How to get started writing a compositing WM?

Question

I would like to write a basic hardware-accelerated window manager, so I\'ve been looking for some documentation on how to get started, but I\'ve only managed to find this tutori

Answer 1

There are two parts in your question: 1) How to write WM 2) how to write composite manager

Some links to help understand part two (in addition to xcompmgr source):

• http://www.talisman.org/~erlkonig/misc/x11-composite-tutorial/ (Uses Qt, but very generic and low level)
• https://github.com/gustavosbarreto/compmgr
• http://projects.mini-dweeb.org/projects/unagi

Window manager, "part one":

• I have simple ~100 loc wm in JavaScript: https://github.com/sidorares/node-x11/blob/master/examples/windowmanager/wm.js
• another minimalist wm (in C), good to start as a reference: https://code.google.com/p/winmalist/
• most important keyword: SubstructureRedirect event mask. A bit of documentation here

Answer 2

The original demo compositing manager was xcompmgr, which I'd recommend for understanding the underlying X extensions.

If you're using OpenGL to do your hardware-accelerated rendering, you'll need to read up on the EXT_texture_from_pixmap extension to avoid copying window contents through userspace. That extension allows you to use hardware-accelerated blits for those copies instead.

You'll probably also be interested in the specification for _NET_WM_SYNC_REQUEST, to allow tear-free rendering synchronized to vertical retrace.