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, 10 insertions, 0 deletions

diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index a416e184d2b..7832541e360 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -1595,6 +1595,11 @@ typedef struct NodeGeometryUVUnwrap {
   uint8_t method;
 } NodeGeometryUVUnwrap;
 
+typedef struct NodeGeometryDistributePointsInVolume {
+  /* GeometryNodePointDistributeVolumeMode. */
+  uint8_t mode;
+} NodeGeometryDistributePointsInVolume;
+
 typedef struct NodeFunctionCompare {
   /* NodeCompareOperation */
   int8_t operation;
@@ -2176,6 +2181,11 @@ typedef enum GeometryNodeTriangulateQuads {
   GEO_NODE_TRIANGULATE_QUAD_LONGEDGE = 4,
 } GeometryNodeTriangulateQuads;
 
+typedef enum GeometryNodeDistributePointsInVolumeMode {
+  GEO_NODE_DISTRIBUTE_POINTS_IN_VOLUME_DENSITY_RANDOM = 0,
+  GEO_NODE_DISTRIBUTE_POINTS_IN_VOLUME_DENSITY_GRID = 1,
+} GeometryNodeDistributePointsInVolumeMode;
+
 typedef enum GeometryNodeDistributePointsOnFacesMode {
   GEO_NODE_POINT_DISTRIBUTE_POINTS_ON_FACES_RANDOM = 0,
   GEO_NODE_POINT_DISTRIBUTE_POINTS_ON_FACES_POISSON = 1,