// Pac-Man’s current position and orientation, and selecting the location four tiles straight
// ahead of him. Works when PacMan is facing left, down, or right, but when facing upwards,
// it's also four tiles to the left
ValueTask <CellIndex> getChaseTargetCell()
{
var pacDir = _pacman.Direction;
CellIndex pacTile = _pacman.Tile.Index;
CellIndex offset = Maze.ConstrainCell(
pacTile + (DirectionToIndexLookup.IndexVectorFor(pacDir) * Vector2s.Four).ToCellIndex());
// for the bug in the original pacman
if (pacDir == GameComponents.Directions.Up)
{
offset = (offset.ToVector2() + new Vector2(-4, 0)).ToCellIndex();
}
var newTarget = Maze.ConstrainCell(pacTile + offset);
return(new ValueTask <CellIndex>(newTarget));
}
// To locate Inky’s target, we first start by selecting the position two tiles in front of Pac-Man
// in his current direction of travel.
// From there, imagine drawing a vector from Blinky’s position to this tile, and then doubling
// the length of the vector. The tile that this new, extended vector ends on will be Inky’s actual target
async ValueTask <CellIndex> getChaseTargetCell()
{
// ReSharper disable once HeapView.BoxingAllocation
var blinky = await _mediator.Send(_getBlinkyRequest);
var blinkyCell = blinky.Tile.Index;
var pacDir = _pacman.Direction;
CellIndex pacCellPos = _pacman.Tile.Index;
var twoCellsInFront = Maze.ConstrainCell(
pacCellPos + (DirectionToIndexLookup.IndexVectorFor(pacDir) * Vector2s.Two).ToCellIndex());
CellIndex diff = twoCellsInFront - blinkyCell;
var diff2 = (diff.ToVector2() * Vector2s.Two).ToCellIndex();
var newTarget = Maze.ConstrainCell(blinkyCell + diff2);
return(newTarget);
}
public override ValueTask <MovementResult> Update(CanvasTimingInformation context)
{
if (!_readyToExit && _door.CanGhostLeave(Ghost))
{
_readyToExit = true;
return(new ValueTask <MovementResult>(MovementResult.NotFinished));
}
if (_finished)
{
Ghost.Direction = new DirectionInfo(Directions.Left, Directions.Left);
Ghost.SetMovementMode(GhostMovementMode.Undecided);
return(new ValueTask <MovementResult>(MovementResult.Finished));
}
Vector2 diff = _cellToMoveTo - _cellToMoveFrom;
if (diff != Vector2.Zero)
{
diff = diff.Normalize();
Ghost.Position = Ghost.Position + diff / Vector2s.Two;
var dir = DirectionToIndexLookup.GetDirectionFromVector(diff);
Ghost.Direction = new DirectionInfo(dir, dir);
}
if (Ghost.Position.Floor() == _cellToMoveTo.Floor())
{
Ghost.Position = _cellToMoveTo;
whenAtTargetCell();
}
return(new ValueTask <MovementResult>(MovementResult.NotFinished));
}
