Vlad Zahorodnii authored Jun 10, 2020 and Vlad Zahorodnii committed Jun 19, 2020

The compositor needs to monitor changes in the mapping between the
surface local coordinates and the buffer coordinates because texture
coordinates correspond to the latter. One way to do it is to monitor
things such as the surface size, the buffer size, the buffer scale,
etc. The main problem with doing so is that there are so many factors
that contribute to how mapping between the surface local coordinate
space and the buffer coordinate space is performed.

In order to provide a generic way for monitoring changes in the mapping
between the surface local coordinate space and the buffer coordinate
space, this patch introduces two new matrices. The first one specifies
how the surface-local coordinates are mapped to buffer coordinates, and
the other one specifies how to map the buffer coordinates to surface
local coordinates.

With the new two matrices, the compositor has a generic way to get
notified when it has to re-compute texture coordinates.