On Fri, 2010-03-12 at 13:46 -0800, Keith Packard wrote: On Fri, 12 Mar 2010 12:47:13 -0800 (PST), Andy Ritger <arit...@nvidia.com> wrote: > > Creating a window the size of the scanout pixmap and then plugging > > the scanout pixmap in as the window's backing pixmap feels a little > > backwards, sequentially. If the intent is just to give the scanout > > pixmap double buffering, you should be able to create a GLXPixmap from > > the scanout pixmap, and create that GLXPixmap with double buffering > > through selection of an appropriate GLXFBConfig. However, the GLX spec > > says that glXSwapBuffers is ignored for GLXPixmaps. > > Precisely. The window kludge is purely to make existing GL semantics > work as expected. > > > However, a more flexible solution would be to provide a mechanism to > > create a scanout window (or maybe a whole window tree), rather than a > > scanout pixmap. The proposed scanout window would not be a child of > > the root window. > > All windows are children of the root window, and we already have a > mechanism for creating windows which are drawn to alternative > pixmaps. Using this mechanism offers a simple way to express the > semantics of the situation using existing operations. > > The goal is to really get applications focused on the notion of pixmaps > containing pixels and windows as being mapped to pixmaps.
Could we achieve this by adding a new redirection type, CompositeRedirectManualForScanout or something? Then the server would create the backing pixmap for the window with a special FOR_SCANOUT usage hint. That way, we could avoid adding new requests or changes to the which-pixmap-backs-this-window semantics, and it ought to make it easier to adapt later if we add a "Create a window with N backing pixmaps" request. You could redirect a child of the COW to keep it from interacting with normal windows. _______________________________________________ xorg-devel@lists.x.org: X.Org development Archives: http://lists.x.org/archives/xorg-devel Info: http://lists.x.org/mailman/listinfo/xorg-devel
