1192960 - Use GLX surface sharing with X11 basic compositor

Status: RESOLVED WONTFIX

(Core :: Graphics: Layers, defect)

Description

[Andrew Comminos [:acomminos]]

Currently GLX surface sharing is only used with the GL compositor. We could also use it with the X11 basic compositor and XRender for good performance gains on some XRender implementations.

Comment 1

[Andrew Comminos [:acomminos]]

Attachment: Use GLX surface sharing with the X11 basic compositor.

This enables GLX shared surfaces with WebGL on the X11 basic compositor. Let's be careful not to awaken bug 1189903, the performance gains from surface sharing should outweigh the cost of faking the lack of alpha channel though.

Try/talos: https://treeherder.mozilla.org/#/jobs?repo=try&revision=fa7805efcf30

Comment 2

[Andrew Comminos [:acomminos]]

Comment on attachment 8645885 [details] [diff] [review]
Use GLX surface sharing with the X11 basic compositor.

The patch appears to be hitting the BadMatch error described in bug 1192648. Looking into it, could be likely due to the GLX pixmap being incompatible with the compositor's GLX context on some configurations.

Comment 3

[u279076]

Andrew, are you still working on this?

Comment 4

[Andrew Comminos [:acomminos]]

While I'm working on improving GLX surface sharing, I don't think we'll be turning this on for the X11 basic compositor anytime soon (primary we just want to use TFP to share textures with the GL compositor).

Comment 5

[Andrew Comminos [:acomminos]]

I'm going to mark this one wontfix, actually- from what I can tell, the alpha channel (and other non-colour channels) of GLX pixmaps is not stored in the actual X11 pixmap server-side, but rather exposed only through GLX and GL via TFP. While there are some GLX implementations that provide "true" 32-bit pixmaps, many implementations do not or ship a restricted set of FB configs (mesa, for example, only appears to expose a single 32-bit FB config). This prohibits us from exposing the alpha channel to XRender.