Training and Consulting

Monster respawning

(c) Alexander Hristov

Currently when we kill a monster nothing special happens, and the monsters are quickly exterminated. We can take several approaches here:

• Spawn new monsters as older ones are killed
• Change the current "level" switching to different backgrounds and different critters
• Making new monsters appear periodically regardless of how many are killed

To illustrate our point, we'll use the first approach here - we'll spawn a new monster for each monster killed. This is as easy as adding the following to our Monster class:

           . . .  
33      public void collision(Actor a) {
34        if (a instanceof Bullet || a instanceof Bomb) {
35          remove();

36          spawn();

37          stage.getPlayer().addScore(20);
38        }
39      }
40      

41      public void spawn() {
42        Monster m = new Monster(stage);
43        m.setX( (int)(Math.random()*Stage.WIDTH) );
44        m.setY( (int)(Math.random()*Stage.PLAY_HEIGHT/2) );
45        m.setVx( (int)(Math.random()*20-10) );
46        stage.addActor(m);
47      }

48      
49      public void fire() {
           . . .