1 files changed, 31 insertions, 18 deletions

diff --git a/source/blender/blenlib/BLI_length_parameterize.hh b/source/blender/blenlib/BLI_length_parameterize.hh
index c44bb94f65d..d81bcbe1e7a 100644
--- a/source/blender/blenlib/BLI_length_parameterize.hh
+++ b/source/blender/blenlib/BLI_length_parameterize.hh
@@ -6,10 +6,10 @@
  * \ingroup bli
  */
 
+#include "BLI_index_mask.hh"
 #include "BLI_math_base.hh"
 #include "BLI_math_color.hh"
 #include "BLI_math_vector.hh"
-#include "BLI_vector.hh"
 
 namespace blender::length_parameterize {
 
@@ -42,26 +42,38 @@ void accumulate_lengths(const Span<T> values, const bool cyclic, MutableSpan<flo
 }
 
 template<typename T>
-inline void linear_interpolation(const Span<T> src,
-                                 const Span<int> indices,
-                                 const Span<float> factors,
-                                 MutableSpan<T> dst)
+inline void interpolate_to_masked(const Span<T> src,
+                                  const Span<int> indices,
+                                  const Span<float> factors,
+                                  const IndexMask dst_mask,
+                                  MutableSpan<T> dst)
 {
   BLI_assert(indices.size() == factors.size());
-  BLI_assert(indices.size() == dst.size());
+  BLI_assert(indices.size() == dst_mask.size());
   const int last_src_index = src.size() - 1;
 
-  for (const int i : dst.index_range()) {
-    const int prev_index = indices[i];
-    const float factor = factors[i];
-    const bool is_cyclic_case = prev_index == last_src_index;
-    if (is_cyclic_case) {
-      dst[i] = math::interpolate(src.last(), src.first(), factor);
+  dst_mask.to_best_mask_type([&](auto dst_mask) {
+    for (const int i : IndexRange(dst_mask.size())) {
+      const int prev_index = indices[i];
+      const float factor = factors[i];
+      const bool is_cyclic_case = prev_index == last_src_index;
+      if (is_cyclic_case) {
+        dst[dst_mask[i]] = math::interpolate(src.last(), src.first(), factor);
+      }
+      else {
+        dst[dst_mask[i]] = math::interpolate(src[prev_index], src[prev_index + 1], factor);
+      }
     }
-    else {
-      dst[i] = math::interpolate(src[prev_index], src[prev_index + 1], factor);
-    }
-  }
+  });
+}
+
+template<typename T>
+inline void interpolate(const Span<T> src,
+                        const Span<int> indices,
+                        const Span<float> factors,
+                        MutableSpan<T> dst)
+{
+  interpolate_to_masked(src, indices, factors, dst.index_range(), dst);
 }
 
 /**
@@ -75,6 +87,7 @@ struct SampleSegmentHint {
 
 /**
  * \param accumulated_segment_lengths: Lengths of individual segments added up.
+ * Each value describes the total length at the end of the segment following a point.
  * \param sample_length: The position to sample at.
  * \param r_segment_index: Returns the index of the segment that #sample_length is in.
  * \param r_factor: Returns the position within the segment.
@@ -82,7 +95,7 @@ struct SampleSegmentHint {
  * \note #sample_length must not be outside of any segment.
  */
 inline void sample_at_length(const Span<float> accumulated_segment_lengths,
-                             float sample_length,
+                             const float sample_length,
                              int &r_segment_index,
                              float &r_factor,
                              SampleSegmentHint *hint = nullptr)
@@ -117,7 +130,7 @@ inline void sample_at_length(const Span<float> accumulated_segment_lengths,
   const float segment_start = prev_point_index == 0 ? 0.0f : lengths[prev_point_index - 1];
   const float segment_end = lengths[prev_point_index];
   const float segment_length = segment_end - segment_start;
-  const float segment_length_inv = safe_divide(1.0f, segment_length);
+  const float segment_length_inv = math::safe_divide(1.0f, segment_length);
   const float length_in_segment = sample_length - segment_start;
   const float factor = length_in_segment * segment_length_inv;