Hi Anders, It is not a safe operation. The DFB core software and drivers may depend upon knowing when CPU based pixel modifications are complete for a variety of reasons (such as cache flushing for the GPU or pushing the buffer to video RAM, etc.). Always perform locking and unlocking has a paired operation.
We just identified a fix for a customer today related to visible caching artifacts, partially because lock/unlock were not used properly (the buffer pointer was being cached). Regards, Timothy -- Timothy Strelchun CE Software Engineering Digital Home Group Intel Corporation The views expressed above are my own and not those of Intel >-----Original Message----- >From: directfb-dev-boun...@directfb.org >[mailto:directfb-dev-boun...@directfb.org] On Behalf Of Anders Bakken >Sent: Tuesday, September 01, 2009 3:40 PM >To: directfb-dev@directfb.org >Subject: [directfb-dev] question about locking > >Is the following a "safe" operation: > >IDirectFBSurface *surfaceOne = ...; >IDirectFBSurface *surfaceTwo = ...; >int bpl; >void *mem; >surfaceOne->Lock(surfaceOne, DSLF_WRITE, &mem, &bpl); >// change the pixels of mem using something other interface >surfaceTwo->Blit(surfaceTwo, surfaceOne, 0, 0, 0); > >Do I need to call surfaceOne->Unlock(surfaceOne); before I >blit surfaceOne onto surfaceTwo? > >If the answer is yes, what if I did this instead: >IDirectFBSurface *surfaceOne = ...; >IDirectFBSurface *surfaceTwo = ...; >IDirectFBSurface *sub; >surfaceOne->GetSubSurface(surfaceOne, 0, &sub); >int bpl; >void *mem; >sub->Lock(sub, DSLF_WRITE, &mem, &bpl); >// change the pixels of mem using something other interface >surfaceTwo->Blit(surfaceTwo, surfaceOne, 0, 0, 0); > >Do I need to call sub->Unlock(sub); before I blit surfaceOne >onto surfaceTwo? > >regards >-- >Anders Bakken >_______________________________________________ >directfb-dev mailing list >directfb-dev@directfb.org >http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev > _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
