/// <summary>Pushes the specified state onto the state stack</summary>
/// <param name="state">State that will be pushed onto the stack</param>
/// <param name="modality">
/// Behavior of the game state in relation to the state(s) below it on the stack
/// </param>
public void Push(IGameState state, GameStateModality modality)
{
Pause();
// If this game state is modal, take all game states that came before it
// from the draw and update lists
if (modality == GameStateModality.Exclusive)
{
this.drawableStates.Clear();
this.updateableStates.Clear();
}
// Add the new state to the update and draw lists if it implements
// the required interfaces
this.gameStates.Add(new KeyValuePair <IGameState, GameStateModality>(state, modality));
appendToUpdateableAndDrawableList(state);
// State is set, now try to enter it
try {
state.Enter();
}
catch (Exception) {
Pop();
throw;
}
}
/// <summary>Switches the game to the specified state</summary>
/// <param name="state">State the game will be switched to</param>
/// <param name="modality">
/// Behavior of the game state in relation to the state(s) below it on the stack
/// </param>
/// <returns>The game state that was replaced on the stack</returns>
/// <remarks>
/// This replaces the running game state on the stack with the specified state.
/// </remarks>
public IGameState Switch(IGameState state, GameStateModality modality)
{
int stateCount = this.gameStates.Count;
if (stateCount == 0)
{
Push(state, modality);
return(null);
}
int lastStateIndex = stateCount - 1;
KeyValuePair <IGameState, GameStateModality> old = this.gameStates[lastStateIndex];
IGameState previousState = old.Key;
// Notify the previous state that it's being left and kill it if desired
previousState.Leave();
disposeIfSupportedAndDesired(previousState);
// If the switched-to state is exclusive, we need to clear the update
// and draw lists. If not, depending on whether the previous state was
// a popup state, we might have to
if (old.Value == GameStateModality.Popup)
{
removeFromUpdateableAndDrawableList(previousState);
}
else
{
this.updateableStates.Clear();
this.drawableStates.Clear();
}
// Now swap out the state and put it in the update and draw lists. If we're
// switching from an exclusive to a pop-up state, the draw and update lists need
// to be rebuilt.
var newState = new KeyValuePair <IGameState, GameStateModality>(state, modality);
this.gameStates[lastStateIndex] = newState;
if (old.Value == GameStateModality.Exclusive && modality == GameStateModality.Popup)
{
rebuildUpdateableAndDrawableListRecursively(lastStateIndex);
}
else
{
appendToUpdateableAndDrawableList(state);
}
// Let the state know that it has been entered
state.Enter();
return(previousState);
}
public void TestPushModality(GameStateModality modality)
{
var alwaysObscured = new TestGameState();
var potentiallyObscured = new TestGameState();
var active = new TestGameState();
using (var manager = new GameStateManager()) {
manager.Push(alwaysObscured);
manager.Push(potentiallyObscured);
manager.Push(active, modality);
Assert.AreEqual(0, alwaysObscured.UpdateCallCount);
Assert.AreEqual(0, alwaysObscured.DrawCallCount);
Assert.AreEqual(0, potentiallyObscured.UpdateCallCount);
Assert.AreEqual(0, potentiallyObscured.DrawCallCount);
Assert.AreEqual(0, active.UpdateCallCount);
Assert.AreEqual(0, active.DrawCallCount);
manager.Update(new GameTime());
manager.Draw(new GameTime());
Assert.AreEqual(0, alwaysObscured.UpdateCallCount);
Assert.AreEqual(0, alwaysObscured.DrawCallCount);
if (modality == GameStateModality.Exclusive)
{
Assert.AreEqual(0, potentiallyObscured.UpdateCallCount);
Assert.AreEqual(0, potentiallyObscured.DrawCallCount);
}
else
{
Assert.AreEqual(1, potentiallyObscured.UpdateCallCount);
Assert.AreEqual(1, potentiallyObscured.DrawCallCount);
}
Assert.AreEqual(1, active.UpdateCallCount);
Assert.AreEqual(1, active.DrawCallCount);
}
}