MeshTools: test compile() with both flat and smooth normals requested.

And clarify the docs about what gets the priority.

src/Magnum/MeshTools/Compile.h

@@ -58,7 +58,9 @@ enum class CompileFlag: UnsignedByte {
      * If the mesh is @ref MeshPrimitive::Triangles, generates normals using
      * @ref MeshTools::generateFlatNormals(). If the mesh is not a triangle
      * mesh or doesn't have 3D positions, this flag does nothing. If the mesh
-     * already has its own normals, these get replaced.
+     * already has its own normals, these get replaced. If
+     * @ref CompileFlag::GenerateSmoothNormals is specified together with this
+     * flag, this flag gets a priority.
      */
     GenerateFlatNormals = 1 << 0,
 

src/Magnum/MeshTools/Test/CompileGLTest.cpp

@@ -122,6 +122,7 @@ constexpr struct {
     {"positions + normals + texcoords", Flag::Normals|Flag::TextureCoordinates2D},
     {"positions + normals + texcoords + colors", Flag::Normals|Flag::TextureCoordinates2D|Flag::Colors},
     {"positions + gen flat normals", Flag::GeneratedFlatNormals},
+    {"positions + gen both smooth and flat normals", Flag::GeneratedSmoothNormals|Flag::GeneratedFlatNormals},
     {"positions + normals, gen flat normals", Flag::Normals|Flag::GeneratedFlatNormals},
     {"positions + gen flat normals + colors", Flag::GeneratedFlatNormals|Flag::Colors},
     {"positions + gen flat normals + texcoords", Flag::GeneratedFlatNormals|Flag::TextureCoordinates2D},