[linux-audio-dev] XAP spec - early scribbles

[torbenh at gmx.de]

On Sat, Mar 01, 2003 at 04:47:55PM +0000, Simon Jenkins wrote:
> torbenh at gmx.de wrote:
> 
> >[...]
> >
> >Another problem i have with moving to the graph ordering side
> >is the opengl stuff in galan which requires the pull model for
> >the data. 
> >
> >It would get somewhat inconsistent if gl data was pulled and 
> >audio data not... but this is also cosmetic...
> > 
> >
> They're not that far apart:
> 
> The point of graph-ordering is achieve pull semantics from a
> push implementation. The graph orderer works out what order
> the data would be pulled through the graph, and the data gets
> pushed through in reverse order to achieve the same effect.

but is the performance of push networks so much higher ?


> 
> A push implementation with push semantics probably wouldn't
> bother to sort the graph: it could rapidly calculate the execution
> order at runtime, executing each node as its data became available.
> 
> OTOH I agree that there's an inconsistency at the implementation
> level, if thats what you're concerned about.

well sort of... opengl is really pulled...

before some thing is rendered a transformation matrix needs to be pushed
onto the Matrix stack... popping it again when the subgraph connected to
the transformation component is done...


> 
> Simon Jenkins
> (Bristol, UK)
> 
> 

-- 
torben Hohn
http://galan.sourceforge.net -- The graphical Audio language