The Southsider

I didn't think you lost interest in Atari. Welcome back. A lot of us have dreamed of visiting Japan, so we appreciate the report. Your description of Tokyo as a conglomeration of smaller cities reminds me of Los Angeles, although the two are certainly different in their own ways.

Welcome back - it sounds like it was a cool trip. Thanks for posting the write-up.

 

Question about Juno First... what does "unrolling" mean? I've read it a bunch of times in programming threads, but have never seen it explained.

I didn't think you lost interest in Atari. Welcome back. A lot of us have dreamed of visiting Japan, so we appreciate the report. Your description of Tokyo as a conglomeration of smaller cities reminds me of Los Angeles, although the two are certainly different in their own ways.

 

Thanks for the kind words. I haven't visited Los Angeles yet so I can't compare, but Tokyo is definitely an experience that I would recommend to anyone.

 

Question about Juno First... what does "unrolling" mean? I've read it a bunch of times in programming threads, but have never seen it explained.

 

It is a fairly straightforward concept that improves speed at the expense of memory. If you have a loop with a fixed (and usually small) number of iterations, then the contents of the loop can be expanded out. This removes the need for a loop counter and can often enable additional optimisations across loop iterations. The following Java code is a simple demonstration of loop unrolling:

 

public class unroll
{
 public static void main(String[] args)
 {
// Normal Loop
for (int x = 4; x > 0; x--)
  System.out.println("Hello World " + x);

// Unrolled
System.out.println("Hello World 4");
System.out.println("Hello World 3");
System.out.println("Hello World 2");
System.out.println("Hello World 1");
 }
}

 

Chris

I think I've found a bug, though I can't be sure it's not an emulator artifact (I don't think so, though). When thrusting forward and firing, if you move to the left and then attempt to move to the right (while still thrusting forward and firing), nothing happens. Conversely, if I'm thrusting and moving to the right, and while doing so I attempt to fire, nothing happens.

 

Going *backwards* is fine -- all this only happens while going forwards.

 

So, in sum: Up+right = can't fire, up+fire = can't go right.

 

(I'm using Stella 2.1 on OS X, for what it's worth)

I think I've found a bug, though I can't be sure it's not an emulator artifact (I don't think so, though). When thrusting forward and firing, if you move to the left and then attempt to move to the right (while still thrusting forward and firing), nothing happens. Conversely, if I'm thrusting and moving to the right, and while doing so I attempt to fire, nothing happens.

Going *backwards* is fine -- all this only happens while going forwards.

So, in sum: Up+right = can't fire, up+fire = can't go right.

(I'm using Stella 2.1 on OS X, for what it's worth)

 

I am unable to reproduce this bug on my machine, though similar things will happen if you hold both left/right or up/down (which are not possible on a joystick). It sounds like there is some problem with the up direction on your emulator - do you have this problem in any other games? Are you using the keyboard, or a joystick with the emulator? I will have another look at the code and see if I can spot any potential problems.

 

Thanks,

Chris

Chris,

 

It turns out that the problem's completely on my end, and was caused a USB keyboard I've got plugged into my laptop that, for whatever reason, can't handle the key combinations in question. When I tried it using the laptop's own keyboard, everything worked fine. (I got the keyboard fairly recently, and I guess I'd never had occasion to try that particular combination of keys, but when I went and tried Battlezone just now I ran into the exact same problem...)

 

My apologies for taking up your time with this!

Chris,

It turns out that the problem's completely on my end, and was caused a USB keyboard I've got plugged into my laptop that, for whatever reason, can't handle the key combinations in question. When I tried it using the laptop's own keyboard, everything worked fine. (I got the keyboard fairly recently, and I guess I'd never had occasion to try that particular combination of keys, but when I went and tried Battlezone just now I ran into the exact same problem...)

My apologies for taking up your time with this!

 

No problem - I am just glad that it wasn't a bug in my code It sounds like the keyboard can't handle more than one key press at a time?

 

Chris

Not exactly, just some weird quirky interaction between those particular keys. Maybe they share a trace on the circuit board, and the designers didn't expect them all to be hit at the same time (??).