feat: add world ref

src/main/java/lab/Bullet.java

@@ -9,10 +9,12 @@ public class Bullet {
 
 	private final Point2D acceleration;
 
+	private final World world;
 	private Point2D position;
 	private Point2D velocity;
 
-	public Bullet(Point2D position, Point2D velocity, Point2D acceleration) {
+	public Bullet(World world, Point2D position, Point2D velocity, Point2D acceleration) {
+		this.world = world;
 		this.position = position;
 		this.velocity = velocity;
 		this.acceleration = acceleration;

src/main/java/lab/BulletAnimated.java

@@ -7,9 +7,11 @@ import javafx.scene.image.Image;
 public class BulletAnimated {
 
 	private static final double SIZE = 40;
+	private final World world;
 	private Image image = new Image(this.getClass().getResourceAsStream("fireball-transparent.gif"));
 
-	public BulletAnimated(Point2D position, Point2D velocity, Point2D acceleration) {
+	public BulletAnimated(World world, Point2D position, Point2D velocity, Point2D acceleration) {
+		this.world = world;
 		this.position = position;
 		this.velocity = velocity;
 		this.acceleration = acceleration;

src/main/java/lab/Cannon.java

@@ -10,17 +10,20 @@ public class Cannon {
 
 	private static final double LENGTH = 60;
 	private static final double WIDTH = 15;
+	private final World world;
 	private Point2D position;
 	private double angle;
+	private double angleDelta = 25;
 
-	public Cannon(Point2D position, double angle) {
+	public Cannon(World world, Point2D position, double angle) {
+		this.world = world;
 		this.position = position;
 		this.angle = angle;
 	}
 
 	public void draw(GraphicsContext gc) {
 		gc.save();
-		gc.transform(new Affine(Transform.rotate(angle, position.getX(), position.getY())));
+		gc.transform(new Affine(Transform.rotate(angle, position.getX(), position.getY() + WIDTH / 2)));
 		gc.setFill(Color.BROWN);
 		gc.fillRect(position.getX(), position.getY(), LENGTH, WIDTH);
 		gc.restore();
@@ -28,6 +31,9 @@ public class Cannon {
 
 	public void simulate(double deltaT) {
 		// do nothing yet
-		angle += 25 * deltaT;
+		angle += angleDelta * deltaT;
+		if (angle >= 90 || angle <= 0) {
+			angleDelta = -angleDelta;
+		}
 	}
 }

src/main/java/lab/World.java

@@ -16,9 +16,9 @@ public class World {
 	public World(double width, double hight) {
 		this.width = width;
 		this.hight = hight;
-		this.bullet = new Bullet(new Point2D(0, 0), new Point2D(30, 30), new Point2D(0, -9.81));
-		this.bullet2 = new BulletAnimated(new Point2D(0, 0), new Point2D(30, 70), new Point2D(0, -9.81));
-		this.cannon = new Cannon(new Point2D(0, 0), 45);
+		bullet = new Bullet(this, new Point2D(0, 0), new Point2D(30, 30), new Point2D(0, -9.81));
+		bullet2 = new BulletAnimated(this, new Point2D(0, 0), new Point2D(30, 70), new Point2D(0, -9.81));
+		cannon = new Cannon(this, new Point2D(0, 0), 45);
 	}
 
 	public void draw(GraphicsContext gc) {
@@ -28,15 +28,15 @@ public class World {
 		// Change coordinate system to human like
 		gc.scale(1, -1);
 		gc.translate(0, -hight);
-		this.bullet.draw(gc);
-		this.bullet2.draw(gc);
-		this.cannon.draw(gc);
+		bullet.draw(gc);
+		bullet2.draw(gc);
+		cannon.draw(gc);
 		gc.restore();
 	}
 
 	public void simulate(double deltaT) {
-		this.bullet.simulate(deltaT);
-		this.bullet2.simulate(deltaT);
-		this.cannon.simulate(deltaT);
+		bullet.simulate(deltaT);
+		bullet2.simulate(deltaT);
+		cannon.simulate(deltaT);
 	}
 }
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