Since 4.5 the point clouds are out of experimental.
The drawing of pointcloud did not allow for correct volume
estimation as the shape are not rendered as closed objects
(i.e. the backfaces were not rendered).
This patch renders the backfaces for the volume occupancy
pass by rendering the pointcloud twice and flipping the
shape alignment matrix. This reverse the winding and
does a backface hit as it would do for a sphere primitive.
This solution even if not perfect avoids adding more
geometry in the Index Buffer. The geometry approach might
be preferable in the future if we find a way to render
the spheres without an IBO or with a JIT generated IBO.
Rel #141490
Pull Request: https://projects.blender.org/blender/blender/pulls/142095
50e876f21d