Monday Games Snap

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You might have heard of my Snaps framework. Then again you might not. I created it for my Begin to Code with C# book. 

The idea behind Snaps is that learning to create Windows 10 Universal Applications is hard because it takes a while to get to the point where you understand enough to have a bit of fun writing C#. 

So I created a bunch of helper functions that grew into an entire library for app and game development. 

As a celebration of being awarded another year as an MVP (thanks Microsoft) I thought I'd put the whole Snaps framework up on GitHub and then people can download and play with it, and maybe even take it further. 

Every week I'll take a Snaps function and explain how to use it, along with a bit of detail about how it works. Monday is now officially "Snaps Day". I'm going to start with the games creation framework and go on from there. 

This week I'm going to tell you how to get started and make your first sprite. You need Visual Studio 2015 or Visual Studio 2017 (it works with either). You'll also need to be running Windows 10 64 bit edition.

You can download the entire framework from GitHub. It's a single Visual Studio Solution that you just have to open. You might get warnings about the dangers of loading projects downloaded from the internet. Ignore those in this case. 

If you run the solution you'll get the Snaps main menu:

On the left you can select the book chapter. On the right you can pick an exercise from the book to run. Pick the one you can see above (Ch15_04_CompleteGame from Chapter 15). It's a complete game with moving sprites and all sorts. Click "Run and App" and the game will start. 

The graphics aren't the best to be honest. But you can control the game by the cursor keys, or mouse/touch on the cursor pad on the lower right hand edge. One sprite will chase you while the others look on. Everything is running under WPF and I'm very impressed with the performance. 

If you want to get ahead of the game you can grab the book and see exactly how the code works. For now though, use Visual Studio to stop the game (go back to VS and press the red Stop button), and take a look at the Solution Explorer on the top right. If you open up the Chapters folder you can find a folder for each chapter:

Open up a chapter and you can find all the sample code. The names of the samples are keyed to the ones you can find when you run the program. Take a look in Chapter 15:

Open up the one indicated (Ch12_02_BallSprite) It creates a single ball sprite and displays it.:

    public void StartProgram()
    {
        SnapsEngine.StartGameEngine(fullScreen: false, framesPerSecond: 60);

        ImageSprite ball = new ImageSprite(imageURL: "ms-appx:///Images/ball.png");

        SnapsEngine.AddSpriteToGame(ball);

        while (true)
        {
            SnapsEngine.DrawGamePage();
        }
    }

All the action takes place in the StartProgram method. It starts the game engine, creates a sprite and adds it to the game. Then, once we've made the sprites, we start a game loop which continuously draws the game page. It does this 60 times a second, because that is the frame rate requested at the start. The image for the ball is an asset which is in the Images folder in the project:

You can use your own images if you like. Drag them to the images folder and make sure that their build action is set to Content (as below). Then use the appropriate name to draw them.

If you run the framework and select this example (Ch12_02_BallSprite) you can see the ball on the screen. If you change the above code and use the handy "Run That Again" button you can see your changes. Don't worry about breaking the examples. You can always download a fresh set from GitHub if it all goes horribly wrong.

You might like to add more sprites, or fiddle with the properties of the existing sprite, in which case Intellisense is your friend:

See what adding :

ball.CenterX++;

.. to the while loop does. You should have:

while (true)
 {
        ball.CenterX++;
        SnapsEngine.DrawGamePage();
 }

If you make anything especially impressive take a video of it, send me the link and I'll start a hall of fame on this page. Because this is a Universal Application it can run on any Windows 10 device, including Xbox One and Raspberry Pi (although it is not as fast on the Pi)

Of course the best way to find out all these things (and learn to program as well) is to buy my book. 

But if you don't want to do that, then I'll have another Monday Snap for you next week.