2D Movement in Unity (Tutorial) Video Lecture | Build a Game: Unity Tutorial (English) - Game Development

one of the most essential parts of
creating a 2-d game is of course player
movement and even though it's one of
those basic mechanics that we often take
for granted creating a really good
player controller can actually be quite
challenging in fact it's something that
even experienced programmers can spend
weeks or even months of development time
getting to feel just right of course
everything depends on what you want your
character to do can you jump can you be
controlled in air can you crouch can he
wall run does he slide down ledges what
about animation and so on now that might
sound a bit overwhelming but as always
with game development there are ways
that we can cheat a little bit if you're
just starting out I really recommend
finding a good character controller
online simply because you don't want to
be stuck doing movement when there are
so many other aspects of game
development that you should explore also
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and the first 500 people will receive
their first two months for free now a
character controller is basically just a
script that takes care of all the more
advanced physics calculations that go
into making your character move so by
using one of these we can focus on
writing a much simpler script that will
just tell the character controller what
to do for the purpose of this video I've
of course gone ahead and prepared a
character controller that we can use as
a base but enough talking about it let's
give our player some moves yeah so we're
here in unity and I've gone ahead and
set up a simple 2d scene using this
Sunnyland
asset from the unity asset store of
course have a link for that in the
description there's not much in here
there's currently just a player which
has nothing on him other than a sprite
renderer as well as a main camera of
course some different tiles making up
our level and I've gone ahead and placed
colliders on the platforms as well as
the ground and then we have a few
background elements so since we're going
to be using a character controller to
help us with our movement
of course first have to get it into
unity - right here on the desktop of
course have a link to where you can
download the script as well as the
entire project so I'm just gonna take
this and drag it into unity and right
away that select our player and drag a
script on there if we have a look at the
different variables that are in a script
we can see that we can adjust a bunch of
different things that has to do with our
character first of all we have the jump
force I'm just gonna set this to a value
of 700 we then have the Crouch speed
which we can adjust using a slider here
and this is basically how much we want
to slow down when crouching I'm just
gonna set this to something like point
four and so we're gonna be moving at 40%
speed while we're crouching we can also
adjust how much we want to smooth out
our movement I'm just going to leave
that as is whether or not we want to be
able to control the character in air
which I definitely do want to and then
we have to define this what is ground
variable and this basically just allows
us to choose what layers we want to act
as a walkable surface for our character
I'm just gonna set this to everything
and then go back in and remove the
player layer because we don't want our
player to be able to walk on top of
himself I'm also going to go to the top
and change this layer to player and then
we have these three empty slots the
first two of what we call checks and we
use these to check whether or not we're
currently standing on the ground so that
we can determine whether or not we can
jump and if we're crouching we want to
know if there's a ceiling above our
heads in order to determine if we can
actually stand up again and to make
things simple we're using these empty
objects to determine where these
locations are let's go ahead and create
these objects that's right click on the
player and let's hit create empty and
I'm gonna switch to the move tool here
by pressing W and now we can see where
the empty object is I think this is
pretty close to our ceiling check but
I'm just going to go ahead and move it
up a tiny bit something around here I'm
then gonna duplicate it by pressing ctrl
D and move this one down to the feet of
our character I'm gonna rename this one
to ground check and the other one to
ceiling check just to stay organized we
can then select our player and drag our
ground check into the ground check slot
and the same thing for this earring
check the last variable here the Crouch
disable Collider we'll talk about later
but a character controller is now set up
and should
work just fine however there are a few
more components that are required in
order to make our player work the first
one of these is of course a rigidbody
because this will enable physics for our
character so that's it a component and
let's search for rigidbody 2d we can
then open up this component and the
first thing that we want to do in here
is probably bump up our gravity scale in
general it feels nicer if your character
has a larger gravity than all the
objects it makes stuff like jumping feel
more snappy I'm gonna set mine to 3 but
you can of course experiment we also
don't want our character to be able to
rotate at all we simply want him to move
around the level but always have him
facing upwards
because of this we can go under
constraints and freeze the rotation on
the set axis and now he should stay the
same at all times finally we need to go
in here and add a Collider for a player
because right now if we play the game we
can see that he simply just falls down
but it can actually be a really good
idea to use multiple colliders when
you're working with a player
this can help smooth out collisions or
make them feel more realistic one fairly
simple setup that I really like is using
two colliders it's circle Collider and a
box Collider let's start by creating the
box Collider so we're going here and add
a box Collider 2d let's open it up and
we should now be able to see it however
the background makes it pretty hard to
see so I'm just gonna go under my main
camera and disable the background for a
second and now when we select the player
we can clearly see the green bounding
box I'm gonna hit F to focus on a player
and then gonna press edit Collider and
we can now scale our Collider to fit our
player one thing that I recommend is
holding down alt to scale on both axes
well the reason for this is that we
don't want any offset on the x axis
because since we are flipping the
character that's gonna make the collider
behave really weird so I'm just gonna
bring this in and I'm also going to
bring it down on the Y and finally
actually want to completely remove this
Collider from the feed of our character
and that's because I found it works much
better to use a circle Collider here so
I'm gonna stop editing this Collider and
add a circle Collider a small circle
Collider 2d let's open this up as well
and we see right now it isn't really
positioned in a way that we would like
so we can of course go in and offset it
on the Y here as well as press
did Collider and kind of bring it in and
I'm gonna go ahead and move it up a tiny
bit more and if you slide on a value
like this in the inspector while holding
down all you'll be able to fine tune
much more neatly something like that
looks pretty good
I'm actually gonna adjust the radius to
be just a tad larger and bring it up a
tiny bit more and finally I'm gonna take
the box Collider and bring it down a
tiny bit
and in whit's a tiny bit there we go
let's stop editing the collider and we
now have these two overlapping colliders
and you can already kind of see what the
benefit of this is because say we want
to move up a slope like this one if we
were only using a box Collider it would
take the edge of this Collider and kind
of push it towards the slope however
since we're using a much more rounded
shape a movement is going to feel much
cleaner when moving up the slope and
that's actually another reason which has
to do with crouching but we'll see that
later so let's move our player back up
and if we now hit play we can see that
immediately our player falls to the
ground and he's ready to start moving so
let's stop playing let's rename the
background here let's select the player
I'm just gonna close all these
components and let's add our player
movement script let's hit a component
search for player movement select new
script create an ad and it's double
click it to open it up in visual studio
and the script that we're gonna be
creating here is fairly simple and the
very first thing that we want to do is
get a reference from a player movement
to our character controller to D so that
we can tell this script to move our
character to do that at the very top of
our script will create a public
character controller 2d variable and
we'll simply call it something like
controller if we then save this and go
into unity we can see that we now get
this empty slot called controller where
we can drag in our character controller
script and now every time we write
controller in our movement script it's
referencing this particular script so if
we were to go in here and write
controller dot move well this would go
ahead and move our character well of
course we can't just tell it to move we
need to specify where we want to move
both in what direction and add what
speed so to do that we need to
get some input from the player and every
time we get input from the player we use
the input class so I'm gonna write input
dot and then we're going to use the
function called get access raw and the
access that we want to get here is the
horizontal axis now what this is is
basically a value between minus 1 and 1
that is going to change depending on the
user input if we press the left arrow
key or the a key on our keyboard this is
going to be minus 1 if you press the
right arrow key or the D key on a
keyboard this is going to be 1 and
similarly if you're using a controller
and press the thumbstick all the way to
the left it's going to be minus 1 and to
the right of course it's going to be 1
so this simply gives us a value that
determines where we want to move on the
horizontal axis to kind of show you this
happening I'm just gonna use a symbol
function called debug deadlock and this
will print out a message to the console
in other words we can simply display our
input here inside the editor so if we
just write out this piece of code here
and save it and then hit play we can see
that in the console here we get a bunch
of messages saying 0 however if I then
press my left arrow key we can see that
it says minus 1 and if I press my right
arrow key we can see that it says 1 so
now we have a way of detecting input I'm
gonna get rid of the debug deadlock here
and we could use this input to move our
character right here but it's not
recommended to move a character inside
of the update method instead we want to
use another function that is dedicated
for physics this function is called
fixed update and it works in much the
same way as update however instead of
being called once every time the
computer draws a frame on the screen
it's called a fixed amount of times per
second hence fixed update so let's just
go ahead and create this function I'm
gonna write void fixed update let's open
and close two parentheses and some curly
brackets and this is where we want to
move our character so in general when it
comes to movement we can say that we use
the update method to get input from our
player and we use the fixed update
method to apply that input to our
character we're not really using the
start function here so I'm just gonna
remove that but we of course need to get
this input from one function to the
other and to do that we need a variable
so at the top here I'm gonna ride float
let's create a very
called something like horizontal move
and by default we'll just set that to
zero then inside of our update method we
can set horizontal move equal to the
result of our input and we'll close that
off with the semicolon then when we want
to actually move our character down here
we can write controller dot move and
this of course takes in a float
determining how much we want to move and
we want to move according to our
horizontal move variable and let's then
close that off with the semicolon
however our move function actually also
takes in two other variables the first
one determines whether or not we should
crouch and the second one determines
whether or not we should jump right now
we'll just say no to both of these so
we'll write comma and then false saying
that we don't want a crouch and comma
false saying that we don't want to jump
but we'll of course implement both of
these in a sec also right now we're
moving our character in the right
direction but we don't have any control
over the speed so let's just go to the
top here and create another public float
and we call this one the run speed and
set it to something like 40 by default
then when we get the input from our
player we'll go ahead and multiply that
input with a run speed so that if the
player wants to move to the left the
horizontal move will be minus 40 and to
the right will be 40 and the final thing
that we need to do in order for this to
work correctly is whenever we're telling
our character to move we actually need
to multiply that movement speed with
time fixed Delta time now time that
fixed Delta time is the amount of time
that elapsed since the last time this
function was called in other words
multiplying with time that fixed Delta
time is going to ensure that we move the
same amount no matter how often this
function is called so that if this
function is called 60 or a hundred times
per second doesn't matter our character
speed is still going to be consistent
across all systems and platforms and now
this should work so let's go ahead and
save this and inside unity we can now
see our run speed which we can adjust
here if we want you let's hit play and
we can now move our character back and
forth inside of our level you'll also
notice that every time our player Falls
he kind of shifts into the ground a
little bit to get rid of this we can go
under rigidbody and change the collision
detection for
discreet - continuous and this should
make sure that he never kind of goes
into the ground in any way so now we're
ready to make our character jump and
this is actually really easy compared to
normal movement all we have to do is
check whether or not we press the jump
key so we'll write if input dot get
button-down so if we press down a
certain button and the button that we
want to check for is jump well then we
want to go ahead and jump and of course
again we want to jump inside of a fixed
update functions so we have to kind of
transfer this information down here and
again the best way to do that is using a
variable so up here will now create a
boolean and a boolean can of course only
be true or false and we'll call this one
jump and we'll set it to false by
default and then if we press the jump
button we're gonna set jump to true and
then down in our fixedupdate
instead of saying always false we never
want to jump we can now just pass in our
jump variable so that if we press this
button and jump becomes true we go ahead
and tell the controller that we want to
jump and of course right after that we
want jump to become false again so that
we don't keep on jumping forever and if
we say that anko into unity and hit play
we should now be able to move around and
whenever we press space voila our
character actually starts jumping super
cool also there's currently a quick
problem that we need to fix that is
whenever we try and jump and then move
towards a platform we can kind of get
stuck on it of course this is not
something that we would like we want to
simply slide off and then fall down to
get rid of this issue is luckily super
easy all we need to do is create a
physics material to do that we'll go to
our project and hit create and will then
select physics material 2d and we want
to create a really slippery material so
that we will simply slide off so let's
just call it slippery and in here we can
adjust to settings the friction and the
bounciness we want the bouncing s to
remain at zero and we'll also set the
friction to zero as well then if we used
to vector player we take this the pre
physics material and drag it into the
material on a box Collider and now when
we play the game we can see that we
slide right off platforms we can still
get stuck on the very corner of this
circle if this happens on earth is going
to depend
on the way you've set up your colliders
in our case we can simply go ahead and
add the slippery material to there as
well and you can now see that we fold
right off of platforms and at this point
some of you might be wondering well we
just wrote jump why does this jump
variable correlate to space and why does
horizontal mean a and D and left and
right well this is actually something
that we can configure visually because
inside of unity if we go to edit project
settings input we see the input manager
here we have the horizontal axis you can
see it's called horizontal here and we
can see the different buttons here that
is left and right arrow key as well as
the a and D key so you can go in here
and change it if you want to and there's
also one in here called jump which
currently has space as the positive
button if you wanted to jump on say W we
could simply write W here instead in
fact let's try right clicking on this
jump entry here and hit duplicate array
element this is gonna go ahead and
create a new button configuration with
the same settings let's rename this one
to crouch and instead of W we'll use the
S key of course if people want to
control the character using the arrow
keys we can set that up as well we'll
just create an alternative positive
button so here it will be up for jumping
and here it will be down for crouching
so now we've set up all of our input and
we're ready to make our character crouch
and doing this is almost as simple as
jumping we go into our update we write
if input get button down and the button
that we want to look for now is the
Crouch that we just created and if this
button is pressed well then we want to
go ahead and crouch so let's create a
variable flat up here it's also gonna be
a pole let's call it crouch and let's
set it to false by default then if we
get the button down we'll set crouch to
true and now down in our fixed update
instead of just passing in false we'll
put in our Crouch valve of course
crouching doesn't work in the same way
as jumping we don't want to just quickly
crouch and then stop instead we want to
stop crouching when we release the
Crouch button in other words we only
want to crouch while holding down Crouch
luckily we can also register whenever we
release a button to do this let's go to
the update function and that's right
else if
if we don't get a button down we might
get a button up so we'll go in put get
button up and again the button we're
talking about here is the Crouch button
and if we get a button up here we'll set
Crouch to false so now if we save this
and go into unity and hit play we should
actually be able to press down in order
to crouch however you will really not
see anything happen here the reason why
is that crouching is of course something
that we display with an animation and we
don't have any animations on our
character however we should see that if
we move and then try and crouch and move
we move at a much slower pace so it is
indeed working we can go between
crouching and normal movement and that
works just fine however one thing that
we also need to have been when crouching
is of course the ability to duck under
your obstacles for example this platform
here if I currently select the player
and we make sure that this mouse is
enabled at the top here of our game view
let's open up our circle and box
colliders we can actually see them here
if you then try and move onto this
platform we can see that we're currently
too tall to get under it that's because
of this box Collider right here what
I've gone ahead and done is under the
character controller 2d I've added this
Crouch disabled Collider so that if you
set up your kaleidos in the same way
that I have we can simply take the box
Collider and drag it in there and now
whenever we crouch the box Collider is
going to be disabled and so we're only
going to be using this circle Collider
in fact we can kind of see this
happening if I now press Crouch we can
see that the Box disappears and if I try
and Crouch my way under the platform it
works we can also see that if I try and
stop crouching so now I'm gonna release
the button while under the platform it's
not going to work and that's because
we've set up our ceiling check correctly
so it's registering that there's
something above us and so we don't want
to be able to stand up until we get to a
point here whether it's no longer
something above us and so we'll stop
crouching that's super cool of course
this currently looks a bit silly since
we don't have the Crouch animation but
you can see that behind the scenes
everything is working as it should and
that pretty much includes this first
every character controller from here
it's completely up to you to try and
expand upon it and
edit different settings to get the
controller feeling the way that you
would like it to of course this
character could really do with some
animation an animation is something
that's really fun and simple to add so
if that's something that you guys want
to see definitely leave a comment down
below
yeh that's pretty much it for this video
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