1 files changed, 90 insertions, 0 deletions
diff --git a/source/blender/io/usd/intern/usd_writer_hair.cc b/source/blender/io/usd/intern/usd_writer_hair.cc
new file mode 100644
index 00000000000..9251425c0b8
--- /dev/null
+++ b/source/blender/io/usd/intern/usd_writer_hair.cc
@@ -0,0 +1,90 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2019 Blender Foundation.
+ * All rights reserved.
+ */
+#include "usd_writer_hair.h"
+#include "usd_hierarchy_iterator.h"
+
+#include <pxr/usd/usdGeom/basisCurves.h>
+#include <pxr/usd/usdGeom/tokens.h>
+
+extern "C" {
+#include "BKE_particle.h"
+
+#include "DNA_particle_types.h"
+}
+
+namespace USD {
+
+USDHairWriter::USDHairWriter(const USDExporterContext &ctx) : USDAbstractWriter(ctx)
+{
+}
+
+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();
+  pxr::UsdGeomBasisCurves curves = pxr::UsdGeomBasisCurves::Define(usd_export_context_.stage,
+                                                                   usd_export_context_.usd_path);
+
+  // TODO(Sybren): deal with (psys->part->flag & PART_HAIR_BSPLINE)
+  curves.CreateBasisAttr(pxr::VtValue(pxr::UsdGeomTokens->bspline));
+  curves.CreateTypeAttr(pxr::VtValue(pxr::UsdGeomTokens->cubic));
+
+  pxr::VtArray<pxr::GfVec3f> points;
+  pxr::VtIntArray curve_point_counts;
+  curve_point_counts.reserve(psys->totpart);
+
+  ParticleCacheKey *strand;
+  for (int strand_index = 0; strand_index < psys->totpart; ++strand_index) {
+    strand = cache[strand_index];
+
+    int point_count = strand->segments + 1;
+    curve_point_counts.push_back(point_count);
+
+    for (int point_index = 0; point_index < point_count; ++point_index, ++strand) {
+      points.push_back(pxr::GfVec3f(strand->co));
+    }
+  }
+
+  pxr::UsdAttribute attr_points = curves.CreatePointsAttr(pxr::VtValue(), true);
+  pxr::UsdAttribute attr_vertex_counts = curves.CreateCurveVertexCountsAttr(pxr::VtValue(), true);
+  if (!attr_points.HasValue()) {
+    attr_points.Set(points, pxr::UsdTimeCode::Default());
+    attr_vertex_counts.Set(curve_point_counts, pxr::UsdTimeCode::Default());
+  }
+  usd_value_writer_.SetAttribute(attr_points, pxr::VtValue(points), timecode);
+  usd_value_writer_.SetAttribute(attr_vertex_counts, pxr::VtValue(curve_point_counts), timecode);
+
+  if (psys->totpart > 0) {
+    pxr::VtArray<pxr::GfVec3f> colors;
+    colors.push_back(pxr::GfVec3f(cache[0]->col));
+    curves.CreateDisplayColorAttr(pxr::VtValue(colors));
+  }
+}
+
+bool USDHairWriter::check_is_animated(const HierarchyContext &) const
+{
+  return true;
+}
+
+}  // namespace USD