Godot Tutorial -- Particles Video Lecture | Godot Game: Learn and Master - Game Development

hello this is Mike again from scratch
and welcome back to our ongoing Godot
game engine tutorial series today we're
gonna be taking a look at particle
systems if I sound a little bit
different to you today I apologize for
that I just learned that what happens in
Vegas stays in Vegas unfortunately does
not apply to the common cold so I am
currently a little bit drugged up and
I'm in that sweet point where I can
still form a loosened sentence but not
be crippled by throat pain so I'm gonna
rush through this a little bit while I
stay at that sweet point so hopefully I
make enough sense well I'm going through
this video so no it's looking back we
are going to be talking about particle
systems now if you're not used of games
in the past a particle system is
basically a whole bunch of sprites or
system generated sprites that are
controlled by an overarching system
mostly what that means is it's a whole
lot of dots or similar sized shapes that
go together to make it more complicated
and structure a common use of its
particle system would be smoke effect
fire sparks sometimes fog we can also be
used for controlling a whole bunch of
sprites using one system something like
a flock of birds which is specifically
something we're going to do today so
particle systems are very useful often
for special effects if you play
something like a first-person shooter
and there's a muzzle flash quite often
that is implemented as a particle effect
I started to tell specifically because
some of these things can actually be
implemented with shaders or trickery
so sometimes it makes sense to use
particles sometimes it does not now
particles are something that are
somewhat supported the GPU level but can
vary in performance from reaching your
machine so sometimes it makes all kinds
of sense to use particles sometimes it
does not also the fidelity of your
particles the number of particles you
use will really affect the visual
approach or the visual look but it will
also add an increase load onto your CPU
or GPU so it is a balancing act also
particles are somewhat of an art form
you're basically creating moving art
when you're defining your particle
system and it is going to take an
artistic eye to get an end result that
looks solid for this version I'm going
to be implementing two different
particle systems one is the simple flame
like you'd see from a torch the other
one as I mentioned earlier was a flock
of birds to very extreme examples of
what you use a particle system for but
it does show somewhat diverse
now Godot does make using particles
quite simple so let's jump right on in
and I'm gonna start off a new project
here once again I'm working out of my
downloads folder particles opened and
create and let's load our new project up
once again I assume you've gone through
all the prior tutorials in the series so
you know everything I'm about to do
about project configuration if you
haven't go back and see them in addition
to this particular tutorial I've also
done a text version it's already live on
game from scratch comm it's be called
part 12 in its particles it also has a
link to a very handy reference site over
what a lot of these properties are from
the Godot wiki itself so I didn't
replicate it I'm not gonna go into a
whole lot of detail about all the
various parameters you're going to see
so you go to game from scratch comm
there's a link right away that will show
you details of what a lot of these
different properties that I don't cover
actually do behind the scenes alright so
first we're gonna need to save our scene
oops
first we need to set a node there's a
root and save our scene and set our
scene active now Godot is remarkably
consistent how it does things and this
is yet again another example as you
might be able to guess particle system
is just a 2d node or another node there
are 2d and 3d specific versions
available eventually I will start
covering the 3d stuff and we just go
ahead and shut my mail down so we're not
inundated with those and as you guess it
is just a matter of creating the right
node and that is particles 2d and that
node the already is pre-configured you
can see it sprang out particles as it
goes we're gonna we're gonna muck around
a bit with what those particular things
do I wouldn't generally trance this is a
position only note so don't scale it
don't rotate it I'm not sure what the
end results are but it isn't really a
note to me to the changing the side of
the widget isn't going to have much
profound effect there is however one
very critical setting and that is
doo-doo-doo-doo hiding and right here
your local space and this is how the
particle will be contained so if I turn
that off you'll see the effect so I move
this particle system around you see
what's happening here now I turn that
off so if you're doing a contrail attach
to another so you're doing the jet of a
jet engine and you're moving along with
another sprite this is probably the
setting you want whether you're doing a
stationary flame you're gonna probably
want to set local space to on like so
notice the weird graphic effect ignore
that for now so this is a standard
particle system now what I want to do so
I'll go ahead and create a torch like
you would imagine attach was so picture
a sprite right here that would be the
handle and this is the flame coming out
so the first thing you can see we're
gonna need to do is change the direction
that we're spraying and that is done in
degrees with the parameter so you got
over here we got your config which
configures the overall okay so I'm not
really sure why config in params are
split up but the parameters you want to
set right here we just go we want to
rotate 180 degrees so this is in degrees
and now you'll see our particle system
instantly updates so it's going up and
down like so so if you wanted to go 90
degrees instead predictably enough the
result will be to the right and 270
degrees would be to the left so like I
said we want to go straight up and down
like so let me zoom in on this guy
you'll see something see how it's
cascading down that's because gravity is
taking a hold and it'd be more profound
if I actually let this lifespan be a
little bit longer and that's this is
actually a very key value to how
particle systems work this is the total
number of particles that are going to
exist across the span of the system so
in two seconds time 32 particles are
released and those two values are going
to go together by default to determine
the rate that they're released at but
after this two seconds go so after a
particle starts here
it goes this way for two seconds and
then dies so you have this constant flow
of 32 particles across or 16 particles
per second
and these go together not to determine
there are other things that are gonna if
you want to change the scale or the way
those things happen you can do that
using this time scale value here or you
can do it with damping which Turner is
how how fast the particles fade off at
their end but I'm gonna keep it this one
actually the two seconds actually works
pretty well for us we might tweak this
number right here the amount of
particles we do but we want our
particles to be constantly strained
otherwise you can use this value you can
change this up a bit and it changes the
way that the particles are distributed
so if you see explosiveness is set to
zero they all explode out at once
whereas we can go mid point and you get
a bit of a slower dispersal but again
not a constant stream and then we'll go
back to one and you'll see this constant
stream this is what this is effect you
would ultimately want for a torch or a
flame look but do be aware that when you
change in Mach with these values
especially time scaling in lifetime it
will have an effect on all of the other
parameters so you won't have to jack
your numbers up for are things like
frame rates etc we'll see later on
okay so the next thing you'll see this
is cascading off like this and if I turn
the timeline up it's more pronounced so
you see they're actually being pulled
back down and that's because gravity is
being applied to this particle system
and we don't want that so first off I do
like the two second rate but I do not
like it cascading like this and that's
gonna be a matter if we just come down
here and when we take gravity instead of
a 9.8 and nice thing with Godot most of
these units are either pixels as in
screen pixels or whatever or they're in
degrees so 9.8 pixels per second of
gravity and we're just going to turn
that into zero so now we don't fall at
all now what you will notice though is
we're going a little excessively in our
flow and that is controlled by Dada
linear velocity and we're going to turn
that one down a little bit to vote it's
a 15 yeah that'll work
and they're spread this is the degrees
that it's fanning out this way yeah I'm
actually okay with what we've got
okay so this is starting to get a little
bit more torch like but in all honesty
looks absolutely nothing like a flame
yet and the easiest way we're gonna move
to the next step is on colors that can
be done by specifying color phases and
the very first one is your very first
color so by default we have one color
phase and it's white we're actually
gonna keep white yeah because if you
look at a flame the most intense point
generally is white then orange then red
so we're just gonna add those other two
so we need to have three color phases
like so you can immediately see the
effect so that's a white to black to
black err transition that we've got
going so now we want to just change each
one of these values Orange RGB value is
FF there'd be three zero zero ish think
that's a little tool there we go so as
you saw you can specify using a HTML
style color codes or you can just use
the sliders here and then there's also
the the Alpha Channel we actually want
to make this one a little bit more
transparent as it gets away and our
final color here is red
yeah went Christy off oh no yeah I'll
put down on that and that position is -
why are you not
so we got our
transitioning between so from our
beginning point midpoint end point as
you know I want my white to be white a
little bit longer so we'll make this one
like that okay so now we're looking
slightly more freely flame-like next
thing we're gonna do is fear our side so
we're gonna start off with our particles
being a little bit bigger as we start
and then we're gonna get smaller as we
go that is done by these two values
right here now be careful here you've
got a set of values here and it's gonna
look like you can't set them that's
because these are the randomness values
these are the values that you change
from particle departed some randomness
to the results so this is basically
saying how much these values can vary by
but what you actually want to say is the
program
you're trying to do a variance between
the particles themselves and what we're
going to do is set our initial size to 3
and our final size 0.5 and now you can
see it's definitely more Flemish I'm
gonna yeah again check the spread down
slightly let's go to 5 and our velocity
is fine there you go in my opinion
that's actually a fairly passable flame
being generated dynamically now the
thing is this is actually used generated
it's using generated sprites basically
it's making rectangle sprites and then
we're setting the size of them one right
there and you notice that they're square
and that may not be ideal you can
obviously tell that they're square here
what you could have done is you could
have created a texture that was round
and just used it instead you could just
create a simple white circle small
circle and use that as the texture we'll
see how to use textures in a moment the
other thing you can do and again here's
their trade off do we want it to look
better or do we want it to run fast what
you could also do here then is change
your size down let's go down to to say
actually even closer got a 1 and we'll
change this guy to 0.2
and then up here add more particles and
so you're gonna get a better result for
sure it looks more realistic but it's
got a higher performance cost and again
it's all going to be a trade-off what
you want to the amount of processing
power you can dedicate to what you're
doing versus the graphic fidelity you
want but as you make the particle
smaller you'll see this is a much more
realistic effect now like I said there's
all there's a bunch of options in here
you can add a little bit of randomness
between your particular particles you
can change the way that they rotate that
amount of gravity is effect on it
radial rotation it's such a like I said
if you go to the link off again from
scratch it's got an illustration of
almost all of these things in effect so
I would suggest going there one other
thing you can do on this particular
guide beyond what we've done is you
could layer another particle system on
top of it so say for example you wanted
to add smoke be as simple as either as a
child or on top its create another
particle system and go so much through
the same same process about what we want
to do is say let's make 64 of these guys
we will turn gravity off again you will
go in the same direction so we need to
slow them down a bit we're using 15 154
there we go and finally I suppose we can
set the color so we want one and the
color will be gray
a good opacity like so and there you see
we got like a smoke effect going on top
down the opacity even more there
so now you've layered on another purpose
is still on top and you're creating a
smoke to go along with your underlying
flame again the more detail the more you
add the more realistic it'll look but at
the same time you are gonna jack up the
processing power of cost but here you go
if we had if we had a graphic right here
of torch this would be a fairly
convincing flame effect for a few
minutes of work that is basically how a
particle system work now as I told you
earlier you could actually use an image
and this we're gonna do next we're
actually use a series of images to show
an animated bird as our particle and we
just go ahead and scrap everything so
well create the exact same process is
still the particles 2d I mean zoom out
so let's move this guy and we're gonna
go to the left instead so 270 we're also
gonna create a few less of them so let's
go with a 16 instead and they are going
to live a lot longer like so and birds
don't all they do get a gravity applied
but generally not in this case so
there's this constant stream out going
this way we'll do a bit more spread so
let's start with a bit more only four
and then one other thing we didn't
really talk about earlier is if you've
got something exactly like our torch
actually when you first enter the scene
the particle system is going to start up
and that's not going to be what you want
you're gonna want that particle system
from very beginning to be a flame if
that's the case what you can use here is
this pre-process value and this is to
say run this particle system for this
amount of time immediately that way when
your particle system starts it's pre
computed for a whole bunch of so two
seconds worth of particle processing
would have already handled and that's
what this process right here does okay
so there is our particle system emitting
our birds now we just need our Birds
that is a matter of we need a texture I
already have one here it is now this is
a limitation I don't know if Godot has
it or not but this is a square
texture an equal number of rows and and
and it doesn't need to be an equal
number but the bottom row needs to be
full and I don't know a way around this
to be honest there's no way to specify
the total number of particles in your
total number of sprites in your sprite
sheet that I can see here so it may be a
limitation that you actually have to use
a sprite sheet that's in a grid so
that's got an equal number of rows as
columns again there might be a way to
get around this but I don't know what it
is but now let's go ahead we'll use that
texture so first of all let's go ahead
and import it another thing is that
texture is very big so we're gonna be
scaling down our particles so you would
probably actually scale down your
texture if you were a much smarter
creature than me game choose and import
okay so now what we're going to do is
set that as a texture Atlas so create a
new Atlas load it use our newly cropped
texture and not quite what we want but
we're getting there now what you're
seeing is a texture sheet of 16
different robin images all being shown
at once so we have to do is narrow it
down here by the number of rows and
columns we've got and bring that texture
back up so as you see I've got one two
three four five columns rows let's get
that mixed up and then four so what we
need to do is come back here and set
five five enter and four enter and now
we have individual birds very cool now
what I told you earlier is those files
are very very big I think each frames
about 350 pixels so that's why you're
seeing what you're seeing now all we
need to do is come on down here and set
the size initial size to about a tenth
now the key thing is we're going to want
to set the final size to because as you
can see our birds are growing constantly
over their lifespan that's obviously not
ideal so there you go we now have a
flock of birds now what you may notice
is our wing speed sucks
and this is determined by your animation
speed here this is how fast she'll goes
through each particular frame of
animation let's go through ten now you
see much better flowing animation of our
flock of birds because they're being
emitted over time you're not seeing that
the if they were a minute all at once I
seen it I could probably do this right
here by using explosiveness alright so
got away for that see now that's not
ideal because every single one of these
birds is basically in lockstep right so
you've got your particles that are
identical and this is where your
randomness comes in
so in randomness what we could do is go
and set one of these values to say I
think two there so now we have I guess
this is actually a zero to one value so
zero point three wait for the next
explosion so now you see the wind speeds
are not all the same we can also start
them off on a different frame so the
next explosion and there you go now they
look a little bit different you can also
change the spread all right they're all
zero ones okay so zero point that that
0.5 and it will randomize the amount
that they're spread out by I guess I'll
have no effect on this system anyway so
that's what these particular values are
for the amount of variance between the
individual instance of the particle and
the system itself and the biggest thing
I want to show you for is so that the
flight patterns are different so the
wings are different it's not gonna be so
obvious as I said if I wasn't using this
explosiveness value because all of our
birds were actually created over a span
of time anyways it will have a bit of
effect it'll make it look a little bit
more natural a little bit more organic
having them so they don't always start
at the exact same point but there you go
there are two different particle systems
the first one like I said you know I
just showed a nice easy relatively CPU
friendly or GPU friendly by
work effect order on flame effect and
here you can see a purple system also
being used to generate birds and again
as you move the system around all of the
created particles are affected by that
whereas if we go back here and turn the
local space off it just moves the spawn
point and then all the corresponding
part was released after come from that
position like so so that's essentially
it that is particles in Godot engine now
you'll find there's no programming in
this particular example because
realistically your entire programming
interface and I'll show you this quickly
all right scroll down we find the damn
thing particle 2ds there it's just
getting set methods for each of the
values you see over here so you can
create one of these programmatically if
you want but these are literally just
get and sets for here now what you'll
notice though a lot of them will take a
parameter set so get randomness for this
parameter and your parameters are
defined here so you have passing program
underscore initial size or final size in
your get call and in your set call same
thing just with the value being passed
after but otherwise it's basically just
the exact same stuff you can set over
here being set over here so not a big
deal but again it is a node 2 so any
other node related stuff we're
positioning etc can all be applied
without issue and I suppose there is one
other thing I should show you and we'll
make a child of this particle systems 2d
the other particle effect here is the
attractor this is like a virtual black
hole basically it will suck things
within its radius in and then what it
does done is up to you and I will show
you now there so everything comes in it
gets sucked in and spit out now the
alternative is we could set this to
instead of spitting them out absorb the
absorption strength it really high
you'll see it's just sucking them in so
if for some reason you needed to catch
all the particles going in a certain
direction or a certain way or you have
an effect that basically is arcing
between two points your particle
attractor 2d is useful for implementing
those and it's this absorption factor
right here that determines if it's going
to be sucked in or not you can also
change the radius like so and what else
would be a matter it's kind of basically
yet to be honest so very handy thing
that's about it
so that is particles in Godot engine I
hope you enjoyed that thank you for your
time bye