public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
RequiredInHierarchyAttribute reqAttr = attribute as RequiredInHierarchyAttribute;
if (!FindRequiredComponent(reqAttr))
{
position.height = EditorGUIUtility.singleLineHeight * 2.0f;
EditorGUI.HelpBox(position, string.Format("Can't find a {0} component in the scene, but it is required.",
reqAttr.requiredType.Name), MessageType.Error);
position.y += EditorGUIUtility.singleLineHeight * 2.0f + 2;
position.height = EditorGUIUtility.singleLineHeight;
}
EditorGUI.PropertyField(position, property, label, true);
}
static UnityEngine.Object FindRequiredComponent(RequiredInHierarchyAttribute reqAttr)
{
return(GameObject.FindObjectOfType(reqAttr.requiredType));
}