[Bf-blender-cvs] [85dd4d4e3ba] sybren-usd: USD: prevent crash when writing hair system with empty pathcache

[Sybren A. Stüvel]

Commit: 85dd4d4e3baa5b33260a5f06c6fbb782a6aa10fb
Author: Sybren A. Stüvel
Date:   Fri Jul 19 11:14:26 2019 +0200
Branches: sybren-usd
https://developer.blender.org/rB85dd4d4e3baa5b33260a5f06c6fbb782a6aa10fb

USD: prevent crash when writing hair system with empty pathcache

Not sure what causes `psys->pathcache` to be `nullptr` in the first place,
but at least this prevents Blender from crashing.

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

M	source/blender/usd/intern/usd_writer_hair.cc

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

diff --git a/source/blender/usd/intern/usd_writer_hair.cc b/source/blender/usd/intern/usd_writer_hair.cc
index af0d23addcd..37bc6a00c9b 100644
--- a/source/blender/usd/intern/usd_writer_hair.cc
+++ b/source/blender/usd/intern/usd_writer_hair.cc
@@ -18,6 +18,11 @@ USDHairWriter::USDHairWriter(const USDExporterContext &ctx) : USDAbstractWriter(
 void USDHairWriter::do_write(HierarchyContext &context)
 {
   ParticleSystem *psys = context.particle_system;
+  ParticleCacheKey **cache = psys->pathcache;
+  if (cache == nullptr) {
+    return;
+  }
+
   pxr::UsdTimeCode timecode = get_export_time_code();
 
   printf("\033[34;1mHAIR writer\033[0m writing %s %s\n",
@@ -35,7 +40,6 @@ void USDHairWriter::do_write(HierarchyContext &context)
   curve_point_counts.reserve(psys->totpart);
   colors.reserve(psys->totpart);
 
-  ParticleCacheKey **cache = psys->pathcache;
   ParticleCacheKey *strand;
   for (int strand_index = 0; strand_index < psys->totpart; ++strand_index) {
     strand = cache[strand_index];