On Thu, Jan 22, 2009 at 2:46 PM, F H <expelia...@googlemail.com> wrote: > > Thank you Mathias, > > Very helpful as usual. > > If I wanted to convey a bit more information between SurfaceFlinger > and the client, would it be best to convey it via the control block or > add it to the Parcel?
Can you elaborate? What information? Mathias > > Fred. > > On 1/22/09, Mathias Agopian <pixelflin...@google.com> wrote: >> >> Hi, >> >> On Tue, Jan 20, 2009 at 3:37 AM, F H <expelia...@googlemail.com> wrote: >>> Hi Mathias, >>> >>> Android typically creates two buffers per surface. Presumably this is so >>> that one of them can be locked by an application for rendering while the >>> other (complete buffer) is available to SurfaceFlinger for compositing? >> >> correct. >> >>> What kinds of surfaces would have only one associated buffer? >> >> Surfaces with content that never changes? :-) >> But why do you ask? SurfaceFlinger never allocate a surface with only 1 >> buffer. >> >> >>> Surface Buffer access is guarded by calls to Lock/Unlock(andPost) - there >>> is >>> another fcunction - nextBuffer which looks like it always returns data >>> pertinent to the front buffer without effecting a lock. >> >> nextBuffer() was an experiment which was never cleaned-up. Don't use >> it (I mean it). nextBuffer will most likely disapear in cupcake. >> >>> Are all accesses to buffers gated through either lockSurface (& >>> corresponding unlock..) >> >> correct. >> >>> or nextBuffer? When is nextBuffer used as opposed to >>> the lockSurface? (Seems like a misleading name). >> >> see above. >> >>> Does the information ultimately get conveyed to a GGLSurface object before >>> any Android rendering is done? >> >> I need to double-check on that. I think this might still be the case. >> >>> I also noticed a limit on the number of Layers a client can have >>> (NUM_LAYERS_MAX), which is set to 31. Does this pose a problem for >>> applications that for example use lots of UI type widgets? >> >> No. A "layer" correspond to a "window" in the UI (like a status-bar, a >> dialog, or the main window). >> >>> Also I guess 31 >>> is used as a number just so that the control block stays smaller than 4k? >> >> Yes. It also simplifies a few things to keep track of surfaces (the >> implementation uses an uint32 as a bit set). >> >> >> Mathias >> >> >>> >>> Thanks, >>> Fred. >>> >>> >>> > >>> >> >> > >> > > > > --~--~---------~--~----~------------~-------~--~----~ unsubscribe: android-porting+unsubscr...@googlegroups.com website: http://groups.google.com/group/android-porting -~----------~----~----~----~------~----~------~--~---
