In fullscreen wayland/weston EGL/GLESv2 clients without X11 (as in weston
launched from a tty), vertices ending up on the top 5-10% portion of the
vertical screen space are being clipped (as in seemingly skipped altogether and
disappearing), despite setting up an appropriate projection matrix + calling
glViewport. This results in flickering sawtooth-like edges on the top of the
screen area.
This effect doesn't show up
- in windowed mode
- in screenshots (weston Super+s)
- in screen capture (weston Super+r)
- while zoomed in using the weston Super+mwheel shortcut, or
- when using weston through X11.
Asking about this on #dri-devel on Freenode lead to the following hypothesis by
pq:
12:30 < pq> so if super+s, or zoom, or having it in a window makes the problem
go away, then the fundamental difference is likely that when weston composites,
everything goes well, but when weston tries to scan out the client image
directly, something breaks.
This occurs at least in mesa 9.2.x through git master.
setup:
Arch Linux x86_64 3.12.6-1,
Radeon HD 5770 w/ {ati-dri, mesa, mesa-libgl}-9.2.5-1, -10.0.1-1, or -git
wayland-1.3.0-1, weston-1.3.1-2 or git.