egl/wayland: Ignore rects from SwapBuffersWithDamage
eglSwapBuffersWithDamage accepts damage-region rectangles to hint the
compositor that it only needs to redraw certain areas, which was passed
through the wl_surface_damage request, as designed.
Wayland also offers a buffer transformation interface, e.g. to allow
users to render pre-rotated buffers. Unfortunately, there is no way to
query buffer transforms, and the damage region was provided in surface,
rather than buffer, co-ordinate space.
Users could in theory account for this themselves, but EGL also requires
co-ordinates to be passed in GL/mathematical co-ordinate space, with an
inversion to Wayland's natural/scanout co-ordinate space, so
transformations other than a 180-degree rotation will fail as EGL
attempts to subtract the region from (its view of the) surface height.
Pending creation and acceptance of a wl_surface.buffer_damage request,
which will accept co-ordinates in buffer co-ordinate space, pessimise to
always sending full-surface damage.
bce64c6c provides the explanation for why we send maximum-range damage,
rather than the full size of the surface: in the presence of buffer
transformations, full-surface damage may not actually cover the entire
surface.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
OSDN Git Service
