private Vector2Int?MovementTowards(AITarget target)
{
movementCalculator.CalculateMovementUnrestricted(AttachedUnit.GetCoordinates());
List <Vector2Int> path = movementCalculator.GetPath(movementCalculator.GetNearestAvailableNeighbor(target.coordinates));
if (path != null)
{
return(path[AttachedUnit.movementRange]);
}
return(null);
}
// Parses all possible targets and tracks the most optimal target
// Use FoundTarget to get the AI's target, and FoundMovePos to get the position the AI should move to
// Both of these may be null
public void FindTarget()
{
movementCalculator.CalculateMovement(AttachedUnit.GetCoordinates(), AttachedUnit.movementRange);
List <AITarget> targets = GetPossibleTargets();
FoundTarget = null;
FoundMovePos = null;
// No targets, no action
if (targets.Count == 0)
{
return;
}
// Check all possible targets from the most valuable to the least valuable
// Take the first target in range
foreach (var target in targets)
{
Vector2Int?movePos = null;
if (IsTargetReachable(target, ref movePos))
{
FoundTarget = target.coordinates;
FoundMovePos = movePos;
return;
}
}
// If no targets were in range, find nearest target and start moving towards it
AITarget closest = new AITarget();
closest.distance = float.MaxValue;
foreach (var target in targets)
{
if (target.distance < closest.distance)
{
closest = target;
}
}
// Find the tile to move to
FoundMovePos = MovementTowards(closest);
}
// Returns true if this target is within attack range
// If this target requires movement before it can be in range, movePos will assume the destination coordinates.
// If no movement is required, movePos will not be altered.
private bool IsTargetReachable(AITarget target, ref Vector2Int?movePos)
{
float distToTarget = Vector2Int.Distance(target.coordinates, AttachedUnit.GetCoordinates());
// Check if target is in range without moving
if (distToTarget <= AttachedUnit.AttackRange)
{
return(true);
}
// Check if target can be in range after moving
if (distToTarget > AttachedUnit.AttackRange + AttachedUnit.movementRange)
{
return(false);
}
// Find tile within movement range that is also in attack range of the desired target
// Prioritize the least amount of movement
int distance = int.MaxValue;
Vector2Int?coordinates = null;
List <Vector2Int> reachableTiles = movementCalculator.GetReachableTiles();
foreach (var tile in reachableTiles)
{
if (Vector2Int.Distance(target.coordinates, tile) <= AttachedUnit.AttackRange)
{
int thisDist = movementCalculator.GetDistance(tile);
if (thisDist < distance)
{
distance = thisDist;
coordinates = tile;
}
}
}
movePos = coordinates;
return(coordinates != null);
}
// Returns a list of possible target points for the Unit, sorted by value (descending order) and distance (ascending order)
private List <AITarget> GetPossibleTargets()
{
List <AITarget> targets = new List <AITarget>();
switch (AttachedSkill.targetType)
{
// Only units can be targeted, thus check the value of targeting all valid Units
case Skill.TargetType.Unit:
{
List <Unit> allUnits = Grid.ActiveGrid.GetAllUnits();
foreach (var unit in allUnits)
{
// Filter out only valid targets
if (AttachedSkill.IsAffected(AttachedUnit, unit))
{
// Check all units that will be affected from targeting this unit
AITarget target;
target.coordinates = unit.GetCoordinates();
target.value = GetValueFor(AttachedSkill.GetAffectedUnits(AttachedUnit, target.coordinates, true));
target.distance = Vector2Int.Distance(AttachedUnit.GetCoordinates(), target.coordinates);
// If there is value to this target, add it to the list
if (target.value > 0)
{
targets.Add(target);
}
}
}
}
break;
// Any tile can be targeted, thus check the values of all tiles
case Skill.TargetType.Tile:
{
for (int x = 0; x < Grid.ActiveGrid.gridSize.x; x++)
{
for (int y = 0; y < Grid.ActiveGrid.gridSize.y; y++)
{
// Check all units that will be affected from targeting this tile
AITarget target;
target.coordinates = new Vector2Int(x, y);
target.value = GetValueFor(AttachedSkill.GetAffectedUnits(AttachedUnit, target.coordinates, true));
target.distance = Vector2Int.Distance(AttachedUnit.GetCoordinates(), target.coordinates);
// If there is value to this target, add it to the list
if (target.value > 0)
{
targets.Add(target);
}
}
}
}
break;
}
targets.Sort((x, y) =>
{
int i = y.value.CompareTo(x.value);
if (i == 0)
{
return(x.distance.CompareTo(y.distance));
}
return(i);
});
return(targets);
}
