Game Maker Studio: Dynamic Camera Tutorial Video Lecture | Game Maker Tutorial: Build Games from Scratch - Game Development

alright guys welcome back quick reminder
for some of you if you're watching this
video as it came out on the 21st of June
then on the 22nd of June tomorrow it
will be the start of my all-day live
streams that will be happening every
Monday for the next few weeks where
they'll gain from scratch there's a
video in the description talks a little
bit more about exactly what that is and
what's going on with that so feel free
to check that out but today what we're
going to be looking at in this tutorial
is we're going to be looking at creating
a dynamic camera that not only just sort
of follows the play around in the simple
way you can set up with views but it
also adjusts for where the mouse
position is at any given time as well so
from the perspective is like a top-down
game like my game from Barragan that
shoots B's camera not only follows the
player around but also kind of adjusts
and faces wherever the mouse cursor is
pointing at any given time so I'm going
to show you how to do that and it's a
cool little system that once you have it
set up is also useful in a bunch of
other ways which I'll probably make
clearer with them a couple of follow up
videos that explore a few of the neat
things you can do with a system so let's
get in there so in order to show you how
this works I have a really really simple
game setup okay just have a big gray
room with like a textured background so
you can see where the camera is in the
room and a simple player object that
literally just sort of moves left right
up and down just in the same way as like
a top-down character kind of would in a
really basic level in views I have a
simple view set up that 640 by 480 that
we're going to use to basically follow
our player around now just to show you
how this looks if like if I set object
to following Joanne disco player so no
settings you need in here by the way
other than just to set up to 640 by 480
or whatever size you want it to be and
positioned roughly where you want it if
I move around you can see how it looks
like by default like follows the player
around that's all well and good but we
want to also adjust for sort of where
we're pointing see I like our mouse
cursor were creating kind of like a
nuclear throne type of thing or just
like a top-down shooter type of thing
similar to a gun that shoots peers or
various different
that means it can also benefit from this
kind of dynamic camera okay so come out
of that I'm going to turn that object
following thing off now so that the view
isn't set up to actually follow any
camera or anything we're going to create
our own camera objects that's going to
basically be an invisible object that's
going to move to whatever position we
want the view to target basically or
again and to move towards so I'm going
to insert a new object when we collide
opj underscore camera and I'm going to
add the step event and drag in our old
favorite engine execute code okay now
the first thing I'm going to do is
establish two important variables nuts
bar x2 and y2 okay in case I haven't
known before I think I have you can
establish two variables with one var
statement just by comma separating them
like that but then it's very important
tell game maker where that line ends
with the semicolon again it's one of a
few times where semicolons are actually
pretty important if you're establishing
multiple local scope bar variables okay
because I've established or is with var
they're temporary and they just change
every frame or whatever they're not
permanent variables you can't really
reference them from other objects and
stuff like that but they exist for this
particular step at them okay the next
thing we're going to do is say move
towards point
oh no not an object mouse X mouse Y zero
okay
that means we're gonna move this object
obj underscore camera towards our mouse
at speed of zero now you might say well
it doesn't doesn't do anything right
it's not moved new dog camera anywhere
it's moving at speed zero but I'm not
actually using this command for the
purpose of actually moving the camera
I'm doing it to set the camera as a
direction
okay so setting this object's direction
to face towards wherever the camera is
and then we can use that direction to
create kind of an offset from the player
okay and create like a circle around the
player um but the camera can move
towards without ever actually moving
outside of that circle okay but we need
to know the direction from
our player object to the mouse okay so
that's why we're pointing it in that
direction okay so and then X - okay the
corner our x-coordinate that we're
moving toward okay that's wise x2 so the
x-coordinate that we're moving ourselves
towards is going to equal obj underscore
player dot X as a given to begin with
right the x-coordinate of our player
plus length the underscore X okay that's
length in a direction on the X component
of okay and then min so the smallest out
of whatever numbers we put in these
brackets 96 is kind of an arbitrary
thing that's going to be the radius of
this circle I was talking about whereby
the camera can't move out with that
circle so whichever is smaller okay
96 or distance to point a mouse X Mouse
why okay
so whichever is smaller either 96 the
maximum radius or the distance to the
mouse okay meaning that if the distance
of the mouse is smaller than 96 it's
within that then it only goes that far
and it will follow wherever the camera
is until it gets to the outer edge of
that circle and then it won't go any
further okay that's to stop the camera
just moving all the way to wherever your
mouse is and just moving away from your
object okay this is what keeps the
camera confined to the space around your
player and then the other thing is we
just need the direction o4 to work out
the length that we're moving because
we're taking our object our player
object's position and we're moving a
certain amount of X based on a line that
we're creating okay in the direction of
the mouse so direction and then we can
close that bracket now we do the same
thing a lot like one okay so y2 equals
obj underscore player dot y plus length
the let's go Y min again 96
distance to point a mouse X Mouse Y
direction
okay so what we've done there is we're
basically finding the x coordinate or
the y corner of the mouse all right but
making sure that it's within kind of
like that radius that circle okay and as
far as it can be pushed to that circle
I'll put up some sort of diagram that
might explain it better than kind of my
confusing words might have done okay
that's basically what we're trying to do
then once we have those coordinates that
we're moving towards as opposed to just
snapping the camera straight there we're
going to do kind of a linear
interpolation type thing I'm just going
to I'm going to move towards it at a
higher speed a when we're further away
from the destination so like when you
move the mouse like really quickly or
like if you're moving really quickly the
camera will move faster towards the
thing and then it will slow to a halt
basically we're just making the camera
like move in a way that like slows to a
stop at the destination rather than just
move straight there or like snaps there
so in order to do that and say X plus
equals x - um - X okay so the difference
between the corner where we want to be
and the coordinate what we're currently
are okay so whatever the difference
between those is divided by 25 okay so
we have the exponent we know we're
moving - we have a current x-coordinate
we find the difference between those
right the distance between those two
spots essentially and we divide it by 25
and then we move that amount towards the
spot okay which means that as the
distance gets smaller or we move a
smaller and smaller amount which means
it will just slide to a stop okay
technically the number it never actually
reaches the exact at X corner what we
want but the distance eventually becomes
so small that it's trivial in the screen
space is actually exactly the same and
we end up with basically exactly the
same spot that we want it to be in so
now we just need to do the same thing in
the y component y plus equals y2 minus y
divided by 25
okay semicolons these lines which I kind
of forgot to do just like that okay and
now all we need to do is make your
camera actually follow this object so
what we need to do is save view
underscore X view R equals negative view
underscore W view divided by 2 plus X
and view on the school Y view equals
minus view underscore H view divided by
2 plus y
basically what this does is like we want
to keep our camera centered on the X and
y position of this this camera object if
we were actually just to set the X and y
position of the camera to be where this
object is we just said that 2 X & Y it's
putting the top-left corner of our view
on the object which is what we don't
want we want the camera to be in the
center so what we're doing there is
we're taking half of the the width of
the view which is like 320 taking
negative 320 and then adding the eggs
coordinate to it and the same for a y
taking negative 240 because 480 is the
height of the view and adding a
y-coordinate to it again that keeps the
camera in the center okay of our view at
all times okay that's all you actually
need for that if I go ahead and write
you know if I run that now nothing will
happen to say I'm and put the object in
the room so if I close that close that
so it fully names or object / Jones go
camera one Cobra Jones still camera in
the room we should now be able to see
the difference so now I walk around and
if I move the mouse around you can see
the camera dynamically moves to wherever
the mouse's with this system as well I
can actually move outside the room I'm
walking well outside the boundaries of
the room right now the camera is still
following me around which is something
you generally can't normally do if
you're using view as an object following
which allows you to yeah you can move
outside the room you move infinitely
really in any given direction that might
be a thing you want it might not if it's
something you don't want it's very easy
way to make it so you can't move the
view outside the room which is going to
clamp our view X view and our view Y
view after moving them so we're going to
save you underscore X view equal
for EM view the school X view zero room
wit - view and the school w view okay
so we're taking the value of UX view and
we're keeping it at a minimum of zero
and a maximum of room width minus VW
view - the bit for the view so we can't
go outside so okay so we can have a
minimum of zero and the far right-hand
side of the screen and then we do the
same thing for y corner change view X
view - y view and room with the room
height and view W view to view each for
you now if I run the game you can see
there are X&Y corner of the camera is
clamped so that like we can't move the
camera outside the top or the sides over
room okay dead simple now it's really
cool it's a really cool little flexible
system and there's very easy ways to add
things like screen shake and stuff to
this that can you can make that work
outside of the room as well and that's a
good easy ways to like make the camera
now focus on specific spots like if
you're doing like a cutscene or
something like that you can just check
for if cuts uniqua true type thing and
then change how you assign X 2 and Y 2
and then once you've changed how you're
assigning X 2 and Y 2 to give it a new
thing to follow or a new place to be um
the rest of the code takes care of
itself and like it'll move and sort of
slow to a stop in the same sort of
smooth way we've got the camera moving
now just with different conditions for
whatever you've got going on in your
game okay I might do another short video
explaining how you might add screen
shake or add like what cutscene camera
to this because it's really quite simple
but for now that's how you do a dynamic
top-down camera that follows both the
mouse and the player object I hope you
guys found that useful um if your watch
the day I came out be sure to check out
my livestream tomorrow twitch TV /sha
nsj I really hope that goes well and
yeah I'll catch you guys next time
thanks for watching subscribing liking
all that nonsense you guys do that I
love so much and yeah see you guys
you