#4 Pro AI in Unity3d using RAIN{INDIE} & FPSControl.com Video Lecture | How to make Video Games: Game Editor Tutorial - Game Development

all right I think we know enough to be
pretty dangerous right now so instead of
going through the basics let's take it
up a notch and let's do some artificial
intelligence now if a character attacks
you in the game that is sort of in an
intelligent character but it is
artificially made so we called
artificial intelligence
now usually artificial intelligence is
the rocket science of the games industry
because it is pretty beautiful to do you
have to give the characters sort of eyes
and ears and all kinds of stuff so they
know where they're supposed to go
however in FPS control we're using a
package by rival theory which are rocket
scientists from New Mexico that have
made it pretty easy for us to to make a
very very very robust AI inside of FPS
control and they do this using behavior
trees and we'll get into that in a
second first let's go set up our
character so I have the scene open here
and I'm going to go with a 2x3 view so
that I can easily see things then I'm
going to turn the lights off for my
scene so I can also easier see things
and I'm going to click on the player and
focus on that object here now I'm going
to go to my project window here on the
right and I'm going to type in shock
trooper to find the shock trooper model
close out the search and it will bring
us to the shock trooper folders here and
I'm choosing the third one so let me get
rid of this sort of visual view I know
that it's nice but here we go one column
layout but it like this better just for
now I'm going to drag that shock trooper
in there and as you can see is pretty
small compared to the player so I'm
going to scale it up just a bunch and
usually that's freako if you see on the
bond
he just gets into your grill it's
usually better to just type it in so it
says 1.8 let's have some clean variables
here 1.8 1.8 is the skill for X Y & Z
excellent now that we have that we're
going to give him let me click on him
again
close out the environment click on the
shock trooper here that we've added and
add a component to him which is under
physics and called character controller
and this is unities way to control a
character inside of the game so we're
going to use that but as soon as I
rigged it up you can see that it's way
too large in this case seems we've
killed the character up it doesn't
really know what to do anymore so if I'm
going towards the right here you can see
I have a bunch of variables I can type
in so the height is definitely too much
I'm going to punch that in as I think it
was 1.8 and then the Y needs to be
refocused it's still too large at 1.8 so
I'm gonna go to a 1.3 for example and
I'm gonna take the radius down so that
it fits my character nice and snug and
there are a couple things that I'm
noticing here we don't want it to go
through the floor and we don't want it
to go too large over the head so there's
a little bit of fiddling here let's go
with a 1.0 instead and that seems to
work pretty nicely let's take the Y down
a bit still goes through the floor a bit
so let's go with a 0.95 that's about
right bring it up just a tad and there
we go just enough to cover their
character entirely and just enough to
make sure it doesn't go through the
floor now there's that but as soon as I
hit play you'll notice the character
does absolutely nothing
it just stands there and that's not very
dangerous so we need to go fix that let
me turn the gizmos in 3d off so they're
a little bit smaller in the screen
perfect and now we're going to rig up
our character for artificial
intelligence so to do that go up to the
menu where it says rain and if you don't
have a Ray menu here you're not in FPS
control you need to be inside of FPS
control and then create AI and then with
a behavior tree mind so what we've just
done is we given the shock trooper all
kinds of aspects as you can see with all
the green lines going on so one of them
that is being created is called a mind
and it doesn't really look like an
object in the scene but it's definitely
something that is very useful because it
gives our character its thinking line so
as soon as I click generate exavation
manager then it creates a script here in
the AI scripts folder called a a AI
manager and doesn't really matter what
name it is it generates it at random for
you as well as attaches it to the mind
now what is an activation manager you
may ask that's basically a little script
that activates our character for us
however we haven't told it exactly what
to activate in the character so when our
on the game right now still nothing
happens that's okay now what do we need
to go do is check out a couple of other
things that have been added one of them
is a sensor and as you can see it's a
block that goes through the floor so I'm
going to hit the move tool and move up
just a bit and the sensor is basically
the range at which this character can
sense other things and with other things
I literally mean anything we can make it
smell things we can make it hear things
we can do all kinds of cool stuff with
it in this case if we look at the sensor
we've selected on the right we see the
sensation name is sight so that means he
can see things that's what site is of
course for okay we can add multiple
sensations to it but I'm just gonna
leave it at sight for now all right then
we have another thing which is called a
path manager also a sort of an invisible
object but what that does is it makes
sure that the
actually knows where to walk and where
he cannot walk and on purpose I'm going
to not fill in the path manager for a
second so you can see what happens when
a character doesn't know what's going on
world it's actually quite funny it just
walks around blind but now there are
more instances here there is an obstacle
avoidance Collider which I'm going to
move upwards also just a little bit
around the character well you make the
radius a little bit smaller here and
this avoids obstacles I'm gonna move it
down just a bit it's okay if it goes a
little bit through the floor but we
don't want him to sense objects when
they get too close so I don't want the
fear to be all the way on the bottom of
his feet all right so there we have that
now we go back to the mind and the mind
wants us to give it a behavior tree file
name as well as a root name before the
character actually starts working now
let me explain this for a second
behavior trees are a sort of a common
way to do artificial intelligence that
was first invented when Halo 2 came out
of course that's a long time ago for a
lot of us but in games it's still pretty
new technology now what happens is is
there is a tree inside of the mind of
the character and the tree has all kinds
of branches and notes so for example if
the character wants to go up out of bed
and grab a glass of water out of the
fridge then the tree would be something
like get up out of bed you know walk
towards the fridge open it and grab the
ball of water you know so that would be
sort of a list of actions that he would
do however if the character was attacked
from somebody while on his way to the
fridge then of course his priority would
not be to grab water anymore so he
starts to do something else and that's
where you know a tree is very handy
because it goes from one branch of
actions to another branch of actions
depending on the priority of the
character so that's what a behavior tree
is so let's go ahead and make one for
our character here
you