Intelligent Enemies - Learning C# by Programming Games - page 365

using Microsoft.Xna.Framework;

1

2
3 class Rocket : AnimatedGameObject

{ 4

protected double spawnTime;

5

protected Vector2 startPosition;

6

7
8 public Rocket( bool moveToLeft, Vector2 startPosition)

{ 9

this .LoadAnimation("Sprites/Rocket/spr_rocket@3", "default", false , 0.5f);

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this .PlayAnimation("default");

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this .Mirror = moveToLeft;

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this .startPosition = startPosition;

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Reset();

14

}

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16
17 public override void Reset()

{

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this .Visible = false ;

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this .position = startPosition; 20

this .velocity = Vector2.Zero;

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∗ this .spawnTime = GameEnvironment.Random.NextDouble() 5;

22

}

23

24
25 public override void Update(GameTime gameTime)

{

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base .Update(gameTime);

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if (spawnTime > 0)

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{

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− = gameTime.ElapsedGameTime.TotalSeconds; spawnTime 30

return ;

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}

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this .Visible = true ;

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this .velocity.X = 600;

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if (Mirror) 35

∗ = − 1f;

this .velocity.X

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// check if we are outside the screen

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Rectangle screenBox = new Rectangle(0, 0, GameEnvironment.Screen.X, 38

GameEnvironment.Screen.Y);

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if (!screenBox.Intersects( this .BoundingBox))

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this .Reset(); 41

}

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}

43

Listing 28.1 A class that represents a moving rocket