[Bf-blender-cvs] [26fb7b9474c] master: Geometry Nodes: do not create unnecessary geometry components

[Jacques Lucke]

Commit: 26fb7b9474c46c8e1fb64230d66610ebf3b29b7f
Author: Jacques Lucke
Date:   Mon May 31 11:12:39 2021 +0200
Branches: master
https://developer.blender.org/rB26fb7b9474c46c8e1fb64230d66610ebf3b29b7f

Geometry Nodes: do not create unnecessary geometry components

Previously, making instances real would always create an (empty)
volume and curve component, even when not necessary.

This also fixes T88653.

===================================================================

M	source/blender/blenkernel/intern/geometry_set_instances.cc

===================================================================

diff --git a/source/blender/blenkernel/intern/geometry_set_instances.cc b/source/blender/blenkernel/intern/geometry_set_instances.cc
index 9abd00c2b4f..69840ba1612 100644
--- a/source/blender/blenkernel/intern/geometry_set_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_set_instances.cc
@@ -544,9 +544,9 @@ static void join_attributes(Span<GeometryInstanceGroup> set_groups,
   }
 }
 
-static void join_curve_splines(Span<GeometryInstanceGroup> set_groups, CurveComponent &result)
+static CurveEval *join_curve_splines(Span<GeometryInstanceGroup> set_groups)
 {
-  CurveEval *new_curve = new CurveEval();
+  Vector<SplinePtr> new_splines;
   for (const GeometryInstanceGroup &set_group : set_groups) {
     const GeometrySet &set = set_group.geometry_set;
     if (!set.has_curve()) {
@@ -558,10 +558,18 @@ static void join_curve_splines(Span<GeometryInstanceGroup> set_groups, CurveComp
       for (const float4x4 &transform : set_group.transforms) {
         SplinePtr new_spline = source_spline->copy();
         new_spline->transform(transform);
-        new_curve->add_spline(std::move(new_spline));
+        new_splines.append(std::move(new_spline));
       }
     }
   }
+  if (new_splines.is_empty()) {
+    return nullptr;
+  }
+
+  CurveEval *new_curve = new CurveEval();
+  for (SplinePtr &new_spline : new_splines) {
+    new_curve->add_spline(std::move(new_spline));
+  }
 
   for (SplinePtr &spline : new_curve->splines()) {
     /* Spline instances should have no custom attributes, since they always come
@@ -573,8 +581,7 @@ static void join_curve_splines(Span<GeometryInstanceGroup> set_groups, CurveComp
   }
 
   new_curve->attributes.reallocate(new_curve->splines().size());
-
-  result.replace(new_curve);
+  return new_curve;
 }
 
 static void join_instance_groups_mesh(Span<GeometryInstanceGroup> set_groups,
@@ -639,14 +646,17 @@ static void join_instance_groups_volume(Span<GeometryInstanceGroup> set_groups,
 {
   /* Not yet supported. Joining volume grids with the same name requires resampling of at least
    * one of the grids. The cell size of the resulting volume has to be determined somehow. */
-  VolumeComponent &dst_component = result.get_component_for_write<VolumeComponent>();
-  UNUSED_VARS(set_groups, dst_component);
+  UNUSED_VARS(set_groups, result);
 }
 
 static void join_instance_groups_curve(Span<GeometryInstanceGroup> set_groups, GeometrySet &result)
 {
+  CurveEval *curve = join_curve_splines(set_groups);
+  if (curve == nullptr) {
+    return;
+  }
   CurveComponent &dst_component = result.get_component_for_write<CurveComponent>();
-  join_curve_splines(set_groups, dst_component);
+  dst_component.replace(curve);
 }
 
 GeometrySet geometry_set_realize_mesh_for_modifier(const GeometrySet &geometry_set)