This replaces header include guards with `#pragma once`.
A couple of include guards are not removed yet (e.g. `__RNA_TYPES_H__`),
because they are used in other places.
This patch has been generated by P1561 followed by `make format`.
Differential Revision: https://developer.blender.org/D8466
Only the volume drawing part is really finished and exposed to the user. Hair
plugs into the existing hair rendering code and is fairly straightforward. The
pointcloud drawing is a hack using overlays rather than Eevee and workbench.
The most tricky part for volume rendering is the case where each volume grid
has a different transform, which requires an additional matrix in the shader
and non-trivial logic in Eevee volume drawing. In the common case were all the
transforms match we don't use the additional per-grid matrix in the shader.
Ref T73201, T68981
Differential Revision: https://developer.blender.org/D6955
This has no user visible impact yet since smoke volumes only support a fixed
set of attributes, but will become important with the new volume object.
For GPU shader compilation, volume grids are now handled separately from
image textures. They are somewhere between a vertex attribute and an image
texture, basically an attribute that is stored as a texture.
Differential Revision: https://developer.blender.org/D6952
This further separates requested attributes and textures from the actual
node graph, that can be retained after the graph has been compiled and
freed. It makes it easier to add volume grids as a native concept, which
sits somewhere between an attribute and a texture.
It also adds explicit link types for UDIM tile mapping, rather than
relying on fairly hidden logic.
