Modifying Your Game
All right, enough talk. You're itching to get into game development and ready to put something cool into your game. Let's make it happen.
Take a look at your Draw
method. Currently, the
method contains the following code:
protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // TODO: Add your drawing code here base.Draw(gameTime); }
The first thing to notice here is the parameter that your Draw
method receives. The parameter is of the type GameTime
and represents the time that has passed
during the execution of your game. Why do you need a variable keeping track of time?
Because computers do not all run at the same speed. This variable helps you
determine when animations and other events should happen based on actual game time
rather than processor speed. The gameTime
variable will be used throughout this book to gauge things such as framerate,
animations, sounds, and other effects. The same parameter is also passed into the
Update
method, because many of the functions
that control those effects need to be performed in the Update
method rather than the Draw
method.
At the end of the method, you call the Game1
object's base Draw
method, which is essential in
order to get cascading calls to Draw
methods in
GameComponent
s and other objects. That might
not make sense to you now, but be assured that you want the base.Draw
call in the code and you should not remove it.
Finally, let's look at the call to Clear
using
the GraphicsDevice ...
Get Learning XNA 3.0 now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.