Geometry Nodes: Distribute Points in Volume

This commit adds a node to distribute points inside of volume grids.
The "Random" mode usese OpenVDB's "point scatter" implementation, and
there is also a "Grid" mode for uniform distributions. Both methods
operate on all of the float grids in the volume, using every voxel with
a value higher than the threshold. The random method is not stable as
the input volume deforms.

Based on a patch by Angus Stanton (@abstanton), which was based on a
patch by Kenzie (@kenziemac130).

Differential Revision: https://developer.blender.org/D15375

1 files changed, 25 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index daae1d6f3e4..971043158e1 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -9614,6 +9614,31 @@ static void def_geo_extrude_mesh(StructRNA *srna)
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_update");
 }
 
+static void def_geo_distribute_points_in_volume(StructRNA *srna)
+{
+  PropertyRNA *prop;
+
+  static const EnumPropertyItem mode_items[] = {
+      {GEO_NODE_DISTRIBUTE_POINTS_IN_VOLUME_DENSITY_RANDOM,
+       "DENSITY_RANDOM",
+       0,
+       "Random",
+       "Distribute points randomly inside of the volume"},
+      {GEO_NODE_DISTRIBUTE_POINTS_IN_VOLUME_DENSITY_GRID,
+       "DENSITY_GRID",
+       0,
+       "Grid",
+       "Distribute the points in a grid pattern inside of the volume"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  RNA_def_struct_sdna_from(srna, "NodeGeometryDistributePointsInVolume", "storage");
+  prop = RNA_def_property(srna, "mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, mode_items);
+  RNA_def_property_ui_text(prop, "Distribution Method", "Method to use for scattering points");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
+}
+
 static void def_geo_distribute_points_on_faces(StructRNA *srna)
 {
   PropertyRNA *prop;