Fleas is like Lemmings, except Fleas are just a single pixel. Each game cycle, one Flea makes a "jump". A jump is an arcing path that travels between 6-8 pixels across. The jump travels upward by 5 pixels and may fall downward by any amount. If the Flea collides with an obstacle during the horizontal leg, he bounces off an reverses direction.
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*......*To make level design easy, I've decided to use unreversed PETSKII for the levels. This lets me use 7168-7679 for custom graphics characters while using ROM characters also. The file format for a series of levels is simply a series of strings (up to 255 characters long). At the start of each level, the program simply prints {clr home}{rvs}{wht} and then prints the level string. Thus, you get full color capability along with some simple compression. The program then checks for reserved characters for the "start" and "destination".
The top left of the screen shows the available user obstacles and how many of each are available (from 1 to 9). Each obstacle is represented by a PETSKII character, so the level may start off with some obstacles in place already.
The second line is where the player's "crane" is. The controls are simply:
J/L - move left/right
K/I - switch object
space - drop object
Now, I need ideas for the obstacles. So far, I'm thinking:
lava/water (C= lb) - simply kills a Flea
bomb (club, or shift-X) - detonates on contact with a Flea, erasing the four neighboring chars along with itself
trampoline (=) - instead of landing on it, a Flea will rebound upward into a 16 pixel high jump.
diagonal ramps (shift-N and shift-M) - not treated differently from any other character, but they're useful for guiding Fleas upward.
walls (shift- -) - not treated differently from any other character, but they're useful for reversing the direction of Fleas.
Any other/better ideas for obstacles?
Thanks!
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I've chosen "Fleas" as my first assembly project because it's pretty easy in a lot of ways. I don't have to design sprite graphics or animation, and I don't have to worry about simultaneously moving multiple sprites. Just one Flea moves at a time, and since a Flea is only 1 pixel big I can reserve 62 custom chars for up to 62 Fleas on screen.
The use of PETSKII graphics greatly simplifies level design effort, and I like how it gives a distinctive VIC20 "look and feel". Also, the level design system is essentially identical to my old animation program. It's merely character by character keyboard input, along with a "cursor drawing" routine.
