Acceleration, Friction, and Wrapping
Employing Acceleration
We still aren't "accelerating" that object so much as setting the velocity. What's the difference between velocity and acceleration?
Velocity is a measure of speed at one instant in time. Acceleration is the change in speed between two instances.
Let's get hands-on. We'll start by changing our conditional statements:
Key presses will now change the variable ySpeed... which means nothing will happen with the ship! Let's add ySpeed to ship._y contstantly. This command goes outside the conditional statements, but remains part of the onEnterFrame function:
Finally, let's initiate ySpeed at 0, so the ship doesn't run right off the screen as soon as the program starts. This is what the updated Actions window will look like:
Test it , but be careful! The ship will quickly run right off the stage:
