This splits the volume related data (properties for rendering and attributes) of the Mesh node
into a new `Volume` node type.
This `Volume` node derives from the `Mesh` class since we generate a mesh for the bounds of the
volume, as such we can safely work on `Volumes` as if they were `Meshes`, e.g. for BVH creation.
However such code should still check for the geometry type of the object to be `MESH` or `VOLUME`
which may be bug prone if this is forgotten.
This is part of T79131.
Reviewed By: brecht
Maniphest Tasks: T79131
Differential Revision: https://developer.blender.org/D8538
In an upcoming bugfix we'll use OpenVDB data structures directly to build mesh
for sparse OpenVDB volumes, loading them OpenVDB grids earlier and removing any
references to Blender data structures makes that easier.
This also makes changes to Blender volumes to support this, so Cycles can take
ownership of a grid without Blender having to keep its own reference to it.
This should also be useful in a future Python API.
Ref D8401
The problem was that Cycles would store a pointer to an object in
`DEGObjectIterData->templ_dupli_object`. This pointer was then accessed
when the iterator was already freed.
Reviewers: brecht
Differential Revision: https://developer.blender.org/D7797
* Space: volume density and step size in object or world space
* Step Size: override automatic step size
* Clipping: values below this are ignored for tighter volume bounds
The last two are Cycles only currently.
Ref T73201
Voxels are loaded directly from the OpenVDB grid. Rendering still only supports
dense grid, so memory usage is not great for sparse volumes, this is to be
addressed in the future.
Ref T73201
Rather than passing around void pointers, various Blender image sources now
subclass this. OIIO is also just another type of image loader.
Also fixes T67718: Cycles viewport render crash editing point density settings
