xFileMesh.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file xFileMesh.cxx
 * @author drose
 * @date 2001-06-19
 */

#include "xFileMesh.h"
#include "xFileToEggConverter.h"
#include "xFileFace.h"
#include "xFileVertex.h"
#include "xFileNormal.h"
#include "xFileMaterial.h"
#include "xFileDataNode.h"
#include "config_xfile.h"
#include "string_utils.h"
#include "eggVertexPool.h"
#include "eggVertex.h"
#include "eggPolygon.h"
#include "eggGroup.h"
#include "eggGroupNode.h"

using std::min;
using std::string;

/**
 *
 */
XFileMesh::
XFileMesh(CoordinateSystem cs) : _cs(cs) {
  _has_normals = false;
  _has_colors = false;
  _has_uvs = false;
  _has_materials = false;
  _egg_parent = nullptr;
}

/**
 *
 */
XFileMesh::
~XFileMesh() {
  clear();
}

/**
 * Empties all data from the mesh.
 */
void XFileMesh::
clear() {
  Vertices::iterator vi;
  for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
    XFileVertex *vertex = (*vi);
    delete vertex;
  }
  Normals::iterator ni;
  for (ni = _normals.begin(); ni != _normals.end(); ++ni) {
    XFileNormal *normal = (*ni);
    delete normal;
  }
  Materials::iterator mi;
  for (mi = _materials.begin(); mi != _materials.end(); ++mi) {
    XFileMaterial *material = (*mi);
    delete material;
  }
  Faces::iterator fi;
  for (fi = _faces.begin(); fi != _faces.end(); ++fi) {
    XFileFace *face = (*fi);
    delete face;
  }

  _vertices.clear();
  _normals.clear();
  _materials.clear();
  _faces.clear();

  _unique_vertices.clear();
  _unique_normals.clear();
  _unique_materials.clear();

  _has_normals = false;
  _has_colors = false;
  _has_uvs = false;
  _has_materials = false;
}

/**
 * Adds the indicated polygon to the mesh.
 */
void XFileMesh::
add_polygon(EggPolygon *egg_poly) {
  XFileFace *face = new XFileFace;
  face->set_from_egg(this, egg_poly);
  _faces.push_back(face);
}

/**
 * Creates a new XFileVertex, if one does not already exist for the indicated
 * vertex, and returns its index.
 */
int XFileMesh::
add_vertex(EggVertex *egg_vertex, EggPrimitive *egg_prim) {
  int next_index = _vertices.size();
  XFileVertex *vertex = new XFileVertex;
  vertex->set_from_egg(egg_vertex, egg_prim);
  if (vertex->_has_color) {
    _has_colors = true;
  }
  if (vertex->_has_uv) {
    _has_uvs = true;
  }

  std::pair<UniqueVertices::iterator, bool> result =
    _unique_vertices.insert(UniqueVertices::value_type(vertex, next_index));

  if (result.second) {
    // Successfully added; this is a new vertex.
    _vertices.push_back(vertex);
    return next_index;
  } else {
    // Not successfully added; there is already a vertex with these
    // properties.  Return that one instead.
    delete vertex;
    return (*result.first).second;
  }
}


/**
 * Creates a new XFileNormal, if one does not already exist for the indicated
 * normal, and returns its index.
 */
int XFileMesh::
add_normal(EggVertex *egg_vertex, EggPrimitive *egg_prim) {
  int next_index = _normals.size();
  XFileNormal *normal = new XFileNormal;
  normal->set_from_egg(egg_vertex, egg_prim);
  if (normal->_has_normal) {
    _has_normals = true;
  }

  std::pair<UniqueNormals::iterator, bool> result =
    _unique_normals.insert(UniqueNormals::value_type(normal, next_index));

  if (result.second) {
    // Successfully added; this is a new normal.
    _normals.push_back(normal);
    return next_index;
  } else {
    // Not successfully added; there is already a normal with these
    // properties.  Return that one instead.
    delete normal;
    return (*result.first).second;
  }
}

/**
 * Creates a new XFileMaterial, if one does not already exist for the
 * indicated material, and returns its index.
 */
int XFileMesh::
add_material(EggPrimitive *egg_prim) {
  int next_index = _materials.size();
  XFileMaterial *material = new XFileMaterial;
  material->set_from_egg(egg_prim);
  if (material->has_material()) {
    _has_materials = true;
  }

  std::pair<UniqueMaterials::iterator, bool> result =
    _unique_materials.insert(UniqueMaterials::value_type(material, next_index));

  if (result.second) {
    // Successfully added; this is a new material.
    _materials.push_back(material);
    return next_index;
  } else {
    // Not successfully added; there is already a material with these
    // properties.  Return that one instead.
    delete material;
    return (*result.first).second;
  }
}


/**
 * Adds the newly-created XFileVertex unequivocally to the mesh, returning its
 * index number.  The XFileMesh object becomes the owner of the XFileVertex
 * pointer, and will delete it when it destructs.
 */
int XFileMesh::
add_vertex(XFileVertex *vertex) {
  if (vertex->_has_color) {
    _has_colors = true;
  }
  if (vertex->_has_uv) {
    _has_uvs = true;
  }

  int next_index = _vertices.size();
  _unique_vertices.insert(UniqueVertices::value_type(vertex, next_index));
  _vertices.push_back(vertex);
  return next_index;
}

/**
 * Adds the newly-created XFileNormal unequivocally to the mesh, returning its
 * index number.  The XFileMesh object becomes the owner of the XFileNormal
 * pointer, and will delete it when it destructs.
 */
int XFileMesh::
add_normal(XFileNormal *normal) {
  if (normal->_has_normal) {
    _has_normals = true;
  }

  int next_index = _normals.size();
  _unique_normals.insert(UniqueNormals::value_type(normal, next_index));
  _normals.push_back(normal);
  return next_index;
}

/**
 * Adds the newly-created XFileMaterial unequivocally to the mesh, returning
 * its index number.  The XFileMesh object becomes the owner of the
 * XFileMaterial pointer, and will delete it when it destructs.
 */
int XFileMesh::
add_material(XFileMaterial *material) {
  if (material->has_material()) {
    _has_materials = true;
  }

  int next_index = _materials.size();
  _unique_materials.insert(UniqueMaterials::value_type(material, next_index));
  _materials.push_back(material);
  return next_index;
}

/**
 * Specifies the egg node that will eventually be the parent of this mesh,
 * when create_polygons() is later called.
 */
void XFileMesh::
set_egg_parent(EggGroupNode *egg_parent) {
  // We actually put the mesh under its own group.
  EggGroup *egg_group = new EggGroup(get_name());
  egg_parent->add_child(egg_group);

  _egg_parent = egg_group;
}

/**
 * Creates a slew of EggPolygons according to the faces in the mesh, and adds
 * them to the previously-indicated parent node.
 */
bool XFileMesh::
create_polygons(XFileToEggConverter *converter) {
  nassertr(_egg_parent != nullptr, false);

  EggVertexPool *vpool = new EggVertexPool(get_name());
  _egg_parent->add_child(vpool);
  Faces::const_iterator fi;
  for (fi = _faces.begin(); fi != _faces.end(); ++fi) {
    XFileFace *face = (*fi);

    EggPolygon *egg_poly = new EggPolygon;
    _egg_parent->add_child(egg_poly);

    // Set up the vertices for the polygon.
    XFileFace::Vertices::reverse_iterator vi;
    for (vi = face->_vertices.rbegin(); vi != face->_vertices.rend(); ++vi) {
      int vertex_index = (*vi)._vertex_index;
      int normal_index = (*vi)._normal_index;
      if (vertex_index < 0 || vertex_index >= (int)_vertices.size()) {
        xfile_cat.warning()
          << "Vertex index out of range in Mesh " << get_name() << "\n";
        continue;
      }
      XFileVertex *vertex = _vertices[vertex_index];
      XFileNormal *normal = nullptr;

      if (normal_index >= 0 && normal_index < (int)_normals.size()) {
        normal = _normals[normal_index];
      }

      // Create a temporary EggVertex before adding it to the pool.
      EggVertex temp_vtx;
      temp_vtx.set_external_index(vertex_index);
      temp_vtx.set_pos(vertex->_point);
      if (vertex->_has_color) {
        temp_vtx.set_color(vertex->_color);
      }
      if (vertex->_has_uv) {
        LTexCoordd uv = vertex->_uv;
        // Windows draws the UV's upside-down.
        uv[1] = 1.0 - uv[1];
        temp_vtx.set_uv(uv);
      }

      if (normal != nullptr && normal->_has_normal) {
        temp_vtx.set_normal(normal->_normal);
      }

      // We are given the vertex in local space; we need to transform it into
      // global space.  If the vertex has been skinned, that means the global
      // space of all of its joints (modified by the matrix_offset provided in
      // the skinning data).
      double net_weight = 0.0;
      LMatrix4d weighted_transform(0.0, 0.0, 0.0, 0.0,
                                   0.0, 0.0, 0.0, 0.0,
                                   0.0, 0.0, 0.0, 0.0,
                                   0.0, 0.0, 0.0, 0.0);
      SkinWeights::const_iterator swi;
      for (swi = _skin_weights.begin(); swi != _skin_weights.end(); ++swi) {
        const SkinWeightsData &data = (*swi);
        WeightMap::const_iterator wmi = data._weight_map.find(vertex_index);
        if (wmi != data._weight_map.end()) {
          EggGroup *joint = converter->find_joint(data._joint_name);
          if (joint != nullptr) {
            double weight = (*wmi).second;
            LMatrix4d mat = data._matrix_offset;
            mat *= joint->get_node_to_vertex();
            weighted_transform += mat * weight;
            net_weight += weight;
          }
        }
      }

      if (net_weight == 0.0) {
        // The vertex had no joint membership.  Transform it into the
        // appropriate (global) space based on its parent.
        temp_vtx.transform(_egg_parent->get_node_to_vertex());

      } else {
        // The vertex was skinned into one or more joints.  Therefore,
        // transform it according to the blended matrix_offset from the
        // skinning data.
        weighted_transform /= net_weight;
        temp_vtx.transform(weighted_transform);
      }

      // Now get a real EggVertex matching our template.
      EggVertex *egg_vtx = vpool->create_unique_vertex(temp_vtx);
      egg_poly->add_vertex(egg_vtx);
    }

    // And apply the material for the polygon.
    int material_index = face->_material_index;
    if (material_index >= 0 && material_index < (int)_materials.size()) {
      XFileMaterial *material = _materials[material_index];
      material->apply_to_egg(egg_poly, converter);
    }
  }

  // Now go through all of the vertices and skin them up.
  EggVertexPool::iterator vi;
  for (vi = vpool->begin(); vi != vpool->end(); ++vi) {
    EggVertex *egg_vtx = (*vi);
    int vertex_index = egg_vtx->get_external_index();

    SkinWeights::const_iterator swi;
    for (swi = _skin_weights.begin(); swi != _skin_weights.end(); ++swi) {
      const SkinWeightsData &data = (*swi);
      WeightMap::const_iterator wmi = data._weight_map.find(vertex_index);
      if (wmi != data._weight_map.end()) {
        EggGroup *joint = converter->find_joint(data._joint_name);
        if (joint != nullptr) {
          double weight = (*wmi).second;
          joint->ref_vertex(egg_vtx, weight);
        }
      }
    }
  }

  if (!has_normals()) {
    // If we don't have explicit normals, make some up, per the DX spec.
    // Since the DX spec doesn't mention anything about a crease angle, we
    // should be as generous as possible.
    _egg_parent->recompute_vertex_normals(180.0, _cs);
  }

  return true;
}

/**
 * Returns true if any of the vertices or faces added to this mesh used a
 * normal, false otherwise.
 */
bool XFileMesh::
has_normals() const {
  return _has_normals;
}

/**
 * Returns true if any of the vertices or faces added to this mesh used a
 * color, false otherwise.
 */
bool XFileMesh::
has_colors() const {
  return _has_colors;
}

/**
 * Returns true if any of the vertices added to this mesh used a texture
 * coordinate, false otherwise.
 */
bool XFileMesh::
has_uvs() const {
  return _has_uvs;
}

/**
 * Returns true if any of the faces added to this mesh used a real material,
 * false otherwise.
 */
bool XFileMesh::
has_materials() const {
  return _has_materials;
}

/**
 * Returns the number of distinct materials associated with the mesh.
 */
int XFileMesh::
get_num_materials() const {
  return _materials.size();
}

/**
 * Returns a pointer to the nth materials associated with the mesh.
 */
XFileMaterial *XFileMesh::
get_material(int n) const {
  nassertr(n >= 0 && n < (int)_materials.size(), nullptr);
  return _materials[n];
}

/**
 * Creates an X structure corresponding to the mesh.
 */
XFileDataNode *XFileMesh::
make_x_mesh(XFileNode *x_parent, const string &suffix) {
  XFileDataNode *x_mesh = x_parent->add_Mesh("mesh" + suffix);

  // First, fill in the table of vertices.
  XFileDataObject &x_vertices = (*x_mesh)["vertices"];

  Vertices::const_iterator vi;
  for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
    XFileVertex *vertex = (*vi);
    x_vertices.add_Vector(x_mesh->get_x_file(), vertex->_point);
  }
  (*x_mesh)["nVertices"] = x_vertices.size();

  // Then, create the list of faces that index into the above vertices.
  XFileDataObject &x_faces = (*x_mesh)["faces"];
  Faces::const_iterator fi;
  for (fi = _faces.begin(); fi != _faces.end(); ++fi) {
    XFileFace *face = (*fi);

    XFileDataObject &x_mesh_face = x_faces.add_MeshFace(x_mesh->get_x_file());
    XFileDataObject &x_faceVertexIndices = x_mesh_face["faceVertexIndices"];
    XFileFace::Vertices::const_iterator fvi;
    for (fvi = face->_vertices.begin();
         fvi != face->_vertices.end();
         ++fvi) {
      x_faceVertexIndices.add_int((*fvi)._vertex_index);
    }
    x_mesh_face["nFaceVertexIndices"] = x_faceVertexIndices.size();
  }
  (*x_mesh)["nFaces"] = x_faces.size();

  // Now, add in any supplemental data.

  if (has_normals()) {
    // Tack on normals.
    make_x_normals(x_mesh, suffix);
  }
  if (has_colors()) {
    // Tack on colors.
    make_x_colors(x_mesh, suffix);
  }
  if (has_uvs()) {
    // Tack on uvs.
    make_x_uvs(x_mesh, suffix);
  }
  if (has_materials()) {
    // Tack on materials.
    make_x_material_list(x_mesh, suffix);
  }

  return x_mesh;
}

/**
 * Creates a MeshNormals table for the mesh.
 */
XFileDataNode *XFileMesh::
make_x_normals(XFileNode *x_mesh, const string &suffix) {
  XFileDataNode *x_meshNormals = x_mesh->add_MeshNormals("norms" + suffix);

  XFileDataObject &x_normals = (*x_meshNormals)["normals"];

  Normals::const_iterator ni;
  for (ni = _normals.begin(); ni != _normals.end(); ++ni) {
    XFileNormal *normal = (*ni);
    x_normals.add_Vector(x_mesh->get_x_file(), normal->_normal);
  }
  (*x_meshNormals)["nNormals"] = x_normals.size();

  // Then, create the list of faces that index into the above normals.
  XFileDataObject &x_faces = (*x_meshNormals)["faceNormals"];
  Faces::const_iterator fi;
  for (fi = _faces.begin(); fi != _faces.end(); ++fi) {
    XFileFace *face = (*fi);

    XFileDataObject &x_normals_face = x_faces.add_MeshFace(x_mesh->get_x_file());
    XFileDataObject &x_faceVertexIndices = x_normals_face["faceVertexIndices"];
    XFileFace::Vertices::const_iterator fvi;
    for (fvi = face->_vertices.begin();
         fvi != face->_vertices.end();
         ++fvi) {
      x_faceVertexIndices.add_int((*fvi)._normal_index);
    }
    x_normals_face["nFaceVertexIndices"] = x_faceVertexIndices.size();
  }
  (*x_meshNormals)["nFaceNormals"] = x_faces.size();

  return x_meshNormals;
}

/**
 * Creates a MeshVertexColors table for the mesh.
 */
XFileDataNode *XFileMesh::
make_x_colors(XFileNode *x_mesh, const string &suffix) {
  XFileDataNode *x_meshColors = x_mesh->add_MeshVertexColors("colors" + suffix);

  XFileDataObject &x_colors = (*x_meshColors)["vertexColors"];

  Vertices::const_iterator vi;
  int i = 0;
  for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
    XFileVertex *vertex = (*vi);
    const LColor &color = vertex->_color;
    x_colors.add_IndexedColor(x_mesh->get_x_file(), i, color);
    i++;
  }

  (*x_meshColors)["nVertexColors"] = x_colors.size();

  return x_meshColors;
}

/**
 * Creates a MeshTextureCoords table for the mesh.
 */
XFileDataNode *XFileMesh::
make_x_uvs(XFileNode *x_mesh, const string &suffix) {
  XFileDataNode *x_meshUvs = x_mesh->add_MeshTextureCoords("uvs" + suffix);

  XFileDataObject &x_uvs = (*x_meshUvs)["textureCoords"];

  Vertices::const_iterator vi;
  for (vi = _vertices.begin(); vi != _vertices.end(); ++vi) {
    XFileVertex *vertex = (*vi);
    x_uvs.add_Coords2d(x_mesh->get_x_file(), vertex->_uv);
  }

  (*x_meshUvs)["nTextureCoords"] = x_uvs.size();

  return x_meshUvs;
}

/**
 * Creates a MeshMaterialList table for the mesh.
 */
XFileDataNode *XFileMesh::
make_x_material_list(XFileNode *x_mesh, const string &suffix) {
  XFileDataNode *x_meshMaterials =
    x_mesh->add_MeshMaterialList("materials" + suffix);

  // First, build up the list of faces the reference the materials.
  XFileDataObject &x_indexes = (*x_meshMaterials)["faceIndexes"];

  Faces::const_iterator fi;
  for (fi = _faces.begin(); fi != _faces.end(); ++fi) {
    XFileFace *face = (*fi);
    x_indexes.add_int(face->_material_index);
  }

  (*x_meshMaterials)["nFaceIndexes"] = x_indexes.size();

  // Now, build up the list of materials themselves.  Each material is a child
  // of the MeshMaterialList node, rather than an element of an array.
  for (size_t i = 0; i < _materials.size(); i++) {
    XFileMaterial *material = _materials[i];

    material->make_x_material(x_meshMaterials,
                              suffix + "_" + format_string(i));
  }

  (*x_meshMaterials)["nMaterials"] = (int)_materials.size();

  return x_meshMaterials;
}

/**
 * Fills the structure based on the raw data from the X file's Mesh object.
 */
bool XFileMesh::
fill_mesh(XFileDataNode *obj) {
  clear();

  int i, j;

  const XFileDataObject &vertices = (*obj)["vertices"];
  for (i = 0; i < vertices.size(); i++) {
    XFileVertex *vertex = new XFileVertex;
    vertex->_point = vertices[i].vec3();
    add_vertex(vertex);
  }

  const XFileDataObject &faces = (*obj)["faces"];
  for (i = 0; i < faces.size(); i++) {
    XFileFace *face = new XFileFace;

    const XFileDataObject &faceIndices = faces[i]["faceVertexIndices"];

    for (j = 0; j < faceIndices.size(); j++) {
      XFileFace::Vertex vertex;
      vertex._vertex_index = faceIndices[j].i();
      vertex._normal_index = -1;

      face->_vertices.push_back(vertex);
    }
    _faces.push_back(face);
  }

  // Some properties are stored as children of the mesh.
  int num_objects = obj->get_num_objects();
  for (i = 0; i < num_objects; i++) {
    if (!fill_mesh_child(obj->get_object(i))) {
      return false;
    }
  }

  return true;
}

/**
 * Fills the structure based on one of the children of the Mesh object.
 */
bool XFileMesh::
fill_mesh_child(XFileDataNode *obj) {
  if (obj->is_standard_object("MeshNormals")) {
    if (!fill_normals(obj)) {
      return false;
    }

  } else if (obj->is_standard_object("MeshVertexColors")) {
    if (!fill_colors(obj)) {
      return false;
    }

  } else if (obj->is_standard_object("MeshTextureCoords")) {
    if (!fill_uvs(obj)) {
      return false;
    }

  } else if (obj->is_standard_object("MeshMaterialList")) {
    if (!fill_material_list(obj)) {
      return false;
    }

  } else if (obj->is_standard_object("XSkinMeshHeader")) {
    // Quietly ignore a skin mesh header.

  } else if (obj->is_standard_object("SkinWeights")) {
    if (!fill_skin_weights(obj)) {
      return false;
    }

  } else {
    if (xfile_cat.is_debug()) {
      xfile_cat.debug()
        << "Ignoring mesh data object of unknown type: "
        << obj->get_template_name() << "\n";
    }
  }

  return true;
}

/**
 * Fills the structure based on the raw data from the MeshNormals template.
 */
bool XFileMesh::
fill_normals(XFileDataNode *obj) {
  int i, j;

  const XFileDataObject &normals = (*obj)["normals"];
  for (i = 0; i < normals.size(); i++) {
    XFileNormal *normal = new XFileNormal;
    normal->_normal = normals[i].vec3();
    normal->_has_normal = true;
    add_normal(normal);
  }

  const XFileDataObject &faceNormals = (*obj)["faceNormals"];
  if (faceNormals.size() != (int)_faces.size()) {
    xfile_cat.warning()
      << "Incorrect number of faces in MeshNormals within "
      << get_name() << "\n";
  }

  int num_normals = min(faceNormals.size(), (int)_faces.size());
  for (i = 0; i < num_normals; i++) {
    XFileFace *face = _faces[i];

    const XFileDataObject &faceIndices = faceNormals[i]["faceVertexIndices"];

    if (faceIndices.size() != (int)face->_vertices.size()) {
      xfile_cat.warning()
        << "Incorrect number of vertices for face in MeshNormals within "
        << get_name() << "\n";
    }

    int num_vertices = min(faceIndices.size(), (int)face->_vertices.size());
    for (j = 0; j < num_vertices; j++) {
      face->_vertices[j]._normal_index = faceIndices[j].i();
    }
  }

  return true;
}

/**
 * Fills the structure based on the raw data from the MeshVertexColors
 * template.
 */
bool XFileMesh::
fill_colors(XFileDataNode *obj) {
  const XFileDataObject &vertexColors = (*obj)["vertexColors"];
  for (int i = 0; i < vertexColors.size(); i++) {
    int vertex_index = vertexColors[i]["index"].i();
    if (vertex_index < 0 || vertex_index >= (int)_vertices.size()) {
      xfile_cat.warning()
        << "Vertex index out of range in MeshVertexColors within "
        << get_name() << "\n";
      continue;
    }

    XFileVertex *vertex = _vertices[vertex_index];
    vertex->_color = LCAST(PN_stdfloat, vertexColors[i]["indexColor"].vec4());
    vertex->_has_color = true;
  }

  return true;
}

/**
 * Fills the structure based on the raw data from the MeshTextureCoords
 * template.
 */
bool XFileMesh::
fill_uvs(XFileDataNode *obj) {
  const XFileDataObject &textureCoords = (*obj)["textureCoords"];
  if (textureCoords.size() != (int)_vertices.size()) {
    xfile_cat.warning()
      << "Wrong number of vertices in MeshTextureCoords within "
      << get_name() << "\n";
  }

  int num_texcoords = min(textureCoords.size(), (int)_vertices.size());
  for (int i = 0; i < num_texcoords; i++) {
    XFileVertex *vertex = _vertices[i];
    vertex->_uv = textureCoords[i].vec2();
    vertex->_has_uv = true;
  }

  return true;
}

/**
 * Fills the structure based on the raw data from the SkinWeights template.
 */
bool XFileMesh::
fill_skin_weights(XFileDataNode *obj) {
  // Create a new SkinWeightsData record for the table.  We'll need this data
  // later when we create the vertices.
  _skin_weights.push_back(SkinWeightsData());
  SkinWeightsData &data = _skin_weights.back();

  data._joint_name = (*obj)["transformNodeName"].s();

  const XFileDataObject &vertexIndices = (*obj)["vertexIndices"];
  const XFileDataObject &weights = (*obj)["weights"];

  if (weights.size() != vertexIndices.size()) {
    xfile_cat.warning()
      << "Inconsistent number of vertices in SkinWeights within " << get_name() << "\n";
  }

  // Unpack the weight for each vertex.
  size_t num_weights = min(weights.size(), vertexIndices.size());
  for (size_t i = 0; i < num_weights; i++) {
    int vindex = vertexIndices[i].i();
    double weight = weights[i].d();

    if (vindex < 0 || vindex > (int)_vertices.size()) {
      xfile_cat.warning()
        << "Illegal vertex index " << vindex << " in SkinWeights.\n";
      continue;
    }
    data._weight_map[vindex] = weight;
  }

  // Also retrieve the matrix offset.
  data._matrix_offset = (*obj)["matrixOffset"]["matrix"].mat4();

  return true;
}

/**
 * Fills the structure based on the raw data from the MeshMaterialList
 * template.
 */
bool XFileMesh::
fill_material_list(XFileDataNode *obj) {
  const XFileDataObject &faceIndexes = (*obj)["faceIndexes"];
  if (faceIndexes.size() > (int)_faces.size()) {
    xfile_cat.warning()
      << "Too many faces in MeshMaterialList within " << get_name() << "\n";
  }

  int material_index = -1;
  int i = 0;
  while (i < faceIndexes.size() && i < (int)_faces.size()) {
    XFileFace *face = _faces[i];
    material_index = faceIndexes[i].i();
    face->_material_index = material_index;
    i++;
  }

  // The rest of the faces get the same material index as the last one in the
  // list.
  while (i < (int)_faces.size()) {
    XFileFace *face = _faces[i];
    face->_material_index = material_index;
    i++;
  }

  // Now look for children of the MaterialList object.  These should all be
  // Material objects.
  int num_objects = obj->get_num_objects();
  for (i = 0; i < num_objects; i++) {
    XFileDataNode *child = obj->get_object(i);
    if (child->is_standard_object("Material")) {
      XFileMaterial *material = new XFileMaterial;
      if (!material->fill_material(child)) {
        delete material;
        return false;
      }
      add_material(material);

    } else {
      if (xfile_cat.is_debug()) {
        xfile_cat.debug()
          << "Ignoring material list object of unknown type: "
          << child->get_template_name() << "\n";
      }
    }
  }

  return true;
}