Java Game Development - 23 - Introduction to Sprites Video Lecture | How to create Games in Java - Gaming Development - Software Development

what is going on guys welcome to your
23rd java game development tutorial and
then this is order we're going to be
talking about sprites and I'm not
talking about the Sodapop I'm talking
about a moving animation now we already
made the type of animation where there
is pretty much a single image and it
just changes image and depending on how
you change it it gives the appearance of
an animation like a face just standing
in one place blinking or a guy standing
there waving his arm but what if we
wanted to have like a ball on a screen
and have it move around the screen well
there's two different types of animation
the first one who ever learned is called
static an animation that stain stays in
the same place on your screen and what
we're going to be building a spray is a
dynamic animation or in other words an
image that moves around your screen like
um like pawn like the ball and pong so
let's go ahead and we'll begin coating
it I made a new class called sprite and
this is going to be a lot easier than
our animation class we already pretty
much got everything built but first in
our sprite class we need a couple things
instead of just like a single image
moving around our screen what I am going
to be building is the animation the guy
with his eyes blinking and he's going to
be not only blinking but he's going to
be blinking and moving around the screen
at the same time so we're going to need
to use that animation so private
animation and we'll just name it a and
what we're going to be doing is saying
alright we want a sprite to move around
on the screen and then it says alright
what do you want to use this spray and
we're going to say we want to use the
sky blinking so that's where that
animation comes in in we need four more
variables after this we need the
position of the sprite which is going to
be changing every time it loops and this
is private float X and you don't want
int because when you're working with
pixels you don't want it to sometimes
you don't want it to move an entire
pixel every time so what if like only in
ten seconds you wanted to move one pixel
well you would haven't moved the tenth
of the pixel every time so that's how
you do that
so private float X to get the x
positioning of the spray or wherever it
is on the screen
private float Y to get the Y positioning
and you need two more which is the
velocity of X and the velocity of the Y
so this x and y is positioning you
should know how much how many pixels
over how many pixels down the velocity
is the speed pretty much velocity is
actually distance over time I believe
but what the what we need to tell it not
only where to go but how fast the move
and the velocity of X is how fast the
left and right should I be moving and
how fast up and down should I be moving
and well you'll see once we start
programming those but that's what these
variables mean so the first thing that
we need is a constructor so let's just
go ahead the constructor right there
they spell it around and good enough and
then go ahead public I name my class
spray just like that and as a parameter
it's going to take that animation object
in other words as your parameter tell
what animation do you want to use
animation a and what you need to do is
set this a equal to a and what this
means is whatever object you're
referring to it's a is equal to a so
this is from whatever object is calling
it which we don't really know right now
but it's going to set it's a right here
equal to whatever object we passed it in
and that's what that you shouldn't how
to use this keyword by now but that's
how you do it
it takes a this arm whatever object and
set C equal to the object we passed in
easy enough so let's go ahead and after
this what we want to do is we need every
time um this method gets called called
update it's going
move the position of the spray because
that's what spreads are all about it's
not just a single object or excuse me a
single image that chills in your one
place on your screen the whole time it's
image that moves around your screen so
in order for your image to move around
you need to change the positioning of it
so in order to do that let's go ahead
and put change position and make sure
you spell that like that and we'll name
this public void update and it's going
to change its position based on the time
that has passed and remember we already
calculated this in another class so long
time passed and how can we calculate the
position based on time packs well first
let's do the X positioning X the
positioning is equal to the speed of X
times time past so although this may be
confusing let me try to explain it to
you guys
now remember velocity is pretty much I
know it's a little bit different but
it's pretty much the same thing as speed
so say you wanted your animation to move
an inch a second so this is your speed
one inch per second right here and if
the time that passed we passed the N one
second then it says all right add one
inch to X so if your velocity was an
inch per second and you only passed in
half a second then X would say alright
I'm only going to increase half an inch
so that's pretty much how that works so
once we figure that growing idea out
just copy that and change these the Y's
same thing for y Y positioning no that's
a velocity of Y there we go and after we
do all that what else can we do with
time passed we need to a update time
passed and what this does is take the
time passed and calculate where in your
animation you should be so this
calculates where on your screen that
image should be should be in the
top-left corner bottom right that's what
this does in your animation update when
you call this method remember we built a
method in your animation class that says
all right according to the time should
my guy's eyes be open should they be
closed should I restart my animation
where in my animation is that so that's
how you give for this tutorial in the
next tutorial we're going to be building
really simple stuff a bunch of get
methods to get the position set the
velocity stuff like that but um just
don't skip over it because it's kind of
important but we're we are well on our
way to animating sprites
so thank you guys for watching don't
forget to subscribe and I'll see you
next tutorial