[OLPC-Games] Activity API

[Kent Quirk]

Hi, Bruno. Thanks for the commentary --it's quite useful.

I completely agree that the pygame event loop is competitive with the 
GTK event loop. It so happens that I've been here before in another 
situation, and through an excruciatingly clever use of Python 
generators, we were able to get the two event loops to cooperate. I hope 
to pull off the same trick here.

The rest of your comments can, I believe, be addressed through 
appropriate integration of pygame libraries. The intent is that games 
written in PyGame will, by default, play nicely in Sugar (i.e., run 
cooperatively within the environment and can be trusted not to gnaw on 
the furniture). After that, we want to provide appropriate libraries so 
that such games can be made to be fully integrated Sugar citizens if the 
developer does the work.

But a lot of what PyGame is about is making sure that children using the 
laptops have a robust game development platform to learn on. We'll 
certainly be creating recipes and guidelines for the professionals, but 
we want someone who's trying to learn to program to have a system that 
lets them learn it in a safe and simple environment. PyGame provides 
that very effectively, and the sheer volume of game development 
tutorials and examples on the net built around PyGame is an energy we'd 
like to tap into.

GCompris also seems to have some things that we hope will be useful on 
the OLPC. Please keep us posted.

    Kent



Bruno Coudoin wrote:
> Hi, I have some concern about pygame on the olpc. In fact, until know, I 
> though activities should use GTK and the hippo canvas.
>
> I understand pygame is more efficient to build games but it has also 
> some drawbacks:
> - We will have 2 different event loops for sugar and the activity, I 
> though the main activity concept was about using a single event loop.
> - Pygame doesn't use pango, last time I checked there was not support 
> for shaping in arabic for example (letter shape depends on the previous 
> one).
> - Layout management, usually games are made for a predefined window 
> size, I though hippo canvas could help in building a dynamic game layout.
> - cairo and pygame integration. I know there is a good support of cairo 
> in GTK, what about pygame.
> - Mixing GTK widgets and pygame. It's sometimes useful to use regular 
> widget in a game, mostly, we sometime use text entries (using all the 
> different character input GTK support, and the assisted technology) In 
> the HIG, it's stated that this is important for the OLPC, does pygame 
> offer a good support for that?
>
> We, in the GCompris project have build and designed over the year a 
> multi activity application that includes about 100 different activities.
>
> To some extend, GCompris core and Sugar play the same role and looks 
> very similar in their design. We also support python and can start 
> python based activities. Based on our 7 years experience in GCompris, 
> over the year we have build an API that is far from perfect but I 
> suggest to use it as a draft to implement in sugar these feature. If we 
> don't create this API that all activity can use, it will be very hard to 
> make the activities behave consistently and to maintain them over the years.
>
> To give you an example of what's needed, each activity may have several 
> levels, how do we represent the level to the user, if each activity 
> implement this, it will be inconsistent.
>
> More important, each activity should provide a translated help, how do 
> we store and display it, it must be set in a common API.
>
> On our wiki, we have documented all the core services we have set in 
> common in GCompris:
> http://gcompris.net/wiki/index.php/GCompris_internals#Core_services
>
> I don't want to say this can be used 'as is' in sugar, anyway, this code 
> is in C in GCompris so forget the reuse, but anyway, it can be used as a 
> draft to define a sugar activity API.
>
> Is there a plan to go this way, does that makes sense?
>
> Bruno.
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>
>   


-- 
------------------------------------------------------------
Kent Quirk           I'm making a game about global warming.
Game Architect                        Track the progress at:
CogniToy                http://www.cognitoy.com/meltingpoint