11 Adding Vibration Effects Session 3.2.2

Session Overview  Describe how the vibration feature of the gamepad works  Show how an XNA program can control gamepad vibration  Add vibration to the Color Nerve game  Look at how we can change the behavior of a game by modifications to the code  Describe how the vibration feature of the gamepad works  Show how an XNA program can control gamepad vibration  Add vibration to the Color Nerve game  Look at how we can change the behavior of a game by modifications to the code Chapter 3.2.2: Adding Vibration Effects2

The Xbox Gamepad Vibration  The gamepad contains two motors which turn weighted flywheels  The wheels turn at different speeds to vibrate the pad  Games can control the power going into the motors to get different levels of vibration  The gamepad contains two motors which turn weighted flywheels  The wheels turn at different speeds to vibrate the pad  Games can control the power going into the motors to get different levels of vibration Chapter 3.2.2: Adding Vibration Effects3

Vibration Speeds  The motor on the left provides low-frequency rumble  The motor on the right provides higher-frequency vibration  XNA allows you to control the power going to either of these motors from a C# program  The motor on the left provides low-frequency rumble  The motor on the right provides higher-frequency vibration  XNA allows you to control the power going to either of these motors from a C# program Chapter 3.2.2: Adding Vibration Effects4

Controlling Gamepad Vibration from XNA  We have used the GamePad class before  It provides the getState method that we used to read the gamepad state  It also provides a method called setVibration which is used to control the vibration of a gamepad  The method is given three parameters  A parameter is a way of feeding information into a method  We have used the GamePad class before  It provides the getState method that we used to read the gamepad state  It also provides a method called setVibration which is used to control the vibration of a gamepad  The method is given three parameters  A parameter is a way of feeding information into a method Chapter 3.2.2: Adding Vibration Effects5 GamePad.SetVibration ( PlayerIndex.One, 1, 0 ) ;

Selecting the Gamepad to Be Controlled  This parameter value identifies the gamepad to be controlled  We used it to tell getState which gamepad to read  You can try to control gamepads that aren’t there, but the method call won’t do anything  This parameter value identifies the gamepad to be controlled  We used it to tell getState which gamepad to read  You can try to control gamepads that aren’t there, but the method call won’t do anything Chapter 3.2.2: Adding Vibration Effects6 GamePad.SetVibration ( PlayerIndex.One, 1, 0 ) ;

Setting the Vibration Levels  This parameter value gives the amount of vibration the left (low frequency) motor should produce  It is given as a floating point value between 0 and 1  If we give the value 1 it will produce maximum vibration  If we give the value 0 the vibration is turned off  This parameter value gives the amount of vibration the left (low frequency) motor should produce  It is given as a floating point value between 0 and 1  If we give the value 1 it will produce maximum vibration  If we give the value 0 the vibration is turned off Chapter 3.2.2: Adding Vibration Effects7 GamePad.SetVibration ( PlayerIndex.One, 1, 0 ) ;

Setting the Vibration Levels  This parameter value gives the amount of vibration the right (high frequency) motor should produce  It is given as a floating point value between 0 and 1  It works in the same way as the left-hand value, but the vibration effect is different  Once you have set a vibration level the pad will continue to vibrate until you tell it something different  This parameter value gives the amount of vibration the right (high frequency) motor should produce  It is given as a floating point value between 0 and 1  It works in the same way as the left-hand value, but the vibration effect is different  Once you have set a vibration level the pad will continue to vibrate until you tell it something different Chapter 3.2.2: Adding Vibration Effects8 GamePad.SetVibration ( PlayerIndex.One, 1, 0 ) ;

Vibration Demonstration Chapter 3.2.2: Adding Vibration Effects9 protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); GamePadState pad1 = GamePad.GetState(PlayerIndex.One); if (pad1.Buttons.X == ButtonState.Pressed) GamePad.SetVibration(PlayerIndex.One, 1, 0); base.Update(gameTime); } protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); GamePadState pad1 = GamePad.GetState(PlayerIndex.One); if (pad1.Buttons.X == ButtonState.Pressed) GamePad.SetVibration(PlayerIndex.One, 1, 0); base.Update(gameTime); }

1. Vibration Demonstration Chapter 3.2.2: Adding Vibration Effects10  This program implements the vibration behavior that we have just seen  However, it does have a problem…  This program implements the vibration behavior that we have just seen  However, it does have a problem…

Making the Vibration Stop  The game program must tell the gamepad to stop vibrating when the button is not pressed  The easiest way to achieve this is to add an else part to the conditional statement  This version of the code will only make the gamepad vibrate when the Blue button is pressed  The game program must tell the gamepad to stop vibrating when the button is not pressed  The easiest way to achieve this is to add an else part to the conditional statement  This version of the code will only make the gamepad vibrate when the Blue button is pressed Chapter 3.2.2: Adding Vibration Effects11 if (pad1.Buttons.X == ButtonState.Pressed) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0); if (pad1.Buttons.X == ButtonState.Pressed) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0);

Adding Vibration to Color Nerve  The Color Nerve program could make the gamepad vibrate when the intensity values get close to wrapping round  The condition must compare two values and trigger when one is greater than the other  We can use the “greater than” operator to do this  The Color Nerve program could make the gamepad vibrate when the intensity values get close to wrapping round  The condition must compare two values and trigger when one is greater than the other  We can use the “greater than” operator to do this Chapter 3.2.2: Adding Vibration Effects12 if (redIntensity > 220) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0); if (redIntensity > 220) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0);

The Greater Than Operator  The Greater Than operator can be placed between two numeric values  It returns true if the number on the left is greater than the number on the right  In all other situations (including equals) it returns false  The Greater Than operator can be placed between two numeric values  It returns true if the number on the left is greater than the number on the right  In all other situations (including equals) it returns false Chapter 3.2.2: Adding Vibration Effects13 if (redIntensity > 220) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0); if (redIntensity > 220) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0);

Combining Tests  If we want the vibration to start when any of the color intensities exceeds 220 we have to test all of them  We can combine the results using logical OR, so that the vibration starts if any of them exceeds the limit  If we want the vibration to start when any of the color intensities exceeds 220 we have to test all of them  We can combine the results using logical OR, so that the vibration starts if any of them exceeds the limit Chapter 3.2.2: Adding Vibration Effects14 if (redIntensity > 220 || greenIntensity > 220 || blueIntensity > 220) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0); if (redIntensity > 220 || greenIntensity > 220 || blueIntensity > 220) GamePad.SetVibration(PlayerIndex.One, 1, 0); else GamePad.SetVibration(PlayerIndex.One, 0, 0);

Using Blocks to Improve Code Appearance  Creating blocks can make your code clearer  In this case it separates the code from the conditions  Creating blocks can make your code clearer  In this case it separates the code from the conditions Chapter 3.2.2: Adding Vibration Effects15 if (redIntensity > 220 || greenIntensity > 220 || blueIntensity > 220) { GamePad.SetVibration(PlayerIndex.One, 1, 0); } else { GamePad.SetVibration(PlayerIndex.One, 0, 0); } if (redIntensity > 220 || greenIntensity > 220 || blueIntensity > 220) { GamePad.SetVibration(PlayerIndex.One, 1, 0); } else { GamePad.SetVibration(PlayerIndex.One, 0, 0); }

2. Color Nerve with Vibration Chapter 3.2.2: Adding Vibration Effects16  This version of the game provides vibration feedback when any of the color intensity values exceeds 220

Summary  The Xbox gamepad has two vibration motors for different frequency vibration of the gamepad  The GamePad class which is part of XNA provides a method called setVibration which controls the intensity of the vibration the motors produce  Once a gamepad has been told to vibrate it will vibrate at that level until given another vibration command or the exit method is called to end an XNA game  The Xbox gamepad has two vibration motors for different frequency vibration of the gamepad  The GamePad class which is part of XNA provides a method called setVibration which controls the intensity of the vibration the motors produce  Once a gamepad has been told to vibrate it will vibrate at that level until given another vibration command or the exit method is called to end an XNA game Chapter 3.2.2: Adding Vibration Effects17

True/False Revision Quiz  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game.  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game. Chapter 3.2.2: Adding Vibration Effects18

True/False Revision Quiz  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game.  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game. Chapter 3.2.2: Adding Vibration Effects19

True/False Revision Quiz  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game.  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game. Chapter 3.2.2: Adding Vibration Effects20

True/False Revision Quiz  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game.  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game. Chapter 3.2.2: Adding Vibration Effects21

True/False Revision Quiz  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game.  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game. Chapter 3.2.2: Adding Vibration Effects22

True/False Revision Quiz  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game.  The Xbox 360 console contains vibration motors.  An XNA program can make the keyboard vibrate.  An XNA program can only control the vibration of one gamepad.  The amount of gamepad vibration is set using a value in the range 0 to 1.  The gamepad stops vibrating when it loses contact with the game. Chapter 3.2.2: Adding Vibration Effects23