There, all set with an Energy meter!
I have changed the Sprinting function so you now only Sprint while holding the sprint key (Left Shift, right now).
The code seems to work pretty well, only draining your energy while you're actively using it. This means that while you're in the air and holding the Sprint key, you don't waste energy. You also don't use energy if you hold the Sprint key without moving.
There are a lot of factors that determine how fast your energy refills after you release the Sprint key:
1) Your dino type. Each dino has a different maximum Energy and a different rate at which it refills.
2) The conditions you're currently in. If you're in the air, you regenerate energy slower than if you're on the ground (preventing abuse of jump-sprinting to move further without resting. We may also make jumping cost energy later on). If you're not moving, you regenerate energy (slightly) faster than if you're moving. If you're underwater, you regenerate energy slower (slightly slower as a swimmer, Muuuch slower as a flyer, and quite a bit slower for everyone else).
We will put in more advanced features for this later on, such as the ability to upgrade refill times in certain situations, among other cool stuff.

Like the Air meter, the Energy meter is only on the screen if it's not full. If you have full energy, the meter disappears from the screen.
Anyway, screenshot time!

