message: tools: Make cgltf dependency optional for now
  Not sure if we should add cgltf as a submodule or just embed it, so for
  now let's make it unnecessary to compile lodviewer.
diff: #include <GLFW/glfw3.h>
  +#ifdef GLTF
  #define CGLTF_IMPLEMENTATION
  #include "cgltf.h"
  +#endif
  #ifdef _WIN32
  #pragma comment(lib, "opengl32.lib")
  @@ -107,6 +109,7 @@ Mesh parseObj(const char* path)
  return result;
  }
  +#ifdef GLTF
  cgltf_accessor* getAccessor(const cgltf_attribute* attributes, size_t attribute_count, cgltf_attribute_type type, int index = 0)
  {
  for (size_t i = 0; i < attribute_count; ++i)
  @@ -125,7 +128,7 @@ const T* getComponentPtr(const cgltf_accessor* a)
  return reinterpret_cast<const T*>(&buffer[offset]);
  }
  -Mesh parseGltfC(const char* path)
  +Mesh parseGltf(const char* path)
  {
  cgltf_options options = {};
  cgltf_data* data = 0;
  @@ -271,14 +274,17 @@ Mesh parseGltfC(const char* path)
  return result;
  }
  +#endif
  Mesh loadMesh(const char* path)
  {
  if (strstr(path, ".obj"))
  return parseObj(path);
  +#ifdef GLTF
  if (strstr(path, ".gltf") || strstr(path, ".glb"))
  - return parseGltfC(path);
  + return parseGltf(path);
  +#endif
  return Mesh();
  }
  