DigiPen Institute of Technology

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1 DigiPen Institute of Technology Presents Session Eight: Behavior DigiPen Institute of Technology th Ave NE, Redmond, WA Phone: (425) DigiPen (USA) Corporation. No part of this work may be published without the written permission of DigiPen (USA) Corporation

2 1 Behavior Overview Contents 2 Game Objects Behavior 2.1 Game Implementation: Condor Behavior Game Implementation: Fire Behavior 5

3 3 Behavior 1 Behavior Overview A behavior is a set of functions, defined by the user, which describes how a game and its objects should behave and act. You can define a behavior to the game and to some of its objects, like sprites and texts. The functions assigned in a game object behavior (the game object is an instance of a class derived from the Game class) are executed successively. 2 Game Objects Behavior In StarTrooper,, the game behavior is divided into several objects that make the game. These objects are: Trooper, Condor, and Fire. The behavior of the Trooper object is a combination of several kinds of behavior: Movement Behavior (already seen) Shooting (already seen) The behavior of the Condor object depends on the collision detection. If it collides with Fire, which means that Fire hits it, it will explode and die with a consequent score increment. If it is hit by the Trooper, which means that condor wins, Condor will die and the score will decrement. Therefore, we have: Condor Behavior The behavior of the Fire object is simple. It will die if it is hit by Condor, otherwise it will continue. Therefore, we have: Fire Behavior 2.1 Game Implementation: Condor Behavior Create a list variables collidedsprites that contains all the sprites with which the enemy collides: List<Sprite> collidedsprites = Game.GetCollidedSprites(this); Test if the list is empty or not; if not empty: if (collidedsprites!= null) o For each element of the list: foreach (Sprite s in collidedsprites) o Test if this element is the fire object: if (s is Fire) //The enemy object will die RaptorGame.Die.Play(); // Playing the enemy explosion animation AnimationIndex = 1; //Incrementing the score by one

4 4 m_score++; //Updating the value of the score displayed //on the screen RaptorGame.Score.Text = Score: + m_score.tostring(); //Removing the enemy sprite from the game Game.Remove(s); o Test if this element is the main character: if (s is Bat) m_collisionwithbat = true; //The enemy object will die RaptorGame.Die.Play(); //The Animation will stop looping Animation.Stop(); //Decrementing the score by one m_score--; //Updating the value of the score displayed //on the screen RaptorGame.Score.Text = Score: + m_score.tostring(); Testing if the animation of the Condor sprite is the explosion animation or not: if (AnimationIndex!= 1) //Testing if it is the last frame of the explosion animation if (Animation.PlayingLastFrame) //delete the explosion sprite Delete the following code in the StarTrooperSprites.cs file under public override void Update() function: Trooper b = StarTooper.Trooper; Vector2 v = new Vector2(b.Position.X - Position.X, b.position.y - Position.Y); v.normalize(); Velocity = v; if (v.x >= 0) ScaleX = 1; ScaleX = -1; Then type the following code in the StarTrooperSprites.cs file under public override void Update() function:

5 5 Trooper b = StarTrooper.Trooper; if (AnimationIndex!= 1) Vector2 v = new Vector2(b.Position.X - Position.X, b.position.y - Position.Y); v.normalize(); Velocity = v; if (v.x >= 0) ScaleX = 1; ScaleX = -1; List<Sprite> collidedsprites = Game.GetCollidedSprites(this); if (collidedsprites!= null) foreach (Sprite s in collidedsprites) if (s is Fire) StarTrooper.Die.Play(); AnimationIndex = 1; m_score++; StarTrooper.Score.Text = "Score: " + m_score.tostring(); Game.Remove(s); if(s is Trooper) m_collisionwithtrooper = true; StarTrooper.Die.Play(); Animation.Stop(); m_score--; StarTrooper.Score.Text = "Score: " + m_score.tostring(); if (Animation.PlayingLastFrame) 2.2 Game Implementation: Fire Behavior If the Condor hits the Fire it will be deleted: this is already seen with the Condor behavior. If the Fire does not hit anything, it will delete itself if it is out of the game: if (y < -100) Then type the following code in the StarTrooperSprites.cs file under public override void Update() function: if (y < -100) When the spacebar is triggered, a new Fire sprite is created, the Shoot sound effect is played, and the text Shoots is incremented and displayed. Delete the following code in the StarTrooperSprites.cs file under public override void Update() function:

6 6 if (Keyboard.IsTriggered(Key.Space)) Fire fire = (Fire)StarTrooper.Fire.Clone(); fire.position = new PointF(Position.X, Position.Y - 35); fire.velocity = new Vector2(0, -4); Game.Add(fire); Then type the following code in the StarTrooperSprites.cs file under public override void Update() function: if (Keyboard.IsTriggered(Key.Space)) Fire fire = (Fire)StarTrooper.Fire.Clone(); fire.position = new PointF(Position.X, Position.Y - 35); fire.velocity = new Vector2(0, -4); Game.Add(fire); StarTrooper.Shoot.Play(); m_shoots++; StarTrooper.Shoots.Text = "Shoots:" + m_shoots.tostring();