Sams Teach Yourself Windows® Phone 7 Game Programming in 24 Hours

Hour 9. Advanced Linear and Angular Velocity

What You’ll Learn in This Hour:

• Calculating angular velocity

• “Pointing” a sprite in the direction of movement

This hour continues along the same path as the preceding hour, regarding sprite transforms, taking it a step further and applying velocity calculations to transform a sprite in useful ways. We will derive the math calculations needed to move a sprite in any desired direction based on its rotation angle (in the top-down view perspective, treating the screen somewhat like a Cartesian coordinate system). Moving a sprite at a desired angle is a very important need in most games, so you will put this technique to use extensively in your own projects. The next related calculations involve “looking” ...