What was the trickiest part of writing “Raster Blaster”?
The collision detection was kind of a nightmare, because no matter what I tried the ball would sometimes stick to a wall and freeze or slide right through. I made a scan-line table; for each scan line on the screen I entered a list of wall locations, together with the slope of the wall at that point. To collision detect the ball with the game board, I used the ball y-coordinate to index into the table and the x-coordinate to check against all the walls at that y. It’s a bit more complicated than this, because the ball can rest against a wall as it rolls–for a nearly horizontal wall–and because there are some physics that need to be modeled–the ball slides and spins, which causes it to hug curved walls. What led you from “Raster Blaster” to “Pinball Construction Set”? I was exposed to GUI’s at Apple, and I had the pinball simulation from “Raster Blaster.” I saw that it would be a small step to do a construction set. This was the kind of program I liked, since there was no game to wri
