Java Game Development - 8 - Beginning Animation Video Lecture | How to create Games in Java - Gaming Development - Software Development

well is going on everyone welcome to
your eighth programming tutorial and how
to make games in Java and in this story
we're going to be talking about
animation now we already learned how to
load images and now that we have those
images we can begin animating them so
the first thing we're going to do is
kind of static animation not really like
I'm moving things around on the screen
but taking a single image in animating
it depending on different ways that the
image looks so for example if I wanted
to animate this face so it looked like a
guy had his eyes open to a guy had his
eyes closed um I would need to do some
simple animation in Java so here are my
two faces eyes open and eyes closed and
we're going to be swapping these images
real quick to give the appearance of
animation so there are pretty much two
different types of animation this is
called
well I call it still animation in the
other animation where like if a ball was
moving around on screen that's what I
call dynamic animation I don't know what
they call it but you know so let's go
ahead and get started because once I
teach you the basics of this animation
the next one is going to seem a lot
easier so the first thing you need to do
is import images so we can actually use
those images and import something called
an ArrayList and if you don't know what
an ArrayList is it's pretty much an
array but you can um like add and delete
elements a lot easier so let's go ahead
and put well let's utilize that first
private array list and I'm going to name
my scenes scenes just like that so now
we have pretty much an array list up
called scenes and what a scene is going
to be is it's pretty much a picture
every picture is a scene so when that
guy has his eyes open that's a scene
when he has his eyes closed
that's another scene so BAM that's all
that is so that now you know and what we
need to do after this is make private
int a limit
scene index now each element in your
array list has an index that's just like
an array pretty much so in pretty much
these are going to be the elements in
this array list right here so simple
enough easy enough so far and now what
we need is variables for two times
private long movie time and if you
couldn't guess this is going to be the
actual time of your animation we're
going to keep tracking this variable how
long your animation has been running and
this is so we can test against you know
other stuff but this is pretty much
going to be the total time that your
animation has been running or your movie
and now let's go ahead and make private
long total time and this is just going
to keep track of the total amount of
time that's allowed your animation to
play and why do we need two different
movie times because we're going to be
comparing these pretty much we're going
to be seeing all right if this movie
time exceeds the total time then we want
our animation to start again and we just
don't want it to freeze so that's why we
need the two different variables right
there so now that we got a bunch of
variables let's go ahead and well let's
go ahead and make our constructor first
so I'm in private and whatever in my
class animation and let's go ahead and
both instructor make sure I spelled that
right yep and the first thing we're
going to want to do since this
constructor is going to be called as
soon as we create our class or object
let's go ahead and just reset everything
to zero so put scenes
remember this ArrayList right here well
set this equal to a new array list and
this just make sure if we had one before
we're starting everything afresh so
we're creating a brand new one and take
that total time and set this equal to
zero to begin with because right now we
didn't do anything to it we're going to
be doing it later on and now after all
that after you set everything to 0 or
create a new we're going to call a
method called start later on so this
sets everything 0 in this method later
on is going to
our animation and I know we didn't
create it yet but bear with me and let
me just add a comment right here just
because I usually add a comment
constructor I probably spelled it wrong
but too bad I just like to add a little
comment above each of my methods not
only to tell me what they do in case I
forget but also when you're scrolling
down your code and you have a bunch of
methods you can easily see where the
methods are so you know just a nice
little coding tip right there and after
this let's go ahead and make a method to
add a scene to the animation so we're
going to do is named public synchronized
and what synchronized means in Java is
you can only run this method at a time
so if we had a thread that was able to
run two methods at once we would only
want to run this one and then when this
is done we can run the other one instead
of running at the same time if you're
like alright Bucky why would you not
want to run two methods at the same time
stupid you're making your program go
slower well sometimes it's necessary and
this is because if you have two methods
that like changed a number or change
variable then one one method ran and the
other method ran at the same time then
you might have the output change
variable in two different ways one would
set the number equal to five and one
would set that number equal to 15 so if
you have them synchronized then you
always know that they're going to wait
for the other one then you have better
control or reprogram you'll see later on
but just name this method add scene and
this is going to take two parameters now
we need two different pieces of
information to add a scene to our
animation or movie we need an image to
add because you know what face do you
want to add eyes closed or eyes open and
now you need a time so once you say
alright I'm going to add this image the
time is how long do you want the image
to appear on the screen one second one
hour so for my first one I'd put
something like add scene face one since
that's the name of my face with my eyes
open and I'll put something like point
two seconds so BAM
and now let's go ahead and change that
total time variable so total time plus
equals T and why am i doing this every
time I add a scene to total time this
total time is going to pretty much be
the sum of all the individual scenes so
if I have three scenes for a second each
this total time is three seconds so now
we know our animation is only supposed
to be three seconds long and that way we
can compare other times to it and that
way we have something steady to compare
and now what I need to do is now that I
got that total time actually need to add
well you'll see scenes and this is
pretty much remember the ArrayList we
created out here we need to add an
object to the scenes ArrayList now let's
go ahead and add that first argument so
what do we want to add to this special
ArrayList called scenes well we're going
to be creating each scene is going to be
its own object we're going to be
creating a whole different class and
specifically to store these scenes and
I'm just going to name it one scene
because each object is going to be only
one scene so again one more time each
picture in essence is going to be an
object
aka a scene so this we're going to build
a constructor in this that takes two
parameters the image itself what picture
do you want to put and the total time so
now with that remember we're going to
build on a class called one scene later
on and this constructor is going to take
the image in total time and we're going
to be doing some stuff to it but for
right now every time you call this
method add scene it's going to change a
total time to the appropriate amount and
it's also going to add a new element to
the scenes ArrayList so if I had three
pictures in here this scenes ArrayList
would have three elements in it and also
it would create a new object and this is
just so we can use it later on
but for now let's just go ahead and add
my comment add seen to ArrayList and set
the time for each scene so now that we
got that set and I'll show you get to
high we're ready to move on to my next
tutorial but for now that's all you get
for this tutorial but I just want to
thank you guys for watching don't forget
to subscribe I'm having an awesome time
doing this can't wait to teach you some
more so again thank you don't forget
subscribe and I'll see you next door