added player loop detection, loose level if last player loops

systems/player_system.go

@@ -18,13 +18,16 @@ type PlayerSystem struct {
 	World         *ecs.World
 	Selector      *generic.Filter4[Position, Velocity, Player, Renderable]
 	GridContainer *grid.GridContainer
+	Width, Height int
 }
 
-func NewPlayerSystem(world *ecs.World, gridcontainer *grid.GridContainer) System {
+func NewPlayerSystem(world *ecs.World, gridcontainer *grid.GridContainer, width, height int) System {
 	system := &PlayerSystem{
 		Selector:      generic.NewFilter4[Position, Velocity, Player, Renderable](),
 		GridContainer: gridcontainer,
 		World:         world,
+		Width:         width,
+		Height:        height,
 	}
 
 	return system
@@ -48,7 +51,7 @@ func (system PlayerSystem) Update() error {
 		}
 
 		// check if the user alters or initiates movement
-		system.CheckMovement(velocity)
+		system.CheckMovement(playerposition, velocity, player)
 
 		// check if player collides with walls or edges
 		system.CheckGridCollision(playerposition, velocity)
@@ -56,6 +59,15 @@ func (system PlayerSystem) Update() error {
 		if count > 1 {
 			// check if player collides with another player, fuse them if any
 			EntitiesToRemove = system.CheckPlayerCollision(playerposition, velocity, query.Entity())
+		} else {
+			// only 1 player left or one is max
+			EntitiesToRemove = system.CheckPlayerLooping(
+				playerposition, velocity, player, query.Entity())
+		}
+
+		if !velocity.Moving() {
+			// disable loop detection
+			player.LoopCount = 0
 		}
 	}
 
@@ -130,17 +142,33 @@ func (system *PlayerSystem) SwitchPlayers() {
 	}
 }
 
-func (system *PlayerSystem) CheckMovement(velocity *components.Velocity) {
+func (system *PlayerSystem) CheckMovement(
+	position *components.Position,
+	velocity *components.Velocity,
+	player *components.Player) {
+
+	moved := false
+
 	if !velocity.Moving() {
 		switch {
 		case ebiten.IsKeyPressed(ebiten.KeyRight):
 			velocity.Change(East)
+			moved = true
 		case ebiten.IsKeyPressed(ebiten.KeyLeft):
 			velocity.Change(West)
+			moved = true
 		case ebiten.IsKeyPressed(ebiten.KeyDown):
 			velocity.Change(South)
+			moved = true
 		case ebiten.IsKeyPressed(ebiten.KeyUp):
 			velocity.Change(North)
+			moved = true
+		}
+
+		if moved {
+			// will be reset every time the user initiates player movement
+			player.LoopPos.Set(position)
+			player.LoopCount = 0
 		}
 	}
 }
@@ -161,9 +189,6 @@ func (system *PlayerSystem) CheckGridCollision(
 					tilepos.Point(), "playerpos", playerposition)
 				intersects, newpos := tilepos.Intersects(playerposition, velocity)
 				if intersects {
-					// slog.Debug("collision detected", "tile",
-					// 	tilepos, "player", playerposition, "new", newpos)
-
 					playerposition.Set(newpos)
 					velocity.Change(Stop)
 				}
@@ -202,3 +227,39 @@ func (system *PlayerSystem) CheckPlayerCollision(
 	// FIXME: add an animation highlighting the fusion
 	return EntitiesToRemove
 }
+
+func (system *PlayerSystem) CheckPlayerLooping(
+	position *components.Position,
+	velocity *components.Velocity,
+	player *components.Player,
+	entity ecs.Entity) []ecs.Entity {
+
+	if player.LoopPos.Rect == nil {
+		// hasn't moved
+		return nil
+	}
+	EntitiesToRemove := []ecs.Entity{}
+
+	ok, _ := player.LoopPos.Intersects(position, velocity)
+	if ok {
+		// Fatal: loop detected with last player
+		player.LoopStart = true
+	} else {
+		// no intersection with old pos anymore
+		if player.LoopStart {
+			// loop detection active
+			player.LoopCount++
+			max := system.Width
+			if velocity.Direction == North || velocity.Direction == South {
+				max = system.Height
+			}
+
+			// we haved moved one time around the whole screen, loose
+			if (player.LoopCount * velocity.Speed) > max {
+				EntitiesToRemove = append(EntitiesToRemove, entity)
+			}
+		}
+	}
+
+	return EntitiesToRemove
+}