Sometimes we were calling wlr_output_impl.set_cursor with a NULL
buffer, but we weren't clearing wlr_output.cursor_front_buffer.
Avoid leaving a dangling buffer behind.
Introduce a helper function output_set_hardware_cursor which calls
wlr_output_impl.set_cursor and keeps cursor_front_buffer in sync.
All graphics drivers supporting cursor planes support ARGB8888,
the default cursor format, so this fallback is almost certainly
unused.
Essentially all cursor themes use alpha transparency to make it
clearer where relative to the screen content the cursor hotspot is.
It is better to fall back to a slightly slower software cursor than
it is to fall back to the opaque square that is a hardware cursor
without an alpha channel.
This makes it possible for the two functions using output_pick_format
(output_pick_cursor_format and output_create_swapchain) to select
different buffer formats.
This organizes the wlr_output implementation into separate files.
This avoids having a single mega-file with lots of unrelated parts
and makes it more obvious what the interactions between all the
parts are.
No functional changes, just moving code around.
Simon Ser
Kirill Primak
Manuel Stoeckl
Isaac Freund