From 89eb05a8908130f8668e4c677d63f3d2b89e68bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=83=C2=83=C3=82=C2=BCvel?=
 <sybren@stuvel.eu>
Date: Sat, 28 Oct 2017 19:18:27 +0200
Subject: Alembic: exporting MetaBalls as mesh

- Only basis balls are exported, as they represent the resulting mesh.
  As a result the mesh is written to Alembic using the name of the basis
  ball.
- MetaBalls are converted to a mesh on every frame, then an
  AbcMeshWriter is used to write that mesh to Alembic.
---
 source/blender/alembic/intern/abc_mball.cc | 122 +++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 source/blender/alembic/intern/abc_mball.cc

(limited to 'source/blender/alembic/intern/abc_mball.cc')

diff --git a/source/blender/alembic/intern/abc_mball.cc b/source/blender/alembic/intern/abc_mball.cc
new file mode 100644
index 00000000000..56bb609ace0
--- /dev/null
+++ b/source/blender/alembic/intern/abc_mball.cc
@@ -0,0 +1,122 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * Contributor(s): Sybren A. Stüvel
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include "abc_mball.h"
+#include "abc_mesh.h"
+#include "abc_transform.h"
+
+extern "C" {
+#include "DNA_meta_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_object_types.h"
+
+#include "BKE_curve.h"
+#include "BKE_depsgraph.h"
+#include "BKE_displist.h"
+#include "BKE_main.h"
+#include "BKE_mball.h"
+#include "BKE_mesh.h"
+#include "BKE_object.h"
+
+#include "DEG_depsgraph.h"
+#include "MEM_guardedalloc.h"
+}
+
+AbcMBallWriter::AbcMBallWriter(
+        Main *bmain,
+        Scene *scene,
+        Object *ob,
+        AbcTransformWriter *parent,
+        uint32_t time_sampling,
+        ExportSettings &settings)
+    : AbcObjectWriter(scene, ob, time_sampling, settings, parent)
+    , m_bmain(bmain)
+{
+	m_is_animated = isAnimated();
+
+	m_mesh_ob = BKE_object_copy(bmain, ob);
+	m_mesh_ob->curve_cache = (CurveCache*)MEM_callocN(
+	                             sizeof(CurveCache),
+	                             "CurveCache for AbcMBallWriter");
+
+	m_mesh_writer = new AbcMeshWriter(scene, m_mesh_ob, parent,
+	                                  time_sampling, settings);
+	m_mesh_writer->setIsAnimated(m_is_animated);
+}
+
+
+AbcMBallWriter::~AbcMBallWriter()
+{
+	delete m_mesh_writer;
+	BKE_object_free(m_mesh_ob);
+}
+
+bool AbcMBallWriter::isAnimated() const
+{
+	MetaBall *mb = static_cast<MetaBall *>(m_object->data);
+	if (mb->adt != NULL) return true;
+
+	/* Any movement of any object in the parent chain
+	 * could cause the mball to deform. */
+	for (Object *ob = m_object; ob != NULL; ob = ob->parent) {
+		if (ob->adt != NULL) return true;
+	}
+	return false;
+}
+
+void AbcMBallWriter::do_write()
+{
+	/* We have already stored a sample for this object. */
+	if (!m_first_frame && !m_is_animated)
+		return;
+
+	Mesh *tmpmesh = BKE_mesh_add(m_bmain, ((ID *)m_object->data)->name + 2);
+	BLI_assert(tmpmesh != NULL);
+	m_mesh_ob->data = tmpmesh;
+
+	/* BKE_mesh_add gives us a user count we don't need */
+	id_us_min(&tmpmesh->id);
+
+	ListBase disp = {NULL, NULL};
+	/* TODO(sergey): This is gonna to work for until EvaluationContext
+	 *               only contains for_render flag. As soon as CoW is
+	 *               implemented, this is to be rethinked.
+	 */
+	EvaluationContext eval_ctx;
+	DEG_evaluation_context_init(&eval_ctx, DAG_EVAL_RENDER);
+	BKE_displist_make_mball_forRender(&eval_ctx, m_scene, m_object, &disp);
+	BKE_mesh_from_metaball(&disp, tmpmesh);
+	BKE_displist_free(&disp);
+
+	BKE_mesh_texspace_copy_from_object(tmpmesh, m_mesh_ob);
+
+	m_mesh_writer->write();
+
+	BKE_id_free(m_bmain, tmpmesh);
+	m_mesh_ob->data = NULL;
+}
+
+bool AbcMBallWriter::isBasisBall(Scene *scene, Object *ob)
+{
+	Object *basis_ob = BKE_mball_basis_find(scene, ob);
+	return ob == basis_ob;
+}
-- 
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