Silverlight Games 101

Silverlight Game Creation with the Popfly Game Creator

Bill Reiss — Sun, 04 May 2008 21:04:12 GMT

The Popfly guys have put together a game engine which you can use to create your own games.

http://blogs.msdn.com/johnmont/archive/2008/04/30/the-new-popfly-game-creator.aspx

It features the wizards and templates you've come to expect if you've played with Popfly and it's worth checking out.

Dr. Popper game, now with networked high scores

Bill Reiss — Sun, 27 Apr 2008 20:26:46 GMT

Those of you who have been following my blog for a while, or have been through the silverlight.net gallery, know about my Dr. Popper game. One of the things I was really looking forward to when I ported it to Silverlight 2 was to provide a server-based high score board. I'm pleased to announce that this is now deployed.

I used a combination of WCF and SubSonic to implement this, and I plan on creating a more general purpose high score system that you can use in your own game, so for now, if you want any more details on how I put this together, let me know.

You can play the new version here:

http://www.bluerosegames.com/brg/games.aspx

My new blog for general Silverlight (non gaming) stuff

Bill Reiss — Wed, 23 Apr 2008 20:58:28 GMT

Don't worry, I'm still mainly going to focus on blogging about game development, but I've had some topics I've wanted to post about lately that were not game related and didn't want to mix everything together in one spot. So I've set up a new blog here:

http://www.bluerosegames.com/SilverlightBrassTacks/

I'll keep posting to both, and put each post where it makes the most sense.

Fast facts about Microsoft MVPs

Bill Reiss — Fri, 11 Apr 2008 00:43:12 GMT

Well it looks like my renewal post the other day generated some interest and discussion, and it prompted Dave Campbell of Silverlight Cream to post his feelings about the MVP program as well:

http://geekswithblogs.net/WynApseTechnicalMusings/archive/2008/04/04/121043.aspx

Scott Vallee just sent me some fast facts about the MVP program that I'd like to share with you:

Worldwide there are more than 100 million participants in technical communities.
Of these participants there are only 4,000 MVPs located across 93 countries, spanning more than 30 languages and more than 90 Microsoft technologies.
There has been a 10 percent to 15 percent MVP audience growth in countries such as China, Russia and Korea.
Over the past few years new regions with MVPs include the Republic of Congo, Ghana, Nepal, Macedonia and Macao
In recent years, a handful of MVPs have been awarded in new categories such as MSN, Xbox, Visual Studio Tools for Office, Microsoft Dynamics and Visual Studio Team System.
MVPs are a diverse group that includes accountants, teachers, artists, government workers, engineers and technologists.

Thanks Scott for the information!

So now I feel even more honored to be part of the program, unfortunately my flight to the MVP Summit tomorrow (Friday) is on American Airlines on an MD80, so hopefully I'll make it up there.

Renewed as MVP for another year, with a bit of a change

Bill Reiss — Fri, 04 Apr 2008 12:20:58 GMT

I'm very happy to share that I've been renewed as a Microsoft MVP for the next year. Along with the renewal, I have been switched from DirectX/XNA as my main competency to Client App Dev, which is where they're putting the MVPs these days that are focusing on Silverlight. So what does this change mean? Not a lot overall, many MVPs focus on more than one area of Microsoft technologies, but it does mean that at events like the MVP Summit coming up, I get access to more sessions with the Silverlight team.

For those that are not familiar with the MVP program, it's all about helping in the community, both online and local. People who contribute significantly to one or the other or both are recognized by Microsoft for their contributions and are awarded on a yearly basis. When it comes time for renewal, you are judged solely on your contributions over the past year, and it's getting harder and harder to get renewed, so I'm grateful to be a part of the program for another year.

Reflecting back on my first year as an MVP, I'm thrilled with how many great people I've met, and the groups I've been able to speak in front of. Over the past year, I've gone from a complete novice speaker terrified to get in front of a small group to someone who's pretty comfortable in front of a group of 100 or more. Working with the community is something I really enjoy, maybe more than I even thought I would, and everything that I've given has come back to me many times over.

People ask me how to become an MVP, and for them I have the following advice:

Find a Microsoft technology that excites and interests you
Get involved in online forums and newsgroups, especially answering questions
Get to know your local Microsoft Dev Evangelists and User Group leaders
Get to know the other MVPs that focus on the same technology as you
Volunteer to speak at any event you have an opportunity to speak at
Start a blog and post useful information in the technology of your choice
Start or become a contributor to an Open Source project, for example on CodePlex
Most importantly: Only pursue MVP if you truly enjoy helping the community. It's a lot of work, and unless the work is rewarding to you, the other benefits probably won't be worth your time.

This is a very exciting year for Silverlight and XNA, and I look forward to contributing to both of these communities of the next year and beyond.

Addicted to Silverlight? There's still hope...

Bill Reiss — Mon, 31 Mar 2008 18:24:45 GMT

Try some Silverlight Rehab, it looks like Microsoft is giving back to the community by providing help for the addicts. You can see some candid video here:

http://on10.net/blogs/tina/Silverlight-Rehab/

The Microsoft MVP Summit 2008 starts 2 weeks from today

Bill Reiss — Mon, 31 Mar 2008 13:31:47 GMT

The Microsoft MVP Summit is a yearly conference where MVPs from around the world come to Seattle and Redmond and meet with other MVPs and Microsoft employees, including some of the people on the product teams that they interact with. I'm fortunate to be able to attend this year, and I look forward to meeting people that I've seen around the same online haunts that I have.

I have officially been switched over from a XNA/DirectX MVP to a Client App Dev MVP which is where the Silverlight and WPF MVPs are currently being put. I am still interested and somewhat active in the XNA community, but I have been spending more of my time on the Silverlight side of things so it made sense to make the switch official. So that means I'll be hanging out during the day with the other Silverlight focused MVPs and the Silverlight team, so I'm pretty excited about that.

So if you're going, try to seek me out, I'd love to meet you. I'll be wearing a Blue Rose Games T-shirt some of the time which should help you recognize me.

Keyboard Input for Silverlight 2 Games

Bill Reiss — Mon, 31 Mar 2008 12:08:16 GMT

Source code for this tutorial: http://silverlightrocks.com/cs/files/folders/silverlight_2_tutorials_source_code/entry342.aspx

Now that we can rotate the ship using the game loop, let's add a way to control this rotation using the keyboard. You main forms of human input in a Silverlight application will typically be the keyboard or the mouse, I'll write a tutorial on mouse input in the future, but the mouse buttons generally behave like the keyboard buttons, and are actually a bit simpler.

Trapping Keyboard Events

Keyboard handling in Silverlight 2 consists of handling the KeyDown and KeyUp events on a FrameworkElement that has focus. The needs of a game are typically a bit different than regular text input since what we're really interested in is whether a key is currently pressed or not. To help with this, I have added another class to the BlueRoseGames.Helpers library. This class in the BlueRoseGames.Helpers.Keyboard.KeyHandler class and it keeps track of the KeyDown and KeyUp events so that all the caller has to do is call a IsKeyPressed method to see if a key is currently pressed.

Here is the source code for the KeyHandler class:

using System;using System.Windows;using System.Windows.Controls;using System.Windows.Documents;using System.Windows.Ink;using System.Windows.Input;using System.Windows.Media;using System.Windows.Media.Animation;using System.Windows.Shapes;using System.Collections.Generic; namespace BlueRoseGames.Helpers.Keyboard{    public class KeyHandler    {        Dictionary<Key, bool> isPressed = new Dictionary<Key, bool>();         FrameworkElement targetElement = null;        public void ClearKeyPresses()        {            isPressed.Clear();        }         public KeyHandler(FrameworkElement target)        {            ClearKeyPresses();            targetElement = target;            target.KeyDown += new KeyEventHandler(target_KeyDown);            target.KeyUp += new KeyEventHandler(target_KeyUp);            target.LostFocus += new RoutedEventHandler(target_LostFocus);        }         void target_KeyDown(object sender, KeyEventArgs e)        {            if (!isPressed.ContainsKey(e.Key))            {                isPressed.Add(e.Key, true);            }        }         void target_KeyUp(object sender, KeyEventArgs e)        {            if (isPressed.ContainsKey(e.Key))            {                isPressed.Remove(e.Key);            }        }                    void target_LostFocus(object sender, RoutedEventArgs e)        {            ClearKeyPresses();                    }         public bool IsKeyPressed(Key k)        {            return isPressed.ContainsKey(k);        }    }}

Basically how it works is that the constructor accepts a FrameworkElement and the KeyUp and KeyDown events are wired up for that FrameworkElement. Then as keys are pressed and released, the current list of pressed keys is kept in the Dictionary. We're only really using the key of the dictionary and not the value. This gives us an indexed quick lookup of the keys that are currently pressed. Then in your game loop, you would call the IsKeyPressed() method for each key that you care about. The LostFocus event is important since if a key is being pressed when you lose focus, you won't see the KeyUp event and the key will get "stuck" in the down position. So on LostFocus, KeyHandler clears all of the currently pressed keys.

So now to use this in the SpaceRocks game.

The hardest part of this whole thing was getting focus to the Silverlight control. If the Silverlight control doesn't have focus, then you're not going to see the key presses. There have been some discussions on the forums lately about how to force focus to the control, and there doesn't seem to be a good way that works cross browser so we're stuck with making the user click on the control to make it get focus.

First we need some text to indicate that the user has to click. We'll put this after the Canvas in the Page.xaml but still inside the Grid element:

<TextBlock x:Name="clickToStart" Width="250" Height="80" Text="Click to Start!" Foreground="White" VerticalAlignment="Top" Margin="50" FontSize="35" TextAlignment="Center"/>

The game should now look like this:

We'll need a using statement in the Page.xaml.cs so that we can access the KeyHandler class:

using BlueRoseGames.Helpers.Keyboard;

Now we won't start our timer until after the control has focus, otherwise the player won't be able to control the ship when the game starts. We'll also want to stop the timer if the control loses focus, which will pause the game. When the control receives focus, we'll want to hide the TextBlock that tells the user to click, and on a loss of focus, we'll display it again.

One last thing we'll need to do is actually handle checking for which keys are pressed. We'll check for A or the Left Cursor Key to turn left, and D or the Right Cursor Key to turn right. This is the updated Page class in Page.xaml.cs:

public partial class Page : UserControl{    StoryboardGameLoop gameLoop;    //   DispatcherTimerGameLoop gameLoop;    KeyHandler keyHandler;     double rotationSpeed = 150;    public Page()    {        InitializeComponent();        this.GotFocus += new RoutedEventHandler(Page_GotFocus);        this.LostFocus += new RoutedEventHandler(Page_LostFocus);        this.MouseLeftButtonDown += new MouseButtonEventHandler(Page_MouseLeftButtonDown);        gameLoop = new StoryboardGameLoop(this);        //  gameLoop = new DispatcherTimerGameLoop();        gameLoop.Update += new GameLoop.UpdateHandler(gameLoop_Update);        keyHandler = new KeyHandler(this);    }     void Page_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)    {        clickToStart.Visibility = Visibility.Collapsed;        gameLoop.Start();    }     void Page_LostFocus(object sender, RoutedEventArgs e)    {        clickToStart.Visibility = Visibility.Visible;        gameLoop.Stop();                }     void Page_GotFocus(object sender, RoutedEventArgs e)    {        clickToStart.Visibility = Visibility.Collapsed;        gameLoop.Start();    }     void gameLoop_Update(TimeSpan elapsed)    {        // do your game loop processing here        if (keyHandler.IsKeyPressed(Key.A) || keyHandler.IsKeyPressed(Key.Left))        {            ship.RotationAngle -= rotationSpeed * elapsed.TotalSeconds;        }        else if (keyHandler.IsKeyPressed(Key.D) || keyHandler.IsKeyPressed(Key.Right))        {            ship.RotationAngle += rotationSpeed * elapsed.TotalSeconds;        }    } }

We're done for now, you should now be able to control the rotation of the ship using the A and D or cursor keys.

Oops found a bug in the last tutorial

Bill Reiss — Mon, 31 Mar 2008 00:44:57 GMT

The DispatcherTimerGameLoop had a problem where it started the timer immediately when it was created instead of waiting for the start event. The tutorial and the source code have been updated with this fix. You can find the updated source code here:

http://silverlightrocks.com/cs/files/folders/silverlight_2_tutorials_source_code/entry337.aspx

Another Silverlight 2 Game Programming Blog

Bill Reiss — Sat, 29 Mar 2008 20:00:54 GMT

I just came across a new Silverlight game programming blog at http://silverlight.net/blogs/msnow/archive/2008/03/25/introduction.aspx

The author is Mike Snow who is a Microsoft employee on the Web Tools team. I think it's great whenever there's more sources for information out there, and I'm sure we'll be covering some different stuff or in a different way, so I look forward to seeing what he comes up with. Welcome, Mike!