1 files changed, 147 insertions, 0 deletions
diff --git a/source/blender/io/usd/intern/usd_writer_abstract.cc b/source/blender/io/usd/intern/usd_writer_abstract.cc
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+++ b/source/blender/io/usd/intern/usd_writer_abstract.cc
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+/*
+ * 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_abstract.h"
+#include "usd_hierarchy_iterator.h"
+
+#include <pxr/base/tf/stringUtils.h>
+
+extern "C" {
+#include "BKE_animsys.h"
+#include "BKE_key.h"
+
+#include "DNA_modifier_types.h"
+}
+
+/* TfToken objects are not cheap to construct, so we do it once. */
+namespace usdtokens {
+// Materials
+static const pxr::TfToken diffuse_color("diffuseColor", pxr::TfToken::Immortal);
+static const pxr::TfToken metallic("metallic", pxr::TfToken::Immortal);
+static const pxr::TfToken preview_shader("previewShader", pxr::TfToken::Immortal);
+static const pxr::TfToken preview_surface("UsdPreviewSurface", pxr::TfToken::Immortal);
+static const pxr::TfToken roughness("roughness", pxr::TfToken::Immortal);
+static const pxr::TfToken surface("surface", pxr::TfToken::Immortal);
+}  // namespace usdtokens
+
+namespace USD {
+
+USDAbstractWriter::USDAbstractWriter(const USDExporterContext &usd_export_context)
+    : usd_export_context_(usd_export_context),
+      usd_value_writer_(),
+      frame_has_been_written_(false),
+      is_animated_(false)
+{
+}
+
+USDAbstractWriter::~USDAbstractWriter()
+{
+}
+
+bool USDAbstractWriter::is_supported(const HierarchyContext * /*context*/) const
+{
+  return true;
+}
+
+pxr::UsdTimeCode USDAbstractWriter::get_export_time_code() const
+{
+  if (is_animated_) {
+    return usd_export_context_.hierarchy_iterator->get_export_time_code();
+  }
+  // By using the default timecode USD won't even write a single `timeSample` for non-animated
+  // data. Instead, it writes it as non-timesampled.
+  static pxr::UsdTimeCode default_timecode = pxr::UsdTimeCode::Default();
+  return default_timecode;
+}
+
+void USDAbstractWriter::write(HierarchyContext &context)
+{
+  if (!frame_has_been_written_) {
+    is_animated_ = usd_export_context_.export_params.export_animation &&
+                   check_is_animated(context);
+  }
+  else if (!is_animated_) {
+    /* A frame has already been written, and without animation one frame is enough. */
+    return;
+  }
+
+  do_write(context);
+
+  frame_has_been_written_ = true;
+}
+
+bool USDAbstractWriter::check_is_animated(const HierarchyContext &context) const
+{
+  const Object *object = context.object;
+
+  if (BKE_animdata_id_is_animated(static_cast<ID *>(object->data))) {
+    return true;
+  }
+  if (BKE_key_from_object(object) != nullptr) {
+    return true;
+  }
+
+  /* Test modifiers. */
+  /* TODO(Sybren): replace this with a check on the depsgraph to properly check for dependency on
+   * time. */
+  ModifierData *md = static_cast<ModifierData *>(object->modifiers.first);
+  while (md) {
+    if (md->type != eModifierType_Subsurf) {
+      return true;
+    }
+    md = md->next;
+  }
+
+  return false;
+}
+
+const pxr::SdfPath &USDAbstractWriter::usd_path() const
+{
+  return usd_export_context_.usd_path;
+}
+
+pxr::UsdShadeMaterial USDAbstractWriter::ensure_usd_material(Material *material)
+{
+  static pxr::SdfPath material_library_path("/_materials");
+  pxr::UsdStageRefPtr stage = usd_export_context_.stage;
+
+  // Construct the material.
+  pxr::TfToken material_name(usd_export_context_.hierarchy_iterator->get_id_name(&material->id));
+  pxr::SdfPath usd_path = material_library_path.AppendChild(material_name);
+  pxr::UsdShadeMaterial usd_material = pxr::UsdShadeMaterial::Get(stage, usd_path);
+  if (usd_material) {
+    return usd_material;
+  }
+  usd_material = pxr::UsdShadeMaterial::Define(stage, usd_path);
+
+  // Construct the shader.
+  pxr::SdfPath shader_path = usd_path.AppendChild(usdtokens::preview_shader);
+  pxr::UsdShadeShader shader = pxr::UsdShadeShader::Define(stage, shader_path);
+  shader.CreateIdAttr(pxr::VtValue(usdtokens::preview_surface));
+  shader.CreateInput(usdtokens::diffuse_color, pxr::SdfValueTypeNames->Color3f)
+      .Set(pxr::GfVec3f(material->r, material->g, material->b));
+  shader.CreateInput(usdtokens::roughness, pxr::SdfValueTypeNames->Float).Set(material->roughness);
+  shader.CreateInput(usdtokens::metallic, pxr::SdfValueTypeNames->Float).Set(material->metallic);
+
+  // Connect the shader and the material together.
+  usd_material.CreateSurfaceOutput().ConnectToSource(shader, usdtokens::surface);
+
+  return usd_material;
+}
+
+}  // namespace USD