[Sugar-devel] Physics Roadmap

[Gary C Martin]

On 18 Jun 2009, at 11:48, Brian Jordan wrote:

> On Wed, Jun 17, 2009 at 7:24 PM, Gary C Martin<gary at garycmartin.com>  
> wrote:
>> On 17 Jun 2009, at 06:29, Edward Cherlin wrote:
>>
>>> Did you look at my Turtle Art version of Alan Kay's third-grade  
>>> gravity
>>> lesson?
>>>
>>> http://wiki.sugarlabs.org/go/File:Gravity.odt
>>
>> I had a read, but it didn't get me very far, sorry – competing with  
>> an Alan
>> Kay presentation is always going to be tough :-) Regarding Physics,  
>> it's
>> more a sandbox for making weird and wonderful little mechanical  
>> devices; but
>> specifically regarding gravity, I think there is a nice feature I'd  
>> like to
>> try and find a way add as some point, 'object trails'.
> +1
>
> I tried this at one point using a black background in Physics and a
> long camera exposure, it's a lot of fun seeing the physical motion in
> one static image.
>
> http://dev.laptop.org/~bjordan/physics/housegolf.jpg
> http://dev.laptop.org/~bjordan/physics/trianglegolf.jpg

Cool :-)

Out of interest, do you know if alpha is supported in the Physics view  
(had a quick dig and it seems not)? The idea being if you could switch  
the self.screen.fill((255,255,255)) display clear to something like  
self.screen.fill((255,255,255,128)) you'd get similar effect on screen  
(motion blur trails).

Ideally though I think 'object trails' should be something you paint  
'daub' onto an object, so that just it alone leaves a trail (or as  
many as you choose). Just a pen line would be enough. I guess you  
could read a given paint 'daub' (simple small circle pinned at the  
place you click) position from frame to frame and just over draw  
trails in pygame, just like the tools currently do (you'd need a  
finite trail history so as not to slow down too much as the trail  
would get redrawn on each frame). Seems quite reasonable :-)

Regards,
--Gary