Here's this month's helping of listing for you to type in. This is a flight combat game where you pilot a high powered fighter jet to intercept marauding enemy aircraft.
You see the pilot's view through the cockpit screen and you have controls to move left and right, up and down and fire missiles. There is only a certain amount of time before your fuel runs out and of course your supply of missiles is limited.
There is only one part to the listing, but it does contain some machine code so type in the whole program and save it before you try to run it.
We've altered the program to work with a joystick so if you want to put it back to its original state - using the keyboard - you'll need to change these numbers in lines 140-180. Sensibly, Kevin Freeman has used Inkey so it is easy to change from one to the other.
| Change | To |
| 72 | 69 |
| 73 | 71 |
| 74 | 46 |
| 75 | 38 |
| 76 | 47 |
Kevin writes - The majority of the program runs in Basic with an RSX to increase printing speed, in the form |SPRITE, x,y,p. X(0-39),y(0-24) referring to a position on the Mode 0 screen, p is a pointer to a memory position containing data for a sprite -the first two bytes being the x,y dimensions.
Note that this sprite handler does not plot over odd numbered pens giving the illusion of depth in the game. If the sprite is plotted at the same position twice then it will erase itself.