Adding Multiple Players

Introduction

Beefball is intended to be a competitive multiplayer game. So far we only have one PlayerBall instance, so let's add some more PlayerBall instances. Previously we added a list for our PlayerBall. We can now add a second PlayerBall with minimal changes to our project.

Adding a new PlayerBall

To add a new PlayerBall:

1. Expand the GameScreen's Objects folder

2. Select the PlayerBallList object

3. Select the Quick Actions tab

4. Click the Add a new PlayerBall to PlayerBall List. Alternatively, you can right-click on the PlayerBallList and select Add Object

5. Change the new PlayerBall's X value to 180

   

You should now see two PlayerBall instances under the PlayerBallList and in game. Also, since we created our collision relationships between the lists, the new PlayerBall can already collide against the walls and the Puck.

Player vs. Player collision

Now that we have two PlayerBall instances, we need to add a new collision relationship. This time, we will create a collision relationship between the PlayerBallList vs itself. To do this:

1. Select the PlayerBallList

2. Select the Collision tab

3. Find the PlayerBallList in the list of items

4. Click the Add button

5. Set Collision Physics to Bounce

If you run you game now, the two PlayerBall instances collide against each other. Also, if we added more players (a third or fourth player) those would also collide with each other automatically.

Adding input for Player 2

We'll assign input on PlayerBall2Instance with code similar to the input-assigning code for PlayerBallInstance. To do this, open GameScreen.cs and modify AssignInput as shown in the following code:

private void AssignInput()
{
    if (InputManager.Xbox360GamePads[0].IsConnected)
    {
        PlayerBallInstance.MovementInput =
            InputManager.Xbox360GamePads[0].LeftStick;
        PlayerBallInstance.BoostInput =
            InputManager.Xbox360GamePads[0].GetButton(Xbox360GamePad.Button.A);
    }
    else
    {
        PlayerBallInstance.MovementInput =
            InputManager.Keyboard.Get2DInput(Microsoft.Xna.Framework.Input.Keys.A,
            Microsoft.Xna.Framework.Input.Keys.D,
            Microsoft.Xna.Framework.Input.Keys.W,
            Microsoft.Xna.Framework.Input.Keys.S);
        PlayerBallInstance.BoostInput =
            InputManager.Keyboard.GetKey(Microsoft.Xna.Framework.Input.Keys.B);
    }

    if (InputManager.Xbox360GamePads[1].IsConnected)
    {
        PlayerBallInstance2.MovementInput =
            InputManager.Xbox360GamePads[1].LeftStick;
        PlayerBallInstance2.BoostInput =
            InputManager.Xbox360GamePads[1].GetButton(Xbox360GamePad.Button.A);
    }
    else
    {
        PlayerBallInstance2.MovementInput =
            InputManager.Keyboard.Get2DInput(Microsoft.Xna.Framework.Input.Keys.Left,
            Microsoft.Xna.Framework.Input.Keys.Right,
            Microsoft.Xna.Framework.Input.Keys.Up,
            Microsoft.Xna.Framework.Input.Keys.Down);
        PlayerBallInstance2.BoostInput = 
            InputManager.Keyboard.GetKey(Microsoft.Xna.Framework.Input.Keys.RightShift);
    }
}

Now each PlayerBall uses a different Xbox360GamePad or set of keys.

Conclusion

Now that we have multiple PlayerBall instances, we have a game that is playable, but it's missing scoring and game rules. The next tutorial adds the ability to score goals.