Windows Phone and XNA Creating and publishing a game in 50 minutes

Rob MilesMicrosoft MVPUniversity of Hull, UK

Agenda• Windows Phone XNA overview

• Getting an idea• Building a game

• Getting market ready• Publishing the game

• Useful resources

Windows Phone XNA overview

Windows Phone as an XNA platform

• Windows Phone is a great platform for games• Performance is impressive, especially in 3D• You can use all the hardware and sensors in your

Windows Phone games• Potential for Xbox Live integration• Support for in-game advertising

Quick overview of XNA• XNA provides everything you need to get started • Full Content Management (integrated into Visual Studio)• Support for 2D Sprite-based gameplay • Support for 3D games

• Common behaviours across the Windows PC, Xbox 360 and Windows Phone• One game engine can run on all platforms

How XNA (and all) games work• Initialise all the resources at the start• fetch all textures, models, scripts etc

• Repeatedly run the game loop:• Update the game world• read the controllers, update the state and position of game

elements• Draw the game world• render the game elements on the viewing device

METHODS IN AN XNA GAME• XNA Game class contains game methods• Initialise all the resources at the start• The Initialize and LoadContent methods

• Repeatedly run the game loop:• Update the game world – Update• Draw the game world - Draw

Making a game

Getting started• Make an empty project• Add your resources• Graphics, sound, 3D

models, scripts• Fill in the methods in

the project

Our single game asset - Smudge• We are going to write a

smudge based game• This is our starting smudge• It is really a sprite in our game

• You can use any texture that you like

Sprite behaviours

• These are the things that our sprite can do• Note that each method is given a reference to the

parent game

interface ISprite{ void Reset(SamplerState game); void Draw(SmudgeGame game); void Update(SmudgeGame game);}

Creating a sprite

• This code runs in the LoadContent method• It creates a new sprite called smudge• smudge is red, at (0,0), a 20th the width of the screen and

not rotated

Texture2D smudgeTexture = Content.Load<Texture2D>("Smudge");

smudge = new Sprite(this, smudgeTexture, Vector2.Zero, Color.Red, 20, 0);

Toughest slide in the presentation!public virtual void Draw(SmudgeGame game){ game.spriteBatch.Draw( spriteTexture, // texture of sprite spritePosition, // vector position on screen null, // source rectangle in texture (all of it) spriteColor, // colour of the light spriteRotation, // rotation – in radians spriteOrigin, // centre of sprite – position and rotation spriteScale, // scale – scaled to fit SpriteEffects.None, 1); // draw everything at the same depth}

This is the draw behaviour for the spritepublic virtual void Draw(SmudgeGame game){ game.spriteBatch.Draw( spriteTexture, // texture of sprite spritePosition, // vector position on screen null, // source rectangle in texture (all of it) spriteColor, // colour of the light spriteRotation, // rotation – in radians spriteOrigin, // centre of sprite – position and rotation spriteScale, // scale – scaled to fit SpriteEffects.None, 1); // draw everything at the same depth}

Easiest slide in the presentation

• This the update method for the sprite• At the moment it does nothing• We can extend the Sprite class to add new types of

behaviours

public virtual void Update(SmudgeGame game){}

Where to next?• We have an incredibly simple sprite engine• Now we need to build on this• How about making a bunch of smudges and drawing

with them?

Making a playfield

• This is my game playfield• It contains all the sprites on the screen• The game will work through the list and draw all the

sprites on each draw cycle

List<ISprite> gameSprites = new List<ISprite>();

Drawing the sprites

• This is how the game draws all the sprites on the screen

• We can add sprites to the collection and they will be drawn for us

foreach (ISprite sprite in gameSprites) sprite.Draw(this);

Where to next?• We could make sprites that bounce around the

screen or fly off the sides• I thought it might be nice to get the user drawing

with the sprites• This is really easy to do with the touchpad

Using the touchpad

• This turns on the touchpad and enables tap and drag events

protected override void Initialize(){ TouchPanel.EnabledGestures = GestureType.Tap | GestureType.FreeDrag; base.Initialize();}

Adding smudges

• This code runs in the Draw method• Each time we get a touch gesture we add a new

smudge where the gesture is

while (TouchPanel.IsGestureAvailable){ GestureSample gesture = TouchPanel.ReadGesture();

gameSprites.Add( new Sprite(this, smudgeTexture, gesture.Position, Color.Red, 20,0));}

Demo 1Drawing with smudges

Where to next?• We can now draw with smudges, which is kind of fun• Now we need to build on this• First thing we need to do is animate the sprite• Make it grow over time?

• We can do this by making a child class with a new Update behaviour

Make a sprite that grows…

• This override of the Update method grows the sprite

class GrowingSprite : Sprite, Isprite{ float spriteGrowSpeed = 0.05f; public override void Update(SmudgeGame game) { spriteScale += spriteGrowSpeed; base.Update(game); }}

Where to next?• The game (if that’s what it is) is still boring• We need to make it more interesting• Perhaps a few different colours would help• Setting the draw colour of a white texture causes

the texture to appear to be that colour

Creating random colours

• This returns a random colour value that can be used to draw each smudge

System.Random colorRand = new Random();

Color randomColor(){ int r = colorRand.Next(256); int g = colorRand.Next(256); int b = colorRand.Next(256); return Color.FromNonPremultiplied(r, g, b, 255);}

Demo 2Coloured growing smudges

Where to next?• This is looking prettier, but we still haven’t got a

game• Also if we add a very large number of smudges the

program slows right down• But it is quite fun to steer the line around the screen

Clearing away smudges

• This code removes old smudges from the list

while (TouchPanel.IsGestureAvailable) { GestureSample gesture = TouchPanel.ReadGesture();

if (gameSprites.Count > smudgesLength) gameSprites.RemoveAt(0);

gameSprites.Add(new GrowingSprite(this, smudgeTexture, gesture.Position, randomColor(), 20, 0));}

Demo 3Shorter smudges

Efficiency and performance• This is not very efficient code• Although it is quick to write it results in objects

being created and destroyed as it runs• However, the objects are very small, and

performance seems to be fine• We can use the performance analysis tools to find

out what is going on if we hit problems

Where to next?• We can add new sprite types• Sprite that drifts across the screen• Sprite that bounces off the edges• The game could produce these as well as drawing

Demo 4Work in progress…

Where to next?• We could use the accelerometer to control the

sprites• We could add images from the camera• We could animate the sprites• We could make the elements rotate• We could make a “Snake” type game• We could make a “Missile Command” type game• We could animate the sprites using sound imput

Selling something• Don’t be afraid to send stuff out there to see if

anyone likes it• If you get good feedback, develop the idea• If you get nothing, move on to the next idea….

Getting Market Ready

Starting Performance Analysis• The performance analysis tool

will tell you where a program is spending most of its time

• Then you can consider optimising those parts

• It is activated from the Debug menu

Performance Analysis Settings

• You can create and activate diagnostic settings that you can use and reuse as you develop the application

Analysis Data

• The analysis provides plenty of good data

Demo 7Performance testing

Creating an Application

The Windows Phone XAP file• The XAP file brings together all the elements

of your program application• It is the item that is actually pushed onto the

device when it is deployed• The XAP file provides a common format for all

Windows Phone apps & games• Declarative, manifest-based installation• Integrated into security model of phone• Tied to your developer identity

XAP File Anatomy

• The XAP file is actually a zip file• It contains manifest files that describe the contents

and the application

AppManifest File

• This file is built for you and identifies the components in the XAP file

<Deployment xmlns="http://schemas.microsoft.com/client/2007/deployment" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" EntryPointAssembly="WindowsPhonePuzzle" EntryPointType="WindowsPhonePuzzle.App" RuntimeVersion="3.0.40624.0"> <Deployment.Parts> <AssemblyPart x:Name="WindowsPhonePuzzle" Source="WindowsPhonePuzzle.dll" /> </Deployment.Parts></Deployment>

WMAppManifest.xml• The other manifest file is very important• It identifies the services that your application wishes to make

use of• It also configures the application itself

• The Marketplace deployment mechanisms can use this to ensure that users know what an application is going to do

• An application that attempts to use a service which is not requested in the WMAppManifest will be rejected by the Marketplace validation process

WMAppManifest.xml Capabilities

• The default file requests all capabilities• However, an application should only ask for the ones it needs

<Capabilities><Capability Name="ID_CAP_LOCATION"/> <Capability Name="ID_CAP_MEDIALIB"/> <Capability Name="ID_CAP_PHONEDIALER"/> <Capability Name="ID_CAP_PUSH_NOTIFICATION"/> <Capability Name="ID_CAP_SENSORS"/> <Capability Name="ID_CAP_WEBBROWSERCOMPONENT"/> <Capability Name="ID_CAP_ISV_CAMERA"/> <Capability Name="ID_CAP_CONTACTS"/> <Capability Name="ID_CAP_APPOINTMENTS"/></Capabilities>

WMAppManifest.xml Details

• The file also tells the Marketplace about your program, name, type, genre

• You need to edit this file so that it holds valid information about your program

<App xmlns="" ProductID="{eb43b2c2-b7e9-4e5c-8aea-8047eb5e335f}" Title="FunkyCamera" RuntimeType="Silverlight" Version="1.0.0.0" Genre="apps.normal" Author="FunkyCamera author" Description="Sample description" Publisher="FunkyCamera">

Editing the manifest

• You can edit this file from Visual Studio

• It is in the Properties entry of the solution

Making Icons

• You will need to prepare icons of a selection of sizes• Then you need to edit your project files to refer to

these

Finding your XAP

• If you want to find your XAP file it is held alongside your binaries • Remember to make a release build

• Rename it to ZIP if you want to look inside

XAP Rules• A XAP file should not be more than 20Mb in size for

Over the Air (OTA) distribution • The limit for all files is 400Mb• For full details of submission requirements and

process description go here:http://go.microsoft.com/?linkid=9730558

Sharing your XAP files• If you want people to run try your app but you don’t

want to give them the source you can distribute the XAP file instead

• They can then load it onto a developer device or the emulator

• They would use the XAP Deployment tool to do this

Local Application Deployment• You can deploy a XAP file onto

an unlocked device, or the emulator by using the Application Deployment tool• Can deploy to the emulator or a

device• You can distribute finished

applications for test

Obfuscation• If you send someone your XAP file they can use

disassemblers and other programs to unpick your assemblies and find out how they work• They can also obtain all your assets (images and sounds)

• An obfuscator tool will change the layout and variable names in your code to make it harder to decode the way a program works

Adding Obfuscation• There are a number of tools that will perform this

obfuscation for you• The Windows Phone Marketplace provides access to

one from PreEmptive solutions that is worth a lookhttp://www.preemptive.com/windowsphone7.html

The Windows Phone Marketplace

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Marketplace Rules• The Marketplace is the only way you can get

executable content onto a phone• Users can buy applications and deploy them onto

their devices• Developers can write applications and deploy them

to their own devices for testing• Registered developers can use up to 3 devices• Student developers can use one device

Joining the Marketplace• Register to be a member of the marketplace for $99

per year• Students can register for free via Dreamspark• Join at: http://create.msdn.com

Payment• Developers can set a price for an application or give it

away free• Developers receive 70% of the price paid for the

application• Payment starts once the developer has earned up to $200• The payment is made by bank transfer• All payments are from the USA, which can cause some

issues• Very good support on the developers site and the Windows Phone

Forums for this

Free and Paid Applications• Developers are limited in the number of free

applications they can make available• Only 100 (!) free apps per developer per year• Can publish further free applications at a extra cost of $20

per application• Developers can publish as many paid applications

as they like

Applications for sale• Applications can be free or paid• Developers can also allow customers to use an

application in “try before buy” mode• Your application can determine which mode it is

running in by calling a status API

Using Trial Mode

• It is easy for an application to determine whether it is running in Trial mode • But remember that a paid application with Trial Mode will not

show up as free in the Marketplace• It might be more effective to also distribute a free “lite”

version of your application

using Microsoft.Phone.Marketplace;

LicenseInformation info = new LicenseInformation();if ( info.IsTrial() ) { // running in trial mode}

Marketplace Submission

Application Validation• When you submit your application for validation the

system performs a number of automated tests• Checks if the application makes use of any capabilities

that were not specified• Checks for any unmanaged or disallowed libraries• Ensures that all the required assets are provided

• Then the application is manually tested to ensure proper behaviour in a number of scenarios

Validation Results• The testing process takes a few days and generates

a testing report that you can use to fix the problems• This will include specific feedback on the issues that

were identified

The Marketplace Test Kit• The Marketplace Test

Kit lets you perform the same tests on your application before you submit it

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Testing Kit User Interface• The test kit checks all

aspects of the submission, including the required assets

• It also itemises the manual tests

Private Beta Testing• Apps can now be

submitted for Private Beta testing

• You can send invitation emails to up to 100

• They have 90 days to test your application

Advertising SDK

Adding Advertisements to Games • Very easy to incorporate ads

into XNA games• Players can click through an

advertisement to a web site or call the advertiser from within your game

• You get 70% of the revenue

Microsoft pubCenter

• Sign up here so that you can incorporate ads in your games• http://pubcenter.microsoft.com

• Find out more about Windows Phone Advertising• http://advertising.microsoft.com/mobile-apps

XNA Resources• XNA Game Studio 4.0 on MSDN http://msdn.microsoft.com/en-us/library/bb200104.aspx

• XNA Game Development Resource Page http://create.msdn.com/en-us/education/gamedevelopment

• Sean Hargreaves Blog http://blogs.msdn.com/b/shawnhar/

• Farseer Physics Engine http://farseerphysics.codeplex.com

Windows Phone resources• Emulator skin switcher

http://wp7emuskinswitcher.codeplex.com/

• “Little Watson” for XNAhttp://www.limguohong.com/2011/05/error-reporting-for-windows-phone-7-little-watson-xna-version/

• Lots of resources:http://weblogs.asp.net/bsimser/archive/2012/01/29/the-big-dummies-guide-for-windows-phone-developer-resources.aspx

• Mehttp://www.robmiles.comTwitter @RobMiles

Subtle Plug • If you are new to C#

programming and XNA game development you could do a lot worse than buy my book

Make Stuff and Have Fun• The Windows Phone platform is very powerful and

very easy to develop for• If you already have C# and Visual Studio skills this is

a great place to take them further• If you are learning how to write .NET applications

and games the Windows Phone is a great place to hone your skills and show off in the Marketplace

Be what’s next: Windows Phone• Find everything here

http://aka.ms/mbl-phone/start • Download your free Windows Phone Dev Tools

http://aka.ms/mbl-phone/tools• Channel9 ‘Get to Mango’ series

http://aka.ms/mbl-phone/mango• Register as a developer

http://aka.ms/mbl-phone/register

© 2012 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.