Geometry Nodes: Split transfer attribute node

This patch replaces the existing transfer attribute node with three
nodes, "Sample Nearest Surface", "Sample Index", and "Sample Nearest".
This follows the design in T100010, allowing for new nodes like UV
sampling in the future. There is versioning so the new nodes replace
the old ones and are relinked as necessary.

The "Sample Nearest Surface" node is meant for the more complex
sampling algorithms that only work on meshes and interpolate
values inside of faces.

The new "Sample Index" just retrieves attributes from a geometry at
specific indices. It doesn't have implicit behavior like the old
transfer mode, which should make it more predictable. In order to not
change the behavior from existing files, the node has a has a "Clamp",
which is off by default for consistency with the "Field at Index" node.

The "Sample Nearest" node returns the index of the nearest element
on a geometry. It can be combined with the "Sample Index" node for
the same functionality as the old transfer node. This node can support
curves in the future.

Backwards compatibility is handled by versioning, but old versions can
not understand these nodes. The warning from 680fa8a523e0 should make
this explicit in 3.3 and earlier.

Differential Revision: https://developer.blender.org/D15909

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/nodes/NOD_static_types.h b/source/blender/nodes/NOD_static_types.h
index 4b055962b58..8f2a4adcf9a 100644
--- a/source/blender/nodes/NOD_static_types.h
+++ b/source/blender/nodes/NOD_static_types.h
@@ -378,6 +378,9 @@ DefNode(GeometryNode, GEO_NODE_RESAMPLE_CURVE, def_geo_curve_resample, "RESAMPLE
 DefNode(GeometryNode, GEO_NODE_REVERSE_CURVE, 0, "REVERSE_CURVE", ReverseCurve, "Reverse Curve", "Swap the start and end of splines")
 DefNode(GeometryNode, GEO_NODE_ROTATE_INSTANCES, 0, "ROTATE_INSTANCES", RotateInstances, "Rotate Instances", "Rotate geometry instances in local or global space")
 DefNode(GeometryNode, GEO_NODE_SAMPLE_CURVE, def_geo_curve_sample, "SAMPLE_CURVE", SampleCurve, "Sample Curve", "Retrieve data from a point on a curve at a certain distance from its start")
+DefNode(GeometryNode, GEO_NODE_SAMPLE_INDEX, def_geo_sample_index, "SAMPLE_INDEX", SampleIndex, "Sample Index", "Retrieve values from specific geometry elements")
+DefNode(GeometryNode, GEO_NODE_SAMPLE_NEAREST_SURFACE, def_geo_sample_nearest_surface, "sample_nearest_surface", SampleNearestSurface, "Sample Nearest Surface", "Calculate the interpolated value of a mesh attribute on the closest point of its surface")
+DefNode(GeometryNode, GEO_NODE_SAMPLE_NEAREST, def_geo_sample_nearest, "SAMPLE_NEAREST", SampleNearest, "Sample Nearest", "Find the element of a geometry closest to a position")
 DefNode(GeometryNode, GEO_NODE_SCALE_ELEMENTS, def_geo_scale_elements, "SCALE_ELEMENTS", ScaleElements, "Scale Elements", "Scale groups of connected edges and faces")
 DefNode(GeometryNode, GEO_NODE_SCALE_INSTANCES, 0, "SCALE_INSTANCES", ScaleInstances, "Scale Instances", "Scale geometry instances in local or global space")
 DefNode(GeometryNode, GEO_NODE_SEPARATE_COMPONENTS, 0, "SEPARATE_COMPONENTS",SeparateComponents, "Separate Components","Split a geometry into a separate output for each type of data in the geometry")
@@ -402,7 +405,6 @@ DefNode(GeometryNode, GEO_NODE_SUBDIVIDE_CURVE, 0, "SUBDIVIDE_CURVE", SubdivideC
 DefNode(GeometryNode, GEO_NODE_SUBDIVIDE_MESH, 0, "SUBDIVIDE_MESH", SubdivideMesh, "Subdivide Mesh", "Divide mesh faces into smaller ones without changing the shape or volume, using linear interpolation to place the new vertices")
 DefNode(GeometryNode, GEO_NODE_SUBDIVISION_SURFACE, def_geo_subdivision_surface, "SUBDIVISION_SURFACE",SubdivisionSurface, "Subdivision Surface","Divide mesh faces to form a smooth surface, using the Catmull-Clark subdivision method")
 DefNode(GeometryNode, GEO_NODE_SWITCH, def_geo_switch, "SWITCH", Switch, "Switch", "Switch between two inputs")
-DefNode(GeometryNode, GEO_NODE_TRANSFER_ATTRIBUTE, def_geo_transfer_attribute, "ATTRIBUTE_TRANSFER", AttributeTransfer, "Transfer Attribute", "Retrieve values from a source geometry and provides them as a field by interpolating them with the context geometry")
 DefNode(GeometryNode, GEO_NODE_TRANSFORM, 0, "TRANSFORM", Transform, "Transform", "Translate, rotate or scale the geometry")
 DefNode(GeometryNode, GEO_NODE_TRANSLATE_INSTANCES, 0, "TRANSLATE_INSTANCES",TranslateInstances, "Translate Instances","Move top-level geometry instances in local or global space")
 DefNode(GeometryNode, GEO_NODE_TRIANGULATE, def_geo_triangulate, "TRIANGULATE", Triangulate, "Triangulate", "Convert all faces in a mesh to triangular faces")