[plt-scheme] MrEd+Allegro on MacOS

From: Jon Rafkind (workmin at ccs.neu.edu)
Date: Sat Mar 1 00:58:23 EST 2008

alex mitchell wrote:
> Hi Jon (and the list),
> The postings about the Tetris game reminded me of the problems I was having
> on MacOS with the Allegro Scheme bindings. A while back I was building a
> simplified version of Logo, using Allegro for the turtle graphics. It was
> working well under Windows, but on MacOS the MrEd UI elements would stop
> responding, or only give intermittent, laggy responces, once the Allegro
> window appeared. 
> Here's a simple example of the problem, which I've tried (unsuccessfully) to
> solve using a separate thread for the game loop. In this example, there's an
> Allegro window showing the sample "Hello world" program, and a MrEd window
> with a single button, which closes the Allegro window. The MrEd button
> sometimes responds to mouse clicks, but sometimes doesn't, and after closing
> the program, DrScheme doesn't respond properly, and needs a "force quit" to
> exit.
I tried your test program and I was able to click the exit button each
time, closing the Allegro window. The drscheme window did not respond to
mouse clicks while the Allegro window was open though, I think thats
because the Allegro window is stealing input events. I'll see if I can
fix that.

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