On Fri, Aug 13, 2004 at 12:12:44PM +0800, Selwyn Tang wrote: > On 08/13/04 11:28, Ville Syrj�l� wrote: > > On Tue, Aug 10, 2004 at 11:10:39PM +0800, Chris Leung wrote: > >>BTW, could I write a directfb program such that it will render a video > >>provider stream in layer 1 and then make the primary layer above the layer > >>1 and display some transparent GUI in primary layer? > > > > Only if the hardware supports alpha blending between the layers. You must > > check the layer capabilities for DLCAPS_ALPHACHANNEL to find out if it's > > possible. With DLCAPS_DST_COLORKEY you could use an opaque GUI. > > AFAIK, all layers additional to the primary layer are provided by the > hardware. And different hardware provides different capabilities when > dealing with layers. But one thing I would like to ask is whether the > layers have specific order, i.e. is layer 1 on top of layer 0?
You can query the layer stacking with IDirectFBDisplayLayer::GetLeveL(). > For > CLE266, there are the overlay layer and the underlay layer. Does it mean > that the overlay layer cover the primary layer, and the primary cover > the underlay? Where can I learn more about the layer support of the > hardware? AFAIK the hardware has only one extra layer but it can be used as an overlay or an underlay. IDirectFBDisplayLayer::SetLevel() should change the behaviour. > > Usually if the layers' can do what you want you should use them. It > > reduces the amount of work the accelerator has to do. > > Do you refer to the software accelerator or the hardware one? Both actually. -- Ville Syrj�l� [EMAIL PROTECTED] http://www.sci.fi/~syrjala/
