#define BITFIELD int
#if defined(VULKAN)
  #extension GL_ARB_shading_language_420pack : require
  #define LAYOUT(X) layout(X)
  #define LAYOUT_STD140(X) layout(std140, X)
#else
  #define LAYOUT(X)
  #define LAYOUT_STD140(X) layout(std140)
#endif
#ifdef VULKAN
#define gl_InstanceID  gl_InstanceIndex
#define gl_VertexID  gl_VertexIndex
#endif