ballistic projectiles for cannons

game/constants.odin

@@ -21,6 +21,7 @@ TOWER_COST :: 50
 MAX_PROJECTILES :: 64
 PROJECTILE_SPEED :: 280 // pixels per second
 PROJECTILE_HIT_RADIUS :: 10
+CANNON_PROJECTILES_SPEED :: 320.0
 
 OVERLAY_BAR_H :: 28
 OVERLAY_PADDING :: 6

game/projectile.odin

@@ -8,6 +8,13 @@ Projectile :: struct {
 	target_slot: int,
 	damage:      int,
 	speed:       f32,
+	mode:        Projectile_Mode,
+	direction:   Vec2,
+}
+
+Projectile_Mode :: enum {
+	Homing, // chases target
+	Ballistic, // flies in a fixed direction
 }
 
 acquire_projectile :: proc(world: ^World) -> ^Projectile {
@@ -33,6 +40,7 @@ spawn_projectile :: proc(world: ^World, from: Vec2, target_slot: int, damage: in
 	p := acquire_projectile(world)
 	if p == nil do return
 
+	p.mode = .Homing
 	p^ = Projectile {
 		active      = true,
 		position    = from,
@@ -42,36 +50,94 @@ spawn_projectile :: proc(world: ^World, from: Vec2, target_slot: int, damage: in
 	}
 }
 
+spawn_ballistic :: proc(world: ^World, from, dir: Vec2, damage: int) {
+	p := acquire_projectile(world)
+	if p == nil do return
+	p^ = Projectile {
+		active    = true,
+		position  = from,
+		direction = dir,
+		mode      = .Ballistic,
+		damage    = damage,
+		speed     = CANNON_PROJECTILES_SPEED,
+	}
+}
+
+hit_enemy_at :: proc(world: ^World, pos: Vec2, damage: int) -> bool {
+	for i in 0 ..< MAX_ENEMIES {
+		e := &world.enemies[i]
+		if !e.active do continue
+		if distance(pos, e.position) <= PROJECTILE_HIT_RADIUS {
+			apply_tower_hit(world, e, damage)
+			return true
+		}
+	}
+	return false
+}
+
 update_projectiles :: proc(world: ^World, dt: f32) {
 	for i in 0 ..< MAX_PROJECTILES {
 		p := &world.projectiles[i]
 		if !p.active do continue
 
-		target, ok := enemy_still_on_map(world, p.target_slot)
-		if !ok {
-			p.active = false
-			continue
+		switch p.mode {
+		case .Homing:
+			update_homing_projectile(world, p, dt)
+		case .Ballistic:
+			update_ballistic_projectile(world, p, dt)
 		}
+	}
+}
 
-		move_toward(&p.position, target.position, p.speed, dt)
+update_homing_projectile :: proc(world: ^World, p: ^Projectile, dt: f32) {
+	target, ok := enemy_still_on_map(world, p.target_slot)
+	if !ok {
+		p.active = false
+		return
+	}
 
-		if distance(p.position, target.position) <= PROJECTILE_HIT_RADIUS {
-			target.health -= p.damage
-			p.active = false
+	move_toward(&p.position, target.position, p.speed, dt)
 
-			if target.health <= 0 {
-				target.active = false
-				push_event(world, .Enemy_Killed, gold_reward = 5)
-			}
+	if distance(p.position, target.position) <= PROJECTILE_HIT_RADIUS {
+		target.health -= p.damage
+		p.active = false
+
+		if target.health <= 0 {
+			target.active = false
+			push_event(world, .Enemy_Killed, gold_reward = 5)
 		}
 	}
 }
 
+update_ballistic_projectile :: proc(world: ^World, p: ^Projectile, dt: f32) {
+	step := p.speed * dt
+	p.position.x += p.direction.x * step
+	p.position.y += p.direction.y * step
+
+	if hit_enemy_at(world, p.position, p.damage) {
+		p.active = false
+		return
+	}
+
+	if p.position.x < 0 ||
+	   p.position.y < 0 ||
+	   p.position.x > MAP_W * TILE_SIZE ||
+	   p.position.y > MAP_H * TILE_SIZE {
+		p.active = false
+	}
+}
+
 render_projectiles :: proc(world: ^World) {
 	for i in 0 ..< MAX_PROJECTILES {
 		p := world.projectiles[i]
 		if !p.active do continue
-		rl.DrawCircle(i32(p.position.x), i32(p.position.y), 4, rl.GOLD)
+		color := rl.GOLD
+		radius: f32 = 4
+		if p.mode == .Ballistic {
+			color = rl.GRAY
+			radius = 6
+		}
+		rl.DrawCircle(i32(p.position.x), i32(p.position.y), radius, color)
 	}
 }
 

game/tower.odin

@@ -232,7 +232,14 @@ update_towers :: proc(world: ^World, dt: f32) {
 			spawn_projectile(world, t.position, slot, damage)
 		case .Cannon:
 			if target := enemy_at_slot(world, slot); target != nil {
-				apply_tower_hit(world, target, damage)
+				len := distance(t.position, target.position)
+				if (len > 0.001) {
+					dir := Vec2 {
+						(target.position.x - t.position.x) / len,
+						(target.position.y - t.position.y) / len,
+					}
+					spawn_ballistic(world, t.position, dir, damage)
+				}
 			}
 		case .Ice:
 			if target := enemy_at_slot(world, slot); target != nil {