UltraHello

Introduction

UlraHello is the new way of saying Hello World! to Ultrabooks. Ultrabooks are devices which are thin, light, have great battery life and still pack the punch in terms of performance. Ultrabooks also have sensors unlike any laptops/desktops. Apart from the conventional uses of sensors they can also be used to do things they were never meant to do! They can be used to create applications which are more aware about their environment and are more alive. UltraHello takes advantage of the UltraBook capabilities and helps you enter a virtual world where you interact with objects/environments using these new sensing capabilities.

This is a WinRT application developed using C# and XAML.  

 

 

Goal:

Revealing the full concept here with screenshots. The screenshots do not represent the final designs as they may be changed for better. Also, new capabilities, levels will be added before the final submission.

Using the Code 

Now let's see how to do some of the things which have been mentioned in this article. The farseer wrapper which I'm using is Physics Helper XAML (available on CodePlex). It is very neat and works on both WP7 and WinRT.

Adding Physics Helper XAML to your project:

1. Get it from http://physicshelperxaml.codeplex.com/
2. Right-click the solution and select "Add Existing Project". Browse to \PhysicsHelperXaml\Farseer Physics Engine Metro\Farseer Physics Engine Metro.csproj in the Physics Helper XAML ZIP download.
3. Right-click the solution and select "Add Existing Project". Browse to \PhysicsHelperXaml\Spritehand.PhysicsHelper.Metro\Spritehand.PhysicsHelper.Metro.csproj in the Physics Helper XAML ZIP download.
4. From your main project, add References to the Farseer Physics Engine Metro and Spritehand.PhysicsHelper.Metro projects. 

Creating Farseer Objects:  

• Add this namespace on top of your XAML page. 

xmlns:FarseerHelper="using:Spritehand.FarseerHelper" 

• Now Create a physics canvas, all the physics enabled sprites will be children of this canvas. MousePickEnabled helps the user to manipulate objects with touch/mouse. 

 <FarseerHelper:PhysicsCanvas Height="768" Width="1366" MousePickEnabled="True">
</ FarseerHelper:PhysicsCanvas >   

•  Now you can create sprites inside the canvas in the following manner: 

<FarseerHelper:PhysicsCanvas Height="768" Width="1366" MousePickEnabled="True">
    <FarseerHelper:PhysicsSprite Height="100" Width="100" Canvas.Left="311" Canvas.Top="540">
    <Rectangle Fill="#FFAC809A" Height="100" Stroke="Black" Width="100"/>
    </FarseerHelper:PhysicsSprite></ FarseerHelper:PhysicsCanvas >   

• Canvas has various other properties like GravityHorizontal and GravityVertical which can help you do some amazing stuff.  Making a sprite Static makes it immovable and this technique should be used to make world boundaries.

I'm not going to explain the basics here since they are alrealy well explained in Physics Helper XAML documentation. Thus, I'll go ahead to the fluid part. Now the blue dots you see in one of the screenshots are definitely not fluid like but I'll tell you techniques to make them so. I'll provide the full source code later.

What are joints?

A joint, as the name suggests, joins two physics sprites. Now this joint can be welded i.e, very stiff or can be elastic. Observe the following syntax:

 <FarseerHelper:PhysicsJoint Height="8" Width="8" Canvas.Left="1086" Canvas.Top="441" BodyOne="_5" BodyTwo="_6" AngleSpringConstant="0.2"/> 

 This is a joint at the (1086, 441) between body _5 and body _6 (sprites) and is elastic with constant 0.2.

Next (Expression Blend): 

 

Those tiny dots are the physics joints, create joints between all the sprites and you'll emulate liquid's force of attraction! Now this might not be very accurate but with extra ellipses to cover empty spaces  this does become very usable! 

A look at the use of sensors:

It is very easy to utilize sensors in WinRT and most of the sensors share the same style of coding:

• Let's use the accelerometer, add the following namespace in your C# code:

using Windows.Devices.Sensors;  

 Accelerometer accelerometer; 

 accelerometer = Accelerometer.GetDefault();
 accelerometer.ReadingChanged += accelerometer_ReadingChanged;
 accelerometer.ReportInterval = accelerometer.MinimumReportInterval; 

Say playerBlock is your PhysicsSprite and you want to move it with accelerometer, do something like (experiment with values please!): 

 void accelerometer_ReadingChanged(Accelerometer sender, AccelerometerReadingChangedEventArgs args)
        {
           
       playerBlock.Position = new Vector2() { X = (float)(playerBlock.Position.X + args.Reading.AccelerationX), Y = (float)(playerBlock.Position.Y - args.Reading.AccelerationY) };
                    playerBlock.Update();
                
            }
         

 Neat Trick:

Pay attention to  playerBlock.Update(); above, this is required to keep the sprite inside the engine in sync with the one you see on the screen. Don't forget this point!. 

Points of Interest 

Ultrabooks are truly amazing devices they bring the aesthetic pleasure on the Windows PCs for the first time along with the sensing capabilities. WinRT also makes it very easy to take advantage of the new capabilities of these systems. Ultrabooks + Windows 8 is definitely the technology due to look forward to!

In the end, I would like all those who use Farseer to please pay attention to the "Neat Trick".

Future Plans: 

• Code for fluid simulation 
• Manipulating gravity with accelerometer  
• Code for producing the Whirl effect  

History 

First Post!