I have noticed a bug in the SGDK2 game framework code that occurs when loading a game sometimes. If you have a sprite on the map that was created dynamically (it's not there when the map is initialized, and no sprite of the same type is there either), then an error occurs because that sprite type's states never got initialized. It only happens if you have never seen that type of sprite in the whole gaming *session*. Once the sprite type is initialized, it stays initialized until you exit the program and you won't see any problem with that sprite type. But if you start the game, load an old saved game, it's possible for some sprites to become active without ever having been created or initialized.
I have fixed the framework code, but not released it yet. For anyone who wants to patch their project because they suspect similar problems, here's how.
1. From the Source Code folder of your project, open "GeneralRules.cs"
2. Search for "Deserialize"
3. A few lines down you will see the following code:
if (unit.AllMaps)
Project.GameWindow.LoadedMaps = unit.Maps;
else
foreach(System.Collections.DictionaryEntry de in unit.Maps)
Project.GameWindow.LoadedMaps[de.Key] = de.Value;
After that and before the closing brace ("}") that follows, add this code:
// If sprites exist on any layer of any map whose static state cache has not
// been initialized, initialize them now.
foreach (MapBase mb in Project.GameWindow.LoadedMaps.Values)
{
// Loop through each property of each map class
foreach (System.Reflection.PropertyInfo lpi in mb.GetType().GetProperties())
{
// If the property represents a map layer
if (lpi.PropertyType.IsSubclassOf(typeof(LayerBase)))
{
// Retrieve the layer object
LayerBase l = (LayerBase)lpi.GetValue(mb, null);
// Loop though each sprite in the layer's sprite collection
foreach (SpriteBase sp in l.m_Sprites)
{
Type spriteType = sp.GetType();
// Get the property containing the sprite type's cached list of states
System.Reflection.FieldInfo statesField = spriteType.GetField("m_SpriteStates",
System.Reflection.BindingFlags.GetField |
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Static);
// If the sprite has not initialized its states
if (statesField.GetValue(sp) == null)
{
// Call the static method that initializes the sprite's states.
System.Reflection.MethodInfo initMethod = spriteType.GetMethod("InitializeStates",
System.Reflection.BindingFlags.InvokeMethod |
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Static);
initMethod.Invoke(null, new object[] { Project.GameWindow.GameDisplay });
}
}
}
}
}
