Xperia™ PLAY tutorial – Angry Mob Games’ optimisation tips using Unity’s tool chain

Hello Developer World! My name is Bogdan Iliesiu from Angry Mob Games, and in the following article, I’d like to share with you a few tips for optimising your games for the Xperia™ PLAY using Unity’s tool chain. To have your game take advantage of the Xperia™ PLAY, game developers will first need to adjust all the game controls. We at Angry Mob Games took some additional steps to make our flagship game, Guerilla Bob, feel much better integrated on the device.

Updated: check out a demo video after the jump!

So here is a quick summary of the steps we took when making Guerrilla Bob for the Xperia™ PLAY:

1. Added support for the device physical buttons and touch pad (the dual joysticks area).

2. Added key navigation for the game menus.

3. Added on-screen control tutorials showing the Xperia™ PLAY (PlayStation®-style) buttons.

4. Optimized the graphics.

In the following section, I’ll give you some more details and code samples on each of the steps above.

Adding support for the physical controls.

Unity has a great sample project, which shows you how to get input from each of the buttons. (I’m sure Unity will put it up on their website, once Unity 3.3 goes live.) For the main gameplay controls, we decided to use only the physical buttons when the Xperia™ PLAY device is slid open, and also hid all the on-screen virtual buttons. When the device slides back up, the UI is shown for the virtual buttons and we let the users control the game using the main touch screen. 

To find out when the phone is slid open, Unity implemented a bool function. It’s not an event, so we need to constantly check for that value. Here’s a short coroutine which does that:

AndroidJavaObject currentConfig = null;

//call this one in Awake()
void InitAndroidConfigLink()
{
using (AndroidJavaClass player = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
{
AndroidJavaObject activity = player.GetStatic<AndroidJavaObject>("currentActivity");
currentConfig = activity.Call<AndroidJavaObject>("getResources").Call<AndroidJavaObject>("getConfiguration");
}
}

IEnumerator CheckForPhoneSlidedStatus()
{
const int NAVIGATIONHIDDEN_UNDEFINED = 0;
//   const int NAVIGATIONHIDDEN_NO = 1;
const int NAVIGATIONHIDDEN_YES = 2;
int nav;
while (true)
{
nav = currentConfig.Get<int>("navigationHidden");
if (nav == NAVIGATIONHIDDEN_YES || nav == NAVIGATIONHIDDEN_UNDEFINED)
{
PhoneSlided = false;
//show controls UI
if (!LeftControlPad.gameObject.active)
{
ShowPads();
PauseButton.gameObject.active = true;
}
}
else
{
PhoneSlided = true;
//hide controls UI
if (LeftControlPad.gameObject.active)
{
SetLeftStickActive(false);
SetRightStickActive(RightStickMode.None);
PauseButton.gameObject.active = false;
}
}
yield return new WaitForSeconds(2F);
}
}

Most of the button inputs are really easy to read, and they all have certain key codes. This is the full list:

Arrow Left: Input.GetKey(KeyCode.LeftArrow)

Arrow Right: Input.GetKey(KeyCode.RightArrow)

Arrow Up: Input.GetKey(KeyCode.UpArrow)

Arrow Down: Input.GetKey(KeyCode.DownArrow)

X: Input.GetKey(“joystick button 0″)

Square: Input.GetKey(“joystick button 1″)

Triangle: Input.GetKey(“joystick button 2″)

Circle: Input.GetKey(“joystick button 3″)

Left Shoulder Button: Input.GetKey(KeyCode.LeftShift)

Right Shoulder Button: Input.GetKey(KeyCode.RightShift)

Select: Input.GetKey(KeyCode.Pause)

Start: Input.GetKey(KeyCode.Return)

Android Menu: Input.GetKey(KeyCode.Menu)

Android Back: Input.GetKey(KeyCode.Escape)

We used the four directional keys to move our character, Bob, around. To do that, we built a movement vector by using:

  directionalKeysVector.x = Input.GetAxis("Horizontal");
directionalKeysVector.y = Input.GetAxis("Vertical");
directionalKeysVector.Normalize();

To be able to do that, you also have to define that axis input name, under Project Settings->Input. The above value is standard when you start a new Unity project.

The trickiest part is getting input from the Xperia™ PLAY touch pad (the middle area with the two round sticks). It acts just like the main touchscreen input.

Here’s some code to get two vectors, one for the left area, and one for the right area of the touch pad (left and right sticks):

private void GetSecondaryTouchInputNoPhases()
{

if (AndroidInput.secondaryTouchEnabled)
{

int count = AndroidInput.touchCountSecondary;
if (count == 0)
{

if (playerControllerOne.Shooting)
{
playerControllerOne.StopShooting();
}

if (directionalKeysVector.sqrMagnitude < 0.1F)
{
leftStickVector = Vector2.zero;
playerControllerOne.MovementDirection = Vector2.zero;
}
}

for (int i = 0; i < count; i++)
{
touch = AndroidInput.GetSecondaryTouch(i);
touchPosition = touch.position;

lDiff = new Vector2(touchPosition.x - secondaryLeftStickCenter.x, 480 - touchPosition.y - secondaryLeftStickCenter.y);
rDiff = new Vector2(touchPosition.x - secondaryRightStickCenter.x, 480 - touchPosition.y - secondaryRightStickCenter.y);

leftStickDown = (lDiff.sqrMagnitude < secondaryPadRadiusInPixels * secondaryPadRadiusInPixels);
rightStickDown = (rDiff.sqrMagnitude 0.01F)
{
playerControllerOne.LookingDirection = rDiff;
}

if (!playerControllerOne.Shooting)
{

playerControllerOne.StartShooting();
}
if (count == 1)
{
if (directionalKeysVector.sqrMagnitude < 0.1F)
{
leftStickVector = Vector2.zero;
playerControllerOne.MovementDirection = Vector2.zero;
}
}
}
}

}
}

For the code above, we used the two vectors for movement and shooting directions. Please note the values for the touchpad width/height, and the various calculations were required when reading the exact touch position.

The code below uses either the arrow keys, or the touchpad left stick to move the character:

void UpdatePhoneInput()
{
if (PhoneSlided)
{
directionalKeysVector.x = Input.GetAxis("Horizontal");
directionalKeysVector.y = Input.GetAxis("Vertical");
directionalKeysVector.Normalize();
GetSecondaryTouchInputNoPhases();
}
else
{
GetPhoneTouchScreenInput();
}

if (playerControllerOne.IsControllable)
{
if (PhoneSlided)
{
if (leftStickVector == Vector2.zero)
{
if (directionalKeysVector.sqrMagnitude > 0.1F)
{
playerControllerOne.MovementDirection = directionalKeysVector;
}
else
{
playerControllerOne.MovementDirection = Vector2.zero;
}
}
}
}
}

I guess that’s all there is to it. Just make sure you turn on ‘NativeActivity’ in the Player Settings.

Adding key navigation for the game menus

We used the arrow keys plus the ‘X’ and ‘O’ buttons to navigate around the menus, much like the console games. ‘X’ seems to be standard for activating a button, and ‘O’ is for canceling and returning to a previous menu state. We also used ‘Start’ and ‘Select’ to enter the Pause menu, during gameplay.

To implement all these, we had a special button class, which stored all the neighbours for up, down, left and right. Each button had a delegate (function) for receiving focus, and one for going back to its original state. If one of its button neighbours was inactive, it would search recursively in that direction, until it found an active button to get focus.

Adding on-screen control tutorials showing the Xperia™ PLAY (PlayStation®-style) buttons

We showed some graphics of which buttons to press, depending on the game context, when showing the first tutorial. For this, we used game pad buttons artwork provided by Sony Ericsson.

Here’s what the interface looks like:

Here’s an archive with all the buttons, each as a different 3D mesh (a plane), with an optimized texture atlas. Each button has a normal and a pressed state. Feel free to use it in your game.

Optimizing the graphics

Optimizing the graphics means pumping them up, as the Xperia™ PLAY device seems to be much more powerful than the iPhone4, for example. It also does a great job handling larger textures. You would need to test your game to see how much you can push it. For Guerrilla Bob, it runs at 60FPS constantly, which is super.

The full hardware specs for the Xperia™ PLAY are here.

So I guess that’s all it takes. The rest is just your awesome game!

If you have any questions, feel free to post them here, so everybody can join the discussion.

If you’d like to see more details about our games, Guerrilla Bob and Predators, you can check out www.angrymobgames.com.

Updated: check out Guerilla Bob running on Xperia™ PLAY below:

 

More information

• Read more about how to use the Xperia PLAY game keys>>>
• Read more and download a tutorial on how to access the touch pad on the Xperia™ PLAY>>>
• Read more about the Xperia™ PLAY on Sony Ericsson Developer World>>>
• Download the Xperia™ PLAY white paper>>>