added player loop detection, loose level if last player loops

TODO.md

@@ -2,9 +2,6 @@
 
 - ignore comments in lvl files
 
-- check  when sphere bounces from  one end to the  other endlessly w/o
-  any solids in between. this is a game lock and equals game over
-
 - Start the game  end timer and add a score FIXME:  put the actual max
   reachable score  into the  level definition  along with  the minimum
   steps required to reach it, also add a step counter
@@ -15,19 +12,8 @@
 - Add some final message when the player reaches the last level, start
   from scratch or a message to buy me some beer, whatever
 
-- Check player-player collisions!
-
-- Add  player mergers, possibly as  an option, so maybe  we could have
-  different primary  and secondary  players: one  pair can  merge, the
-  other not. Like S + s and M + m or something.
-
 - Add shaders for animation (player destruction etc)
 
-- Add player HUD + Stats (as hud_system!)
-
-- Entity Observers don't work, removed entities remain there, errors
-  about dead entities, had to add Alive checks, and in obstacle_system
-  even remove the player manually from the world.
 
 
 ## Collider Rework

assets/levels/05-space.lvl

@@ -4,14 +4,14 @@ Background: background-lila
                     
                     
                     
-        #           
+        W           
                     
                     
-        S           
+        S      # o  
                     
                     
                     
-        #           
-                    
                     
+        o           
+                #   
                     

components/player.go

@@ -5,6 +5,9 @@ import "github.com/hajimehoshi/ebiten/v2"
 type Player struct {
 	IsPrimary bool
 	Sprites   []*ebiten.Image
+	LoopPos   *Position
+	LoopStart bool
+	LoopCount int
 }
 
 func (player *Player) SwitchSprite() *ebiten.Image {

game/levels.go

@@ -44,7 +44,7 @@ func NewLevel(game *Game, cellsize int, plan *assets.RawLevel) *Level {
 	systemlist = append(systemlist, systems.NewObstacleSystem(game.World, gridcontainer))
 
 	systemlist = append(systemlist,
-		systems.NewPlayerSystem(game.World, gridcontainer))
+		systems.NewPlayerSystem(game.World, gridcontainer, game.ScreenWidth, game.ScreenHeight))
 
 	systemlist = append(systemlist, systems.NewParticleSystem(game.World, game.Cellsize))
 

grid/grid.go

@@ -90,6 +90,7 @@ func NewGrid(world *ecs.World,
 				vel.Speed = config.PLAYERSPEED
 				player.IsPrimary = tile.IsPrimary
 				player.Sprites = tile.Tiles
+				player.LoopPos = &components.Position{Cellsize: tilesize}
 			case tile.Collectible:
 				entity := colmapper.New()
 				pos, render, _ = colmapper.Get(entity)

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
+}