Loïc Molinari authored Mar 08, 2023 and Pekka Paalanen committed Jun 12, 2023

Move vertex clipper back to single-precision floating point
intermediates. Since positions are sent down the graphics hardware as
single-precision values, this prevents useless conversions between
single and double precision values and lets compilers fit twice as
much data into vector registers. It also removes a copy by letting the
clipper store vertices directly into the vertex buffer.

This is mostly reverting the conversion to double-precision that
happened along with the switch to the weston_coord struct for vertex
coordinates (commit 10e70bf2).

Signed-off-by: Loïc Molinari <loic.molinari@gmail.com>