On Mon, Oct 13, 2008 at 7:04 PM, Lucio Torre <[EMAIL PROTECTED]> wrote:
> during the scheduled update functions, if things are moving, your node
> may have already moved, and the other node may have not.

Ok, I get it now. You're right on this, could occur some errors when
transforming between nodes that are moving.

> whats required for this is adding one or two matrix3 multiplications
> per node in the system each frame. is this too expensive? shoud this
> be done only on demand?

I don't know if this is too expensive, but it disturbs me to add this
overhead to people who couldn't care less about having this function.
They will probably hate me later for insisting on that :)

I was wondering... when you do call CocosNode.transform it knows how
to create all the transforms based on the parameters of the node. It's
easy to do a function that does the inverse transform based on that
parameters too. Wrapping the call with a glPushMatrix / glPopMatrix
pair we could transform the point using the inverse transforms of the
parents of the node all the way up to the screen with opengl calls. We
could store the position on the column of a matrix and then get it
back by fetching the matrix value from opengl after the transforms.
This would be on demand.

-- 
Kao Cardoso Félix

Página pessoal: http://www.inf.ufrgs.br/~kcfelix
Blog: http://kaofelix.blogspot.com

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