alice-teacher Screen flickers when moving accellerating camera

[Vanderhyde, James]

Some of my students are making car race games. They came up with a way to do player control or the car using the COMBINE option on the keyboard event with a move forward duration 1. It actually has a very nice feel of acceleration, because the combined movement instructions stack up until a max speed is hit due to the fixed frame rate.

However, something weird happens when you set the camera’s vehicle property to the car. The screen flickers as the camera accelerates. I’m attaching an Alice program that exhibits the behavior. Use up arrow to move forward and right arrow to turn. The flicker occurs sporadically, but more frequently if you try turning. The flicker also happens just moving the camera, so it does not seem to be connected to the vehicle. But the vehicle makes it worse, it seems.

Alice 3.6.0.1 +build .500
MacOS Mojave 10.14.6
Intel Core i7
Intel Iris Pro graphics

James
—
James Vanderhyde
Associate Professor and Department Chair
Computer Science
Saint Xavier University
3700 W. 103rd St.
Chicago, IL 60655
773-298-3454
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