pedohorse/yuria

Julia Language wrangle for SideFx Houdini

This is a slowly moving personal project. Tested only on linux with h18.5, h19.0 and julia 1.7.1

Building

Linux

download julia release 1.7.1 (or try later ones)
put it's contents into:
- julia directory in the root of the repository - this is needed just for includes
- julia directory in hfs/<version>/dso/julia - compiled .so will be looking for julia library there
adjust paths in tasks.json if you are using vscode

should work. now you can add path to hfs directory to your HOUDINI_PATH (or move it somewhere already in HOUDINI_PATH), and houdini will load it

use HOUDINI_DSO_ERROR=2 to catch so loading errors

ye, it's not yet very streamlined

other OSes

not yet.

due to some os-specific things in julia it might not be as simple as just recompiling it. MacOS has higher chance to not require any modifications, while windows handles signals completely different.

Installing

to your user dir

find appropriate sop_julia.so (or dll on windows (or whatever extention mac is using)) for appropriate houdini version. Build should not matter, only major.minor versions are important.
copy it to your houdini userdir's dso folder, like houdini19.0/dso
unpack julia release 1.7.1 (or the version you built .so with) to julia folder in the same place
your file structure should look like this:

houdini19.0
      |\dso
         |\sop_julia.so
         |\julia
             |\bin
             |\lib
             |\share
             ....

anywhere else

You can put in anywhere DSOs are scanned for in your setup,
Just make sure that wherever you put the sop_julia.so - the julia release dir (see above) is right next to it.

using

The plugin provides a SOP node haned juliasnippet, there you can put initialization code (usings, includes and declarations), and the code of a function to run every cook

Attribute bindings happen bu name, according to attribute masks in node parameters
So if you map P - P will be available in function code (not initialization code) as a 3xN matrix
If you rebind it - you will loose connection to houdini. So instead - modify it inplace only DO NOT RESIZE BINDED ATTRIBUTES INPLACE - houdini will not catch that (yet)

Vertex, Point, Primitive, Detail attributes - all are considered for binding (and in that order)
You should not have different class attributes with same names, only first one (in order above) will be binded in that case.

If you want julia to run multithreaded - provide environment variable to houdini JULIA_NUM_THREADS=auto (or any specific value instead of auto)
BUTT BEWARE - in multithreaded mode the problem below may apply.

If that variable is not provided - julia will start in single-threaded mode, you can check number of threads with Threads.nthreads()

Environment variables:

All julia environment variables will work as expected, nothing is set differently from the defaults.
Therefore it's important to set JULIA_NUM_THREADS=auto in case you want multithreaded julia

while all julia variables start with JULIA_
all plugin-specific veriables start with YURIA_

YURIA_DEBUG - if set all debug output about plugin's work will be printed to stdout.

installing Julia packages

For now there is no embedded into houdini julia console.
So you will need to start julia shell of the same version you use for houdini (also the same JULIA_PROJECT if set, and other config environment variables)

install all the packages you need the standard way through julia's interactive shell. After that you will be able to import them into houdini snippets.

Known Problems:

~~There is a problem of (as it seems) julia's GC sometimes conflicting with houdini~~ the problem seem to be mitigated, you can see discussion here

why yuria?

pedohorse / yuria