Blender Git Loki

Cycles: Changed isovalue compaison for volume meshes to include equals - probably suboptimal volume meshes, but correct renders at least

OpenVDB modifier: Changed the "sparse render" name to "in memory render", defaulting to sparse data structure

Cycles: Enabled direct sampling of OpenVDB data in the CPU kernel.

OpenVDB: Disable simplification when rendering sparse

Simplification would mess up some values that Cycles needs when doing
sparse renders, so this commit disables render simplification when
sparse rendering is enabled, ensuring the values will be correct.

OpenVDB: Expose `index_offset` property in RNA

OpenVDB: Set `clipping` to 0.0

OpenVDB: Make filepath of current frame available

This makes `abs_path` in the OpenVDB modifier return the path to the
frame that should currently be read (taking into account the current
frame, the frame offset, and frame overrides).

This is a bit hackish, as it duplicates the frame calculation and path
generation code, but it was the quickest and easiest way to achieve
this, in contrast to adapting and exposing the existing functions to
work with this use-case.

OpenVDB: Add sparse render option

This option prevents the cache from being loaded into memory.

OpenVDB: Make "simplify" available for render

Cycles: Fixed OpenVDB path names, there was a possible memory corruption when generating the absolute path to a VDB file.

Cycles: More work on OpenVDB rendering.

Moved it out of ImageManager to a VolumeManager. Added custom transforms to OpenVDB to swap and mirror XYZ.

Cycles: First attempts at making OpenVDB modifier show up in render

OpenVDB: Added backwards compatibility with Tangent 2.78 builds.

Merge branch 'master_upstream' into luca_openvdb_import_28

Fixed split option UI for OpenVDB modifier

Fix volume not visible in render with "hide volume"

This fixes an issue that caused volumes to disappear in renders when the
"hide volume" or "hide uunselected" display options are enabled.

The issue was that the modifier is called prior to rendering, with the
"MOD_APPLY_RENDER" flag, as expected. However immediately after, and
while still rendering, the modifier is called again, without the render
flag, causing it to be recomputed as it should be for the viewport
display. This happens because Blender allows you to work while
rendering, and thus the display version of the modifiers has to be
computed.

The issue is of course that while this is not a problem for meshes, as
they are copied and passed along the modifier stack, data which is read
directly (such as volume data), is still subject to side-effects.

This commit prevents the modifier from updating the data while a render
is in progress, thus keeping the render data intact. This unfortunately
causes the minor side-effect of full resolution smoke being displayed in
the viewport after rendering, even when the "simplify" option is used.
Note however that this causes no extra data loading, and thus
performance is unaffected. Also note that the hiding options don't
suffer from this side effect, and so if the volume is hidden, it's
hidden state will still be in effect after the render, as hiding does
not rely on the cache being reloaded.

Fix mistake in VDB modifier UI code

When implementing the split grid channels and the velocity grids, I
forgot to update a bit of code in the UI. This fixes that issue.

Fix crashes and errors with internal smoke sims

Some special properties for VDB were causing Blender smoke sims to
crash.

Import OpenVDB velocity grids

This imports the OpenVDB velocity grid into Blender's own data
structure, making it available for rendering.

Fix OpenVDB start/end frame on copy

Start/end frames were being reset when copying the OpenVDB object.