enemy movement and object pool

game/constants.odin

@@ -7,3 +7,9 @@ TILE_SIZE :: 32 // size of tiles in pixels
 SCREEN_W :: MAP_W * TILE_SIZE
 SCREEN_H :: MAP_H * TILE_SIZE
 
+MAX_ENEMIES :: 64
+MAX_WAVES :: 5
+MAX_TOWERS :: 32
+
+TOWER_COST :: 50
+

game/enemy.odin

@@ -1,29 +1,77 @@
 package game
 
 Enemy :: struct {
-	position: Vec2,
-	health:   int,
-	active:   bool,
-	speed:    f32,
+	position:   Vec2,
+	health:     int,
+	max_health: int,
+	active:     bool,
+	path_index: int,
+	speed:      f32,
 }
 
-spawn_enemy :: proc(world: ^World) {
+acquire_enemy :: proc(world: ^World) -> ^Enemy {
+	// create an object pool with fixed slots to reuse instead of allocate/free every spawn
+	for i in 0 ..< MAX_ENEMIES {
+		if !world.enemies[i].active {
+			return &world.enemies[i]
+		}
+	}
+
+	return nil
+}
+
+spawn_enemy :: proc(world: ^World, health: int, speed: f32) {
 	if len(world.path) == 0 do return // don't spawn enemies if no paths exist
 
-	world.enemy = Enemy {
-		position = world.path[0],
-		health   = 40,
-		speed    = 60,
-		active   = true,
+	e := acquire_enemy(world) // grab a free slot
+	if e == nil do return // if there are no slots, skil spawning
+
+	e^ = Enemy {
+		position   = world.path[0],
+		health     = health,
+		max_health = health,
+		speed      = speed,
+		path_index = 1,
+		active     = true,
 	}
 }
 
-update_enemy :: proc(world: ^World, dt: f32) {
-	e := &world.enemy
-	if !e.active do return
-	if len(world.path) == 0 do return
-
-	target := world.path[len(world.path) - 1]
-	move_toward(&e.position, target, e.speed, dt)
+spawn_group :: proc(world: ^World, count: int) {
+	for _ in 0 ..< count {
+		spawn_enemy(world, 20, 60)
+	}
+}
+
+update_enemies :: proc(world: ^World, dt: f32) {
+	for i in 0 ..< MAX_ENEMIES {
+		e := &world.enemies[i]
+		if !e.active do continue
+
+		if len(world.path) == 2 do return
+
+		if e.path_index >= len(world.path) {
+			world.base_health -= 1
+			e.active = false
+			continue
+		}
+
+		target := world.path[e.path_index]
+		move_toward(&e.position, target, e.speed, dt)
+
+		dx := target.x - e.position.x
+		dy := target.y - e.position.y
+		if dx * dx + dy * dy < 16.0 {
+			e.path_index += 1
+		}
+	}
+}
+
+active_enemy_count :: proc(world: ^World) -> int {
+	count := 0
+	for i in 0 ..< MAX_ENEMIES {
+		if world.enemies[i].active do count += 1
+	}
+
+	return count
 }
 

game/render.odin

@@ -15,8 +15,9 @@ render_world :: proc(world: ^World) {
 		rl.DrawCircle(i32(p.x), i32(p.y), 3, rl.GOLD)
 	}
 
-	if world.enemy.active {
-		e := world.enemy
+	for i in 0 ..< MAX_ENEMIES {
+		e := world.enemies[i]
+		if !e.active do continue
 		rl.DrawCircle(i32(e.position.x), i32(e.position.y), 11, rl.MAROON)
 		rl.DrawText(
 			fmt.ctprintf("%d", e.health),
@@ -25,9 +26,13 @@ render_world :: proc(world: ^World) {
 			12,
 			rl.WHITE,
 		)
+	}
 
+	if (world.base_health == 0) {
+		rl.DrawText("**GAME OVER**", 20, 20, 20, rl.RED)
 	}
 	rl.DrawText(fmt.ctprintf("Gold: %d", world.gold), 10, 10, 20, rl.BLACK) // Gold HUD
 	rl.DrawText(fmt.ctprintf("Base HP: %d", world.base_health), 10, 32, 20, rl.BLACK) // HP HUD
+	rl.DrawText(fmt.ctprintf("Enemies: %d", active_enemy_count(world)), 10, 54, 18, rl.DARKGRAY)
 }
 

game/world.odin

@@ -7,7 +7,7 @@ World :: struct {
 	base_health: int,
 	world_map:   Map,
 	path:        [dynamic]Vec2,
-	enemy:       Enemy,
+	enemies:     [MAX_ENEMIES]Enemy,
 }
 
 init_world :: proc() -> World {
@@ -27,9 +27,9 @@ update_world :: proc(world: ^World, dt: f32) {
 	}
 
 	if rl.IsKeyPressed(.SPACE) {
-		spawn_enemy(world)
+		spawn_group(world, 3)
 	}
 
-	update_enemy(world, dt)
+	update_enemies(world, dt)
 }