First Guide to Silverlight Physics Helper Library

Prerequisite:

• Microsoft Expression Blend 4
• Microsoft Silverlight 4 Tools
• Physics Helper for Silverlight

Setting up the Project in Expression Blend:

Basic Understanding:

Playing with the XAML:

• Let us play with the XAML to create a simple application (without writing any code). For doing this, open your MainPage.xaml page using Microsoft Expression Blend and replace the Grid panel with Canvas. This step is necessary because the library can recognize only canvas.
• Now we will create a ‘U’ shape valley area where we will through a ball and the ball will run along the path. To do this, first we will add a Rectangle inside the XAML page and set some background color to it.

• Add an Ellipse on top of the Rectangle, so that it can look like a valley. It will look like below snapshot.

• Now select the Rectangle and the Ellipse. Right click on the selection to open up the context menu. Click "Combine" => "Subtract". This will subtract the part of the Ellipse from the Rectangle and merge them as a Path control.

• The subtracted area will look like below snapshot. Once you are done with it, give a proper name to the newly created Path. In our example we will use "frictionArea". In this area we will through a ball which will run through the edge of the path.

• Add a new small Ellipse and name it as "ball". This ball will run through the frictionArea. Resize the ball to 82 x 82 pixel. Now set it's Left position (i.e. Canvas.Left) to 23 and Top position (i.e. Canvas.Top) to -500. This will position the ball far away from the surface.

• Now drop one "PhysicsController" and one "PhysicsStaticHolder" inside your canvas from the Assets tab (as mentioned earlier).

•  Select "PhysicsController" and goto it's Properties panel. As mentioned in the below image, set it's FrictionDefault to 5, GravityHorizontal to 0 (zero), GravityVertical to 500 and select MousePickEnabled to True. As the named suggests, FrictionDefault will add friction to your controls controller, GravityHorizontal will set the horizontall acceleration and GravityVertical will add the vertical fall down speed. In our example we don't need any horizontal speed as our ball will run in a valley. Hence we need some vertical acceleration so that it can fall down to the surface.

• Now click on the "PhysicsStaticHolder" and set it's Body to "frictionArea" from the Properties panel. Only one element you can set here. If you need more elements as the surface group them inside a Canvas and set the canvas as the Body to the PhysicsStaticHolder.

Running the Demo:

End Note: