[Newbies] The bouncing sound

Sun Feb 24 07:03:15 UTC 2008

Hi Scott,

Scott Wallace wrote:
> Of course it's the "fence" that allows this second solution to work.  
> If your student didn't know about the "fence", I suppose he/she felt 
> an urge to use "bounce" in an attempt to contend with the situation at 
> the boundary, and that led to the complications we've seen.

This basically describe the situation. Is there a place somewhere where 
the fence is described (other than an email thread)? I know (now) that 
the balloon pops up from the playfield option in the World menu ....
>
> This is probably a case where trying things out very early in the 
> authoring process would have been helpful.  Trying out the simple 
> "forward" script would have revealed that it already worked, with the 
> only task remaining being to experiment with different values for the 
> scaling factor to get the best "feel," and hence the siren song of 
> "bounce" might have been avoided.
I agree with you on this. But at the same time, in the early process of 
working with Squeak/E-toys - or really almost any development 
environment, there are significant forces other than logical 
progression/procedure that come into play. Having said that, what turned 
out to be helpful in class was discussion that ensued about the fence 
issue. For  example: (1) how quickly an explanation for the fence was 
available on the list, (2) how flexible features in a development 
environment are very different from fixed menu choices in an application 
(3) how close to the surface the solution actually was, eg, a menu 
choice in playfield, (4) soon to surface shortly - the difference 
between Squeak and Squeakland, (5), and discussion of the tradeoffs that 
features sometimes bring.

.... One more question that seems to have come up. The student found 
today that saving the project in 3.9 (as a PR) doesn't seem to be 
reliable. At least that's the report I have. The symptom specifically, 
is some of the tiles that trigger on and off scripts don't seem to work 
after being saved into a PR file (and then being reloaded). I have no 
idea at the moment is this is the inexperience of someone new to Squeak 
or if its something else. From the students' experience, saving the 
project to a PR file is disabling some scripts whereas saving it in an 
image seems to be just fine.

I'm going to follow up on this and see what I can learn ....

Ab,

Mark

>
> Cheers
>
>   -- Scott
>
>
> On Feb 23, 2008, at 4:56 PM, polishookm wrote:
>
>> Scott, thanks very much for both solutions (and that great 
>> explanation about the fence).
>>
>> The solution you've proposed here is pretty much what the student 
>> began with. Except his scaling factor was slightly higher.
>>
>> I'll see if I can post the project once it's finished.
>>
>> Ab,
>>
>> Mark
>>
>> Scott Wallace wrote:
>>> And here's a very different, and perhaps nicer, one-line solution.
>>>
>>>
>>> ------------------------------------------------------------------------ 
>>>
>>>
>>>
>>>
>>> Cheers,
>>>
>>> -- Scott
>>>
>>>
>>> On Feb 23, 2008, at 2:10 PM, Scott Wallace wrote:
>>>
>>>> "Bounce" is particularly unsuited to this example, because it 
>>>> reverses the direction the paddle is "heading" and hence reverses 
>>>> the motion brought about by "forward" commands.  This makes it hard 
>>>> to retain an intuitive relationship between the joystick and the 
>>>> motion of the paddle.
>>>>
>>>> FWIW here's a script giving good, or at least intuitive, 
>>>> joystick/paddle action:
>>>>
>>>> <positionPaddle.jpg>
>>>>
>>>> Cheers,
>>>>
>>>> -- Scott
>>>>
>>>>
>>>>
>>>> On Feb 23, 2008, at 5:30 AM, Herbert König wrote:
>>>>
>>>>> 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
>>>>> known.
>>>>>
>>>>> 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.
>>>>>
>>>>> Finally:
>>>>>
>>>>> - Attached is my changed 3.9 Project. --> Not to the list but private
>>>>> mail
>>>>>
>>>>> - 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.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Herbert                            mailto:herbertkoenig at gmx.net
>>>>>
>>>>> _______________________________________________
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>>>>> Beginners at lists.squeakfoundation.org
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>>>>
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>>
>> -- 
>> Mark Polishook, D.M.A.
>> Technology Coordinator
>> Morehead Hall, Rm 132
>> Center for Academic Advising and Adult Learning
>> Montclair State University
>> Montclair, NJ 07043
>>
>> (973)-655-7114
>> http://www.montclair.edu/AcademicAdvising/html
>> polishookm at mail.montclair.edu
>>
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>
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-- 
Mark Polishook, D.M.A.
Technology Coordinator
Morehead Hall, Rm 132
Center for Academic Advising and Adult Learning
Montclair State University
Montclair, NJ 07043

(973)-655-7114
http://www.montclair.edu/AcademicAdvising/html
polishookm at mail.montclair.edu