private async Task<bool> MoveCoreAsync(Point sourcePosition, Point targetPosition, ITransactionWithMoveSupport transaction)
{
var source = await GetAsync(sourcePosition);
var target = await GetAsync(targetPosition);
var oldSource = source;
var oldTarget = target;
source.Tile.EnsureNotNull();
target.Tile.EnsureNotNull();
if (source.Tile.Entity == Entity.None)
{
// Cancel if there's no entity to move
transaction.IsSealed = true;
return false;
}
var move = new EntityMoveInfo(source.Tile.Entity, sourcePosition, targetPosition);
transaction.Moves.Push(move);
IBeginMoveArgs beginMoveArgs = new GameplayArgs(transaction, this);
IDetachArgs detachArgs = new GameplayArgs(transaction, this);
IAttachArgs attachArgs = new GameplayArgs(transaction, this);
// OnBeginMove: Notify entity that a move has been initiated
await source.Tile.Entity.BeginMoveAsync(beginMoveArgs);
beginMoveArgs.ValidateResult();
if (transaction.IsSealed) return false;
var newSource = source.WithTile(Tile.Compose(source.Tile, beginMoveArgs.ResultingEntity));
if (transaction.Set(sourcePosition, source, newSource))
source = newSource;
move.Entity = beginMoveArgs.ResultingEntity;
// Detach: Remove the entity from the source tile
await source.Tile.DetachEntityAsync(detachArgs);
detachArgs.ValidateResult();
if (transaction.IsSealed) return false;
// Attach: Add the entity to the target tile
await target.Tile.AttachEntityAsync(attachArgs);
attachArgs.ValidateResult();
if (transaction.IsSealed) return false;
// Detach from old tile, attach to new tile have succeeded
// => Apply changes to transaction
var newSource2 = source.WithTile(detachArgs.Result);
if (transaction.Set(sourcePosition, source, newSource2))
source = newSource2;
var newTarget = target.WithTile(attachArgs.Result);
if (transaction.Set(targetPosition, target, newTarget))
target = newTarget;
// Emit events
var moveEvent = new EntityMoveEvent(sourcePosition, targetPosition, oldSource.Tile, target.Tile);
transaction.Emit(moveEvent);
if (source.Tile.Entity != Entity.None)
{
// A new entity has been created at source position
var spawnEvent = new EntitySpawnEvent(sourcePosition, source.Tile.Entity);
transaction.Emit(spawnEvent);
}
if (oldTarget.Tile.Entity != Entity.None)
{
// The entity at target position has either been replaced
// or it has been moved/collected/... during a nested move
var oldTargetEntityOverwritten =
!(transaction.Events.OfType<EntityDespawnEvent>().Any(ev => ev.Position == targetPosition) ||
transaction.Events.OfType<EntityMoveEvent>().Any(ev => ev.SourcePosition == targetPosition));
if (oldTargetEntityOverwritten)
{
// If replaced, emit despawn event
var despawnEvent = new EntityDespawnEvent(targetPosition, oldTarget.Tile.Entity);
transaction.Emit(despawnEvent);
}
}
transaction.Moves.Pop();
return true;
}
private void OnChunkUnloaded(KeyValuePair<Point, IChunk> kvp)
{
for (var y = 0; y < Chunk.Size; y++)
{
for (var x = 0; x < Chunk.Size; x++)
{
var localPosition = new Point(x, y);
var globalPosition = kvp.Key * Chunk.Size + localPosition;
var tileInfo = kvp.Value[localPosition];
Dependencies.RemoveDependenciesOf(tileInfo.Tile, globalPosition);
Dependencies.RemoveDependenciesOn(globalPosition);
// For entities emit a despawn event
if (tileInfo.Tile.Entity != Entity.None)
{
var despawnEvent = new EntityDespawnEvent(globalPosition, tileInfo.Tile.Entity);
_eventSource.OnNext(despawnEvent);
}
}
}
_eventSource.OnNext(new ChunkRemovedEvent(kvp.Value));
}
private void OnDespawn(EntityDespawnEvent e)
{
_despawnSubscription.Dispose();
_isDespawned = true;
}