message: Fix makeShadingFrame for normal mapping
diff: @@ -109,10 +109,9 @@ inline linear3f makeShadingFrame(const DifferentialGeometry& dg,
  const uniform linear2f& normalRot,
  uniform float normalScale = 1.f)
  {
  - linear3f f = makeShadingFrame(dg);
  -
  if (valid(normalMap))
  {
  + linear3f f = make_LinearSpace3f(normalize(dg.dPds), normalize(dg.dPdt), dg.Ns);
  // get normal from texture
  vec3f localN = getNormal(normalMap, dg.st) * make_vec3f(normalScale, normalScale, 1.f);
  // rotate in 2D (tangent space) to account for tc transformations
  @@ -123,6 +122,6 @@ inline linear3f makeShadingFrame(const DifferentialGeometry& dg,
  }
  else
  {
  - return f;
  + return makeShadingFrame(dg);
  }
  }
  