It's a nice saturday morning, I'm sat in my summer-house, the place where all my game ideas are born. I've come up with an idea for a new project involving ability to shoot at things.
Rather than try and do Space Invaders, which when you break it all down is no easy task, I'm going to go for something that will turn out looking similar to a cross between Dizzy and Ghosts N Goblins.
Imagine, Eric in Monsterland with the ability to shoot at things as well as all the movements with the stick. I figured out how to use the fire button after 20 years of never looking it up properly.
It would be a reasonable idea to be able to jump forwards and shoot at the same time, you'd just be firing at whatever pixel up in the air you are instead of it being at a fixed position. What are a few extra variables to the venerable TI99/4A? .... I'd obviously have to have it constantly looking for sprite positions to turn them off when they're getting to the edges of the screen. There's nothing worse than firing a shot and it turns up and the other side of the screen wrapping over when it's not meant to.
We could have enemies that are only present if the DEAD(X) variable is reading 1 and not 0. That enemy can fire at you so long as it is not already firing, which we will have a register for that with the variable FIRE(X) ... I put these into arrays so that we have the option of more than one thing firing at a time, should I get to a point where I'm comfortable I can take on such a task with the code.
There's really no reason why we couldn't have the same level of background graphics achieved in Eric In Monsterland. The trees, ditches and the graveyard were all drawn onto the screen from simple subroutines that for example, draws a tree. We simply ask for the tree in say line 1100, like this : 1100 TH=13 :: TT=1 :: GOSUB 9100 and line 9100 draws the tree according to the TT which is tree-type, (dark green or light green leaves) and TH which is the tree height. Once you've done it this way you can draw a tree using only 22 or so bytes calling the subroutine.
If memory becomes an issue I will look into making this a .DSK image that has a few files on it that can be chained together retaining the variable values needed such as score, best-score, shots vs hits accuracy readings and of course what screen you're on. This sounds to be do-able.
Music, now I'm a bit funny with that. Actually having music in the background in a game using anything like a PSG sound chip or the TI one, becomes an irritation for me. So I may end up just putting a little intro sequence in whenever you re-spawn from death or on the first introduction to the game. Sound effects will be done hopefully using the SL Compiler to get them to play with no frame update interruption.
So there it is in a nutshell and it's working title is "Spooks 'n' Spectres"
I'll keep typing away each time there's an update on this project. Expect some code and possibly even artwork for an advert at some point.