Re: [Gnu3dkit-dev] OGL 2.0 shading

[Philippe C . D . Robert]

On Sunday, January 26, 2003, at 11:39  Uhr, Gerard Iglesias wrote:
> On Sunday, January 26, 2003, at 05:43 PM, Philippe C.D. Robert wrote:
> > On Sunday, January 26, 2003, at 12:16  Uhr, Gerard Iglesias wrote:
> > > Maybe the G3DCamera would be able to be present in a 3D scene, as a 
> > > 3D node ? Maybe not a simple 3D note pointing to the camera will do 
> > > the trick, but I like the idea of a camera being a graphic node ?
> >
> > I don't like this concept too much, although I am aware that many 
> > scene graphs use it. Why do you think it should be done this way?
>
> Because a lot of camera can be used in a scene with different role,  
> and sometimes I want to see them and control them in the scene from 
> the point of view of an other.

I agree this should be supported, see below.

> But the camera you see and control in the scene can be a kind of 
> special 3D node that is a camera manipulator, not the camera itself...

Yes, exactly. Either you use a node transformation to position the 
matrix and/or use a so called rotator to orientate the cam.

> And maybe the thing I am confused is the way the camera is designed is 
> a mix of a 3D view plus the frustum camera, without being a view. Ok, 
> I forgot that this way allow to connect the camera to an NSView or 
> something else, hence doesn't depend on AppKit (it was the way I was 
> trying to use gnistep+3DKit 2 years ago, when I was still in a 
> graphics company :( ).

My idea was to provide a clean MVC concept here, so the camera is the 
controller which displays the model (=scene) using a view. This is an 
important difference to the original NeXT 3DKit, where the camera was a 
subclass of NSView.

> But it would be better to me to separate the view functionalities to 
> the frustum ones.

What do you mean exactly here? Should we again provide a separate 
G3DFrustum object as in 0.3.x? I removed this separation because it did 
IMHO not add value to the design but cause communication overhead 
during rendering (when view-frustum culling).

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