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So what's the problem that we'll get with our current code?

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Because we're saying an update, do a thing every single frame.

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If I'm on a fast computer, then it's going to do that a lot of times and maybe have my car move different

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to someone who's on a slower computer and they're doing things less per second.

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So we need to understand how to use time, delta time and what it is time to tell to.

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Time is a way that unity can tell us how long each frame took to execute.

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So on a fast computer, it's going to take a short amount of time for each frame on a slow computer,

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it'll take a longer amount of time.

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And then when we multiply something by the amount of time it took for each frame, it allows us to make

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things frame rate independent.

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So in other words, the game behaves the same on fast computers as it will on slow computers.

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Or if you're working on a mobile device versus a computer, etc. We want to make sure on everything

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we get the same sort of behavior.

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So let me give you a little example here, if that hasn't clicked just yet on UPDATE.

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So in other words, each frame we want to move our player one unit to the left.

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So on a slow computer, we might be getting, say, ten frames per second on a fast computer, we might

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be getting, say, 100 frames per second.

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And it's going to vary even on a fast computer.

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Sometimes it'll be 100 frames, sometimes it'll be 200 frames, some 150 frames, depending upon what

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else the computer needs to calculate.

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It bounces up and down.

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So we need to smooth all of that out.

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But look, in my example here, if we have ten frames per second, that means each frame is 0.1 second.

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Yes, .1.41.1.

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If you do that ten times and reaches 1/2 on a fast computer, if we've got one 100 frames, then each

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frame is lasting 0.01 of a second because 100 of the 0.0 ones is going to add up to 1/2.

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So the distance per second.

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Remember, we're saying move one to the left, every single frame.

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So one, and we're doing ten frames per second if we multiply by 0.1.

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In other words, how long is a frame we get a value of one.

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It'll move one to the left.

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If we're saying in a fast computer one frame and we're doing that 100 times per second, then we need

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to multiply that by 0.01 to continue to get our one unit.

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So that's just a little bit of an example of showing that when we multiply by this time Delta time,

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in other words, how long is each frame taking?

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We can end up with exactly the same value no matter how fast the computer is running.

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And so if I jump back over into my code here, I can find my sticker amount and my move amount.

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The steer amount, I've got a value from minus one to plus one because it's on the horizontal axis multiplying

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by the sticker amount, which at the moment I think in my code I've got as 0.05.

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Yep.

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And then I'm finally going to multiply that by time capital T, dot delta, small D and then capital

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T time, delta time.

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It's as simple as that.

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So really simple micro challenge for you here.

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Do the same for our move amount times that by time delta time.

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Pretty easy.

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That's why I didn't give this to you as a challenge.

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Slide time.

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Delta time.

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So now they're both frame rate independent.

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However, when we save this jump back over into unity, we're now going to be getting exactly the same

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behavior on all computers.

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But it's going to have messed up our tuning because we tuned it in a way where we weren't frame rate

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independent.

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So now when I move, I'm moving, but so slowly you can't even see it.

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So now we'd need to go in to change the steer speed and move speed so that our car drives properly.

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And this is what I'm going to give to you as a challenge.

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So if you will change your speed amount in the inspector to have your car respond to input as you would

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like it to.

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So in other words, to drive and steer at the right speed.

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Pause video.

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Take on that challenge now.

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Okay.

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So first I'm going to do is try increasing it a lot to say 101 hundred just to see what happens there.

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I'm going to click on play push forward backwards to fast on the movement and not terrible on the steering.

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So I'm going to iterate while in play mode.

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I'm going to bring the steer speed down, say to 20 no wrong one.

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I'm going to move the move speed down to 20 and then click back in the game window.

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Moving, moving.

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Not too bad.

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I think it's steering a little bit too slowly because it's taking a while to do a big arc like that.

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So I'm going to increase my steer speed to 200 click back in the game window.

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Now, as I drive around, it's not too bad, you know, that's pretty good.

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I could have the steer speed a little bit more.

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I think probably to 300.

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Want it to feel nice and snappy.

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Click back in the game window and remember, okay, now it's feeling kind of cool.

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So I need to remember these values.

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320 click out of play mode.

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I'll lose my values, but pretty easy.

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320 are the two values that I came up with.

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You're welcome to come up with whatever values you want.

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You don't have to do the same as mine.

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Your game should feel the way you want your game to feel.

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And that is all for this lecture.

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We've added frame rate independence by using time delta time.

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I'll see you in the next lecture.