// Action Selection Thread, runs minimax on the current State to get the best Action. Also keeps a history and updates it based on the successes and fails of the AI
protected static void selectAction(object arg)
{
Thread.Sleep(1000); // Sleep to prevent race conditions on game load
PaddleController __this = (PaddleController)arg;
ActionStateMap.GameObjectState localState = new ActionStateMap.GameObjectState(Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, 0.0f);
int maxHistory = 1000;
int historyIndex = 0;
Tuple <ActionStateMap.GameAction, ActionStateMap.ActionState>[] previousActions = new Tuple <ActionStateMap.GameAction, ActionStateMap.ActionState> [maxHistory];
while (!(__this.closeThreads.WaitOne(0)))
{
if (__this.currStateLock.WaitOne(1000))
{
localState.copy(__this.currState);
__this.currStateLock.ReleaseMutex();
ActionStateMap.GameObjectState currState = localState;
Tuple <double, ActionStateMap.GameAction, ActionStateMap.ActionState> nextAction = __this.minimax(currState, 3);
if (nextAction.Item2.getTag() != __this.currAction.getTag())
{
__this.setNextAction(nextAction.Item2);
}
// Store history and adjust weight on success and fail
previousActions[historyIndex] = Tuple.Create(nextAction.Item2, nextAction.Item3);
historyIndex++;
if (historyIndex >= maxHistory)
{
bool success = __this.successEvent.WaitOne(0);
bool fail = __this.failEvent.WaitOne(0);
__this.successEvent.Reset();
__this.failEvent.Reset();
historyIndex = 0;
for (int i = 0; i < maxHistory; i++)
{
if (success)
{
previousActions[i].Item2.updateActionProbabilities(previousActions[i].Item1, 1.0);
}
if (fail)
{
previousActions[i].Item2.updateActionProbabilities(previousActions[i].Item1, -1.0);
}
}
}
}
}
}
// Helper function for Minimax, traverses down a State's outecomes to get the best weight based on the predictions
protected double minimax_helper(ActionStateMap.GameObjectState currState, int depth, bool maximizingPaddle)
{
if (maximizingPaddle)
{
List <Tuple <double, ActionStateMap.GameAction, ActionStateMap.ActionState> > bestActions = paddleStateMap.getBestActions(currState);
if (depth == 0 || actionComplete.WaitOne(0) || minimaxTimeoutEvent.WaitOne(0))
{
return(bestActions[0].Item1); // should be sorted from the getBestActions function
}
double bestAction = -1.0;
foreach (var action in bestActions)
{
double actionResult = minimax_helper(action.Item2.predictNextState(currState), depth - 1, !maximizingPaddle);
if (actionResult < 0.0)
{
actionResult = action.Item1;
}
if (actionResult > bestAction)
{
bestAction = actionResult;
}
}
return(bestAction);
}
else //maximizingPlayer
{
List <Tuple <double, ActionStateMap.GameAction, ActionStateMap.ActionState> > minActions = playerStateMap.getBestActions(currState);
if (minActions.Count < 1)
{
return(-1.0);
}
if (depth == 0 || actionComplete.WaitOne(0) || minimaxTimeoutEvent.WaitOne(0))
{
return(minActions[0].Item1); // should be sorted from the getBestActions function
}
double minAction = double.MaxValue;
foreach (var action in minActions)
{
double actionResult = minimax_helper(action.Item2.predictNextState(currState), depth - 1, !maximizingPaddle);
if (actionResult < minAction)
{
minAction = actionResult;
}
}
return(minAction);
}
}
// Update thread for the Player StateMap. Records movements of the Player
protected static void updatePlayerMap(object arg)
{
Thread.Sleep(1000); // Sleep to prevent race conditions on game load
PaddleController __this = (PaddleController)arg;
ActionStateMap.GameObjectState localState = new ActionStateMap.GameObjectState(Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, 0.0f);
ActionStateMap.GameObjectState prevState = new ActionStateMap.GameObjectState(Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, Vector3.zero, 0.0f);
while (!(__this.closeThreads.WaitOne(0)))
{
if (__this.currStateLock.WaitOne(1000))
{
localState.copy(__this.currState);
__this.currStateLock.ReleaseMutex();
__this.playerStateMap.recordAction(prevState, localState);
prevState.copy(localState);
Thread.Sleep(100);
}
}
}
// Update is called once per frame
void Update()
{
// Start the Action Selection and Observation threads
if (!threadsStarted)
{
actionSelectionThread.Start(this);
playerObservationThread.Start(this);
timeoutThread.Start(this);
threadsStarted = true;
}
// Cap the velocity of the paddle
Rigidbody rb = GetComponent <Rigidbody>();
if (rb.velocity.magnitude > maximumVelocity)
{
rb.velocity = rb.velocity.normalized * maximumVelocity;
}
// Update the current state information
controllerVel_R = (controller_R.transform.position - lastControllerPos_R) / Time.deltaTime;
lastControllerPos_R = controller_R.transform.position;
if (currStateLock.WaitOne(0))
{
currState = new ActionStateMap.GameObjectState(controller_R.transform.position, controllerVel_R, transform.position, GetComponent <Rigidbody>().velocity, target.transform.position, Vector3.zero, Time.deltaTime);
currStateLock.ReleaseMutex();
}
actionLock.WaitOne(); // Lock to prevent the Action from changing while executing
if (currAction != null)
{
if (currAction.execute(gameObject, controller_R.gameObject, target))
{
actionComplete.Set();
}
}
actionLock.ReleaseMutex();
handleSuccessEvent();
}
// Main minimax function. Finds the highest weighted Action the AI has access to
protected Tuple <double, ActionStateMap.GameAction, ActionStateMap.ActionState> minimax(ActionStateMap.GameObjectState currState, int depth)
{
minimaxEndEvent.Reset();
minimaxTimeoutEvent.Reset();
List <Tuple <double, ActionStateMap.GameAction, ActionStateMap.ActionState> > bestActions = paddleStateMap.getBestActions(currState);
if (depth == 0 || actionComplete.WaitOne(0) || minimaxTimeoutEvent.WaitOne(0))
{
return(bestActions[0]); // should be sorted from the getBestActions function
}
Tuple <double, ActionStateMap.GameAction, ActionStateMap.ActionState> bestAction = Tuple.Create(Double.MinValue, bestActions[0].Item2, bestActions[0].Item3);
foreach (var action in bestActions)
{
double actionResult = minimax_helper(action.Item2.predictNextState(currState), depth - 1, false);
if (actionResult < 0.0)
{
actionResult = action.Item1;
}
if (actionResult > bestAction.Item1)
{
bestAction = Tuple.Create(actionResult, action.Item2, action.Item3);
}
}
minimaxEndEvent.Set();
return(bestAction);
}
