public void OnGUI()
{
EditorGUILayout.BeginVertical();
{
horizontalNormals = EditorGUILayout.ObjectField("Horizontal normals", horizontalNormals, typeof(Texture2D), true) as Texture2D;
VerticalNormals = EditorGUILayout.ObjectField("Vertical normals", VerticalNormals, typeof(Texture2D), true) as Texture2D;
EditorGUILayout.Space();
OutputTexture = EditorGUILayout.ObjectField("Output texture", OutputTexture, typeof(Texture2D), true) as Texture2D;
if (horizontalNormals == null || VerticalNormals == null)
GUI.enabled = false;
if (GUILayout.Button("Generate normals"))
GenerateNormalsMap(horizontalNormals, VerticalNormals);
GUI.enabled = true;
}
EditorGUILayout.EndVertical();
}