Fix T91904: Assert when loading empty CurveProfile

Somehow, the file from T71329 has an empty curve profile. While that may
be a problem in itself, it's reasonable to avoid asserts or crashes when
loading or drawing such a CurveProfile. This commit just makes sure the
table always has a single vertex, and adds some checks in drawing code.

1 files changed, 6 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/curveprofile.cc b/source/blender/blenkernel/intern/curveprofile.cc
index 78ec05838c2..7f2a2bc342d 100644
--- a/source/blender/blenkernel/intern/curveprofile.cc
+++ b/source/blender/blenkernel/intern/curveprofile.cc
@@ -594,7 +594,8 @@ int BKE_curveprofile_table_size(const CurveProfile *profile)
   /** Number of table points per control point. */
   const int resolution = 16;
 
-  return std::clamp((profile->path_len - 1) * resolution + 1, 0, PROF_TABLE_MAX);
+  /* Make sure there is always one sample, even if there are no control points. */
+  return std::clamp((profile->path_len - 1) * resolution + 1, 1, PROF_TABLE_MAX);
 }
 
 /**
@@ -1006,7 +1007,10 @@ static void curveprofile_make_table(CurveProfile *profile)
   CurveProfilePoint *new_table = (CurveProfilePoint *)MEM_callocN(
       sizeof(CurveProfilePoint) * (n_samples + 1), __func__);
 
-  create_samples(profile, n_samples - 1, false, new_table);
+  if (n_samples > 1) {
+    create_samples(profile, n_samples - 1, false, new_table);
+  }
+
   /* Manually add last point at the end of the profile */
   new_table[n_samples - 1].x = 0.0f;
   new_table[n_samples - 1].y = 1.0f;