implement window surface

[David Reveman]

On Tue, 2005-05-17 at 15:44 -0600, Brian Paul wrote: 
> Jon Smirl wrote:
> > Don't I need to implement window surfaces in the fbdev EGL driver? In
> > other words the ability to create a surface that will draw to a
> > clipped rectangle on an existing screen surface.  Without clipped
> > surfaces how can you implement a non-composed Xserver?
> 
> The eglCreateWindowSurface() function is designed to be used in 
> conjunction with the native window system's windows (X window or Win32 
> window, etc).  It takes a <NativeWindowType> parameter.  So you'd use 
> the native window system API to manage the window (XMoveWindow, 
> XResizeWindow, XMapWindow, etc).
> 
> So in our X-less EGL environment we'd probably need to add all those 
> sorts of functions.
> 
> Another option I've been considering is to develop a new OpenGL/Mesa 
> extension that extends the glScissor feature to allow clipping against 
> a list of rectangles, not just one.  This would be used to implement 
> cliprects for window regions.  The DRI drivers already support this 
> internally for window clipping so it shouldn't be too hard to implement.
> 
> What do the XGL people think of that?

That would be nice. There's a clip rects interface in glitz that is
currently implemented using glScissor and multiple drawing operations.
It'd be very easy to have this utilize an extension like this when
available. 

-David