Diffusion KWin e3f0b537b6b4

[effects/coverswitch] Fix broken reflection on multi-monitor setup

Authored by poboiko on Mar 25 2018, 10:26 AM.

Description

[effects/coverswitch] Fix broken reflection on multi-monitor setup

ModelViewMatrix used to paint windows (which is aware about
multi-monitor configuration) was overriden by reflectionMatrix when
painting reflections, leading to wrong placement of reflections.
Now we just multiply old matrix and reflection matrix.

BUG: 378688

Differential Revision: https://phabricator.kde.org/D10465