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‫Hello and welcome.

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‫In this lecture, we're going to be setting up our grabber so that we can actually get hold of our gargoyle

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‫statue and take it around with us in front of us.

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‫Let's dive in and see how we do this.

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‫So it's time for us to start calling this grab component at location with a rotation.

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‫Now, as I said before, there's actually two parts to this.

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‫We need to grab the component and then later we need to set its target location and rotation as well

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‫so that it moves around.

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‫So first things first in our grab function, we're going to need to get hold of a pointer to our physics

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‫handle.

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‫So I'm going to copy the line from Begin Play and I'm going to go over in to the grabber and I'm going

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‫to put it in here.

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‫And to protect ourselves from this being null.

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‫Well, what should happen?

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‫Well, actually, there's nothing that we want to do.

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‫If we don't have a physics handle, we can't grab anything.

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‫So we could put the whole body of this grab function into an if statement, but that can look a little

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‫bit messy.

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‫So what we can do instead is what's known as an early return.

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‫Essentially, we just say if the physics handle.

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‫Equals equals null pointer.

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‫You have to put a double equals sign here.

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‫Otherwise it's an assignment.

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‫Then we can go down to do some braces and we can just put a return in here.

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‫So what this is going to do is if we've got a null point for the physics handle, it returns straight

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‫away and doesn't execute the rest of the function, thus making it safe in the rest of the function

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‫to use the physics handle as we wish.

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‫So we are going to do that.

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‫We're going to go down into where we have a hit.

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‫I think we don't need these log messages anymore.

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‫So I'm going to remove the alt statement.

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‫I'm going to remove basically everything from the body of the if statement and we're going to use our

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‫grabber.

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‫So we're going to do the physics handle arrow grab component at location with rotation.

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‫Then we have to provide it with a component we're trying to grab.

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‫If you have a look, the thing that it's expecting is a you primitive component.

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‫Let's see if we've got anything of the sort in our hit result.

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‫I'm just going to pop over to the documentation page for it and look for you primitive component and

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‫you can see that get component would return the primitive component that was hit perfect.

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‫That's just what we need.

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‫So we're going to look for the hit result dot get component and that's going to give us what we want

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‫for the first argument.

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‫Now next is an F name for a bone.

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‫Now we don't actually want to grab anything by a particular bone.

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‫This would be the case if we had a skeletal mesh, but we don't.

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‫We have a static mesh, so we just use name, underscore none.

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‫And generally speaking, with F names where we're talking about bones, this comes up quite a lot.

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‫If you don't want to put anything in, you use name, underscore none.

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‫Now we need the location that we're going to grab it at.

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‫And we've already said that we've looked into this.

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‫It's the hit result dot impact point and then the rotation, well, the current rotation of that component

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‫will do or the current rotation of the actor, whichever you prefer.

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‫So the hits result get components.

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‫We're going to grab that hit results get component dot arrow because it's a pointer to get component

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‫rotation like.

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‫So now we can put the closing parentheses on a separate line and I'll put semicolon there to finish

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‫off the statement, and that should be effective at grabbing our components.

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‫Now the next part of the puzzle is in tick component where we want to again use the physics handle.

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‫So I'm going to copy the code for now, knowing that copying code to three places is a bit too many,

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‫and we might want to think about pulling it out into a function so that we reuse that.

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‫But intake component, we're going to use the physics handle, we're going to early return if we can't

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‫get hold of a physics handle.

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‫And then what we're going to do is we're going to try and set that target location.

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‫So we're going to do physics, handle arrow set target location and rotation.

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‫And let's have a little bit of a think about this.

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‫What kind of target location might we be interested in setting?

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‫Well, essentially, it's going to be the same as we did with the end point.

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‫We're going to take our current location, then move it outwards in the forward direction by a certain

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‫distance.

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‫Now, this will be configurable.

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‫You could use the max grab distance, but I find that in practice that feels too far away.

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‫So if we go to our grab a H, we're going to create a new use property called Edit Anywhere and it's

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‫going to be a float called the hold distance.

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‫And I'm going to set this to 200.

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‫So it's going to be much closer to the player.

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‫Now, if we go into the grab of CP, we can go into our tick function and try and create this target

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‫location.

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‫So it's going to be an F vector called target location.

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‫We're going to set that equal to the get component location, plus the get forward vector multiplied

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‫by the hold distance.

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‫So then we can use that as the target location.

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‫That's going to be our first argument and then we need the target rotation.

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‫Well, for that, I'm just going to use the rotation of the current component so that as we look around,

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‫we're going to rotate the object with our view so we can just do the get component rotation to get the

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‫rotation of the current grabber scene component.

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‫Now let's put a semicolon on the end of that line and recompile and see how this works.

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‫Now, after we've compiled successfully, let's select the gargoyle and just make sure that we change

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‫its mobility from START.

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‫Stick to movable because we do need it to be able to move in response to physics and let's make sure

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‫that it's simulating physics.

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‫Let's go to the physics category and check the simulate physics button.

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‫Let's hit play and try and pick it up.

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‫So I think it's happening at the moment, but it does seem to be stuck inside the floor, so that's

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‫not ideal.

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‫Let's try and lift it up a little bit so that it's not stuck inside the floor.

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‫Let it drop onto the floor like that, and now try and pick it up.

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‫Now it does seem to have got stuck inside the floor again, so let's just try a second time.

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‫Okay.

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‫So it's a little bit unreliable and sometimes if you catch it straight away, it picks up the gargoyle

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‫just fine and you can pick it up like that.

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‫I'm noticing the rotation isn't correct, and this is because I've used the wrong thing in the grabbing

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‫the physics component.

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‫I got the rotation of the gargoyle, and now we're trying to keep that rotation.

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‫What I actually needed to use was the rotation that we're using in pick the rotation of the grabber.

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‫So let's go ahead and change that and recompile and we'll just hit play again and try and grab it.

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‫There you go.

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‫This time I grabbed it and I got the correct rotation, the exact rotation that it had.

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‫And you can see that it does look like it's being grabbed on a spring.

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‫If I try and push it through a wall, it tries not to go through the wall as much as it can.

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‫It does eventually pop through the wall, but it is trying to observe physics as I move it around.

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‫So I like to challenge you now to pull out a new function called get physics handle.

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‫It's going to be private.

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‫It should return a U.

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‫Physics handle component, and it should remove this duplicated code of needing to get the owner and

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‫find a component by class.

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‫You can also make it potentially const see if you can and make it log.

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‫If we don't have a physics handle component, give a warning log so that it shows up and we know that

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‫we've done something wrong.

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‫Pause the video and have a go.

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‫Okay.

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‫Welcome back.

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‫First of all, we go to the head of file where we're going to put this in the private section, but

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‫underneath the Q properties, I'm going to have it return a U physics handle component and put an asterisk

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‫here.

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‫Now, because we are using this type here in the header, we need to actually take our include and cut

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‫it out of the grabber.

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‫So they include regarding the physics handle, we need to put it in the grabber h where we're going

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‫to put it above the generated.

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‫H That's the last thing always in our header files.

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‫And why do we not need to have it in the CP as well?

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‫Well, because we're including grabber h.

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‫So anything that we put in grab a H will automatically be in the C p so we can put the include in there.

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‫Now we can go down to where we're defining this function and call it the get physics handle pair of

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‫parentheses like that.

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‫And I think this should be const it shouldn't change anything in our grabber to call this function.

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‫So let's go over to the CP and go to the bottom where I'm going to paste in definition, I'm going to

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‫stick a U grabber colon, colon at the front, and then I'm removing the semicolon, adding a pair of

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‫braces.

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‫And what we want to do is take where we've got this get over line and we're just going to cut that out

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‫and replace it with get physics.

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‫Handle like so.

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‫And then in the get physics handle, we can simply return the get owner find component by class, etc.

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‫and now we can replace this also where we're doing it in tick component, we're getting hold of the

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‫physics handle.

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‫Let's replace that little bit of code with get physics handle.

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‫Now it's such a small piece of code, it's almost not worth it, but it's definitely worth it for the

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‫practice at this point and for the fact that we might add some log messages now and begin play.

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‫We don't actually need to get the physics to handle at all, so I'm just going to remove that code there.

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‫But what I am going to do is I'm going to add a log message.

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‫So we're going to create a variable to store our result here, because if we return and then try to

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‫print a log message, that's not going to work.

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‫So we're going to have a new physics handle component called result because that's what we're going

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‫to return out of here.

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‫And we'll say if the result is equal to null pointer, well, then we need to you log with a warning

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‫or in fact, an error really.

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‫And we're going to say grab a requires a U physics handle component and then after the if statement.

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‫So this will happen.

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‫Whether or not it is null, we're going to return the result.

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‫So let's go ahead and compile that and check it all works.

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‫Seems to have succeeded and I can see it must be working because when I left click in the scene I'm

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‫getting the blue or debug orbs being drawn and they wouldn't be drawn if we weren't getting hold of

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‫that physics handle component.

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‫Great stuff.

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‫So in this lecture we've been able to grab our gargoyle statue using our grabber, albeit sometimes

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‫it can be a little bit unreliable.

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‫And we're going to sort this out in upcoming lectures.

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‫So I will see you there.