Bouncing Ball

Ah, a big ball bouncing around the screen. Although a bit of a cliché, it's one of my favorite demos. It manages a large area of full resolution graphics without any flicker or other compromises. There's even a little blip of sound when it bounces off the screen edges.

To run the Model 3 version on the trs80gp emulator type:



Press 0 .. 9 to change ball speed from 0 to 9 pixels/frame. Press I to invert the display and reveal the intensive video writes that squeeze out the high-res graphics. Pressing space-bar will restart.

Included is a version that will work on a slightly modifed Model I. It is ballm1.cas and requires Tim Halloran's VBLANK mod. Or you can run it under trs80gp:

    trs80gp -m1 -m1_vblank ballm1.cas

Original Version

The original version was Model 3 only and lacked sound.


Press keys 1 though 7 to speed up the ball's motion. 1 makes it go a bit faster, 7 a lot faster. And holding all of them down will make it go at top speed.

George Phillips, October 29, 2022. george -at-