[Newbies] The bouncing sound

Herbert König herbertkoenig at gmx.net
Sat Feb 23 13:30:32 UTC 2008

Hi Mark,

p> That's an interesting observation. Did you, perchance, play with it to
p> see what a more intuitive (for you) solution would look like? I had the

thanks for asking, that made me try :-))

p> All suggestions welcome ...

Nearly everything i know about Etoys is from the Squeak video DVD. So
I opened the viewer of the paddle and it has a tile "PongPaddleA's
heading" which jumps between 0 and 180 when bouncing.

So the simple solution would be to add a "PongPaddleA's heading = 0"
to the script. I thought I'd just have to drop the tile onto the
script. But this doesn't work, the script doesn't accept the tile.

This reminded me of several posts on squeak dev that 3.9 is not good
for etoys. So I guess the Thing to do is follow Scott's advice and use
a Squeakland image.

Dropping the Project onto a 3.8 image doesn't work, this is also

So I redid it from Ground up in my 3.8 image using an arrow as the
pong paddle (guess why). It made the sound but didn't turn on bounce.
There I learned that one has to drag a tile by the arrow to get it
into a script.

Then I tried this in 3.9 and in 3.9 the arrow also didn't turn and the
the trick with fixing the heading of the sketch also worked.

So I proved my accusations on 3.9 unfounded, Sorry 3.9 :-))

Now drop the one who did (against better knowledge) something the
first time and let the project leader speak up.

What I did with fixing the heading of the paddle in the script was "an
ugly hack". The price to pay is more uglyness if we ever want to use
"Paddle turn by Joysticks leftRigt" by having to simulate differential
geometry by "absolute geometry".

So the way to go is find out what makes the Sketch (the inspector
shows the paddle is a SketchMorph) misbehave on bounce. Maybe there is
a reason and then you should use a wide line as your paddle.


- Attached is my changed 3.9 Project. --> Not to the list but private

- Maybe this is off topic here, at least you might get better advice
on the squeakland mailing list (where I'm not subscribed).

- I'd be curious and willing to comment on further development of the
project, maybe by private mail unless somebody here also wants to
follow this.


Herbert                            mailto:herbertkoenig at gmx.net

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