message: sample-page-curl: flip the backface image.
diff: @@ -75,6 +75,7 @@ fragment {
  if (gl_FrontFacing) {
  c = texture(materialParams_IMAGE_A, uv);
  } else {
  + uv.x = 1.0 - uv.x;
  c = texture(materialParams_IMAGE_B, uv);
  }
  