81bd49d4fe
This patch adds support for selecting pointclouds.
Since pointclouds were not properly drawn to the selection buffer (as diagonsed by output from `glReadPixels` and Renderdoc), they were not able to be selectable by depth picking or occlusion queries. In `basic_engine`, objects were rendered with a shader which draws to a depth buffer but only assumes a single position vertex attribute. Pointclouds, though, require at least another vertex attribute `pos_inst` which provides the instance offsets. Thus, this patch adds another shader variant for pointclouds which supports these two attributes and renders the points appropriately.
{F11652666}
Addresses T92415
Reviewed By: fclem
Differential Revision: https://developer.blender.org/D13059