[glb export] Export bones. (#3087)

![image](https://github.com/open-goal/jak-project/assets/48171810/0f26e77b-af68-4450-882e-762a501bdef4)

common/math/geometry.h

@@ -50,4 +50,78 @@ math::Vector4f bsphere_of_triangle(const Vector3f* vertices);
 inline bool point_in_bsphere(const Vector4f& sphere, const Vector3f& pt) {
   return (sphere.xyz() - pt).squared_length() <= (sphere.w() * sphere.w());
 }
+
+template <typename T>
+math::Matrix<T, 4, 4> affine_inverse(const math::Matrix<T, 4, 4>& in) {
+  math::Matrix<T, 4, 4> result;
+
+  // transpose rotation
+  for (int i = 0; i < 3; i++) {
+    for (int j = 0; j < 3; j++) {
+      result(i, j) = in(j, i);
+    }
+  }
+
+  result(3, 0) = 0;
+  result(3, 1) = 0;
+  result(3, 2) = 0;
+  result(3, 3) = 1;
+  result(0, 3) = 0;
+  result(1, 3) = 0;
+  result(2, 3) = 0;
+  for (int rx = 0; rx < 3; rx++) {
+    for (int cx = 0; cx < 3; cx++) {
+      result(rx, 3) -= result(rx, cx) * in(cx, 3);
+    }
+  }
+
+  return result;
+}
+
+template <typename T>
+math::Matrix<T, 4, 4> inverse(const math::Matrix<T, 4, 4>& m) {
+  math::Matrix<T, 4, 4> im;
+  T A2323 = m(2, 2) * m(3, 3) - m(2, 3) * m(3, 2);
+  T A1323 = m(2, 1) * m(3, 3) - m(2, 3) * m(3, 1);
+  T A1223 = m(2, 1) * m(3, 2) - m(2, 2) * m(3, 1);
+  T A0323 = m(2, 0) * m(3, 3) - m(2, 3) * m(3, 0);
+  T A0223 = m(2, 0) * m(3, 2) - m(2, 2) * m(3, 0);
+  T A0123 = m(2, 0) * m(3, 1) - m(2, 1) * m(3, 0);
+  T A2313 = m(1, 2) * m(3, 3) - m(1, 3) * m(3, 2);
+  T A1313 = m(1, 1) * m(3, 3) - m(1, 3) * m(3, 1);
+  T A1213 = m(1, 1) * m(3, 2) - m(1, 2) * m(3, 1);
+  T A2312 = m(1, 2) * m(2, 3) - m(1, 3) * m(2, 2);
+  T A1312 = m(1, 1) * m(2, 3) - m(1, 3) * m(2, 1);
+  T A1212 = m(1, 1) * m(2, 2) - m(1, 2) * m(2, 1);
+  T A0313 = m(1, 0) * m(3, 3) - m(1, 3) * m(3, 0);
+  T A0213 = m(1, 0) * m(3, 2) - m(1, 2) * m(3, 0);
+  T A0312 = m(1, 0) * m(2, 3) - m(1, 3) * m(2, 0);
+  T A0212 = m(1, 0) * m(2, 2) - m(1, 2) * m(2, 0);
+  T A0113 = m(1, 0) * m(3, 1) - m(1, 1) * m(3, 0);
+  T A0112 = m(1, 0) * m(2, 1) - m(1, 1) * m(2, 0);
+
+  T det = m(0, 0) * (m(1, 1) * A2323 - m(1, 2) * A1323 + m(1, 3) * A1223) -
+          m(0, 1) * (m(1, 0) * A2323 - m(1, 2) * A0323 + m(1, 3) * A0223) +
+          m(0, 2) * (m(1, 0) * A1323 - m(1, 1) * A0323 + m(1, 3) * A0123) -
+          m(0, 3) * (m(1, 0) * A1223 - m(1, 1) * A0223 + m(1, 2) * A0123);
+  det = 1 / det;
+
+  im(0, 0) = det * (m(1, 1) * A2323 - m(1, 2) * A1323 + m(1, 3) * A1223);
+  im(0, 1) = det * -(m(0, 1) * A2323 - m(0, 2) * A1323 + m(0, 3) * A1223);
+  im(0, 2) = det * (m(0, 1) * A2313 - m(0, 2) * A1313 + m(0, 3) * A1213);
+  im(0, 3) = det * -(m(0, 1) * A2312 - m(0, 2) * A1312 + m(0, 3) * A1212);
+  im(1, 0) = det * -(m(1, 0) * A2323 - m(1, 2) * A0323 + m(1, 3) * A0223);
+  im(1, 1) = det * (m(0, 0) * A2323 - m(0, 2) * A0323 + m(0, 3) * A0223);
+  im(1, 2) = det * -(m(0, 0) * A2313 - m(0, 2) * A0313 + m(0, 3) * A0213);
+  im(1, 3) = det * (m(0, 0) * A2312 - m(0, 2) * A0312 + m(0, 3) * A0212);
+  im(2, 0) = det * (m(1, 0) * A1323 - m(1, 1) * A0323 + m(1, 3) * A0123);
+  im(2, 1) = det * -(m(0, 0) * A1323 - m(0, 1) * A0323 + m(0, 3) * A0123);
+  im(2, 2) = det * (m(0, 0) * A1313 - m(0, 1) * A0313 + m(0, 3) * A0113);
+  im(2, 3) = det * -(m(0, 0) * A1312 - m(0, 1) * A0312 + m(0, 3) * A0112);
+  im(3, 0) = det * -(m(1, 0) * A1223 - m(1, 1) * A0223 + m(1, 2) * A0123);
+  im(3, 1) = det * (m(0, 0) * A1223 - m(0, 1) * A0223 + m(0, 2) * A0123);
+  im(3, 2) = det * -(m(0, 0) * A1213 - m(0, 1) * A0213 + m(0, 2) * A0113);
+  im(3, 3) = det * (m(0, 0) * A1212 - m(0, 1) * A0212 + m(0, 2) * A0112);
+  return im;
+}
 }  // namespace math

decompiler/CMakeLists.txt

@@ -58,6 +58,7 @@ add_library(
         level_extractor/extract_actors.cpp
         level_extractor/extract_collide_frags.cpp
         level_extractor/extract_common.cpp
+        level_extractor/extract_joint_group.cpp
         level_extractor/extract_level.cpp
         level_extractor/extract_merc.cpp
         level_extractor/extract_tfrag.cpp

decompiler/level_extractor/common_formats.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "common/common_types.h"
+#include "common/math/Vector.h"
 
 namespace level_tools {
 
@@ -8,4 +9,21 @@ struct TextureRemap {
   u32 original_texid;
   u32 new_texid;
 };
+
+struct Joint {
+  std::string name;
+  int parent_idx = -1;  // -1 for magic ROOT joint.
+  math::Matrix4f bind_pose_T_w;
+};
+
+/*!
+ * Data extracted from art groups that is not needed for .FR3, but is potentially needed for other
+ * stuff (skeleton export).
+ */
+struct ArtData {
+  std::string art_group_name;
+  std::string art_name;
+  std::vector<Joint> joint_group;
+};
+
 }  // namespace level_tools

decompiler/level_extractor/extract_joint_group.cpp

@@ -0,0 +1,46 @@
+#include "extract_joint_group.h"
+
+#include "common/math/geometry.h"
+
+#include "decompiler/util/goal_data_reader.h"
+
+namespace decompiler {
+
+void extract_joint_group(const ObjectFileData& ag_data,
+                         const DecompilerTypeSystem& dts,
+                         GameVersion /*version*/,
+                         std::map<std::string, level_tools::ArtData>& out) {
+  auto locations = find_objects_with_type(ag_data.linked_data, "art-joint-geo");
+  for (auto loc : locations) {
+    TypedRef ref(Ref{&ag_data.linked_data, 0, loc * 4}, dts.ts.lookup_type("art-joint-geo"));
+    auto name = read_string_field(ref, "name", dts, false);
+    auto& data = out[name];
+    data.art_name = name;
+    data.art_group_name = ag_data.name_in_dgo;
+    ASSERT(data.joint_group.empty());
+    const int length = read_plain_data_field<int32_t>(ref, "length", dts);
+    Ref iter = get_field_ref(ref, "data", dts);
+    std::map<int, int> offset_to_joint;
+    for (int i = 0; i < length; i++) {
+      auto& njoint = data.joint_group.emplace_back();
+      Ref joint = deref_label(iter);
+      joint.byte_offset -= 4;
+      bool inserted = offset_to_joint.insert({joint.byte_offset, i}).second;
+      ASSERT(inserted);
+      TypedRef tjoint = typed_ref_from_basic(joint, dts);
+      ASSERT(tjoint.type->get_name() == "joint");
+      ASSERT(read_plain_data_field<int32_t>(tjoint, "number", dts) == i);
+      njoint.name = read_string_field(tjoint, "name", dts, true);
+      memcpy_from_plain_data((u8*)njoint.bind_pose_T_w.data(),
+                             get_field_ref(tjoint, "bind-pose", dts), 4 * 4 * sizeof(float));
+      if (get_word_kind_for_field(tjoint, "parent", dts) == LinkedWord::PTR) {
+        auto pjoint = deref_label(get_field_ref(tjoint, "parent", dts));
+        njoint.parent_idx = offset_to_joint.at(pjoint.byte_offset - 4);
+      } else {
+        ASSERT(i == 0 || i == 1);
+      }
+      iter.byte_offset += 4;
+    }
+  }
+}
+}  // namespace decompiler

decompiler/level_extractor/extract_joint_group.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "common/custom_data/Tfrag3Data.h"
+
+#include "decompiler/ObjectFile/ObjectFileDB.h"
+#include "decompiler/data/TextureDB.h"
+#include "decompiler/level_extractor/common_formats.h"
+
+namespace decompiler {
+void extract_joint_group(const ObjectFileData& ag_data,
+                         const DecompilerTypeSystem& dts,
+                         GameVersion version,
+                         std::map<std::string, level_tools::ArtData>& out);
+}

decompiler/level_extractor/extract_level.cpp

@@ -12,6 +12,7 @@
 #include "decompiler/level_extractor/BspHeader.h"
 #include "decompiler/level_extractor/extract_actors.h"
 #include "decompiler/level_extractor/extract_collide_frags.h"
+#include "decompiler/level_extractor/extract_joint_group.h"
 #include "decompiler/level_extractor/extract_merc.h"
 #include "decompiler/level_extractor/extract_shrub.h"
 #include "decompiler/level_extractor/extract_tfrag.h"
@@ -122,12 +123,14 @@ void extract_art_groups_from_level(const ObjectFileDB& db,
                                    const TextureDB& tex_db,
                                    const std::vector<level_tools::TextureRemap>& tex_remap,
                                    const std::string& dgo_name,
-                                   tfrag3::Level& level_data) {
+                                   tfrag3::Level& level_data,
+                                   std::map<std::string, level_tools::ArtData>& art_group_data) {
   const auto& files = db.obj_files_by_dgo.at(dgo_name);
   for (const auto& file : files) {
     if (file.name.length() > 3 && !file.name.compare(file.name.length() - 3, 3, "-ag")) {
       const auto& ag_file = db.lookup_record(file);
       extract_merc(ag_file, tex_db, db.dts, tex_remap, level_data, false, db.version());
+      extract_joint_group(ag_file, db.dts, db.version(), art_group_data);
     }
   }
 }
@@ -273,8 +276,9 @@ void extract_common(const ObjectFileDB& db,
   confirm_textures_identical(tex_db);
 
   tfrag3::Level tfrag_level;
+  std::map<std::string, level_tools::ArtData> art_group_data;
   add_all_textures_from_level(tfrag_level, dgo_name, tex_db);
-  extract_art_groups_from_level(db, tex_db, {}, dgo_name, tfrag_level);
+  extract_art_groups_from_level(db, tex_db, {}, dgo_name, tfrag_level, art_group_data);
 
   std::set<std::string> textures_we_have;
 
@@ -322,7 +326,7 @@ void extract_common(const ObjectFileDB& db,
   if (dump_levels) {
     auto file_path = file_util::get_jak_project_dir() / "glb_out" / "common.glb";
     file_util::create_dir_if_needed_for_file(file_path);
-    save_level_foreground_as_gltf(tfrag_level, file_path);
+    save_level_foreground_as_gltf(tfrag_level, art_group_data, file_path);
   }
 }
 
@@ -339,12 +343,14 @@ void extract_from_level(const ObjectFileDB& db,
     return;
   }
   tfrag3::Level level_data;
+  std::map<std::string, level_tools::ArtData> art_group_data;
   add_all_textures_from_level(level_data, dgo_name, tex_db);
 
   // the bsp header file data
   auto bsp_header =
       extract_bsp_from_level(db, tex_db, dgo_name, config.hacks, extract_collision, level_data);
-  extract_art_groups_from_level(db, tex_db, bsp_header.texture_remap_table, dgo_name, level_data);
+  extract_art_groups_from_level(db, tex_db, bsp_header.texture_remap_table, dgo_name, level_data,
+                                art_group_data);
 
   Serializer ser;
   level_data.serialize(ser);
@@ -366,7 +372,7 @@ void extract_from_level(const ObjectFileDB& db,
     auto fore_file_path = file_util::get_jak_project_dir() / "glb_out" /
                           fmt::format("{}_foreground.glb", level_data.level_name);
     file_util::create_dir_if_needed_for_file(fore_file_path);
-    save_level_foreground_as_gltf(level_data, fore_file_path);
+    save_level_foreground_as_gltf(level_data, art_group_data, fore_file_path);
   }
   file_util::write_text_file(entities_folder / fmt::format("{}_actors.json", level_data.level_name),
                              extract_actors_to_json(bsp_header.actors));

decompiler/level_extractor/extract_merc.cpp

@@ -181,20 +181,6 @@ MercCtrl extract_merc_ctrl(const LinkedObjectFile& file,
   return ctrl;
 }
 
-/*!
- * Find the word indices for the merc ctrls (the type tags)
- */
-std::vector<int> find_merc_ctrls(const LinkedObjectFile& file) {
-  std::vector<int> result;
-  for (size_t i = 0; i < file.words_by_seg.at(0).size(); i++) {
-    const auto& word = file.words_by_seg[0][i];
-    if (word.kind() == LinkedWord::TYPE_PTR && word.symbol_name() == "merc-ctrl") {
-      result.push_back(i);
-    }
-  }
-  return result;
-}
-
 namespace {
 /*!
  * Merc models tend to have strange texture ids. I don't really understand why.
@@ -1616,7 +1602,7 @@ void extract_merc(const ObjectFileData& ag_data,
     file_util::create_dir_if_needed(file_util::get_file_path({"debug_out/merc"}));
   }
   // find all merc-ctrls in the object file
-  auto ctrl_locations = find_merc_ctrls(ag_data.linked_data);
+  auto ctrl_locations = find_objects_with_type(ag_data.linked_data, "merc-ctrl");
 
   // extract them. this does very basic unpacking of data, as done by the VIF/DMA on PS2.
   std::vector<MercCtrl> ctrls;

decompiler/level_extractor/fr3_to_gltf.cpp

@@ -4,6 +4,7 @@
 
 #include "common/custom_data/Tfrag3Data.h"
 #include "common/math/Vector.h"
+#include "common/math/geometry.h"
 
 #include "decompiler/level_extractor/tfrag_tie_fixup.h"
 
@@ -11,6 +12,17 @@
 
 namespace {
 
+/*!
+ * Remove 4096 meter scaling from a transformation matrix.
+ */
+math::Matrix4f unscale_translation(const math::Matrix4f& in) {
+  auto out = in;
+  for (int i = 0; i < 3; i++) {
+    out(i, 3) /= 4096.;
+  }
+  return out;
+}
+
 /*!
  * Convert fr3 format indices (strip format, with UINT32_MAX as restart) to unstripped tris.
  * Assumes that this is the tfrag/tie format of stripping. Will flip tris as needed so the faces
@@ -557,6 +569,10 @@ int add_material_for_tex(const tfrag3::Level& level,
                          int tex_idx,
                          std::unordered_map<int, int>& tex_image_map,
                          const DrawMode& draw_mode) {
+  if (tex_idx < 0) {
+    // anim textures, just use default material
+    return 0;
+  }
   int mat_idx = (int)model.materials.size();
   auto& mat = model.materials.emplace_back();
   auto& tex = level.textures.at(tex_idx);
@@ -759,7 +775,114 @@ void add_shrub(const tfrag3::Level& level,
   }
 }
 
+int make_weights_accessor(const std::vector<tfrag3::MercVertex>& vertices, tinygltf::Model& model) {
+  // first create a buffer:
+  int buffer_idx = (int)model.buffers.size();
+  auto& buffer = model.buffers.emplace_back();
+  buffer.data.resize(sizeof(float) * 4 * vertices.size());
+
+  // and fill it
+  u8* buffer_ptr = buffer.data.data();
+  for (const auto& vtx : vertices) {
+    float weights[4] = {vtx.weights[0], vtx.weights[1], vtx.weights[2], 0};
+    memcpy(buffer_ptr, weights, 4 * sizeof(float));
+    buffer_ptr += 4 * sizeof(float);
+  }
+
+  // create a view of this buffer
+  int buffer_view_idx = (int)model.bufferViews.size();
+  auto& buffer_view = model.bufferViews.emplace_back();
+  buffer_view.buffer = buffer_idx;
+  buffer_view.byteOffset = 0;
+  buffer_view.byteLength = buffer.data.size();
+  buffer_view.byteStride = 0;  // tightly packed
+  buffer_view.target = TINYGLTF_TARGET_ARRAY_BUFFER;
+
+  int accessor_idx = (int)model.accessors.size();
+  auto& accessor = model.accessors.emplace_back();
+  accessor.bufferView = buffer_view_idx;
+  accessor.byteOffset = 0;
+  accessor.componentType = TINYGLTF_COMPONENT_TYPE_FLOAT;
+  accessor.count = vertices.size();
+  accessor.type = TINYGLTF_TYPE_VEC4;
+  return accessor_idx;
+}
+
+int make_bones_accessor(const std::vector<tfrag3::MercVertex>& vertices, tinygltf::Model& model) {
+  // first create a buffer:
+  int buffer_idx = (int)model.buffers.size();
+  auto& buffer = model.buffers.emplace_back();
+  buffer.data.resize(sizeof(float) * 4 * vertices.size());
+
+  // and fill it
+  u8* buffer_ptr = buffer.data.data();
+  for (const auto& vtx : vertices) {
+    s32 indices[4];
+    for (int i = 0; i < 3; i++) {
+      indices[i] = vtx.mats[i] ? vtx.mats[i] - 1 : 0;
+    }
+    indices[3] = 0;
+    memcpy(buffer_ptr, indices, 4 * sizeof(s32));
+    buffer_ptr += 4 * sizeof(s32);
+  }
+
+  // create a view of this buffer
+  int buffer_view_idx = (int)model.bufferViews.size();
+  auto& buffer_view = model.bufferViews.emplace_back();
+  buffer_view.buffer = buffer_idx;
+  buffer_view.byteOffset = 0;
+  buffer_view.byteLength = buffer.data.size();
+  buffer_view.byteStride = 0;  // tightly packed
+  buffer_view.target = TINYGLTF_TARGET_ARRAY_BUFFER;
+
+  int accessor_idx = (int)model.accessors.size();
+  auto& accessor = model.accessors.emplace_back();
+  accessor.bufferView = buffer_view_idx;
+  accessor.byteOffset = 0;
+  accessor.componentType = TINYGLTF_COMPONENT_TYPE_UNSIGNED_INT;  // blender doesn't support INT...
+  accessor.count = vertices.size();
+  accessor.type = TINYGLTF_TYPE_VEC4;
+  return accessor_idx;
+}
+
+int make_inv_matrix_bind_poses(const std::vector<level_tools::Joint>& joints,
+                               tinygltf::Model& model) {
+  // first create a buffer:
+  int buffer_idx = (int)model.buffers.size();
+  auto& buffer = model.buffers.emplace_back();
+  buffer.data.resize(sizeof(float) * 16 * joints.size());
+
+  // and fill it
+  for (int m = 0; m < (int)joints.size(); m++) {
+    auto matrix = unscale_translation(joints[m].bind_pose_T_w);
+    for (int i = 0; i < 4; i++) {
+      for (int j = 0; j < 4; j++) {
+        memcpy(buffer.data.data() + sizeof(float) * (i * 4 + j + m * 16), &matrix(j, i), 4);
+      }
+    }
+  }
+
+  // create a view of this buffer
+  int buffer_view_idx = (int)model.bufferViews.size();
+  auto& buffer_view = model.bufferViews.emplace_back();
+  buffer_view.buffer = buffer_idx;
+  buffer_view.byteOffset = 0;
+  buffer_view.byteLength = buffer.data.size();
+  buffer_view.byteStride = 0;  // tightly packed
+  buffer_view.target = TINYGLTF_TARGET_ARRAY_BUFFER;
+
+  int accessor_idx = (int)model.accessors.size();
+  auto& accessor = model.accessors.emplace_back();
+  accessor.bufferView = buffer_view_idx;
+  accessor.byteOffset = 0;
+  accessor.componentType = TINYGLTF_COMPONENT_TYPE_FLOAT;
+  accessor.count = joints.size();
+  accessor.type = TINYGLTF_TYPE_MAT4;
+  return accessor_idx;
+}
+
 void add_merc(const tfrag3::Level& level,
+              const std::map<std::string, level_tools::ArtData>& art_data,
               tinygltf::Model& model,
               std::unordered_map<int, int>& tex_image_map) {
   const auto& mverts = level.merc_data.vertices;
@@ -773,9 +896,12 @@ void add_merc(const tfrag3::Level& level,
       level.merc_data.indices, level.merc_data.models, model, draw_to_start, draw_to_count);
   int colors = make_color_buffer_accessor(mverts, model);
 
+  auto joints_accessor = make_bones_accessor(mverts, model);
+  auto weights_accessor = make_weights_accessor(mverts, model);
+
   for (size_t model_idx = 0; model_idx < level.merc_data.models.size(); model_idx++) {
     const auto& mmodel = level.merc_data.models[model_idx];
-
+    const auto& art = art_data.find(mmodel.name);
     int node_idx = (int)model.nodes.size();
     auto& node = model.nodes.emplace_back();
     model.scenes.at(0).nodes.push_back(node_idx);
@@ -785,6 +911,54 @@ void add_merc(const tfrag3::Level& level,
     mesh.name = node.name;
     node.mesh = mesh_idx;
 
+    if (art != art_data.end() && !art->second.joint_group.empty()) {
+      node.skin = model.skins.size();
+      auto& skin = model.skins.emplace_back();
+      const auto& game_bones = art->second.joint_group;
+      int n_bones = game_bones.size();
+      std::vector<std::vector<int>> children(n_bones);
+      for (size_t i = 0; i < game_bones.size(); i++) {
+        if (game_bones[i].parent_idx >= 0) {
+          children.at(game_bones[i].parent_idx).push_back(i);
+        }
+      }
+      skin.skeleton = model.nodes.size();
+      for (int i = 0; i < n_bones; i++) {
+        const auto& gbone = game_bones[i];
+        skin.joints.push_back(skin.skeleton + i);
+        auto& snode = model.nodes.emplace_back();
+        snode.name = gbone.name;
+
+        // bind pose is bind_T_w
+        // for glb we want bind_parent_T_bind_child
+        // so bindp_T_w * inverse(bindc_T_w)
+        math::Matrix4f matrix;
+        if (gbone.parent_idx >= 0) {
+          matrix = unscale_translation(game_bones.at(gbone.parent_idx).bind_pose_T_w) *
+                   inverse(unscale_translation(gbone.bind_pose_T_w));
+
+        } else {
+          // I think this value is ignored anyway.
+          for (int r = 0; r < 4; r++) {
+            for (int c = 0; c < 4; c++) {
+              matrix(r, c) = (r == c) ? 1 : 0;
+            }
+          }
+        }
+
+        for (int r = 0; r < 4; r++) {
+          for (int c = 0; c < 4; c++) {
+            snode.matrix.push_back(matrix(c, r));
+          }
+        }
+        for (auto child : children.at(i)) {
+          snode.children.push_back(skin.skeleton + child);
+        }
+      }
+      ASSERT(skin.skeleton + n_bones == (int)model.nodes.size());
+      skin.inverseBindMatrices = make_inv_matrix_bind_poses(game_bones, model);
+    }
+
     for (size_t effect_idx = 0; effect_idx < mmodel.effects.size(); effect_idx++) {
       const auto& effect = mmodel.effects[effect_idx];
       for (size_t draw_idx = 0; draw_idx < effect.all_draws.size(); draw_idx++) {
@@ -798,6 +972,8 @@ void add_merc(const tfrag3::Level& level,
         prim.attributes["POSITION"] = position_buffer_accessor;
         prim.attributes["TEXCOORD_0"] = texture_buffer_accessor;
         prim.attributes["COLOR_0"] = colors;
+        prim.attributes["JOINTS_0"] = joints_accessor;
+        prim.attributes["WEIGHTS_0"] = weights_accessor;
         prim.mode = TINYGLTF_MODE_TRIANGLES;
       }
     }
@@ -847,7 +1023,9 @@ void save_level_background_as_gltf(const tfrag3::Level& level, const fs::path& g
                             true);  // write binary
 }
 
-void save_level_foreground_as_gltf(const tfrag3::Level& level, const fs::path& glb_file) {
+void save_level_foreground_as_gltf(const tfrag3::Level& level,
+                                   const std::map<std::string, level_tools::ArtData>& art_data,
+                                   const fs::path& glb_file) {
   // the top level container for everything is the model.
   tinygltf::Model model;
 
@@ -864,7 +1042,7 @@ void save_level_foreground_as_gltf(const tfrag3::Level& level, const fs::path& g
 
   std::unordered_map<int, int> tex_image_map;
 
-  add_merc(level, model, tex_image_map);
+  add_merc(level, art_data, model, tex_image_map);
 
   model.asset.generator = "opengoal";
   tinygltf::TinyGLTF gltf;

decompiler/level_extractor/fr3_to_gltf.h

@@ -1,10 +1,16 @@
 #pragma once
 
+#include <map>
+
 #include "common/custom_data/Tfrag3Data.h"
 #include "common/util/FileUtil.h"
 
+#include "decompiler/level_extractor/common_formats.h"
+
 /*!
  * Export the background geometry (tie, tfrag, shrub) to a GLTF binary format (.glb) file.
  */
 void save_level_background_as_gltf(const tfrag3::Level& level, const fs::path& glb_file);
-void save_level_foreground_as_gltf(const tfrag3::Level& level, const fs::path& glb_file);
+void save_level_foreground_as_gltf(const tfrag3::Level& level,
+                                   const std::map<std::string, level_tools::ArtData>& art_data,
+                                   const fs::path& glb_file);

decompiler/util/goal_data_reader.cpp

@@ -421,3 +421,15 @@ u8 deref_u8(const Ref& ref, int byte) {
   memcpy(vals, &word.data, 4);
   return vals[total_offset & 3];
 }
+
+std::vector<int> find_objects_with_type(const decompiler::LinkedObjectFile& file,
+                                        const std::string& name) {
+  std::vector<int> result;
+  for (size_t i = 0; i < file.words_by_seg.at(0).size(); i++) {
+    const auto& word = file.words_by_seg[0][i];
+    if (word.kind() == decompiler::LinkedWord::TYPE_PTR && word.symbol_name() == name) {
+      result.push_back(i);
+    }
+  }
+  return result;
+}

decompiler/util/goal_data_reader.h

@@ -91,3 +91,5 @@ u8 deref_u8(const Ref& ref, int byte);
 float deref_float(const Ref& ref, int array_idx);
 u64 deref_u64(const Ref& ref, int dw_offset);
 std::string inspect_ref(const Ref& ref);
+std::vector<int> find_objects_with_type(const decompiler::LinkedObjectFile& file,
+                                        const std::string& name);