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‫Welcome back.

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‫In this video we will have a look at is trigger.

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‫And you have seen physical bodies already.

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‫You have seen colliders, all those kind of things.

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‫Now let's add a new component, which is a trigger and it's actually not even a new component.

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‫And that's the beauty, because it is simply the collider itself.

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‫So you can make a collider is trigger.

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‫For example, our player could be a trigger or a new object.

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‫So let's create a new object into our game, a 3D object.

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‫Let's go with a cube.

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‫And what I will do with the cube, I will change the position to reset.

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‫So I'm going to reset it and I'm going to drag it a little bit up and to the side.

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‫Now let's change the scale of Y to, let's say five and the scale of X two.

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‫Let's go with three.

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‫So now we will have a wall here and maybe it's better if I move the wall to the side and change the

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‫X to one and to Z two.

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‫Let's go with four.

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‫So now I have this huge ball here and what I want to happen is if I walk through or if the ball passes

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‫into this cube, I want something to be triggered.

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‫So I want something to happen.

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‫For example, I want the whole thing to disappear.

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‫So let's say I want the wall to disappear, which is this cube.

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‫So let's give it a is trigger.

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‫The cube itself gets an is trigger.

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‫Let's have a look.

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‫What that does is it deactivates its collider in terms of it's not a wall anymore so it's not a wall

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‫that we cannot pass through anymore.

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‫So now as you can see, our ball simply ignores it.

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‫It just walks through.

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‫So if we want this wall to do anything, whenever something passes it or hits it, then we need to create

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‫a new script.

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‫So I'm just going to call the script trigger script.

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‫So let's go ahead and create a new script, right click create and then see sharp script and call it

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‫trigger script.

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‫Now I'm going to assign that trigger script to my cube.

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‫So let's go ahead and add the component scripts and trigger script.

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‫And now let's open trigger script up.

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‫And there is only one thing that I need in here, so I won't need to start an update method.

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‫And again, it's not that important that you understand the code in itself, but it's more important

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‫that you understand the principles.

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‫So whenever something needs to happen, when our object is hit by another object, we need to use the

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‫on trigger enter method.

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‫There's a method called on trigger.

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‫Enter is called when the collider other enters the trigger and other could be our player for example.

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‫So let's do that.

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‫I just pressed enter.

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‫I chose the on trigger entry method and now it's created for me automatically here.

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‫So what I can enter here is, for example, print triggered.

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‫So I'm just gonna print something onto the console and you will see what that does in a second.

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‫So let's do that.

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‫So now our cube, it's really important that our cube has this trigger script.

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‫Now we run the code.

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‫And let's pass through our trigger.

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‫And as you can see on the console here, it says Trigger.

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‫So now let's trigger once again.

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‫Let's try to get the ball back.

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‫There we are and let's hit it again.

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‫You can see it's called three.

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‫It was called three times already, and that's because we passed through it three times.

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‫What you could use that for is, for example, to get rid of this whole game object.

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‫So let's do that.

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‫Let's go back into the code and we call Trigger now and we also call the destroy method.

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‫And I'm just going to give game object.

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‫So what that will do and I'm just going to use game object as the parameter, what the parameter is,

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‫what the destroy method is.

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‫If you don't know those things yet, we will get into that later.

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‫So the destroy method, what it will do, it will simply destroy the game object that contains this

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‫trigger script.

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‫So that's what this line here says.

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‫So let's have a look how this looks in game.

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‫So I'm going to simply trigger this event.

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‫And you see, our wall has disappeared.

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‫So if we set up our game slightly differently, so I'm just going to go ahead and position my ball at

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‫the bottom straight away and move it to the left.

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‫And now I'm going to move my cube a little bit and I'm going to duplicate that cube multiple times,

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‫and now I move the cubes one after the other.

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‫So let's just move them.

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‫And this one as well.

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‫And the last one as well.

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‫So now if I start it off, what will happen is that one after the other will disappear that we are.

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‫I simply duplicated them with using control dx or command d based on which system you are using.

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‫So right click duplicate is another option.

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‫So if you duplicate it this way, then the object will be duplicated at the same position.

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‫So that's why you cannot see that there are two objects.

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‫So you need to move one in order to see that there are two objects, in fact.

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‫So let's go ahead and do that again.

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‫And now, as you can see, the destroy method is called.

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‫Now, what we could do is deactivate.

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‫That is trigger onto any of our objects or all of them are objects, at least of our cube objects.

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‫So let's do that real quick, except for the last two.

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‫And now what I want to add as well is a rigid body to all of them, or except while the first ones at

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‫least.

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‫So let's add a physics rigid body to cube cube.

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‫One, two, three.

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‫And that's it.

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‫So physics.

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‫Granted, Buddy, and add physics.

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‫It's important that you use physics and not physics to DX because otherwise it won't work.

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‫Now let's run it again.

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‫And now let's try to hit it with our ball.

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‫And as you can see, the first one still had a trigger.

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‫Now, boom, boom.

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‫And those two, they just fall off.

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‫So the ones that had a trigger, they disappeared and the ones that didn't have a trigger.

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‫So for five.

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‫And I think that's it.

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‫They had a trigger still, so they disappeared.

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‫But the other ones didn't disappear.

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‫Because they didn't have the trigger method activated and that's why they weren't destroyed.

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‫So now let's get rid of the trigger method from each of them.

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‫And what that will allow us to do is to have a little domino game.

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‫So let's go ahead and hit them off.

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‫Maybe we should make our player a bit bigger.

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‫I'm going to pause the game again.

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‫Go ahead and change the radius.

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‫Or actually the scale of our player to, let's say three times three times three.

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‫And let's drag it up a little bit.

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‫And now what we could do is.

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‫Go to here, you can use global or local.

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‫So now we are global and now I can move your camera towards the front and move it up a little bit.

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‫So now you have a better angle at things.

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‫So let's start it again.

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‫And now let's move it.

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‫And as you can see, not all of them are moving.

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‫Why is that one not moving?

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‫Maybe you can figure it out.

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‫As you can see now, I can move it just at the edge of it.

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‫Maybe you know why it's not moving.

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‫I hope you know it.

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‫It is because it doesn't have a rigid body.

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‫So Q.

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‫Q one, two and three have a rigid body, but they are not here in the order of their naming, so.

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‫Q One is the first one.

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‫The cube is the right one.

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‫Two is this one and three is that one.

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‫So the fourth is the one to the right and the fifth is this one.

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‫And those two, they don't have a physics body.

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‫That's why they cannot be influenced by physics.

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‫So let's change that.

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‫Let's give them a physics body as well.

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‫Physics and rigid body.

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‫Now, let's go ahead and play that again.

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‫Or maybe let's even get rid of this central one.

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‫So let's delete this that cube here, delete and let's run it again.

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‫And now let's hit it.

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‫And as you can see, we have this little domino game here.

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‫And let's try to get on top of it.

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‫Yeah.

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‫Perfect.

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‫Our ball can with its force, it can move on top of it.

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‫It can move around those objects.

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‫And now you could go ahead and play, create your own little game, a little domino game or a little

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‫collection game where you can collect game objects and make them disappear with the destroy method.

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‫All right.

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‫So that's it for now.

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‫Regarding Collider's rigid body and its trigger.

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‫We will use those extensively in our games.

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‫So no worries if you don't really get a grasp of it completely yet.

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‫But we will get there and you will see it within real games.

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‫So see you in the next video.