Re: [Gnu3dkit-dev] G3DRenderer.h

[Philippe C . D . Robert]

On Sunday, March 16, 2003, at 10:18  Uhr, Brent Gulanowski wrote:
> On Sunday, March 16, 2003, at 02:36  PM, Philippe C.D. Robert wrote:
>
> > > My question about G3DGeometry is answered. The geometry classes will 
> > > stay in the scene graph, and access the renderer through the drawing 
> > > commands. Will you have geometry classes that work in parallel with 
> > > the interface groups (polygons, points, curves, quadrics, blobby, 
> > > subdivision, patches, producedural)?
> >
> > Yes, there will be such classes. BTW it is the renderer action which 
> > accesses the data (geometry, shaders, ... ), not the other way >> around!
>
> Erm, all I want to know is, who sends the messages to the renderer? 
> Who calls the methods in the renderer API? The "action"? What class 
> exists which represents an action? Does this class act as the brains, 
> first asking the scene for its data, then passing it to the renderer 
> via the RenderMan-style interface which you have produced?

An instance of G3DRenderAction is used for this purpose. It traverses 
the graph and renders the scene by first calling the appropriate 
methods on its renderer (context management, optimised state handling, 
shader setup and so on) and then requesting the geometry to draw itself.

So you can use n render actions using m different renderer backends 
concurrently on the same scene. This also makes life in a multithreaded 
environment much easier as this is non intrusive.

-Phil
--
Philippe C.D. Robert
http://www.nice.ch/~phip