make enemy move

game/enemy.odin

@@ -4,6 +4,7 @@ Enemy :: struct {
 	position: Vec2,
 	health:   int,
 	active:   bool,
+	speed:    f32,
 }
 
 spawn_enemy :: proc(world: ^World) {
@@ -11,8 +12,18 @@ spawn_enemy :: proc(world: ^World) {
 
 	world.enemy = Enemy {
 		position = world.path[0],
-		health   = 20,
+		health   = 40,
+		speed    = 60,
 		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)
+}
+

game/math2d.odin

@@ -1,6 +1,37 @@
 package game
 
+import "core:math"
 Vec2 :: struct {
 	x, y: f32,
 }
 
+grid_to_center :: proc(gx, gy: int) -> Vec2 {
+	return Vec2{f32(gx * TILE_SIZE + TILE_SIZE / 2), f32(gy * TILE_SIZE + TILE_SIZE / 2)}
+}
+screen_to_grid :: proc(px, py: f32) -> (int, int) {
+	gx := int(px) / TILE_SIZE
+	gy := int(py) / TILE_SIZE
+	return gx, gy
+}
+
+distance :: proc(a, b: Vec2) -> f32 {
+	dx := b.x - a.x
+	dy := b.y - a.y
+	return math.sqrt(dx * dx + dy + dy)
+}
+
+move_toward :: proc(pos: ^Vec2, target: Vec2, speed, dt: f32) {
+	dist := distance(pos^, target)
+	if dist < 1.0 do return
+
+	step := speed * dt
+	if step >= dist {
+		pos^ = target
+	} else {
+		dx := target.x - pos.x
+		dy := target.y - pos.y
+		pos.x += dx / dist * step
+		pos.y += dy / dist * step
+	}
+}
+

game/path.odin

@@ -5,10 +5,7 @@ build_path :: proc(world_map: ^Map, path: ^[dynamic]Vec2) {
 	for y in 0 ..< MAP_H {
 		for x in 0 ..< MAP_W {
 			if world_map.tiles[y][x] == .Path {
-				append(
-					path,
-					Vec2{f32(x * TILE_SIZE + TILE_SIZE / 2), f32(y * TILE_SIZE + TILE_SIZE / 2)},
-				)
+				append(path, grid_to_center(x, y))
 			}
 		}
 	}

game/render.odin

@@ -18,6 +18,14 @@ render_world :: proc(world: ^World) {
 	if world.enemy.active {
 		e := world.enemy
 		rl.DrawCircle(i32(e.position.x), i32(e.position.y), 11, rl.MAROON)
+		rl.DrawText(
+			fmt.ctprintf("%d", e.health),
+			i32(e.position.x) - 4,
+			i32(e.position.y) - 18,
+			12,
+			rl.WHITE,
+		)
+
 	}
 	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

game/world.odin

@@ -22,8 +22,6 @@ init_world :: proc() -> World {
 
 // update world, never draw
 update_world :: proc(world: ^World, dt: f32) {
-	_ = dt
-
 	if rl.IsKeyPressed(.G) {
 		world.gold += 10
 	}
@@ -31,5 +29,7 @@ update_world :: proc(world: ^World, dt: f32) {
 	if rl.IsKeyPressed(.SPACE) {
 		spawn_enemy(world)
 	}
+
+	update_enemy(world, dt)
 }