message: Flip Tangents and Bitangents on backfaces.
diff: void computeShadingParams() {
  #if defined(HAS_ATTRIBUTE_TANGENTS)
  highp vec3 n = vertex_worldNormal;
  +#if defined(MATERIAL_HAS_ANISOTROPY) || defined(MATERIAL_HAS_NORMAL) || defined(MATERIAL_HAS_CLEAR_COAT_NORMAL)
  + highp vec3 t = vertex_worldTangent;
  + highp vec3 b = vertex_worldBitangent;
  +#endif
  #if defined(MATERIAL_HAS_DOUBLE_SIDED_CAPABILITY)
  if (isDoubleSided()) {
  n = gl_FrontFacing ? n : -n;
  +#if defined(MATERIAL_HAS_ANISOTROPY) || defined(MATERIAL_HAS_NORMAL) || defined(MATERIAL_HAS_CLEAR_COAT_NORMAL)
  + t = gl_FrontFacing ? t : -t;
  + b = gl_FrontFacing ? b : -b;
  +#endif
  }
  #endif
  @@ -20,7 +28,7 @@ void computeShadingParams() {
  #if defined(MATERIAL_HAS_ANISOTROPY) || defined(MATERIAL_HAS_NORMAL) || defined(MATERIAL_HAS_CLEAR_COAT_NORMAL)
  // We use unnormalized post-interpolation values, assuming mikktspace tangents
  - shading_tangentToWorld = mat3(vertex_worldTangent, vertex_worldBitangent, n);
  + shading_tangentToWorld = mat3(t, b, n);
  #endif
  #endif
  