Add a ground. Add support for multiple objects and materials in MDL

3 files changed, 308 insertions, 76 deletions

diff --git a/include/model.h b/include/model.h
index 0730809..10c9cdf 100644
--- a/include/model.h
+++ b/include/model.h
@@ -1,9 +1,15 @@
 #pragma once
 
+#include <assert.h>
 #include <stddef.h>
 #include <stdint.h>
 
-constexpr size_t ModelPathLen = 256;
+constexpr size_t ModelPathLen      = 256;
+constexpr size_t ModelNameLen      = 64;
+constexpr size_t ModelMaxObjects   = 256; // uint8_t
+constexpr size_t ModelMaxMaterials = 256; // uint8_t
+constexpr size_t ModelMaxVerts     = 4294967296; // uint32_t
+constexpr size_t ModelMaxFaces     = 4294967296; // uint32_t
 
 typedef uint16_t mdIdx;
 typedef struct mdVert { mdIdx position, texcoord, normal; } mdVert;
@@ -11,9 +17,18 @@ typedef struct mdTri  { mdVert v0, v1, v2; } mdTri;
 typedef struct mdVec2 { float x, y;        } mdVec2;
 typedef struct mdVec3 { float x, y, z;     } mdVec3;
 
-typedef struct Material {
+typedef struct ModelObject {
+  uint32_t offset;   // FlatModel: offset into indices. IndexedModel: offset into tris.
+  uint32_t count;    // FloatModel: number of indices.  IndexedModel: number of tris.
+  uint8_t  material; // Material index.
+  uint8_t  pad[3];
+  char     name[ModelNameLen];
+} ModelObject;
+
+typedef struct ModelMaterial {
+  char name[ModelNameLen];
   char diffuseTexture[ModelPathLen];
-} Material;
+} ModelMaterial;
 
 // Every three indices form a triangle, and each index indexes all attribute
 // arrays simultaneously. This is best for a fast, linear-scan rendering.
@@ -28,6 +43,8 @@ typedef struct FlatModel {
   uint32_t offsetTexcoords;
   uint32_t offsetNormals;
   /*
+  [objects]   -- numObjects   Object
+  [materials] -- numMaterials Material
   [indices]   -- numIdxs  mdIdx
   [positions] -- numVerts mdVec3
   [texcoords] -- numVerts mdVec2
@@ -53,6 +70,8 @@ typedef struct IndexedModel {
   uint32_t offsetTexcoords;
   uint32_t offsetNormals;
   /*
+  [objects]   -- numObjects   Object
+  [materials] -- numMaterials Material
   [triangles] -- numTris      mdTri
   [positions] -- numPositions mdVec3
   [texcoords] -- numTexcoords mdVec2
@@ -68,9 +87,42 @@ typedef enum ModelType {
 
 typedef struct Model {
   uint32_t type;
-  Material material;
+  // Counts.
+  uint8_t  numObjects;
+  uint8_t  numMaterials;
+  uint8_t  pad[2];
+  // Offsets.
+  uint32_t offsetObjects;
+  uint32_t offsetMaterials;
+  // Model details.
   union {
     FlatModel    flat;
     IndexedModel indexed;
   };
 } Model;
+
+static inline const ModelObject* modelObjects(const Model* model) {
+  assert(model);
+  switch (model->type) {
+  case ModelTypeIndexed:
+    return (const ModelObject*)(model->indexed.data + model->offsetObjects);
+  case ModelTypeFlat:
+    return (const ModelObject*)(model->flat.data    + model->offsetObjects);
+  default:
+    assert(false);
+    break;
+  }
+}
+
+static inline const ModelMaterial* modelMaterials(const Model* model) {
+  assert(model);
+  switch (model->type) {
+  case ModelTypeIndexed:
+    return (const ModelMaterial*)(model->indexed.data + model->offsetMaterials);
+  case ModelTypeFlat:
+    return (const ModelMaterial*)(model->flat.data    + model->offsetMaterials);
+  default:
+    assert(false);
+    break;
+  }
+}
diff --git a/src/main.c b/src/main.c
index dcd0335..225af5f 100644
--- a/src/main.c
+++ b/src/main.c
@@ -31,9 +31,13 @@ static constexpr R Fovy = (R)(90 * TO_RAD);
 static constexpr R Near = 0.1f;
 static constexpr R Far  = 100.0f;
 
-#define DEBUG_EVENT_LOOP 1
+static constexpr size_t MaxTextures = 256;
 
-#ifdef DEBUG_EVENT_LOOP
+static const char* StateFile = "game.bin";
+
+#define DEBUG_EVENT_LOOP 0
+
+#if DEBUG_EVENT_LOOP
 #define EVENT_LOOP_PRINT printf
 #else
 #define EVENT_LOOP_PRINT(...)
@@ -68,13 +72,55 @@ typedef struct State {
   SDL_Window*      window;
   void*            gfx_mem;
   swgfx*           gfx;
-  Model*           model;
-  sgImage      texture;
   Camera           camera;
   CameraController camera_controller;
   Uint64           last_tick;
+  Model*           model;
+  size_t           numTextures;
+  sgImage          textures[MaxTextures];
 } State;
 
+static bool StateWrite(const State* state, FILE* file) {
+  assert(state);
+  assert(file);
+  return fwrite(&state->camera, sizeof(state->camera), 1, file) == 1;
+}
+
+static bool StateRead(FILE* file, State* state) {
+  assert(file);
+  assert(state);
+  Camera camera;
+  if (fread(&camera, sizeof(camera), 1, file) != 1) {
+    return false;
+  }
+  state->camera = camera;
+  return true;
+}
+
+static bool StateSave(const State* state, const char* path) {
+  assert(state);
+  assert(path);
+  FILE* file = fopen(path, "wb");
+  if (!file) {
+    return false;
+  }
+  const bool result = StateWrite(state, file);
+  fclose(file);
+  return result;
+}
+
+static bool StateLoad(const char* path, State* state) {
+  assert(path);
+  assert(state);
+  FILE* file = fopen(path, "rb");
+  if (!file) {
+    return false;
+  }
+  const bool result = StateRead(file, state);
+  fclose(file);
+  return result;
+}
+
 static sgVec3 SgVec3FromMathVec3(vec3 v) {
   return (sgVec3){v.x, v.y, v.z};
 }
@@ -82,8 +128,9 @@ static sgVec3 SgVec3FromMathVec3(vec3 v) {
 static CameraCommand CameraCommandFromInput(
     const bool* keyboard_state, const SDL_MouseButtonFlags mouse_flags) {
   assert(keyboard_state);
-  if (keyboard_state[SDL_SCANCODE_W]) {
-    printf("W: %d\n", keyboard_state[SDL_SCANCODE_W]);
+  // Control is used for save/load/quit, etc.
+  if (keyboard_state[SDL_SCANCODE_LCTRL]) {
+    return (CameraCommand){};
   }
   return (CameraCommand){
     .CameraMoveLeft     = keyboard_state[SDL_SCANCODE_A],
@@ -146,22 +193,34 @@ static bool Update(State* state, R dt) {
   return true;
 }
 
-static void RenderIndexedModel(swgfx* gfx, const IndexedModel* model) {
+static void RenderIndexedModel(swgfx* gfx, const IndexedModel* model, const ModelObject* object) {
   assert(gfx);
   assert(model);
-  const sgTriIdx*  tris   = (const sgTriIdx*)(model->data + model->offsetTris);
+  assert(object);
+  assert((object->offset + object->count) <= model->numTris);
+  const sgTriIdx*  tris   = (const sgTriIdx*)(model->data + model->offsetTris) + object->offset;
   const sgVec3* positions = (const sgVec3*)  (model->data + model->offsetPositions);
-  const sgVec2* texcoords = (const sgVec2*)(model->data + model->offsetTexcoords);
-  sgTrianglesIndexedNonUniform(gfx, model->numTris, tris, positions, texcoords);
+  const sgVec2* texcoords = (const sgVec2*)  (model->data + model->offsetTexcoords);
+  sgTrianglesIndexedNonUniform(gfx, object->count, tris, positions, texcoords);
 }
 
-static void RenderModel(swgfx* gfx, const Model* model) {
+static void RenderModel(swgfx* gfx, const sgImage* textures, const Model* model) {
   assert(gfx);
+  assert(textures);
   assert(model);
-  switch (model->type) {
-  case ModelTypeIndexed: RenderIndexedModel(gfx, &model->indexed); break;
-  case ModelTypeFlat: /* TODO: Render flat models. */ break;
-  default: assert(false); break;
+  const ModelObject* objects = modelObjects(model);
+  for (size_t i = 0; i < model->numObjects; ++i) {
+    const ModelObject* object = &objects[i];
+    // TODO: This indexing into the textures array assumes that we have loaded a
+    //  single model. Generalize later.
+    assert((size_t)object->material < MaxTextures);
+    const sgImage* texture = &textures[object->material];
+    sgTexture(gfx, texture);
+    switch (model->type) {
+      case ModelTypeIndexed: RenderIndexedModel(gfx, &model->indexed, object); break;
+      case ModelTypeFlat: /* TODO: Render flat models. */ break;
+      default: assert(false); break;
+    }
   }
 }
 
@@ -225,15 +284,19 @@ static bool Render(State* state) {
   sgModelId(state->gfx);
   sgView(state->gfx, SgVec3FromMathVec3(cam->spatial.p), SgVec3FromMathVec3(cam->spatial.f));
   sgPerspective(state->gfx, cam->fovy, cam->aspect, cam->near, cam->far);
-  sgTexture(state->gfx, &state->texture);
-  RenderModel(state->gfx, state->model);
-  /*sgIdx indices[3] = {0, 1, 2};
-  sgVec3 positions[3] = {
+  RenderModel(state->gfx, state->textures, state->model);
+  /*const sgIdx indices[3] = {0, 1, 2};
+  const sgVec3 positions[3] = {
     (sgVec3){0, 0, 0},
     (sgVec3){5, 2, 0},
     (sgVec3){8, 8, 0},
   };
-  sgTrianglesIndexed(state->gfx, 3, indices, positions);*/
+  const sgVec2 texcoords[3] = {
+    (sgVec2){0, 0},
+    (sgVec2){0.5, 0.5},
+    (sgVec2){1.0, 1.0},
+  };
+  sgTrianglesIndexed(state->gfx, 3, indices, positions, texcoords);*/
   sgPresent(state->gfx, WindowDims, window_surface->pixels);
 
   if (!SDL_UpdateWindowSurface(state->window)) {
@@ -284,23 +347,28 @@ static bool Initialize(State* state) {
     return false;
   }
 
-  const char* model_path = "/home/jeanne/blender/box_textured.mdl";
+  const char* model_path = "/home/jeanne/blender/boxout.mdl";
   if (!(state->model = read_file(model_path))) {
     fprintf(stderr, "Failed to load model: [%s]\n", model_path);
     return false;
   }
-  if (state->model->material.diffuseTexture[0] != 0) {
+  if ((size_t)state->model->numMaterials > MaxTextures) {
+    fprintf(stderr, "Model material count is larger than max textures, increase limit\n");
+    return false;
+  }
+  const ModelMaterial* materials = modelMaterials(state->model);
+  for (size_t i = 0; i < state->model->numMaterials; ++i) {
+    const ModelMaterial* material = &materials[i];
     // TODO: When doing lighting, need to gamma-correct here.
-    sgImage texture = {0};
+    sgImage* texture = &state->textures[state->numTextures++];
     int channels = 0;
     constexpr int desired_channels = 4;
-    texture.pixels = (sgPixel*)stbi_load(state->model->material.diffuseTexture, &texture.width, &texture.height, &channels, desired_channels);
-    if (!texture.pixels) {
-      fprintf(stderr, "Failed to read texture: [%s]\n", state->model->material.diffuseTexture);
+    texture->pixels = (sgPixel*)stbi_load(material->diffuseTexture, &texture->width, &texture->height, &channels, desired_channels);
+    if (!texture->pixels) {
+      fprintf(stderr, "Failed to read texture: [%s]\n", material->diffuseTexture);
       return false;
     }
     assert(channels == desired_channels);
-    state->texture = texture;
   }
 
   Camera* camera    = &state->camera;
@@ -324,16 +392,19 @@ static bool Initialize(State* state) {
 static void Shutdown(State* state) {
   assert(state);
 
-  if (state->texture.pixels) {
-    free(state->texture.pixels);
-    state->texture = (sgImage){0};
+  for (size_t i = 0; i < state->numTextures; ++i) {
+    sgImage* texture = &state->textures[i];
+    if (texture->pixels) {
+      free(texture->pixels);
+      *texture = (sgImage){0};
+    }
   }
 
   if (state->model) {
     free(state->model);
     state->model = nullptr;
   }
-  
+
   if (state->gfx) {
     sgDel(&state->gfx);
   }
@@ -412,6 +483,22 @@ int main() {
           case SDLK_D:
             running = false;
             break;
+          // Save state.
+          case SDLK_S:
+            if (StateSave(&state, StateFile)) {
+              fprintf(stderr, "State saved\n");
+            } else {
+              fprintf(stderr, "Failed to save state\n");
+            }
+            break;
+          // Load state.
+          case SDLK_L:
+            if (StateLoad(StateFile, &state)) {
+              fprintf(stderr, "State loaded\n");
+            } else {
+              fprintf(stderr, "Failed to load state\n");
+            }
+            break;
           default:
             break;
           }
diff --git a/tools/ase/main.c b/tools/ase/main.c
index 30c6812..5bffed0 100644
--- a/tools/ase/main.c
+++ b/tools/ase/main.c
@@ -163,25 +163,36 @@ static inline bool IsLexeme(const Lexer* lexer, const char* expected) {
 }
 
 // Reasonable limits for the parser implementation.
-// The model spec does not impose a limit on tris, but vertex attributes are
-// indexed by uint16_t.
+// The model spec does not impose a limit on tris or materials. Vertex
+// attributes are indexed by uint32_t.
 #define MAX_TRIS  65536
 #define MAX_VERTS 65536
 
+typedef struct ObjectData {
+  ModelObject modelObject;
+  char        materialName[ModelNameLen]; // For linking objects and materials.
+} ObjectData;
+
 // Temporary storage for model data. A Model can be outputted from this.
 typedef struct ModelData {
-  uint32_t numTris;
-  uint32_t numPositions;
-  uint32_t numNormals;
-  uint32_t numTexcoords;
-  Material material;
-  char     mtl_file [PATH_MAX];
-  mdTri    tris     [MAX_TRIS];
-  mdVec3   positions[MAX_VERTS];
-  mdVec3   normals  [MAX_VERTS];
-  mdVec2   texcoords[MAX_VERTS];
+  uint32_t   numTris;
+  uint32_t   numPositions;
+  uint32_t   numNormals;
+  uint32_t   numTexcoords;
+  uint32_t   numObjects;
+  ObjectData objects[ModelMaxObjects];
+  char       mtl_file [PATH_MAX];
+  mdTri      tris     [MAX_TRIS];
+  mdVec3     positions[MAX_VERTS];
+  mdVec3     normals  [MAX_VERTS];
+  mdVec2     texcoords[MAX_VERTS];
 } ModelData;
 
+typedef struct MaterialsData {
+  uint32_t      numMaterials;
+  ModelMaterial materials[ModelMaxMaterials];
+} MaterialsData;
+
 #define PRINT(STR)       printf("%s%.*s\n", STR, (int)lexer->lexeme.length, lexer->lexeme.str)
 #define LEX(STR)         IsLexeme(lexer, STR)
 #define NEXT_LEXEME()    { if (!NextLexeme(lexer)) break; else PRINT("~ "); }
@@ -197,6 +208,12 @@ typedef struct ModelData {
 static bool ParseObj(Lexer* lexer, ModelData* modelData) {
   assert(lexer);
   assert(modelData);
+#define PRINT_FINALIZED_OBJECT() { \
+    assert(curObject < ModelMaxObjects); \
+    ModelObject* const object = &modelData->objects[curObject].modelObject; \
+    printf("> Finalized: %s (tris offset: %u, count: %u)\n", object->name, object->offset, object->count); \
+  }
+  size_t curObject = 0;
   bool consumeNext = true;
   for (;;) {
     if (consumeNext) {
@@ -209,8 +226,22 @@ static bool ParseObj(Lexer* lexer, ModelData* modelData) {
       NEXT_STRING(modelData->mtl_file);
       PRINT("> material: ");
     } else if (LEX("o")) {
-      NEXT_LEXEME(); // object name
+      // Print line for finalized previous object.
+      if (modelData->numObjects > 0) {
+        PRINT_FINALIZED_OBJECT();
+      }
+      // Next object.
+      modelData->numObjects++;
+      curObject = modelData->numObjects - 1;
+      assert(curObject < ModelMaxObjects);
+      ModelObject* const object = &modelData->objects[curObject].modelObject;
+      object->offset = modelData->numTris;
+      NEXT_STRING(object->name);
       PRINT("> object: ");
+    } else if (LEX("usemtl")) {
+      const size_t curObject = modelData->numObjects - 1; // Object comes before material.
+      assert(curObject < ModelMaxObjects);
+      NEXT_STRING(modelData->objects[curObject].materialName);
     } else if (LEX("v")) {
       float x, y, z;
       NEXT_FLOAT(&x);
@@ -267,28 +298,65 @@ static bool ParseObj(Lexer* lexer, ModelData* modelData) {
         modelData->tris[modelData->numTris++] =
           (mdTri){vertices[0], vertices[2], vertices[3]};
       }
+      // Increase current object's triangle count.
+      assert(curObject < ModelMaxObjects);
+      ModelObject* const object = &modelData->objects[curObject].modelObject;
+      object->count += (numVerts == 3) ? 1 : 2;
     }
   }
+  if (modelData->numObjects > 0) {
+    PRINT_FINALIZED_OBJECT(); // Print line for the last finalized object.
+  }
   return true;
 }
 
-static bool ParseMtl(Lexer* lexer, Material* material) {
+static bool ParseMtl(Lexer* lexer, MaterialsData* materialData) {
   assert(lexer);
-  assert(material);
+  assert(materialData);
+  size_t cur = (size_t)-1;
   for (;;) {
     NEXT_LEXEME();
     if (LEX("newmtl")) {
-      NEXT_LEXEME(); // Material name.
+      cur++;
+      assert(cur < ModelMaxMaterials);
+      NEXT_STRING(materialData->materials[cur].name);
+      materialData->numMaterials++;
       PRINT("> material: ");
     } else if (LEX("map_Kd")) {
-      READ_LINE(material->diffuseTexture);
+      assert(cur < ModelMaxMaterials);
+      READ_LINE(materialData->materials[cur].diffuseTexture);
     }
   }
   return true;
 }
 
-static bool WriteModelFile(const ModelData* modelData, const char* path) {
+static bool LinkMaterials(ModelData* modelData, MaterialsData* materialsData) {
+  assert(modelData);
+  assert(materialsData);
+  bool all_linked = true;
+  for (size_t i = 0; i < modelData->numObjects; ++i) {
+    bool found = false;
+    ObjectData* object = &modelData->objects[i];
+    for (size_t j = 0; !found && (j < materialsData->numMaterials); ++j) {
+      if (strcmp(object->materialName, materialsData->materials[j].name) == 0) {
+        object->modelObject.material = j;
+        found = true;
+      }
+    }
+    all_linked = all_linked && found;
+  }
+  return all_linked;
+}
+
+static void AssertOffset(FILE* file, size_t offset) {
+  const long int pos = ftell(file);
+  constexpr size_t headerSize = sizeof(Model);
+  assert((headerSize + offset) == (size_t)pos);
+}
+
+static bool WriteModelFile(const ModelData* modelData, const MaterialsData* materialsData, const char* path) {
   assert(modelData);
+  assert(materialsData);
   assert(path);
   
   bool success = false;
@@ -297,16 +365,19 @@ static bool WriteModelFile(const ModelData* modelData, const char* path) {
   
   // Fill the Model header.
   model.type               = ModelTypeIndexed;
+  model.numObjects         = modelData->numObjects;
+  model.numMaterials       = materialsData->numMaterials;
+  model.offsetObjects      = 0; // 'data' member.
+  model.offsetMaterials    = model.offsetObjects + (modelData->numObjects * sizeof(ModelObject));
   IndexedModel* indexed    = &model.indexed;
   indexed->numTris         = modelData->numTris;
   indexed->numPositions    = modelData->numPositions;
   indexed->numNormals      = modelData->numNormals;
   indexed->numTexcoords    = modelData->numTexcoords;
-  indexed->offsetTris      = 0; // 'data' member.
-  indexed->offsetPositions = indexed->offsetTris      + (modelData->numTris      * sizeof(mdTri));
-  indexed->offsetNormals   = indexed->offsetPositions + (modelData->numPositions * sizeof(mdVec3));
-  indexed->offsetTexcoords = indexed->offsetNormals   + (modelData->numNormals   * sizeof(mdVec3));
-  memcpy(&model.material, &modelData->material, sizeof(Material));
+  indexed->offsetTris      = model.offsetMaterials    + (materialsData->numMaterials * sizeof(ModelMaterial));
+  indexed->offsetPositions = indexed->offsetTris      + (modelData->numTris          * sizeof(mdTri));
+  indexed->offsetNormals   = indexed->offsetPositions + (modelData->numPositions     * sizeof(mdVec3));
+  indexed->offsetTexcoords = indexed->offsetNormals   + (modelData->numNormals       * sizeof(mdVec3));
 
   if ((file = fopen(path, "wb")) == nullptr) {
     fprintf(stderr, "Failed opening output file for writing: %s\n", path);
@@ -317,22 +388,42 @@ static bool WriteModelFile(const ModelData* modelData, const char* path) {
     fprintf(stderr, "Failed writing Model header\n");
     goto cleanup;
   }
+  // Objects.
+  AssertOffset(file, model.offsetObjects);
+  for (size_t i = 0; i < modelData->numObjects; ++i) {
+    const ObjectData* data = &modelData->objects[i];
+    const ModelObject* object = &data->modelObject;
+    if (fwrite(object, sizeof(ModelObject), 1, file) != 1) {
+      fprintf(stderr, "Failed writing object\n");
+      goto cleanup;
+    }
+  }
+  // Materials.
+  AssertOffset(file, model.offsetMaterials);
+  if (fwrite(materialsData->materials, sizeof(ModelMaterial), materialsData->numMaterials, file) != materialsData->numMaterials) {
+    fprintf(stderr, "Failed writing materials\n");
+    goto cleanup;
+  }
   // Tris.
+  AssertOffset(file, indexed->offsetTris);
   if (fwrite(&modelData->tris, sizeof(mdTri), modelData->numTris, file) != modelData->numTris) {
     fprintf(stderr, "Failed writing triangles\n");
     goto cleanup;
   }
   // Positions.
+  AssertOffset(file, indexed->offsetPositions);
   if (fwrite(&modelData->positions, sizeof(mdVec3), modelData->numPositions, file) != modelData->numPositions) {
     fprintf(stderr, "Failed writing positions\n");
     goto cleanup;
   }
   // Normals.
+  AssertOffset(file, indexed->offsetNormals);
   if (fwrite(&modelData->normals, sizeof(mdVec3), modelData->numNormals, file) != modelData->numNormals) {
     fprintf(stderr, "Failed writing normals\n");
     goto cleanup;
   }
   // Texcoords.
+  AssertOffset(file, indexed->offsetTexcoords);
   if (fwrite(&modelData->texcoords, sizeof(mdVec2), modelData->numTexcoords, file) != modelData->numTexcoords) {
     fprintf(stderr, "Failed writing texture coordinates\n");goto cleanup;
   }
@@ -404,48 +495,50 @@ int main(int argc, const char** argv) {
   const char* filePath = argv[1];
   const char* outPath  = (argc > 2) ? argv[2] : "out.mdl";
   
-  bool       success   = false;
-  uint8_t*   fileData  = nullptr;
-  size_t     dataSize  = 0;
-  ModelData* modelData = nullptr;
-  Lexer      lexer     = {0};
-  
-  // TODO: Map file to memory instead?
+  bool          success   = false;
+  uint8_t*      fileData  = nullptr;
+  size_t        dataSize  = 0;
+  ModelData     modelData = {0};
+  MaterialsData materialsData = {0};
+  Lexer         lexer     = {0};
+
   if (!ReadFile(filePath, &fileData, &dataSize)) {
-    goto cleanup;
-  }
-  if ((modelData = calloc(1, sizeof(ModelData))) == nullptr) {
+    fprintf(stderr, "Failed to read model file\n");
     goto cleanup;
   }
   LexerMake((const char*)fileData, dataSize, &lexer);
-  if (!ParseObj(&lexer, modelData)) {
+  if (!ParseObj(&lexer, &modelData)) {
+    fprintf(stderr, "Failed to parse OBJ\n");
     goto cleanup;
   }
-  if (modelData->mtl_file[0] != 0) {
+  if (modelData.mtl_file[0] != 0) {
     free(fileData);
     fileData = nullptr;
     char dir[PATH_MAX];
     char mtl[PATH_MAX];
     GetParentDir(filePath, dir);
-    PathConcat(dir, modelData->mtl_file, mtl);
+    PathConcat(dir, modelData.mtl_file, mtl);
     if (!ReadFile(mtl, &fileData, &dataSize)) {
+      fprintf(stderr, "Failed to read MTL file\n");
       goto cleanup;
     }
     LexerMake((const char*)fileData, dataSize, &lexer);
-    if (!ParseMtl(&lexer, &modelData->material)) {
+    if (!ParseMtl(&lexer, &materialsData)) {
+      fprintf(stderr, "Failed to parse MTL file\n");
+      goto cleanup;
+    }
+    if (!LinkMaterials(&modelData, &materialsData)) {
+      fprintf(stderr, "Failed to link materials\n");
       goto cleanup;
     }
   }
-  if (!WriteModelFile(modelData, outPath)) {
+  if (!WriteModelFile(&modelData, &materialsData, outPath)) {
     goto cleanup;
   }
   
   success = true;
   
 cleanup:
-  if (modelData) {
-    free(modelData);
-  }
   if (fileData) {
     free(fileData);
   }