AnimationExporter.cpp

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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.
 */
 
#include "AnimationExporter.h"
#include "AnimationClipExporter.h"
#include "BCAnimationSampler.h"
#include "GeometryExporter.h"
#include "MaterialExporter.h"
#include "collada_utils.h"
 
std::string EMPTY_STRING;
 
std::string AnimationExporter::get_axis_name(std::string channel_type, int id)
{
 
  static std::map<std::string, std::vector<std::string>> BC_COLLADA_AXIS_FROM_TYPE = {
      {"color", {"R", "G", "B"}},
      {"specular_color", {"R", "G", "B"}},
      {"diffuse_color", {"R", "G", "B"}},
      {"alpha", {"R", "G", "B"}},
      {"scale", {"X", "Y", "Z"}},
      {"location", {"X", "Y", "Z"}},
      {"rotation_euler", {"X", "Y", "Z"}}};
 
  std::map<std::string, std::vector<std::string>>::const_iterator it;
 
  it = BC_COLLADA_AXIS_FROM_TYPE.find(channel_type);
  if (it == BC_COLLADA_AXIS_FROM_TYPE.end()) {
    return "";
  }
 
  const std::vector<std::string> &subchannel = it->second;
  if (id >= subchannel.size()) {
    return "";
  }
  return subchannel[id];
}
 
bool AnimationExporter::open_animation_container(bool has_container, Object *ob)
{
  if (!has_container) {
    char anim_id[200];
    sprintf(anim_id, "action_container-%s", translate_id(id_name(ob)).c_str());
    openAnimation(anim_id, encode_xml(id_name(ob)));
  }
  return true;
}
 
void AnimationExporter::openAnimationWithClip(std::string action_id, std::string action_name)
{
  std::vector<std::string> anim_meta_entry;
  anim_meta_entry.push_back(translate_id(action_id));
  anim_meta_entry.push_back(action_name);
  anim_meta.push_back(anim_meta_entry);
 
  openAnimation(translate_id(action_id), action_name);
}
 
void AnimationExporter::close_animation_container(bool has_container)
{
  if (has_container) {
    closeAnimation();
  }
}
 
bool AnimationExporter::exportAnimations()
{
  Scene *sce = export_settings.get_scene();
 
  LinkNode *export_set = this->export_settings.get_export_set();
  bool has_anim_data = bc_has_animations(sce, export_set);
  int animation_count = 0;
  if (has_anim_data) {
 
    BCObjectSet animated_subset;
    BCAnimationSampler::get_animated_from_export_set(animated_subset, *export_set);
    animation_count = animated_subset.size();
    BCAnimationSampler animation_sampler(export_settings, animated_subset);
 
    try {
      animation_sampler.sample_scene(export_settings, /*keyframe_at_end = */ true);
 
      openLibrary();
 
      BCObjectSet::iterator it;
      for (it = animated_subset.begin(); it != animated_subset.end(); ++it) {
        Object *ob = *it;
        exportAnimation(ob, animation_sampler);
      }
    }
    catch (std::invalid_argument &iae) {
      fprintf(stderr, "Animation export interrupted");
      fprintf(stderr, "Exception was: %s", iae.what());
    }
 
    closeLibrary();
 
#if 0
    /* TODO: If all actions shall be exported, we need to call the
     * AnimationClipExporter which will figure out which actions
     * need to be exported for which objects
     */
    if (this->export_settings->include_all_actions) {
      AnimationClipExporter ace(eval_ctx, sw, export_settings, anim_meta);
      ace.exportAnimationClips(sce);
    }
#endif
  }
  return animation_count;
}
 
/* called for each exported object */
void AnimationExporter::exportAnimation(Object *ob, BCAnimationSampler &sampler)
{
  bool container_is_open = false;
 
  /* Transform animations (trans, rot, scale). */
  container_is_open = open_animation_container(container_is_open, ob);
 
  /* Now take care of the Object Animations
   * Note: For Armatures the skeletal animation has already been exported (see above)
   * However Armatures also can have Object animation.
   */
  bool export_as_matrix = this->export_settings.get_animation_transformation_type() ==
                          BC_TRANSFORMATION_TYPE_MATRIX;
 
  if (export_as_matrix) {
    /* export all transform_curves as one single matrix animation */
    export_matrix_animation(ob, sampler);
  }
 
  export_curve_animation_set(ob, sampler, export_as_matrix);
 
  if (ob->type == OB_ARMATURE && export_as_matrix) {
 
#ifdef WITH_MORPH_ANIMATION
    /* TODO: This needs to be handled by extra profiles, postponed for now */
    export_morph_animation(ob);
#endif
 
    /* Export skeletal animation (if any) */
    bArmature *arm = (bArmature *)ob->data;
    for (Bone *root_bone = (Bone *)arm->bonebase.first; root_bone; root_bone = root_bone->next) {
      export_bone_animations_recursive(ob, root_bone, sampler);
    }
  }
 
  close_animation_container(container_is_open);
}
 
/*
 * Export all animation FCurves of an Object.
 *
 * Note: This uses the keyframes as sample points,
 * and exports "baked keyframes" while keeping the tangent information
 * of the FCurves intact. This works for simple cases, but breaks
 * especially when negative scales are involved in the animation.
 * And when parent inverse matrices are involved (when exporting
 * object hierarchies)
 */
void AnimationExporter::export_curve_animation_set(Object *ob,
                                                   BCAnimationSampler &sampler,
                                                   bool export_as_matrix)
{
  BCAnimationCurveMap *curves = sampler.get_curves(ob);
  bool keep_flat_curves = this->export_settings.get_keep_flat_curves();
 
  BCAnimationCurveMap::iterator it;
  for (it = curves->begin(); it != curves->end(); ++it) {
    BCAnimationCurve &curve = *it->second;
    std::string channel_type = curve.get_channel_type();
    if (channel_type == "rotation_quaternion") {
      /* Can not export Quaternion animation in Collada as far as i know)
       * Maybe automatically convert to euler rotation?
       * Discard for now. */
      continue;
    }
 
    if (export_as_matrix && curve.is_transform_curve()) {
      /* All Transform curves will be exported within a single matrix animation,
       * see export_matrix_animation()
       * No need to export the curves here again.
       */
      continue;
    }
 
    if (!keep_flat_curves && !curve.is_animated()) {
      continue;
    }
 
    BCAnimationCurve *mcurve = get_modified_export_curve(ob, curve, *curves);
    if (mcurve) {
      export_curve_animation(ob, *mcurve);
      delete mcurve;
    }
    else {
      export_curve_animation(ob, curve);
    }
  }
}
 
void AnimationExporter::export_matrix_animation(Object *ob, BCAnimationSampler &sampler)
{
  bool keep_flat_curves = this->export_settings.get_keep_flat_curves();
 
  std::vector<float> frames;
  sampler.get_object_frames(frames, ob);
  if (!frames.empty()) {
    BCMatrixSampleMap samples;
    bool is_animated = sampler.get_object_samples(samples, ob);
    if (keep_flat_curves || is_animated) {
      bAction *action = bc_getSceneObjectAction(ob);
      std::string name = encode_xml(id_name(ob));
      std::string action_name = (action == nullptr) ? name + "-action" : id_name(action);
      std::string channel_type = "transform";
      std::string axis;
      std::string id = bc_get_action_id(action_name, name, channel_type, axis);
 
      std::string target = translate_id(name) + '/' + channel_type;
 
      BC_global_rotation_type global_rotation_type = get_global_rotation_type(ob);
      export_collada_matrix_animation(
          id, name, target, frames, samples, global_rotation_type, ob->parentinv);
    }
  }
}
 
BC_global_rotation_type AnimationExporter::get_global_rotation_type(Object *ob)
{
  bool is_export_root = this->export_settings.is_export_root(ob);
  if (!is_export_root) {
    return BC_NO_ROTATION;
  }
 
  bool apply_global_rotation = this->export_settings.get_apply_global_orientation();
 
  return (apply_global_rotation) ? BC_DATA_ROTATION : BC_OBJECT_ROTATION;
}
 
/* Write bone animations in transform matrix sources. */
void AnimationExporter::export_bone_animations_recursive(Object *ob,
                                                         Bone *bone,
                                                         BCAnimationSampler &sampler)
{
  bool keep_flat_curves = this->export_settings.get_keep_flat_curves();
 
  std::vector<float> frames;
  sampler.get_bone_frames(frames, ob, bone);
 
  if (!frames.empty()) {
    BCMatrixSampleMap samples;
    bool is_animated = sampler.get_bone_samples(samples, ob, bone);
    if (keep_flat_curves || is_animated) {
      export_bone_animation(ob, bone, frames, samples);
    }
  }
 
  for (Bone *child = (Bone *)bone->childbase.first; child; child = child->next) {
    export_bone_animations_recursive(ob, child, sampler);
  }
}
 
BCAnimationCurve *AnimationExporter::get_modified_export_curve(Object *ob,
                                                               BCAnimationCurve &curve,
                                                               BCAnimationCurveMap &curves)
{
  std::string channel_type = curve.get_channel_type();
  BCAnimationCurve *mcurve = nullptr;
  if (channel_type == "lens") {
 
    /* Create an xfov curve */
 
    BCCurveKey key(BC_ANIMATION_TYPE_CAMERA, "xfov", 0);
    mcurve = new BCAnimationCurve(key, ob);
 
    /* now tricky part: transform the fcurve */
    BCValueMap lens_values;
    curve.get_value_map(lens_values);
 
    BCAnimationCurve *sensor_curve = nullptr;
    BCCurveKey sensor_key(BC_ANIMATION_TYPE_CAMERA, "sensor_width", 0);
    BCAnimationCurveMap::iterator cit = curves.find(sensor_key);
    if (cit != curves.end()) {
      sensor_curve = cit->second;
    }
 
    BCValueMap::const_iterator vit;
    for (vit = lens_values.begin(); vit != lens_values.end(); ++vit) {
      int frame = vit->first;
      float lens_value = vit->second;
 
      float sensor_value;
      if (sensor_curve) {
        sensor_value = sensor_curve->get_value(frame);
      }
      else {
        sensor_value = ((Camera *)ob->data)->sensor_x;
      }
      float value = RAD2DEGF(focallength_to_fov(lens_value, sensor_value));
      mcurve->add_value(value, frame);
    }
    /* to reset the handles */
    mcurve->clean_handles();
  }
  return mcurve;
}
 
void AnimationExporter::export_curve_animation(Object *ob, BCAnimationCurve &curve)
{
  std::string channel_target = curve.get_channel_target();
 
  /*
   * Some curves can not be exported as is and need some conversion
   * For more information see implementation of get_modified_export_curve()
   * note: if mcurve is not NULL then it must be deleted at end of this method;
   */
 
  int channel_index = curve.get_channel_index();
  /* RGB or XYZ or "" */
  std::string channel_type = curve.get_channel_type();
  std::string axis = get_axis_name(channel_type, channel_index);
 
  std::string action_name;
  bAction *action = bc_getSceneObjectAction(ob);
  action_name = (action) ? id_name(action) : "constraint_anim";
 
  const std::string curve_name = encode_xml(curve.get_animation_name(ob));
  std::string id = bc_get_action_id(action_name, curve_name, channel_target, axis, ".");
 
  std::string collada_target = translate_id(curve_name);
 
  if (curve.is_of_animation_type(BC_ANIMATION_TYPE_MATERIAL)) {
    int material_index = curve.get_subindex();
    Material *ma = BKE_object_material_get(ob, material_index + 1);
    if (ma) {
      collada_target = translate_id(id_name(ma)) + "-effect/common/" +
                       get_collada_sid(curve, axis);
    }
  }
  else {
    collada_target += "/" + get_collada_sid(curve, axis);
  }
 
  BC_global_rotation_type global_rotation_type = get_global_rotation_type(ob);
  export_collada_curve_animation(
      id, curve_name, collada_target, axis, curve, global_rotation_type);
}
 
void AnimationExporter::export_bone_animation(Object *ob,
                                              Bone *bone,
                                              BCFrames &frames,
                                              BCMatrixSampleMap &samples)
{
  bAction *action = bc_getSceneObjectAction(ob);
  std::string bone_name(bone->name);
  std::string name = encode_xml(id_name(ob));
  std::string id = bc_get_action_id(id_name(action), name, bone_name, "pose_matrix");
  std::string target = translate_id(id_name(ob) + "_" + bone_name) + "/transform";
 
  BC_global_rotation_type global_rotation_type = get_global_rotation_type(ob);
  export_collada_matrix_animation(
      id, name, target, frames, samples, global_rotation_type, ob->parentinv);
}
 
bool AnimationExporter::is_bone_deform_group(Bone *bone)
{
  bool is_def;
  /* Check if current bone is deform */
  if ((bone->flag & BONE_NO_DEFORM) == 0) {
    return true;
  }
  /* Check child bones */
 
  for (Bone *child = (Bone *)bone->childbase.first; child; child = child->next) {
    /* loop through all the children until deform bone is found, and then return */
    is_def = is_bone_deform_group(child);
    if (is_def) {
      return true;
    }
  }
 
  /* no deform bone found in children also */
  return false;
}
 
void AnimationExporter::export_collada_curve_animation(
    std::string id,
    std::string name,
    std::string collada_target,
    std::string axis,
    BCAnimationCurve &curve,
    BC_global_rotation_type global_rotation_type)
{
  BCFrames frames;
  BCValues values;
  curve.get_frames(frames);
  curve.get_values(values);
  std::string channel_target = curve.get_channel_target();
 
  fprintf(
      stdout, "Export animation curve %s (%d control points)\n", id.c_str(), int(frames.size()));
  openAnimation(id, name);
  BC_animation_source_type source_type = (curve.is_rotation_curve()) ? BC_SOURCE_TYPE_ANGLE :
                                                                       BC_SOURCE_TYPE_VALUE;
 
  std::string input_id = collada_source_from_values(
      BC_SOURCE_TYPE_TIMEFRAME, COLLADASW::InputSemantic::INPUT, frames, id, axis);
  std::string output_id = collada_source_from_values(
      source_type, COLLADASW::InputSemantic::OUTPUT, values, id, axis);
 
  bool has_tangents = false;
  std::string interpolation_id;
  if (this->export_settings.get_keep_smooth_curves()) {
    interpolation_id = collada_interpolation_source(curve, id, axis, &has_tangents);
  }
  else {
    interpolation_id = collada_linear_interpolation_source(frames.size(), id);
  }
 
  std::string intangent_id;
  std::string outtangent_id;
  if (has_tangents) {
    intangent_id = collada_tangent_from_curve(
        COLLADASW::InputSemantic::IN_TANGENT, curve, id, axis);
    outtangent_id = collada_tangent_from_curve(
        COLLADASW::InputSemantic::OUT_TANGENT, curve, id, axis);
  }
 
  std::string sampler_id = std::string(id) + SAMPLER_ID_SUFFIX;
 
  COLLADASW::LibraryAnimations::Sampler sampler(sw, sampler_id);
 
  sampler.addInput(COLLADASW::InputSemantic::INPUT, COLLADABU::URI(EMPTY_STRING, input_id));
  sampler.addInput(COLLADASW::InputSemantic::OUTPUT, COLLADABU::URI(EMPTY_STRING, output_id));
  sampler.addInput(COLLADASW::InputSemantic::INTERPOLATION,
                   COLLADABU::URI(EMPTY_STRING, interpolation_id));
 
  if (has_tangents) {
    sampler.addInput(COLLADASW::InputSemantic::IN_TANGENT,
                     COLLADABU::URI(EMPTY_STRING, intangent_id));
    sampler.addInput(COLLADASW::InputSemantic::OUT_TANGENT,
                     COLLADABU::URI(EMPTY_STRING, outtangent_id));
  }
 
  addSampler(sampler);
  addChannel(COLLADABU::URI(EMPTY_STRING, sampler_id), collada_target);
 
  closeAnimation();
}
 
void AnimationExporter::export_collada_matrix_animation(
    std::string id,
    std::string name,
    std::string target,
    BCFrames &frames,
    BCMatrixSampleMap &samples,
    BC_global_rotation_type global_rotation_type,
    Matrix &parentinv)
{
  fprintf(
      stdout, "Export animation matrix %s (%d control points)\n", id.c_str(), int(frames.size()));
 
  openAnimationWithClip(id, name);
 
  std::string input_id = collada_source_from_values(
      BC_SOURCE_TYPE_TIMEFRAME, COLLADASW::InputSemantic::INPUT, frames, id, "");
  std::string output_id = collada_source_from_values(samples, id, global_rotation_type, parentinv);
  std::string interpolation_id = collada_linear_interpolation_source(frames.size(), id);
 
  std::string sampler_id = std::string(id) + SAMPLER_ID_SUFFIX;
  COLLADASW::LibraryAnimations::Sampler sampler(sw, sampler_id);
 
  sampler.addInput(COLLADASW::InputSemantic::INPUT, COLLADABU::URI(EMPTY_STRING, input_id));
  sampler.addInput(COLLADASW::InputSemantic::OUTPUT, COLLADABU::URI(EMPTY_STRING, output_id));
  sampler.addInput(COLLADASW::InputSemantic::INTERPOLATION,
                   COLLADABU::URI(EMPTY_STRING, interpolation_id));
 
  /* Matrix animation has no tangents */
 
  addSampler(sampler);
  addChannel(COLLADABU::URI(EMPTY_STRING, sampler_id), target);
 
  closeAnimation();
}
 
std::string AnimationExporter::get_semantic_suffix(COLLADASW::InputSemantic::Semantics semantic)
{
  switch (semantic) {
    case COLLADASW::InputSemantic::INPUT:
      return INPUT_SOURCE_ID_SUFFIX;
    case COLLADASW::InputSemantic::OUTPUT:
      return OUTPUT_SOURCE_ID_SUFFIX;
    case COLLADASW::InputSemantic::INTERPOLATION:
      return INTERPOLATION_SOURCE_ID_SUFFIX;
    case COLLADASW::InputSemantic::IN_TANGENT:
      return INTANGENT_SOURCE_ID_SUFFIX;
    case COLLADASW::InputSemantic::OUT_TANGENT:
      return OUTTANGENT_SOURCE_ID_SUFFIX;
    default:
      break;
  }
  return "";
}
 
void AnimationExporter::add_source_parameters(COLLADASW::SourceBase::ParameterNameList &param,
                                              COLLADASW::InputSemantic::Semantics semantic,
                                              bool is_rot,
                                              const std::string axis,
                                              bool transform)
{
  switch (semantic) {
    case COLLADASW::InputSemantic::INPUT:
      param.push_back("TIME");
      break;
    case COLLADASW::InputSemantic::OUTPUT:
      if (is_rot) {
        param.push_back("ANGLE");
      }
      else {
        if (!axis.empty()) {
          param.push_back(axis);
        }
        else if (transform) {
          param.push_back("TRANSFORM");
        }
        else {
          /* assumes if axis isn't specified all axises are added */
          param.push_back("X");
          param.push_back("Y");
          param.push_back("Z");
        }
      }
      break;
    case COLLADASW::InputSemantic::IN_TANGENT:
    case COLLADASW::InputSemantic::OUT_TANGENT:
      param.push_back("X");
      param.push_back("Y");
      break;
    default:
      break;
  }
}
 
std::string AnimationExporter::collada_tangent_from_curve(
    COLLADASW::InputSemantic::Semantics semantic,
    BCAnimationCurve &curve,
    const std::string &anim_id,
    std::string axis_name)
{
  Scene *scene = this->export_settings.get_scene();
 
  std::string channel = curve.get_channel_target();
 
  const std::string source_id = anim_id + get_semantic_suffix(semantic);
 
  bool is_angle = (bc_startswith(channel, "rotation") || channel == "spot_size");
 
  COLLADASW::FloatSourceF source(mSW);
  source.setId(source_id);
  source.setArrayId(source_id + ARRAY_ID_SUFFIX);
  source.setAccessorCount(curve.sample_count());
  source.setAccessorStride(2);
 
  COLLADASW::SourceBase::ParameterNameList &param = source.getParameterNameList();
  add_source_parameters(param, semantic, is_angle, axis_name, false);
 
  source.prepareToAppendValues();
 
  const FCurve *fcu = curve.get_fcurve();
  int tangent = (semantic == COLLADASW::InputSemantic::IN_TANGENT) ? 0 : 2;
 
  for (int i = 0; i < fcu->totvert; i++) {
    BezTriple &bezt = fcu->bezt[i];
 
    float sampled_time = bezt.vec[tangent][0];
    float sampled_val = bezt.vec[tangent][1];
 
    if (is_angle) {
      sampled_val = RAD2DEGF(sampled_val);
    }
 
    source.appendValues(FRA2TIME(sampled_time));
    source.appendValues(sampled_val);
  }
  source.finish();
  return source_id;
}
 
std::string AnimationExporter::collada_source_from_values(
    BC_animation_source_type source_type,
    COLLADASW::InputSemantic::Semantics semantic,
    std::vector<float> &values,
    const std::string &anim_id,
    const std::string axis_name)
{
  BlenderContext &blender_context = this->export_settings.get_blender_context();
  Scene *scene = blender_context.get_scene();
  /* T can be float, int or double */
 
  int stride = 1;
  int entry_count = values.size() / stride;
  std::string source_id = anim_id + get_semantic_suffix(semantic);
 
  COLLADASW::FloatSourceF source(mSW);
  source.setId(source_id);
  source.setArrayId(source_id + ARRAY_ID_SUFFIX);
  source.setAccessorCount(entry_count);
  source.setAccessorStride(stride);
 
  COLLADASW::SourceBase::ParameterNameList &param = source.getParameterNameList();
  add_source_parameters(param, semantic, source_type == BC_SOURCE_TYPE_ANGLE, axis_name, false);
 
  source.prepareToAppendValues();
 
  for (int i = 0; i < entry_count; i++) {
    float val = values[i];
    switch (source_type) {
      case BC_SOURCE_TYPE_TIMEFRAME:
        val = FRA2TIME(val);
        break;
      case BC_SOURCE_TYPE_ANGLE:
        val = RAD2DEGF(val);
        break;
      default:
        break;
    }
    source.appendValues(val);
  }
 
  source.finish();
 
  return source_id;
}
 
/*
 * Create a collada matrix source for a set of samples
 */
std::string AnimationExporter::collada_source_from_values(
    BCMatrixSampleMap &samples,
    const std::string &anim_id,
    BC_global_rotation_type global_rotation_type,
    Matrix &parentinv)
{
  COLLADASW::InputSemantic::Semantics semantic = COLLADASW::InputSemantic::OUTPUT;
  std::string source_id = anim_id + get_semantic_suffix(semantic);
 
  COLLADASW::Float4x4Source source(mSW);
  source.setId(source_id);
  source.setArrayId(source_id + ARRAY_ID_SUFFIX);
  source.setAccessorCount(samples.size());
  source.setAccessorStride(16);
 
  COLLADASW::SourceBase::ParameterNameList &param = source.getParameterNameList();
  add_source_parameters(param, semantic, false, "", true);
 
  source.prepareToAppendValues();
 
  BCMatrixSampleMap::iterator it;
  /* could be made configurable */
  int precision = (this->export_settings.get_limit_precision()) ? 6 : -1;
  for (it = samples.begin(); it != samples.end(); it++) {
    BCMatrix sample = BCMatrix(*it->second);
    BCMatrix global_transform = this->export_settings.get_global_transform();
    DMatrix daemat;
    if (this->export_settings.get_apply_global_orientation()) {
      sample.apply_transform(global_transform);
    }
    else {
      sample.add_transform(global_transform);
    }
    sample.get_matrix(daemat, true, precision);
    source.appendValues(daemat);
  }
 
  source.finish();
  return source_id;
}
 
std::string AnimationExporter::collada_interpolation_source(const BCAnimationCurve &curve,
                                                            const std::string &anim_id,
                                                            const std::string axis,
                                                            bool *has_tangents)
{
  std::string source_id = anim_id + get_semantic_suffix(COLLADASW::InputSemantic::INTERPOLATION);
 
  COLLADASW::NameSource source(mSW);
  source.setId(source_id);
  source.setArrayId(source_id + ARRAY_ID_SUFFIX);
  source.setAccessorCount(curve.sample_count());
  source.setAccessorStride(1);
 
  COLLADASW::SourceBase::ParameterNameList &param = source.getParameterNameList();
  param.push_back("INTERPOLATION");
 
  source.prepareToAppendValues();
 
  *has_tangents = false;
 
  std::vector<float> frames;
  curve.get_frames(frames);
 
  for (unsigned int i = 0; i < curve.sample_count(); i++) {
    float frame = frames[i];
    int ipo = curve.get_interpolation_type(frame);
    if (ipo == BEZT_IPO_BEZ) {
      source.appendValues(BEZIER_NAME);
      *has_tangents = true;
    }
    else if (ipo == BEZT_IPO_CONST) {
      source.appendValues(STEP_NAME);
    }
    else {
      /* BEZT_IPO_LIN */
      source.appendValues(LINEAR_NAME);
    }
  }
  /* unsupported? -- HERMITE, CARDINAL, BSPLINE, NURBS */
 
  source.finish();
 
  return source_id;
}
 
std::string AnimationExporter::collada_linear_interpolation_source(int tot,
                                                                   const std::string &anim_id)
{
  std::string source_id = anim_id + get_semantic_suffix(COLLADASW::InputSemantic::INTERPOLATION);
 
  COLLADASW::NameSource source(mSW);
  source.setId(source_id);
  source.setArrayId(source_id + ARRAY_ID_SUFFIX);
  source.setAccessorCount(tot);
  source.setAccessorStride(1);
 
  COLLADASW::SourceBase::ParameterNameList &param = source.getParameterNameList();
  param.push_back("INTERPOLATION");
 
  source.prepareToAppendValues();
 
  for (int i = 0; i < tot; i++) {
    source.appendValues(LINEAR_NAME);
  }
 
  source.finish();
 
  return source_id;
}
 
std::string AnimationExporter::get_collada_name(std::string channel_type) const
{
  /*
   * Translation table to map FCurve animation types to Collada animation.
   * Todo: Maybe we can keep the names from the fcurves here instead of
   * mapping. However this is what i found in the old code. So keep
   * this map for now.
   */
  static std::map<std::string, std::string> BC_CHANNEL_BLENDER_TO_COLLADA = {
      {"rotation", "rotation"},
      {"rotation_euler", "rotation"},
      {"rotation_quaternion", "rotation"},
      {"scale", "scale"},
      {"location", "location"},
 
      /* Materials */
      {"specular_color", "specular"},
      {"diffuse_color", "diffuse"},
      {"ior", "index_of_refraction"},
      {"specular_hardness", "specular_hardness"},
      {"alpha", "alpha"},
 
      /* Lights */
      {"color", "color"},
      {"fall_off_angle", "falloff_angle"},
      {"spot_size", "falloff_angle"},
      {"fall_off_exponent", "falloff_exponent"},
      {"spot_blend", "falloff_exponent"},
      /* Special blender profile (todo: make this more elegant). */
      {"blender/blender_dist", "blender/blender_dist"},
      /* Special blender profile (todo: make this more elegant). */
      {"distance", "blender/blender_dist"},
 
      /* Cameras */
      {"lens", "xfov"},
      {"xfov", "xfov"},
      {"xmag", "xmag"},
      {"zfar", "zfar"},
      {"znear", "znear"},
      {"ortho_scale", "xmag"},
      {"clip_end", "zfar"},
      {"clip_start", "znear"}};
 
  std::map<std::string, std::string>::iterator name_it = BC_CHANNEL_BLENDER_TO_COLLADA.find(
      channel_type);
  if (name_it == BC_CHANNEL_BLENDER_TO_COLLADA.end()) {
    return "";
  }
  std::string tm_name = name_it->second;
  return tm_name;
}
 
/*
 * Assign sid of the animated parameter or transform for rotation,
 * axis name is always appended and the value of append_axis is ignored
 */
std::string AnimationExporter::get_collada_sid(const BCAnimationCurve &curve,
                                               const std::string axis_name)
{
  std::string channel_target = curve.get_channel_target();
  std::string channel_type = curve.get_channel_type();
  std::string tm_name = get_collada_name(channel_type);
 
  bool is_angle = curve.is_rotation_curve();
 
  if (!tm_name.empty()) {
    if (is_angle) {
      return tm_name + std::string(axis_name) + ".ANGLE";
    }
    if (!axis_name.empty()) {
      return tm_name + "." + std::string(axis_name);
    }
 
    return tm_name;
  }
 
  return tm_name;
}
 
#ifdef WITH_MORPH_ANIMATION
/* TODO: This function needs to be implemented similar to the material animation export
 * So we have to update BCSample for this to work. */
void AnimationExporter::export_morph_animation(Object *ob, BCAnimationSampler &sampler)
{
  FCurve *fcu;
  Key *key = BKE_key_from_object(ob);
  if (!key) {
    return;
  }
 
  if (key->adt && key->adt->action) {
    fcu = (FCurve *)key->adt->action->curves.first;
 
    while (fcu) {
      BC_animation_transform_type tm_type = get_transform_type(fcu->rna_path);
 
      create_keyframed_animation(ob, fcu, tm_type, true, sampler);
 
      fcu = fcu->next;
    }
  }
}
#endif