Quoting Alex SONG ([EMAIL PROTECTED]): > On Wed, 12 Jun 2002, Denis Oliver Kropp wrote: > > <snip> > > > df_dok uses the same surface for blit and stretch-blit (melted.png). > > yes it does, i looked at blit_colorkey for some stupid reason. well it > doesn't seem to happen with df_dok then. is this because the source > surface is not being written to (since melted.png is only rendered at the > start) ?
yes. > > The alternating would happen if software writes to a surface and blits from it > > using hardware afterwards. This is a common case for displaying videos. > > yes i noticed the problems while displaying videos. i will clarify my > problem again. when i display a video with software stretchblit it is fine > and let's call this speed speed1. i then change the software stretchblit > to a hardware blit and this i also fine. now when i change back to a > software stretchblit it gets played back at speed2. now the problem is > that speed2 is much slower than speed1. so what i am feeling is that > something is not being reset properly as a stretchblit is capable of > speed1 but for some reason it can't after swithing from a hardware blit. > > in both cases the software is writing to a surface and then blitting using > hardware and software. there is no reason why stretchblit should have > different performance from the first time and the second time. this is why > i think there is a bug somewhere. It's not a bug, it's just a stupid heuristic. Imagine the following sequence: Action | S | V | --------------------------------------------- Surface created | + | . | Software writes to surface | + | . | writes to system memory Software stretch blits from surface | + | . | reads from system memory Hardware blits from surface | + | + | copied to video memory Software writes to surface | - | + | writes to video memory Software stretch blits from surface | - | + | reads from video memory S = system memory instance V = video memory instance . = invalid (not allocated) + = stored (allocated, contains recent data) - = restore (allocated, but data is outdated) -- Best regards, Denis Oliver Kropp .------------------------------------------. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | "------------------------------------------" Convergence GmbH -- Info: To unsubscribe send a mail to [EMAIL PROTECTED] with "unsubscribe directfb-dev" as subject.
