[Bf-blender-cvs] [7029cc2f8ad] master: Fix T88126: Curve resample crash for single point input

[Hans Goudey]

Commit: 7029cc2f8adf9a5882f247324c59d4c25e18c287
Author: Hans Goudey
Date:   Sun May 9 01:13:06 2021 -0500
Branches: master
https://developer.blender.org/rB7029cc2f8adf9a5882f247324c59d4c25e18c287

Fix T88126: Curve resample crash for single point input

The spline `length` function assumed that the curve always had evaluated
edges. That is clearly false. This commit adds a check to `length` and a
special case for a single point in the curve resample node.

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

M	source/blender/blenkernel/intern/spline_base.cc
M	source/blender/nodes/geometry/nodes/node_geo_curve_resample.cc

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

diff --git a/source/blender/blenkernel/intern/spline_base.cc b/source/blender/blenkernel/intern/spline_base.cc
index e2b1118a0b2..447e8a5b0a5 100644
--- a/source/blender/blenkernel/intern/spline_base.cc
+++ b/source/blender/blenkernel/intern/spline_base.cc
@@ -61,7 +61,8 @@ int Spline::evaluated_edges_size() const
 
 float Spline::length() const
 {
-  return this->evaluated_lengths().last();
+  Span<float> lengths = this->evaluated_lengths();
+  return (lengths.size() == 0) ? 0 : this->evaluated_lengths().last();
 }
 
 int Spline::segments_size() const
diff --git a/source/blender/nodes/geometry/nodes/node_geo_curve_resample.cc b/source/blender/nodes/geometry/nodes/node_geo_curve_resample.cc
index 9c7b036bda0..c8733955a32 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_curve_resample.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_curve_resample.cc
@@ -99,6 +99,13 @@ static SplinePtr resample_spline(const Spline &input_spline, const int count)
   std::unique_ptr<PolySpline> output_spline = std::make_unique<PolySpline>();
   output_spline->set_cyclic(input_spline.is_cyclic());
   output_spline->normal_mode = input_spline.normal_mode;
+
+  if (input_spline.evaluated_edges_size() < 1) {
+    output_spline->resize(1);
+    output_spline->positions().first() = input_spline.positions().first();
+    return output_spline;
+  }
+
   output_spline->resize(count);
 
   Array<float> uniform_samples = input_spline.sample_uniform_index_factors(count);