In the 2D world of Windows Phone 7 game programming, the presentation of images or animations with X and Y axes is straightforward. You just need to know that the original point (0, 0) is located at the top left of the touchscreen, and the screen width and height. Now, in a 3D world, things are different, as there are now X, Y, and Z axes and the original point is not simply sitting at the top left of the touchscreen. In this recipe, you will learn how to deal with the new coordinate system.
In 3D programming, especially for Windows Phone 7, the first thing we must make sure of is the coordinate system, which is on either the right hand or the left hand. In Windows Phone 7 XNA 3D programming, the coordinate system is on the right-hand, which means the increasing Z axis points towards you when you are playing a Windows Phone 7 game.
The next step is to set the camera, like the eye, to make the objects in the...