GameMaker: Studio - Alarms & Projectiles Video Lecture | Game Maker Tutorial: Build Games from Scratch - Game Development

alright guys welcome back I hope you all
had a very very good Christmas very good
new year I know I did a very very busy
Christmas to say the least as you might
have noticed from me the lack of new
content on this channel but now I'm back
and ready to start regularly pumping out
these videos again christmas is out of
the way shoutouts to all my new
subscribers there's like five hundred of
you guys now that's absolutely
ridiculous and think this was gonna be
anywhere near as popular as it's turning
out to be so that's really cool I'm
pretty motivated now just to get more of
this content out you guys as quick as I
can so before I get into this video I
was just gonna say like while I'm
planning to do whether or not it'll work
out this way or not is basically record
new content more or less every weekend
and then put that content out through
throughout the week so that hopefully
hopefully what that will do is create
kind of a constant source a constant
stream of like of new content you guys
saw those not the sort of this huge
space of time where you know and you're
not getting any any new tutorials or
anything like that so that's the plan
what it is we're gonna be looking at
today is following on from our last
tutorial on basic projectiles is I
promise to follow up to that video where
I would explain a few more slightly
in-depth things through projectors I'm
actually going to explain something
that's actually I suppose quite a bit
simple but not it does go a little bit
further than what we had before just for
a few little things that you might want
to do with your shooing mechanic if you
are making a top-down shooter just based
on top-down shooters that are already
out there because if I run the game that
we had at the end of the last tutorial
assuming it compiles any time today
there we go okay so assuming you know
what we had before was this where you
could move around and you pressed face
and every time you press space it would
shoot but if you held space you know you
you only got one projectile every time
you press space now that's not really I
mean sure maybe you maybe that's how you
want your game to be if you want to
attack a match space for something or
you have to mash it button or whatever
then you've already got a system you
want but for a lot of top-down shooters
well people will typically do is have a
system whereby they you hold the bun
down and you get a constant stream of
bullets I packed a lot of shoes I played
recently have it you don't even have to
press a button they're just optimally
you're you're always firing anyway so
some games have actually literally
stepped up and removed that requirement
entirely which might be a thing to think
about but that's a more of a game design
thing but either way I was going to show
you guys first of all just how to create
that kind of system whereby a while
you're holding space you are constantly
shooting I mean you might from what
you've learned before be able to do this
in the sense that you might think well
if I repeat the code for shooting which
is an AA space thing instance create you
know this business create bullet thing
if we just put that into the step event
under like a keyboard check for DKR into
score space or something like that or
leo and then that would that would
surely just create a bullet every frame
and it would but that's probably still
not what you want because you would then
be firing almost this constant beam of
bullets out and you probably want some
kind of delay or some kind of space in
that so this gives me a good opportunity
to teach you guys about alarms because
this is the way I would do it anyway I
mean there's a number of ways you could
do this you could do in the step and use
counters or all kinds of things but the
easiest way to do most sort of like
repeated timing based on things in your
game is to use a thing called things
called alarms so let me just demonstrate
first of all how we would start doing
as you may have noticed I've made the
fun a lot bigger in the execute code
window now so hopefully I won't have to
do quite as much so deep zooming in
stuff you guys to be able to see exactly
what's going on in the code but instead
of this line here I mean we'll leave
this line here for a second because
we'll want to copy and paste in a minute
but what we're going to do instead of
this line of code is set up an alarm the
whenever that alarm goes off we'll fire
our bullet instead of firing our bullet
whenever whenever we press the spacebar
so what an alarm is is an event
basically it was the best way of
describing it so it's one of these like
events over here that is basically on a
timer that you set based on a number of
frames so if I said something like alarm
zero equals five for example when man
that would set our zeroth alarm it
counts to something like ten I think
like the very first one is zero so
that's the only one we need at the
moment so we set alarm number zero to be
five and then five frames from when we
set that the alarm would go off and then
the event the actions in the event that
we can add over here if I just close
this quickly
and event alarm zero like all these
actions here now no that's alarm zero
would here would go well however I mean
that's not exactly how we need to do it
though
what we need to do is say if alarm zero
is equal to minus one now that might be
a bit confusing but still and they
explain what that means
what alarm does when we set it to
something like five or ten will every
frame of your game the alarm will tick
down by one until it hits zero when your
alarm hits zero all the actions go off
and then the alarm is set to minus one
which means that it's not counting down
anymore it's not counting it's not going
to do anything
someone took both if we set that to zero
it would be when the alarm triggers
that's not only one
we want to know when the alarm is not
set so when the alarm is not being set
we set the alarm to five when we're
pressing the spacebar and in fact we
don't want to use the press event
anymore now what we want to do is use
just the adjust the space event so
whenever this button is being held from
now on we want to say if the alarm zero
is not set then set it to five frames so
five frames from when we press the
spacebar all the things in alarm zero
will go off so what we need that to be
is simply this line of code which is the
line which shoots out bullet so if we
remove that now we go to alarm zero code
execute code and put that line of code
in there and then what we also need to
do oh no no I think I should be it
actually if I remember correctly
okay cool so now if my press spacebar
yeah then you hold spacebar you can see
that there's now a delay in between each
bullet but we're firing a constant
stream of bullets out which is probably
you know a much better system for a good
doing a top-down shooter and so on I
mean now you've got that I mean you
couldn't vary the spacing between these
bullets just by changing the length of
time on your alarm so if you go to your
object player and you say when you press
space
if the alarm isn't set yet set it to I
don't know nine then when we compiled
that you can see the distance between
each bullet is much larger than it was
before so now that we've done that
something we can look at doing now is
some an effect that's in a lot of
top-down shooters which is when you
collect upgrades and stuff especially
you don't just fire one stream of
bullets you would often fire like
multiple streams of bullets and
sometimes as bullets would go like in
different directions you create like
this like cones of like streams of
bullets so I mean that's a very easy
effect a replicating game maker as well
so if I show you how to do that I mean
it will start to get explain a few more
concepts and you'll be able to
understand how to create some of these
sort of special effects by yourself so
well at the moment what we do when ever
the alarm goes off is we fire a single
bullet now say we don't want to do that
where you want to fire three bullets
that all go in like like a cone shape of
directions so I mean first thing we need
to do is simply copy this one code like
three times so well twice so now we
create three bullets instead of one
obviously though what this will do is
we'll create them in the exact same
place and all fire the exact same speed
in the exact same direction so it'll
just look like they kind of overlap at
the moment so we need to be able to do
things to these different bullets to
make them go in different directions or
behave differently so the way we can do
that is by using sort of a special
little trick you can do with instance
create which is if I do this that's
equally as valid a line of code as this
one is now what that says is bullet one
equals instance create X Y minus 16
object but well that means is when we
create this bullet we assign that bullet
to the variable bullet one so if we do
anything in this code now like if this
object makes a reference to bullet 1
it's making a reference to this object
that it's just created I'm gonna do the
same thing with these line of subcode
and couple it to bullet 3 now I've got
bullet one bullet two and bullet three
that are being created and now what we
can do is simply set bullet to dump
Direction equals and now this number one
might confuse you a little bit but I'm
gonna say a hundred and three I'm gonna
set the direction to be K T now how
direction works is like if you're if you
don't have like direction is basically
like the the second component of your
object's velocity you know everything
has a direction on a speed so I mean if
we set our direction to be zero its
default direction when its speed is
raised is to just move to the right like
if you just set speed if you don't set H
speed you notice that VP you just set
speed to be a value and it will travel
your object will travel in that speed in
the direction there is your direction
variable whatever you set your speed -
so now direction is a bit weird in the
it's in line degrees but it counts sort
of counterclockwise from right it's
really confusing I'm not really sure how
why it's laid out this way but like
basically zero a direction of zero would
be straight to the right a direction of
monkey would be straight up 180 would be
left 270 would be down
so like it's 360 degrees going
counterclockwise from right which is
very strange you would expect it to at
least be clockwise so if it started at
right it would go something like 0 90
180 270 personally I always expect it to
be like zero to be straight up and then
like 90 would be right and then like 180
would be down and so on but that's don't
ask me why it's laid out that way it
just is and so the way we want to shoot
up is to shoot so to shoot directly up
we were to 90 degrees up but we want to
give bullet to and bullet 3 a little bit
of an offset so we were going to set
them to 180 respectively on bullet one
direction can equal 90 now of course
this means we need to make a slight
change in our bullet object so the
instead of setting our V speed to be
minus 8 or just saying our speed to be 8
so that it takes the direction that
we're saying and it just it goes it goes
with that direction so ok now we hit a 5
now when we press base yeah we're
creating this this stream this cone
stream of bullets like I'm not spreading
out and shooting link in a big arc
that's the sort of thing you might do
when you collect like an upgrade or
something in your game I mean if you
think you've seen how I use if
statements and things like that you
probably other work out how to do that
kind of thing and fairly soon and that's
that so that's just a couple of little
things about shooting that you could do
a little bit differently and there's
just you know just to give you a little
bit of inspiration maybe a few sort of
ideas on how you can kind of modify and
change the way your ship shoots and your
top-down shooter and hopefully gives you
a basic understanding of how like it's
assigning an instance you create to a
variable works or bullet one bullet 2
and so on and how how direction speed
works and hopefully how alarms work
alarms there
very important thing to understand there
or incredibly useful so yeah that's that
that's some more advanced sort of
shooting tips or youth there and I'll
see you next time guys