// A player's danger zone must be calculated from a World and a blockWorld
public DangerZone(int playerNum, World world, BlockWorld blockWorld)
{
// Init danger array
dangerZoneArray = new float[World.BlocksWidth, dangerZoneHeight];
// Init to zero
for (int i = 0; i < World.BlocksWidth; i++)
{
for (int j = 0; j < dangerZoneHeight; j++)
{
dangerZoneArray[i, j] = 0.0f;
}
}
// Store block world as a copy for modification
this.blockWorld = blockWorld.Clone();
// Uses exact filtering to compute a belief distribution for player position
// and weapon type/ammo
sourceBeliefs = new Dictionary <IJCoords, ProjectileSourceBelief>();
computeSourceBeliefs(playerNum, world);
// For each source belief computed by exact filtering, run the trajectory
runTrajectories();
}
// Runs trajectories of projectile source beliefs
void runTrajectories()
{
// Iterate through each possibility
foreach (KeyValuePair <IJCoords, ProjectileSourceBelief> entry in sourceBeliefs)
{
ProjectileSourceBelief sourceBelief = entry.Value;
int sourceI = entry.Key.I;
int sourceJ = entry.Key.J;
int sourceAmmo = sourceBelief.Ammo;
float sourceProbability = sourceBelief.Probability;
// Iterate through each weapon type for each possibility
foreach (WeaponType weaponType in sourceBelief.PossibleWeapons)
{
if (weaponType == WeaponType.Lightning)
{
// Add danger to all above for lightning - easy
for (int j = -World.FloorLevelJ; j < World.BlocksHeight; j++)
{
if (j < sourceJ)
{
addDanger(sourceI, j, sourceProbability * LightningDangerWeight);
}
}
}
else
{
// Recursively add values to the danger zone 2D array
// Use same blockworld for both directions since paths won't cross
BlockWorld newBlockWorld = blockWorld.Clone();
addDangerToBlockAndNeighbors(sourceI, sourceJ, weaponType, sourceProbability, sourceAmmo, true, newBlockWorld);
addDangerToBlockAndNeighbors(sourceI, sourceJ, weaponType, sourceProbability, sourceAmmo, false, newBlockWorld);
}
}
}
}
// Outputs the optimal path
public Path ComputeBestPath(BlockWorld blockWorld)
{
HeapPriorityQueue <Path> frontier = new HeapPriorityQueue <Path>(MaxNodes);
HashSet <BlockWorld> explored = new HashSet <BlockWorld>();
// Initial state, path
BlockWorld initialState = blockWorld;
Path initialPath = new Path(0, new List <BlockWorld>()
{
initialState
});
// Add the initial path to the frontier
frontier.Enqueue(initialPath, 0 + Heuristic(initialState));
// Find paths
int expansions = 0;
while (frontier.Count > 0)
{
Path path = frontier.Dequeue();
BlockWorld lastWorld = path.Last();
// Return the no path
if (expansions > MaxExpansions)
{
return(null);
}
// Check goal
if (GoalFunction(lastWorld))
{
return(path);
}
// Mark as explored
explored.Add(lastWorld);
// Iterate over possible actions
List <BlockWorldAction> possibleActions = lastWorld.ApplicableActions();
foreach (BlockWorldAction action in possibleActions)
{
// Try the action on a cloned block world
BlockWorld newWorld = lastWorld.Clone();
newWorld.Advance(action);
// Check if explored already
bool alreadyExplored = false;
foreach (BlockWorld exploredWorld in explored)
{
if (exploredWorld.PropertiesEqual(newWorld))
{
alreadyExplored = true;
break;
}
}
if (!alreadyExplored)
{
// Extend path
Path newPath = path.ExtendedPath(newWorld, CostFunction(newWorld));
// Add to frontier
frontier.Enqueue(newPath, Heuristic(newWorld) + newPath.Cost);
}
}
expansions++;
}
// No solution exists
return(null);
}
// Recursively add danger to the 2D array
void addDangerToBlockAndNeighbors(int i, int j, WeaponType type, float probability, int ammo,
bool facingRight, BlockWorld blockWorld, bool isFalling = false)
{
// Base cases
if (probability < epsilon)
{
return;
}
if (ammo == 0)
{
return; // Master mode has negative ammo - do not return
}
// Blow out ground if there is any at the current position. If there is
if (blockWorld.CheckGroundByIndex(i, j))
{
// Another base case for immutable ground
bool immutable = blockWorld.CheckGroundImmutableByIndex(i, j);
if (immutable)
{
return; // End of the line
}
// Blow out ground otherwise
blockWorld.SetGroundByIndex(i, j, false);
addDangerToBlockAndNeighbors(i, j, type, probability * groundBlowoutFactor, ammo - 1,
facingRight, blockWorld);
return;
}
else
{
int normalized = facingRight ? -1 : 1;
switch (type)
{
case WeaponType.Rockets: {
addDanger(i, j, probability * RocketsDangerWeight);
addDangerToBlockAndNeighbors(i + normalized, j, type, probability, ammo,
facingRight, blockWorld);
break;
}
case WeaponType.Bombs: {
addDanger(i, j, probability * BombsDangerWeight);
addDangerToBlockAndNeighbors(i, j + 1, type, probability, ammo, facingRight, blockWorld);
break;
}
case WeaponType.Minions: {
addDanger(i, j, probability * MinionsDangerWeight);
bool groundDown = blockWorld.CheckGroundByIndex(i, j + 1);
bool groundRight = blockWorld.CheckGroundByIndex(i + normalized, j);
bool goRight = false;
bool goDown = false;
// Do natural motion - right first unless hasn't fallen
if (!groundRight && !groundDown)
{
if (isFalling && blockWorld.CheckGroundByIndex(i + normalized, j + 1))
{
goRight = true;
}
else
{
goDown = true;
}
}
else if (!groundRight && groundDown)
{
goRight = true;
}
else if (groundRight && !groundDown)
{
goDown = true;
}
else
{
// Block worlds diverge, so make a new one
BlockWorld newBlockWorld = blockWorld.Clone();
// Go both directions
addDangerToBlockAndNeighbors(i + normalized, j, type, probability / 2.0f,
ammo, facingRight, blockWorld, false);
addDangerToBlockAndNeighbors(i, j + 1, type, probability / 2.0f,
ammo, facingRight, newBlockWorld, true);
}
// Do sole motions
if (goRight)
{
addDangerToBlockAndNeighbors(i + normalized, j, type, probability,
ammo, facingRight, blockWorld, false);
return;
}
if (goDown)
{
addDangerToBlockAndNeighbors(i, j + 1, type, probability,
ammo, facingRight, blockWorld, true);
return;
}
break;
}
}
}
}