Re: Some considerations
Jon Smirl <jonsmirl-/[email protected]>
| Newsgroups | gmane.comp.freedesktop.xserver |
|---|---|
| Message-ID | <[email protected]> |
--- [email protected] wrote: > 3) How is current hardware going to like it? Consumer level stuff is fast, but > has a history of not handling concurrency well. It sounds like you want each > app to use Cairo, preferably via the OpenGL back-end. The simplest model would > be to give each app its own OpenGL context, but I have a feeling that current > hardware would really not like that at all. This made we thing of some different ways to optimize. Working from the assumption that the OpenGL API will always be available, you can see that it will be used to various degrees by different windows. For example the main window manager window is always going to use it to do compositing and a 3D app is alway going to use it. But what about toolkit based windows? Supposed the toolkit has two themes, a fancy one that uses the GL API for eye candy, etc and a plain one that only uses Cairo. Even though the GL API is available to the Cario only toolkit version, the GL API is never going to be touched. The graphics libraries can detect this condition. Windows can start out being allocated in AGP space and being drawn with a software Cairo renderer. Only when the GL API gets touched do these windows need to get promoted into VRAM. By being in AGP space it is then possible for the compositor to directly pick up the window contents. This will be great for simple things like dialogs and message popups. This also has some neat implications for direct rendered 2D. From what I've seen I'll bet Cairo to system AGP RAM, that is latter picked up by the compositing engine will be very competitive to a GL based Cairo. But we'll still need the GL based Cairo for windows that mix content. You'll also need the GL Cairo for high end systems that turn on the GL based widget set. A key performance question will be where does the font bitmap cache live, AGP or VRAM? ===== Jon Smirl jonsmirl-/[email protected] __________________________________ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree