[EMAIL PROTECTED] wrote:
> > OK. Especially if LibGGI2D is oriented towards hardware acceleration,
> > complex clipping should not be too much different from hardware chipsets
> > capabilities.
>
> Yeah. It might make sense to implement a simple z-buffer operations thingy
> or similar for LibGGI3D and base windowing toolkits on that.
>
> Basically that is what they want: Multiple planes stacked on to of each
> other, with different depth.
Since 'they' is addressed at windowing system implementors, I'll respond
here in the name of the berlin project.
The situation we have is that we manage a scene graph with polymorphic graphic
nodes. Each node defines it's own extension and shape. Further, it can be
translucent. This situation can't simply be managed be redrawing 'exposed'
graphic nodes. Instead, if a region gets damaged we need to traverse the
scene graph and redraw each graphic node which intersects. Yet the problem
remains: how can we clip to the shape of the actual parent graphic if it
can have arbitrary shapes ?
The most common situation is a rectangular graphic. Next comes a transformed
rectangle (i.e. if you consider the union of multiple possibly transformed
rectangles, you get an arbitrary convex polygon). And finally there are
arbitrary shapes.
At least for the last we need a stencil buffer. Is there a way to design
clipping in GGI which is incremental, i.e. which allows more than none or
everything (none being simple scissor and everything being stencil), something
in between ?
> Could you give an API wishlist ? I might attack reimplementing LibGGI2D in a
> way that makes it more consistent with the other extensions and allowing
> to HW-Accelerate much of it.
speaking about wishlist, may I remember you of one important wish we have:
a drawable (visual) store. Some functionality with which we can allocate
(hopefully video) memory to draw into which then can be mapped to the screen.
Regards, Stefan
_______________________________________________________
Stefan Seefeld
Departement de Physique
Universite de Montreal
email: [EMAIL PROTECTED]
_______________________________________________________
...ich hab' noch einen Koffer in Berlin...
