[etoys-dev] SQ-94 - Flip and Tumble

Tue Aug 17 08:22:00 EDT 2010

Hehe, you're welcome. We don't advertise this feature much. When you play more with it you will see why - it is much harder to see which heading an object actually has. And it interacts weirdly (if not to say buggy) with rotating via the blue halo handle. Plus it adds nothing to the simulation model itself, it's just visual glitz, so to say. Drawing objects from a top-view works much better if the goal is to understand what's happening.

Btw, changing the forward direction directly is easier than using the tile. Shift-click the green nose arrow and drag it into your desired "forward" direction.

- Bert -

On 17.08.2010, at 13:46, Steve Thomas wrote:

> Bert,
> 
> Congratulations!!! You have just solved a problem that has frustrated kids all over! (okay the problem was solved already but no one I know other than you knew the solution).
> 
> For whatever reason kids love to make fish tanks (just look at http://www.etoysillinois.org/library.php?tags=Seaside).  
> And every kid I have seen try and do this runs into the same problem. When the fish gets to the end of the tank it "swims" out of the tank.  Well this is nice because it leads them to discover (either through the help guides or by bugging the teacher to find out) about the bounce tile.  This leads to the problem that the When you paint a fish and it bounces off the walls it looks like it swimming upside down.  The kids usually come up with a solution that they have to draw the fish in a certain way so that even though the graphic "flipped" you can't tell.  But by setting the "rotation style" you have solve the problem and you can draw assymetrical fish and that "swim properly"
> 
> My description is probably hard to follow so here is a test for all your Fish loving Etoy fans.
> Draw a fish on the screen.
> Bring up its halo and create a script with "forward by 5" then run it once
> Is it swimming in the correct direction?
> If not, play with the heading and "forward direction" settings ("forward direction" tile can be found using the search or in the geometry category)
> Now get the fish to swim to the left or right.
> What happens when it reaches the wall?
> Can you fix it so it doesn't swim out of the tank?
> Hint: Look in the excellent quick guides (that big "?" in the upper left will open them for you)  and click on "Script Tiles" and then "bounce motion"
> When the fish bounces does it look like you expected or what you want?
> Can you describe how the fish graphic "transformed" (in Spanish, transformado, in German verwandelt, in Greek μετατρέπονται, In Japanese: 変換,
> in kid speak: "it looks different".  Don't get hung up on the names (especially the ones mathemeticians use ;)  just figure out what they mean, that's the important thing. You only need to know the names to pass the test in school. To past the tests in life knowing the meanings and how to use them is MUCH more important.
> Try drawing a fish on a piece of paper and cutting it out. Then move it through the air in an imaginary fish tank you can see in your mind (seeing things again? Good ;) How do you do to the fish when it reaches the edge of the tank and turns around?  Make the fish move the way you would expect a real fish to move. Then make it move the way it just moved in Etoys. This is the problem with Etoys (and anything else you use to make a model), it does what you tell it (or in this case its default behavior) and not necessarily exactly what happens in the real world.
> Know have your fish swim left and right and down a little.
> What happens when it bounces off the bottom of your ocean?
> Can you do that with your paper fish? Can you describe how you had to make your paper fish move?
> Hey imagine you are a fish and make yourself or a friend move like that crazy Etoy's fish you just created.
> Okay, now how can we make our Etoys fish look more like a real fish?
> Well do what Uncle Bert suggested and get the halo for your fish, click on the menu icon, then on "set rotation style". Then try and find a rotation style that makes your Etoys fish swim more like a real fish.
> Once you do this, can you figure out how this will change how the turn tiles work? (Good luck, it is far from obvious and really hard to figure out, but I am confident with patience and perseverance you can do it, or just about anything else you put your mind to).
> Dank Onkel Bert!!!
> Stephen
> 
> On Tue, Aug 17, 2010 at 6:32 AM, Bert Freudenberg <bert at freudenbergs.de> wrote:
> You still make it sound like the new flip tiles and the old rotation-style tile were somehow equivalent. They are not.
> 
> I agree, however, that having a tile to set the rotation style is not strictly necessary - because it it available as menu item. I am not sure why it was added in the first place. Perhaps because tiles are more discoverable than menu entries. I couldn't imagine using this tile in a script. But changing the rotation style in the viewer while an object is bouncing around the screen is enlightening (though the up-down style seems to be there just for completeness, have not found an application yet).
> 
> Anyway, independent of the new flip tiles: Do we want to hide the rotation-style tile?
> 
> - Bert -
> 
> On 17.08.2010, at 04:10, Steve Thomas wrote:
> 
>> Okay read Bert's comment in Tracker and I now understand that the graphic is flipped without changing heading (which differs from the implementation using "rotation style" which by design changes heading to cause the flip).
>> 
>> So given that we want to have the minimum set of tiles from which you can create things.  Why do we need both?
>> I understand the need to keep the older rotation style methods so older projects don't break, but IMNSOBOWO we should hide the rotation style tile.
>> 
>> Stephen
>> 
>> On Mon, Aug 16, 2010 at 9:20 AM, Steve Thomas <sthomas1 at gosargon.com> wrote:
>> 
>> 
>> On Mon, Aug 16, 2010 at 8:52 AM, Bert Freudenberg <bert at freudenbergs.de> wrote:
>> 
>> On 16.08.2010, at 04:01, Steve Thomas wrote:
>> 
>>> Tried the new flip and tumble works great (for sketches, would be nice if this worked for all costumes, polygons would be trivial ;)
>>> 
>>> Now that we have flip and tumble, do we need rotation style?  To me its confusing to have both and flip and tumble are much simpler to learn and use.
>> 
>> Yes we need it. How else would you make a painted object go upright on the screen?
>> 
>> I agree we need the ability the "flip left right" and "flip up down" functionality and the new tiles (now called "flip" and "tumble")
>> provide that functionality. 
>> 
>> When I asked do we need rotation style, I was referring to the scripting tile in the graphic category of the viewer not removing the functionality which is provided in the code and accesible via the new "flip" and "tumble" tiles.
>>  
>> It disables actual rotation and automatically flips the graphic depending on heading. Flip and tumble are just one-shot operations that change the graphics. 
>> Yes I understand that as you increase heading the graphic reaches a tipping point around 90 or 180 degrees. I just don't see why we need both methods, although to ensure old projects work, I was suggesting simply hiding the tile "rotation style".
>> 
>> Stephen
>> 
>>> I think we hide the "rotation style" tile when in Etoys Friendly mode.
>> 
>> Did you mean to write "we should"?
>>  
>> Yes. Although "we" is probably a poor choice of words as I do no coding, that is left to over burdened, yet much appreciated developers such as yourself.
>> 
>> Stephen 
>> - Bert -
> 
> 
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