Asteroid Escape

[+Atarius Maximus]

I updated this game in 2024, see that post here:

 

I spent some time writing a simple 4k game using the standard kernel. I was getting the itch to write a program, it's been over a year now. It could use a bit of polish as there is no level or difficulty progression at the moment. Beyond that it is a complete and playable game. The screenshots don't show everything. I used both players missiles to create a scrolling starfield effect.

 

You're caught in an endless asteroid belt and it's your mission to ram and destroy the escaping cargo ship without crashing into an asteroid yourself. Your fighter ship is specially designed to take out the cargo ship by ramming it. You gain a point each time you destoy the ship. If you're destroyed, the game is over. There's only one life.

 

You fly on the outskirts of the asteroid belt, either just above or below it. Push up or down to enter the asteroid belt to try and take out the escaping Cargo ship. Your momentum requires an angled 45 degree attack, push up or down on the joystick to move to the other side of the asteroid belt. When on the outskirts, you can thrust forward or backward by pushing left or right. You can also turn on the afterburners by pushing down when you're on the bottom, and up when you're on top to fly faster. The game will continue as long as you can survive. Enjoy!

 

Comments and suggestions are welcomed. I may make some further changes and enhancements, although I'd likely have to bump up the rom size.

 

Steve

escape1.txt

escape1.txt.bin

[TrekMD]

Cool, I'll be trying this out.

[Arenafoot]

I got up to 6! The angles are hard to figure out.

[Mountain King]

Nice work. Very unique game play. I was able to get 18 but I don't have a screenshot.

A couple of minor points:

The star field moves faster than the asteroids. I am curious what it would look like if it was reversed. It would be closer to how perspective works assuming the asteroids are closer than the stars.

Is there a better way to make the asteroids look like asteroids? You chose to use playfield graphics, To maybe vary the size you could use the pfheights option.

I think it would be cool if there was more of an indication either visually or audibly that your ship was in ramming mode. It would add to the satisfaction destroying the ship.

 

But very cool game. I played it for about a half hour until I started to get good.

[Mountain King]

okay 21 is my best now.

[Mountain King]

I got up to 6! The angles are hard to figure out.

You can actually thrust and decelerate while in ramming mode so you can change your vector in mid ram. This might help you avoid the asteroids.

[+Atarius Maximus]

Nice work. Very unique game play. I was able to get 18 but I don't have a screenshot.

A couple of minor points:

The star field moves faster than the asteroids. I am curious what it would look like if it was reversed. It would be closer to how perspective works assuming the asteroids are closer than the stars.

Is there a better way to make the asteroids look like asteroids? You chose to use playfield graphics, To maybe vary the size you could use the pfheights option.

I think it would be cool if there was more of an indication either visually or audibly that your ship was in ramming mode. It would add to the satisfaction destroying the ship.

 

But very cool game. I played it for about a half hour until I started to get good.

 

Thanks for the compliments.

 

I can play around with the star field speed, but the star field is more convincing at higher speeds. The slower it goes the more it just looks like blinking dots on the screen. Still, it's something I can mess with. This game would be much more visually appealing if I made it with the DPC kernel or on the 7800, but honestly I was just trying to keep it simple. I did think of using pfheights to vary the size, however pfheights seems to be incompatible with pfres, and I am using pfres to reduce the number of playfield lines to gain some extra RAM. I needed the extra 16 variables. I did a little research on the forums and others have also reported problems using pfheights and pfres at the same time. Making a change visually or audibly when you're in "ramming mode" shouldn't be too hard, I can take a look.

 

Glad you enjoyed playing. Your high score is better than mine at the moment.

 

Steve

[+Atarius Maximus]

Based on Mountain King's suggestions I updated this version so the player's ship sprite changes to an angled view when you're moving through the asteroid field, along with a sound effect to go with it.

escape2.txt

escape2.txt.bin

[Mountain King]

Very cool! I like the improvement. The cargo ship re materializes after a second so I've been challenging myself by trying to ram the ship more than once. May be you could add cargo ships of different strengths or sizes that you have to ram multiple times. Also I noticed you can wrap yourself around from the right side of the screen to the left side.

[Arenafoot]

Cool changes! I actually got double digits this time!

 

[+Atarius Maximus]

Very cool! I like the improvement. The cargo ship re materializes after a second so I've been challenging myself by trying to ram the ship more than once. May be you could add cargo ships of different strengths or sizes that you have to ram multiple times. Also I noticed you can wrap yourself around from the right side of the screen to the left side.

 

Thanks. Changing the strength or size is a good idea. The game is pretty simplistic as it is now, I know that. I could also add a fuel gauge and a random powerup to get more fuel that also goes through the asteroid field. In order to avoid any flicker, I can't have more than one cargo ship on the screen at once, and any kind of powerup option would have to use the same player sprite as the cargo ship, so they couldn't be on screen at the same time. I know it's just a limitation of the standard kernel, I could make this game much more interesting with DPC+.

[+Atarius Maximus]

Cool changes! I actually got double digits this time!

 

 

Nice job. I've always preferred games like this that you can sit down and finish a game within a minute or two and just try and get a high score. My best so far is 26. Getting a higher score really just requires some patience - I'd let the screen roll pretty often until I saw an obvious gap that I knew I'd be able to make. It's still pretty easy to make a mistake sometimes, though.

[Mountain King]

Here's my new high score 37. I actually try to hit the cargo ship twice as it passes. But I totally agree with you about sitting down and being able to play a game for a few minutes.

[iesposta]

I managed to save 162 bytes with this re-write.

Just something I like to do.

Makes the code harder to follow though.

 

With this kernel it would stay the same compiled size until enough saving tricks were done, then it jumped from 277 left to 344 left to 439 - the final being when I made the empty sprites just one line...

I probably broke something, but I couldn't see anything wrong.

 

escape2.bas.txt

[bogax]

With this kernel it would stay the same compiled size until enough saving tricks were done, then it jumped from 277 left to 344 left to 439 - the final being when I made the empty sprites just one line...

I probably broke something, but I couldn't see anything wrong.

 

escape2.bas.txt

 

Just guessing

 

if you read an item in a table from the next page it takes longer

since timing is critical in the kernel bB pads the code with 0s so that

(some) tables (eg sprite data) don't cross a page boundary

if you remove enough stuff, suddenly the 0 padding disappears

and the space left jumps

 

 

I think you could squeeze out a few more bytes

[+Atarius Maximus]

I know it was almost a year ago, but thanks iespota for the code optimization, and bogax for the suggestion.

 

I was just browsing through the forums and saw RevEng's thread about the TIA bug starfield effect. I thought it might look cool with this game, so I added it in. I removed the ball barrier from the game in order to use the ball as part of the starfield effect instead, but no other changes were made. It does look pretty cool!

 

Maybe I'll go ahead and bankswitch this game and make some other improvements...

escape5.bas

escape5.bas.bin

[iesposta]

bogax is great with tables and lots of nested loops.

My optimizations are pretty good -- if I do say so myself.

[+Atarius Maximus]

bogax is great with tables and lots of nested loops.

My optimizations are pretty good -- if I do say so myself.

Yes, he is. It was late last night when I posted, and in my haste I typed in the wrong name. I was intending on thanking you, iesposta.

[+Atarius Maximus]

Just spent a little more time playing around with the starfield effect. I added a narrow band of fast moving stars in the middle of the screen that help define the asteroid belt. I'm not done yet (colors and speed will change for sure), but wanted to share this build because it's a pretty cool looking effect.

escape6.bas

escape6.bas.bin

[Arenafoot]

Just spent a little more time playing around with the starfield effect. I added a narrow band of fast moving stars in the middle of the screen that help define the asteroid belt. I'm not done yet (colors and speed will change for sure), but wanted to share this build because it's a pretty cool looking effect.

BTW, versions 2, 5 & 6 all work on the Atari Flashback Portable. IMO, I think 5 looks better on it.