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River Raid Ending?


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#26 A.J. Franzman OFFLINE  

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Posted Sat Apr 8, 2006 12:20 AM

Does the original seed start the sequence at the first of those 57337 levels?

#27 Thomas Jentzsch OFFLINE  

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Posted Sat Apr 8, 2006 12:51 AM

So I guess this answers the questions others have had then... is it at level 57338 that the game goes haywire?

No, it just repeats.

Any other River Raid mysteries you'd care to illuminate? :)

You can always have a look into my River Raid disassembly. Maybe just reading the initial comments.

#28 Thomas Jentzsch OFFLINE  

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Posted Sat Apr 8, 2006 12:53 AM

Does the original seed start the sequence at the first of those 57337 levels?

Uhm, which one should be the first level, when they are generated randomly? The one with the lowest seed?

#29 A.J. Franzman OFFLINE  

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Posted Sat Apr 8, 2006 1:00 AM

You only just posted that the cycle repeats! So obviously there is no "first" level of the pseudorandom sequence.

If it did not repeat (i.e. the game ends, freezes or crashes at a specific level), then the first level would of course be the one furthest from the ending.

Edited by A.J. Franzman, Sat Apr 8, 2006 1:03 AM.


#30 Thomas Jentzsch OFFLINE  

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Posted Sat Apr 8, 2006 1:13 AM

You only just posted that the cycle repeats! So obviously there is no "first" level of the pseudorandom sequence.

You are absolutely right.

#31 G.Whiz OFFLINE  

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Posted Mon Apr 10, 2006 9:32 PM

Okay, so why end the game at one million then? Rollover was obviously possible -- Space Invaders did it. Why not just let you continue onward? And is it possible to hack it now so it doesn't freeze?

~G

#32 D.Yancey OFFLINE  

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Posted Tue Apr 11, 2006 5:43 AM

Okay, so why end the game at one million then? Rollover was obviously possible -- Space Invaders did it. Why not just let you continue onward? And is it possible to hack it now so it doesn't freeze?

~G


Have you finished it up to the first million yet? ;)

#33 G.Whiz OFFLINE  

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Posted Tue Apr 11, 2006 6:57 AM

Okay, so why end the game at one million then? Rollover was obviously possible -- Space Invaders did it. Why not just let you continue onward? And is it possible to hack it now so it doesn't freeze?

~G


Have you finished it up to the first million yet? ;)


Ha! No, but I think some have... in my case it is just a hypothetical question. I'm more interested to know about the workings of Activision -- why limit the game this way, as they did others? Does it take more RAM to go past 1,000,000, even with a rollover?

~G

#34 kisrael OFFLINE  

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Posted Tue Apr 11, 2006 7:36 AM

Well, one million comes from being more than the typical six digit display can show. I think the !!!! is there so that for, say, the patch club, someone doesn't say "no, that's a MILLION five hundred, not just five hundred..."....that kind o thing.

#35 FujiSkunk OFFLINE  

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Posted Tue Apr 11, 2006 11:53 AM

So obviously there is a fixed number of possible configurations available by changing the seed. How many? (My first guess is 256 but I don't know all of the factors involved.)

No, there are 2^16-1 = 65535 values possible (0, 0 is not allowed). 57337 of those will jump somewhere into the sequence of the original River Raid (being 57337 sections long), the others create a different, shorter sequence.


Thomas, are you saying that there are only two sequences total, one with 57337 levels and another with 8198 levels?

Well, one million comes from being more than the typical six digit display can show. I think the !!!! is there so that for, say, the patch club, someone doesn't say "no, that's a MILLION five hundred, not just five hundred..."....that kind o thing.


That and the Activision programmers thought it would probably give gamers a goal to work toward, like the kill screen on games like Pac-Man.

#36 Thomas Jentzsch OFFLINE  

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Posted Tue Apr 11, 2006 12:44 PM

Thomas, are you saying that there are only two sequences total, one with 57337 levels and another with 8198 levels?

Probably, though I haven't checked this. But with the original seed, all levels in the 2nd sequence are out of scope, that's for sure.

#37 Nukey Shay OFFLINE  

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Posted Wed Apr 12, 2006 1:50 PM

The one-million point goal was kind of a trademark with Activision games. While it would be possible to remove that goal, getting there is such a long chore anyway...so it's not really necessary. Though if you were after something like saving program space, that would be an easy target to save a few bytes.

#38 D.Yancey OFFLINE  

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Posted Wed Apr 12, 2006 9:50 PM

There is never a dull moment in River Raid. You can have a break anytime you lose a plane, so that's nice. It is every bit of 3 hours + to get to one million.

You guys are talking about the generating of the scenery and enemies in River Raid and how it never repeats. You should check out some of the WEIRD patterns that are generated in the river scenes in River Raid II after about 500,000 points. Absolute murder! And you better enter the river with full fuel or you're as good as dead. :)

#39 Nukey Shay OFFLINE  

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Posted Fri Apr 14, 2006 1:06 PM

Okay, so why end the game at one million then? Rollover was obviously possible -- Space Invaders did it. Why not just let you continue onward? And is it possible to hack it now so it doesn't freeze?


BTW the game should easily be possible to hack to ignore a score rollover. Just search for the loop that uses branches to the tag .maxedOut...and just comment out everything from that point down to (and including) the jmp instruction. That should prevent it from altering the score pointers to "!" and freezing the game.

#40 batari OFFLINE  

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Posted Fri Apr 14, 2006 11:41 PM

I had a little fun this evening with TJ's disassembly. I changed the game to allow you to select from 4 completely different rivers, each 65535 units long (if I've done it correctly, that is.) Selection matrix:

Game	River	# players
1		 1		1
2		 1		2
3		 2		1
4		 2		2
5		 3		1
6		 3		2
7		 4		1
8		 4		2

Attached Files



#41 D.Yancey OFFLINE  

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Posted Sat Apr 15, 2006 9:57 AM

Great hack! The 4 rivers are certainly different. Is there a method in determining which variation is most difficult or are they simply generated the same way as the original in a different order and starting point?

#42 batari OFFLINE  

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Posted Sun Apr 16, 2006 12:40 AM

Great hack! The 4 rivers are certainly different. Is there a method in determining which variation is most difficult or are they simply generated the same way as the original in a different order and starting point?

They are generated a little differently than the original, but all 4 new rivers are generated in a similar manner to each other. All have the objects in a different order. I imagine that the 4 rivers will likely be about equal in difficulty, but I haven't played them enough to be sure.

#43 kisrael OFFLINE  

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Posted Sun Apr 16, 2006 6:02 AM

Batari: he does the things the rest of us just talk about.

I'd recommend some variation of that, or "the coder you wish you were", for your profille's "Custom Status"...

Seriously, you rarely fail to impress.

#44 mugnatto OFFLINE  

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Posted Sat May 6, 2006 7:35 AM

Great hack! The 4 rivers are certainly different. Is there a method in determining which variation is most difficult or are they simply generated the same way as the original in a different order and starting point?

They are generated a little differently than the original, but all 4 new rivers are generated in a similar manner to each other. All have the objects in a different order. I imagine that the 4 rivers will likely be about equal in difficulty, but I haven't played them enough to be sure.



Batari: you could have earned hundreds of thousands of dollars in the 80s with this hack and a name such as Super River Raid where I live, in Brazil. No RR hack I know is this good!

#45 Random Terrain OFFLINE  

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Posted Wed Apr 2, 2008 5:04 PM

Why a random generator was implemented in the first place is because space in a rom cartridge is limited...it was the easiest way to insure that the game levels would be the same from game-to-game (without all of them mapped out in memory). Why it wasn't possible to override this function is obvious...there'd be no way to gaurantee that a seed value could be discovered which allowed very easy gameplay...or which featured very difficult gameplay. So Activision's own 15,000 pt. benchmark and !!!!!! goal would become irrelevant.

I don't care about how easy or hard the rivers would be if they were random. Just let them be whatever they'll be. If a game starts out too hard, I could hit the reset button.

I just play for the fun of it because I'm in the mood to play that game. I play until I get bored with it or until I have to get back to work or until I get in the mood to play another type of game. The score only means something to me if I get a new life after a certain number of points.

So now we have 4 rivers for River Raid and random levels for H.E.R.O. on game 5:

http://www.atariage....s...st&p=738734

I'd like River Raid even more if could have more than 4 rivers. Just have it randomly start out with any one of 255 rivers. If it starts out too hard, hit the reset button.

Has anyone hacked Pitfall! so the screens are random every time? I love swinging on the vines, but I only play for about 5 or 10 minutes since the rest of the gameplay is boring to me. Having different screens every time I play would be nice.

#46 supercat OFFLINE  

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Posted Wed Apr 2, 2008 5:28 PM

Has anyone hacked Pitfall! so the screens are random every time? I love swinging on the vines, but I only play for about 5 or 10 minutes since the rest of the gameplay is boring to me. Having different screens every time I play would be nice.


There was a hack which varied the starting point, but the overall sequence remained the same. A nicer approach, if a byte were available to hold the "game number", would have been to adjust the routines to move left/right:
moveleft:
  lda gamenumber
  eor screen
  sta screen
  (insert old moveleft code here)
  lda gamenumber
  eor screen
  sta screen
moveright:
  lda gamenumber
  eor screen
  sta screen
  (insert old moveright code here)
  lda gamenumber
  eor screen
  sta screen
When gamenumber is zero, this would yield the same sequence as normal PitFall!, but non-zero game numbers would generate different sequences of 256 rooms.

#47 Random Terrain OFFLINE  

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Posted Wed Apr 2, 2008 7:10 PM

There was a hack which varied the starting point, but the overall sequence remained the same. A nicer approach, if a byte were available to hold the "game number", would have been to adjust the routines to move left/right:

moveleft:
  lda gamenumber
  eor screen
  sta screen
  (insert old moveleft code here)
  lda gamenumber
  eor screen
  sta screen
moveright:
  lda gamenumber
  eor screen
  sta screen
  (insert old moveright code here)
  lda gamenumber
  eor screen
  sta screen
When gamenumber is zero, this would yield the same sequence as normal PitFall!, but non-zero game numbers would generate different sequences of 256 rooms.

Does that mean a person who can hack game code could make a version of Pitfall that has random rooms? Or is there no space to do it?

#48 supercat OFFLINE  

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Posted Wed Apr 2, 2008 9:40 PM

Does that mean a person who can hack game code could make a version of Pitfall that has random rooms? Or is there no space to do it?


It would probably be doable. Nukey has managed to squeeze in enough other goodies.

That having been said, I'd prefer numbered pseudo-random to random, since that would allow players to compete in hundreds of new "worlds".

#49 thomasholzer OFFLINE  

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Posted Thu Apr 3, 2008 10:45 AM

My ex finished River Raid, took her 7.5 hours, and yes after the !!!!!! the game just didn't start again.
Whereas Mario Bros. after 1 Mill it started over again.

#50 kisrael OFFLINE  

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Posted Wed Mar 24, 2010 10:16 AM

Reviving an old thread...
Years ago, B.Watson started making maps of River Raid, using a hack that meant your plane never got hit and never ran out of fuel.
He then did some cleverness to stitch the resulting screens together...
I posted his result here: http://kisrael.com/2005/11/28/

Does anyone think we could get a longer more complete map? Maybe broken up into slices that can be displayed side by side for convenience or as one giant web page you can just scroll and scroll and scroll...

Anyone got the techie chops for this? I guess you just need the right hacked ROM and an emulator that can take a screenshot every X frames, then a bit of Image Magick to slice and dice the results....

Posted Image

Edited by kisrael, Wed Mar 24, 2010 10:23 AM.





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