point towards the mouse?

On Nov 10, 2009, at 11:02 PM, Darius Clarke wrote:

> For point 1 you can use the slope formula m = (y1-y2)/(x1-x2) and then arcTan m to get degrees.
>
> arcTan may have to come from Smalltalk mode.
>
> Cheers,
> Darius
>
> On Tue, Nov 10, 2009 at 10:53 PM, Hilaire Fernandes <[hidden email]> wrote:
> For point 2.,  you may have to write the script in Smalltalk mode then
> use the code
>
> ActiveHand x to get abscissa of the mouse pointer
>
> Hilaire
>
>
> 2009/11/11 Bill Kerr <[hidden email]>:
> > 1) Is it possible to get an arrow to point towards the mouse pointer in
> > etoys?

FWIW I attach a working example... notice that it's all done with tiles -- no textual scripting.

Attached below is another solution, using an invisible "sprite".

 -- Scott








On Nov 11, 2009, at 1:02 AM, Scott Wallace wrote:

> On Nov 10, 2009, at 11:02 PM, Darius Clarke wrote:
>
>> For point 1 you can use the slope formula m = (y1-y2)/(x1-x2) and then arcTan m to get degrees.
>>
>> arcTan may have to come from Smalltalk mode.
>>
>> Cheers,
>> Darius
>>
>> On Tue, Nov 10, 2009 at 10:53 PM, Hilaire Fernandes <[hidden email]> wrote:
>> For point 2.,  you may have to write the script in Smalltalk mode then
>> use the code
>>
>> ActiveHand x to get abscissa of the mouse pointer
>>
>> Hilaire
>>
>>
>> 2009/11/11 Bill Kerr <[hidden email]>:
>>> 1) Is it possible to get an arrow to point towards the mouse pointer in
>>> etoys?
>
>
> FWIW I attach a working example... notice that it's all done with tiles -- no textual scripting.
>
> -- Scott
>
>
> <pointTowardCursor.002.pr>_______________________________________________
> squeakland mailing list
> [hidden email]
> http://lists.squeakland.org/mailman/listinfo/squeakland


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Hi,Bill

You'll find the tiles mouseX and mouseY in the playfield category of a playfield or of the world.

get an arrow fom object catalog/graphics

move the ble rotation handle sligtly to make te center or rotation visible and move it shift/drag to the foot of the arrow.
get the viewer of the arrow category polygon, et the arrow's vertex .cursor to 2 (head of the arrow).

now just build the tiles :

arrow's x at cursor _ playfield's mousex
arrow's y at cursor _ playfield's mousey

You probably just need to find where the tiles mouse and mousey were lying, but this will help other people.

On Nov 11, 2009, at 2:20 AM, Bill Kerr wrote:

> On Wed, Nov 11, 2009 at 8:38 PM, Scott Wallace <[hidden email]> wrote:
>> Attached below is another solution, using an invisible "sprite".
>
> How did you make the invisible sprite Scott?
> I just clicked on your Sprite's show key and nothing appeared
> Is it just an empty drawing which you keep? I haven't tried that yet
>
> I almost worked out that one myself after my intial post
> But I made a visible sprite and then shrunk it - it sort of worked but because the sprite was visible once it was ticking I couldn't use the mouse to switch off the clock or anything else because the sprite got in the way

Heh, heh...  The sprite is a tiny RectangleMorph, which is:

(a)  Invisible -- color transparent, borderWidth 0.
(b)  Locked -- so that the sprite doesn't get in the way of mouse use.

 -- Scott_______________________________________________

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Ah, I found your blog entry now. Attached is a project that I think does what you wanted - I did not hide the dots, would be simple though.

This task is a bit geared towards Scratch - it's more complicated in Etoys as there is no reification of the mouse pointer. Might be a nice idea to make a player for it though ...

- Bert -