1 files changed, 170 insertions, 0 deletions
diff --git a/source/blender/io/alembic/exporter/abc_writer_nurbs.cc b/source/blender/io/alembic/exporter/abc_writer_nurbs.cc
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index 00000000000..c856f894f0e
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+++ b/source/blender/io/alembic/exporter/abc_writer_nurbs.cc
@@ -0,0 +1,170 @@
+/*
+ * 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.
+ */
+
+/** \file
+ * \ingroup balembic
+ */
+
+#include "abc_writer_nurbs.h"
+#include "abc_writer_transform.h"
+#include "intern/abc_axis_conversion.h"
+
+#include "DNA_curve_types.h"
+#include "DNA_object_types.h"
+
+#include "BLI_listbase.h"
+
+#include "BKE_curve.h"
+
+using Alembic::AbcGeom::FloatArraySample;
+using Alembic::AbcGeom::OBoolProperty;
+using Alembic::AbcGeom::OCompoundProperty;
+using Alembic::AbcGeom::ONuPatch;
+using Alembic::AbcGeom::ONuPatchSchema;
+
+AbcNurbsWriter::AbcNurbsWriter(Object *ob,
+                               AbcTransformWriter *parent,
+                               uint32_t time_sampling,
+                               ExportSettings &settings)
+    : AbcObjectWriter(ob, time_sampling, settings, parent)
+{
+  m_is_animated = isAnimated();
+
+  /* if the object is static, use the default static time sampling */
+  if (!m_is_animated) {
+    m_time_sampling = 0;
+  }
+
+  Curve *curve = static_cast<Curve *>(m_object->data);
+  size_t numNurbs = BLI_listbase_count(&curve->nurb);
+
+  for (size_t i = 0; i < numNurbs; i++) {
+    std::stringstream str;
+    str << m_name << '_' << i;
+
+    while (parent->alembicXform().getChildHeader(str.str())) {
+      str << "_";
+    }
+
+    ONuPatch nurbs(parent->alembicXform(), str.str().c_str(), m_time_sampling);
+    m_nurbs_schema.push_back(nurbs.getSchema());
+  }
+}
+
+bool AbcNurbsWriter::isAnimated() const
+{
+  /* check if object has shape keys */
+  Curve *cu = static_cast<Curve *>(m_object->data);
+  return (cu->key != NULL);
+}
+
+static void get_knots(std::vector<float> &knots, const int num_knots, float *nu_knots)
+{
+  if (num_knots <= 1) {
+    return;
+  }
+
+  /* Add an extra knot at the beginning and end of the array since most apps
+   * require/expect them. */
+  knots.reserve(num_knots + 2);
+
+  knots.push_back(0.0f);
+
+  for (int i = 0; i < num_knots; i++) {
+    knots.push_back(nu_knots[i]);
+  }
+
+  knots[0] = 2.0f * knots[1] - knots[2];
+  knots.push_back(2.0f * knots[num_knots] - knots[num_knots - 1]);
+}
+
+void AbcNurbsWriter::do_write()
+{
+  /* we have already stored a sample for this object. */
+  if (!m_first_frame && !m_is_animated) {
+    return;
+  }
+
+  if (!ELEM(m_object->type, OB_SURF, OB_CURVE)) {
+    return;
+  }
+
+  Curve *curve = static_cast<Curve *>(m_object->data);
+  ListBase *nulb;
+
+  if (m_object->runtime.curve_cache->deformed_nurbs.first != NULL) {
+    nulb = &m_object->runtime.curve_cache->deformed_nurbs;
+  }
+  else {
+    nulb = BKE_curve_nurbs_get(curve);
+  }
+
+  size_t count = 0;
+  for (Nurb *nu = static_cast<Nurb *>(nulb->first); nu; nu = nu->next, count++) {
+    std::vector<float> knotsU;
+    get_knots(knotsU, KNOTSU(nu), nu->knotsu);
+
+    std::vector<float> knotsV;
+    get_knots(knotsV, KNOTSV(nu), nu->knotsv);
+
+    const int size = nu->pntsu * nu->pntsv;
+    std::vector<Imath::V3f> positions(size);
+    std::vector<float> weights(size);
+
+    const BPoint *bp = nu->bp;
+
+    for (int i = 0; i < size; i++, bp++) {
+      copy_yup_from_zup(positions[i].getValue(), bp->vec);
+      weights[i] = bp->vec[3];
+    }
+
+    ONuPatchSchema::Sample sample;
+    sample.setUOrder(nu->orderu + 1);
+    sample.setVOrder(nu->orderv + 1);
+    sample.setPositions(positions);
+    sample.setPositionWeights(weights);
+    sample.setUKnot(FloatArraySample(knotsU));
+    sample.setVKnot(FloatArraySample(knotsV));
+    sample.setNu(nu->pntsu);
+    sample.setNv(nu->pntsv);
+
+    /* TODO(kevin): to accommodate other software we should duplicate control
+     * points to indicate that a NURBS is cyclic. */
+    OCompoundProperty user_props = m_nurbs_schema[count].getUserProperties();
+
+    if ((nu->flagu & CU_NURB_ENDPOINT) != 0) {
+      OBoolProperty prop(user_props, "endpoint_u");
+      prop.set(true);
+    }
+
+    if ((nu->flagv & CU_NURB_ENDPOINT) != 0) {
+      OBoolProperty prop(user_props, "endpoint_v");
+      prop.set(true);
+    }
+
+    if ((nu->flagu & CU_NURB_CYCLIC) != 0) {
+      OBoolProperty prop(user_props, "cyclic_u");
+      prop.set(true);
+    }
+
+    if ((nu->flagv & CU_NURB_CYCLIC) != 0) {
+      OBoolProperty prop(user_props, "cyclic_v");
+      prop.set(true);
+    }
+
+    m_nurbs_schema[count].set(sample);
+  }
+}