River Raid Randomised

[Urchlay]

The "River Raid Bold" thread got me thinking about this game:

https://atariage.com/forums/topic/293861-river-raid-bold/

So here's a simple River Raid hack. The terrain and enemy placement is
partially randomized, based on player input. Basically the LFSR that's
used to generate the map is clocked an extra time, every time the player
fires a shot.

The "preview" you see before starting the game is still the original
layout. Whichever level you start out on, looks like the original map for
at least the first screens' worth, until you start shooting. Carefully
counting your shots will result in repeatable maps.

The random enemies still follow the rules of the game: the balloon
doesn't appear until level 3, the diagonally-moving enemy planes don't
appear until level 5, etc. Lower levels have fewer enemies, as usual.

As usual, even-numbered levels split into multiple paths with islands
in the center of the river, and odd-numbered levels only have one path.
The random terrain doesn't actually make the game more difficult, except
that it means you can't memorize the maps.

The "Press START key Use joystick 1" text has been replaced with "Randomised
by Urchlay", so you can tell which version of the game you're playing. Also,
for reference, the md5sum of the ROM is 0842355056c3f7f8598a9ae38df3ccfe.

Download here:

http://urchlay.naptime.net/~urchlay/src/river_raid_random_hack.rom

This is a raw ROM dump. In your emulator, select "Standard 8KB cartridge".

If anyone's really interested, I can post a .xex file and/or a .car file
with a header.

Edited July 31, 2019 by Urchlay

[_The Doctor__]

but of course, XEX and car

:)

[carlsson]

Nice! For us casual players, the random levels are barely noticable compared to the original, though I suppose die hard riverraiders would get thrown off.

[Urchlay]

the random levels are barely noticable compared to the original

It's definitely a subtle effect. Probably the most noticeable thing is
that if you get killed & start a level over, it's different the next
time around. So memorization doesn't help.

I'm just glad someone's playing it!

[twh/f2]

its indeed a very subtle effect only - a lot less of an impact that I imagined until I tried it out.

I expected some more intense changes also on the "terrain department" but again it's more subtle than obvious.

 

But interesting anyway. thanks for you for sharing this with us.

 

To me River Raid by Carol Shaw and her idea for an random-computational repeatable level engine is much of an WOW for me forever I guess. All this and still delivering a very balanced game with "unlimited" levels. Unbelievable.

 

 

[+Stephen]

5 hours ago, twh/f2 said:

its indeed a very subtle effect only - a lot less of an impact that I imagined until I tried it out.

I expected some more intense changes also on the "terrain department" but again it's more subtle than obvious.

 

But interesting anyway. thanks for you for sharing this with us.

 

To me River Raid by Carol Shaw and her idea for an random-computational repeatable level engine is much of an WOW for me forever I guess. All this and still delivering a very balanced game with "unlimited" levels. Unbelievable.

Indeed!  I wonder, with Pitfall and River Raid being released months apart, both by Activision, did Carol or David Crane use the technique first?  Did they work together on it, etc.

 

Another amazing bit of coding in River Raid which I think is often overlooked, at least on the 8-bit Atari, is the scrolling DLIs.

[carlsson]

In the book "Racing the Beam: The Atari Video Computer System" there is a passage about the work environment at Activision, being "more atelier than software shop" and how the developers worked in large rooms to be able to discuss design and programming. For instance David Crane is supposed to have helped out with sound effects in River Raid. Algorithmically generated levels with pseudorandom had been used since in Atari's Maze on the 2600 and of course Rogue, though with different seeds every time so you wouldn't get the same map.

[Urchlay]

but of course, XEX and car

car

xex

[adam242]

22 hours ago, Stephen said:

Another amazing bit of coding in River Raid which I think is often overlooked, at least on the 8-bit Atari, is the scrolling DLIs.

 

Agreed. That the majority of the enemy craft are 'just' one player, changing position, color and width every scanline, constantly scrolling downward (at varying speed!) is damned impressive.