answer me these questions three...
I mentioned in my first WIP article that I have three criteria for evaluating a game idea.
- Is my concept really technically feasible?
- Is it interesting?
- Is it fun?
These are sometimes tough to answer without a prototype, so I'll often throw one together to evaluate these points.
While it may seem like insanity to code up something I may well throw away on a system as tough to program for as the 2600, I generally work in batari Basic, so it takes very little time. In a lot of ways, bB is like a RAD environment for the 2600.
a math war, in space...
Ever since I was a little kid I was fascinated by the gravity simulation in Spacewar!, and I always felt the 2600 version went light on the physics, so I thought I'd code up a version that was a bit more accurate.*
Gravity follows an inverse-square law. So if your ship moves out 2 times as far from the sun the force of gravity should drop to 1/4 of the previous amount...
Since the 6502 isn't particularly good at calculating the required math for this on the fly, I needed to use a lookup table. Using the fact that the table is symmetrical in nature, I was able to give it a decent range of coordinates while still being able to squeeze it into a single 4k bank.
After that, it was a cinch to add the code for basic gameplay.
I think from a simulation point of view, cywar succeeded. Its relatively easy to put yourself in a circular or elliptical orbit around the sun, and depending on your initial velocity the orbit can be very stable. (or you can watch it slowly decay)
A few things to note:
- There are more rotational positions for the ship than in Asteroids or Spacewar 2600, providing finer control over the thrusting and shooting.
- The ship's velocity is added to the initial missile velocity.
- Flipping the difficulty switches to A makes gravity act on the missiles.
- Hitting the select switch toggles between regular and inverse gravity.
For me this prototype provided a "yes" answer to the first two questions. For the question of fun, the answer isn't all that strong. For me it's a bit fun... kind of like Combat with less variety. Or unsurprisingly, like Spacewar 2600 with a better gravity simulation.
I think the gravity mechanic might be more fun as part of a multi-screen space adventure, rather than just a straight Spacewar! knockoff. Maybe something like "journey to the planets" for the A8, with a touch of space combat like Star Trek 2600, with some planet combat like jrok's "redshirts".
Get yourself to a planet of interest, set yourself up in a stable orbit, and beam the crew down for their away mission! It's an idea that's shelf-worthy anyway.
* - It should be mentioned that this is by no means a slam on spacewar for the 2600. It's a 2k rom, and does an admirable job of faking gravity given those constraints.