressive sound effect of the arcade is when you hit the mother ship. Although, to get that sound you'd probably want a medium/high pitch triangle wave which obviously is beyond the TIA. I reckon still, that something better could be done.

[PacManPlus]

@Trebor: Thanks for the screen shots.

 

@ ZylonBane: I changed the Bonus Ship sound, thanks!. I double-spaced 'Game Over' so it was better centered on the screen. I have OCD when it comes to things like that.

 

@Rybags: Of all the sounds I did in this game, the UFO death was the only one I thought nobody would complain about because I figured it sounded good, and close to the arcade. Sound effects are a little difficult for me, as my specialty is music (I did all of the music in LadyBug for the 2600, and the theme song for the unreleased 'RipOff'). As far as the shots, maybe I could at least add the delay (I'm already doing that for the shields)... Thanks!

 

 

Before anybody says anything, the messages 'PLAY PLAYER <1>' and 'PLAY PLAYER <2>' were moved up from the center of the screen because I needed the area to do the swap of the invaders between player one and player two, and because I didn't want to overwrite the invaders that were on the screen. Being that the other messages were up in the third line (like 'Game Over'), I thought I'd be consistent.

 

Bob

[Rybags]

Of all the colour schemes over the versions, I just like the one with white everything/green shields.

 

Although it might be nice if your version allowed selecting among several such options.

[TrekMD]

This continues to look awesome. I do like the latest color scheme better than the previous one. If you do make this into a cart, I definitely want one!

[PacManPlus]

Of all the colour schemes over the versions, I just like the one with white everything/green shields.

 

Although it might be nice if your version allowed selecting among several such options.

 

 

Ok, that makes two requests for this. I may have to look into it

 

I don't beleive this should affect the HSC, correct? The colors you pick should have no effect on the score, right?

[Rybags]

Early colour variants actually just used cellophane over the monitor, so it affected everything appearing in that region.

 

Doing it to emulate that would have nostalgia value - there's yet another option.

 

 

Put it this way - you may as well outdo 2600 Space Invaders. By the time all these requests are fulfilled, you'll end up with a game with "2112 game variations".

[PacManPlus]

Put it this way - you may as well outdo 2600 Space Invaders. By the time all these requests are fulfilled, you'll end up with a game with "2112 game variations".

 

I never cared for Rush

Edited July 11, 2008 by PacManPlus

[PacManPlus]

Early colour variants actually just used cellophane over the monitor, so it affected everything appearing in that region.

 

That isn't what I meant I meant I don't believe I should have a separate entry in the High Score Cart for the different color values. Do you agree?

Edited July 11, 2008 by PacManPlus

[Lord Helmet]

I love it when a game gets to this point...just polishing it up and adding arcade-like features

 

I'm playing the latest version on PSP 7800. Great work Bob!

[ZylonBane]

It's pretty varied on the color scheme you can imitate depending on which machine/version you're basing it upon.

Aha, this is what threw me. The only color scheme I'm used to is the one from Space Invaders Part II. Now that I'm looking at all the samples, I see that PacManPlus mixed a couple different color schemes together. With yellow-green invaders, the player ship should have been blue, not green.

 

I double-spaced 'Game Over' so it was better centered on the screen. I have OCD when it comes to things like that.

I thought it might be that. But isn't the text a sprite that you can manually center to the pixel?

 

I think the UFO sound is probably as good as it can get. As I discovered the hard way when trying to reproduce the invader death sound, TIA has very little high-frequency resolution.

 

Something else I've noticed, but have been reluctant to mention because it's such a vague complaint, is the invader shot algorithm. It seems to fairly often have the same invader firing two shots in quick succession, which almost never happens in the arcade version.

[PacManPlus]

Yeah, I was trying for the median of the color and readability. It lead to me taking some liberties with the hues

 

 

The only sprites in this game are the player & invader shots, the shields, the ufo, and the players. Everything else is in character mode.

 

 

I did want to re-visit the shot placement algorithm. It seems in the arcade the shots seem to be more in the player's general area; not just randomly placed like they are here.

 

... looks like I have some work to do:

1) Put a delay when the player's shot hits the 'ceiling' or an invader's shot

2) Allow for a selection of a 'color pallette' on the options screen

3) Put an 'invader shot delay' so they don't start firing immediately... Maybe use the same delay that I use for the player before putting him/her on the screen.