Creating Spit Spot! (Part 3 : Swift in Xcode) Video Lecture | Swift in Xcode: The Complete iOS Development Guide - App Development

hey what's going on everybody today is
gonna be part four on how to do
spit-spot we will be dealing a lot with
how the enemy interacts with the main
character in the center and also how to
restart our game so let's get started
alright so let's open up our shooter
Xcode project and just make this a bit
bigger and today we will be dealing more
with the collision of the main character
so first thing we need to do is actually
create a new variable so just say var
hits will be equal to zero so this will
be the amount of hits the main person
has encountered now if we want these
hits to go up we need to go down here
and right underneath this did begin
contact function I'm going to create a
new function called collision main so
just go func collision main open
parenthesis and inside of here we're
going to create an sk sprite node so
just type in enemy this will be the name
of our sk sprite note and then colon s
case bright node and then close off with
the parentheses now open curly bracket
enter close curly bracket and now inside
of this we want to create an if
statement now this if segment is going
to be if the hits is less than two
meaning we were hit once so that's gonna
put zero to one and then twice we're
gonna go one to two and then three times
then we're going to call the other
function and then the next thing we need
to do is open curly bracket enter close
curly bracket and inside of here if you
notice my game as soon as the enemy hits
the main ball if you're in the game play
the ball grows so we're gonna make that
ball grow right now just by easily
saying main ball to run action sk action
dot scale by and we're gonna be going by
a scale of one point five and the
duration will just be a very quick zero
point four seconds like so so we're
going to make the ball grow and what do
we want to happen with the enemy so
we're going to make our enemy be
affected by gravity and that'll make it
fall down and then we're going to also
remove the actions from our enemy as
well enemy dot physics body dot affected
by gravity we're gonna set this equal to
true and then we're also gonna remove
all the actions so say enemy dot remove
all actions like so and another thing we
want to happen to our main ball is we're
just going to change the color for a
very brief period of time
meaning that it's it's been hit and
that's why it's growing so we're gonna
say main ball dot run action and this
will be an SK action dot sequence and
inside of this we're going to change our
color from the normal color that we have
to a red color and then back to our
normal color that we have so inside of
this we're going to say open square
bracket close square bracket and this
will be SK action dot colorize with
color now this color will be a UI color
dot red color the color blend factor
will be equal to 1.0 seconds we want the
red color to ultimately take over what
our main ball looks like and the
duration of this will just be a very
quick a 0.1 seconds we want this to go
by very fast so people can continue on
with their gameplay then after this we
needed comma and we're gonna say SK
action dot colorize with color and
inside of this will this will be an SK
color so just type in SK color open
parenthesis and this will be an RGB
value of what I have for my main ball so
if we go right up here you'll see that
the RGB value for my main ball is 0.2
0.2 and 0.2 with an alpha of 1.0 so
let's go to our main ball again and this
will be the red value of 0.2 0.2 and 0.2
with a alpha of 1.0 so it's not going to
be see-through and it's going to be a
dark grey color as we set it before our
color blend factor will be 1.0 of
meaning that again that the color is
going to take over our object and the
duration of this will be again a very
quick 0.1 seconds now this function is
actually not going to be called right
now so we need to actually go right up
here to our first body right at these
last two that I have right here so this
will be the first body not name equals
main ball and the second body not name
equals enemy so inside of here we're
gonna go collision main meaning we want
to call this function right down here
and then we're going to set the enemy
equal to our second body as you can see
right here our second body dot name will
be equal to enemy and then this others
else if statement our first body name
will be equal to enemy so inside of our
second one and we're just gonna type in
collision main and just type in first
body and now if we were to build and run
this now one thing you will notice
that our enemies are actually not
touching the balls so let's head back
over to our project and right down here
in the enemies function we're going to
change a few things
so in our enemy dot physics body dynamic
equals false we're actually going to set
this equal to true and we're also going
to say enemy dot physics body dot
affected by gravity and we will set this
equal to false and now this is going to
make it more visible to the other
objects so if we were to build and run
this now you will see that our enemy is
gonna come in and as soon as it hits the
ball now it's going to grow right now as
you can see it's growing really really
big so we're gonna make it stop at a
certain point so let's head back over to
our project and inside of our collision
main right here and inside of this if
statement we want to say hits plus plus
meaning we want to add one to the hits
every time and now if we were to build
and run this we were we're gonna have a
level at which it stops so we hit it and
there you have it now another thing is
these enemy balls keep coming now I
don't want this to keep happening
because if as you can see the nodes are
building up right here and it's just
gonna use more of the processing power
if we head right over here to our little
graph right here you're gonna see that
it's using 51% of our CPU and it's gonna
keep growing as more and more nodes come
in so we don't want that to happen so
we're gonna go right down here in our
collision main and we're also gonna say
enemy timer dot invalidate so we're
going to invalidate to our enemy timer
or basically the function that calls our
enemies so let's build and run this now
and as you will see we have one two
three and that should stop our enemy
timer from coming in now another thing
you can do i wanted this little action
of them falling when they hit the ball
so if we were to build and run this
right now as you could see the balls are
gonna hit but as soon as they hit they
kind of fall not all of them do but most
of them do so if you want but this might
not be the most practical because we're
good we're still getting more nodes than
i would like to so let's head back over
here and i'm just going to say enemy dot
remove from parent and we're just gonna
delete the enemy off of our scene and
now for ever to build and run this the
enemy is gonna hit our ball and just
destroy itself like so now again it only
does the
if you're in that if statement so let's
head back over to our collision main so
inside of this we want to have an else
statement as well so we're gonna type in
else open curly bracket enter close
curly bracket and we are going to say
enemy dot remove from parent and also we
don't want this enemy timer to invalid a
when the hits are less than two because
that's in the middle of the gameplay so
I've misplaced that we need to put this
enemy timer down and validate right in
our else statement like so now this
should make all our enemies go away as
soon as they touch the ball so let's
build and run this you have one two
three they all hit the enemy and boom
all of our enemies are gone and we just
have this one node left so let's say you
want to play this game again and again
and again I feel let's head back over to
our project and we're gonna go right up
here and ready to create a new variable
and this variable will be game started
so it's going to see if our game has
started and right now we're gonna set
this equal to false because we want we
don't want as soon as the game loads to
before the person playing to be attacked
by enemies if they don't really know
what they're doing
we want them to get a custom with the
game a little bit more and then they can
start getting attacked by enemies so
using this game started method we're
actually gonna go down here and we're
gonna go right into our touches began
and this will allow us to start our game
again and again so we're gonna say if
the game started is equal equal to false
then open curly bracket enter close
curly bracket then we want to start our
enemy timers so we're gonna say enemy
timer will be equal to and we actually
created this right up here in our did
move to view so just take this enemy
timer right here we're just gonna copy
and delete that off of our did move to
view because we don't want the enemies
to start coming at us as soon as the
view loads and then we're gonna go right
down here to our touches began and just
paste that right into there now when the
game started equals equals false next
thing we need to do is we're gonna just
say game started will be equal to true
so we're going to make the games start
now also when this game starts we want
our main character to be set down to a
smaller size so we're gonna say main
ball run action and this will be in SK
action dot scale too now what do we want
our main ball to scale down to
let's go right up here to our main ball
dot size and this size right here is
actually a bit wrong so we actually need
to go up go over to our calculator out
quick and we're just going to do a
calculation of 100 times 1.5 equals
equals and this will be 225 on the third
time it gets it doesn't grow at all so
it's going to be 225 so let's head back
over here and I'm going to go to my main
ball dot size and set the width to 225
and my height will be 225 now let's head
back over to our main ball dot run
action and we want it to scale down to a
third of its value so now let's
calculate what we wanted to scale down
to so let's head back over to our
calculator and I'm just going to say 100
divided by 225 and this will be equal 0
point 4 4 4 so let's head back over to
our project and we're gonna make it
scale down by 0.4 4 with a duration of
0.2 seconds we're gonna make this very
fast so now let's build and run this and
now as you will see I have my main ball
I click the screen and it's going to get
down to this smaller size and you can of
course adjust the size to your likings
like so and you can of course adjust the
size to your likings
so now let's head back over to our
project and inside of this touches began
we're also going to have an else
statement now this will basically mean
as soon as the game has started we want
to all the rest of our normal functions
to continue so now if we were to build
and run this with our else statement you
will see that I will press play and the
ball is not shot as soon as I press play
and you can play your game like so now
one thing you will notice if I if I hit
the enemy and it's above me and it comes
down and falls on top of the main
character that still counts as a hit now
we don't want that to happen we want the
ball to just fall right behind it so
let's head back over to our project and
we're just going to change with our
collision bullet we're just going to
change the contact test of our enemy so
we're going to say enemy dot physics
body contact test bitmask will be equal
to 0 now I don't want this to hit
anything so I'm automatically just going
to set it as 0 now let's hit go down
here and I'm just going to say enemy dot
name will be equal to nil it's not going
to have a name and we also need to say
enemy dot physics body dot collision
bitmask and we will set this equal to
zero as well we don't want to code
collide with anything so now let's build
the run now as you can see if I end the
game if the game is still thinking it's
going on so let's head back over to our
project and we're just gonna go right up
here to our collision main and right
inside of our else statement here we're
gonna say game started will be equal to
false and now if we were to build and
run this we will have our game to be
able to play over and over again so
let's play right now
nah-ha and this so this is another air
that might occur in your gameplay now in
order to fix this you need to just say
if the contact dot body a is not equal
to nil meaning that there is a body a so
we're going to type in not equal to new
and our contact dot body b is not equal
to nil open curly braket and then close
curly bracket right after all of that
and you can also just select all of this
right click and we're going to change
that structure and shift right and now
as you can see we have this if statement
and now if the contact is not equal to
no meaning that there is something
inside of our contact now then we're
going to run this and this will prevent
any errors like this to occur now
building run and now I can click on the
screen and if I hit the enemy everything
is working fine right now and if I get
hit by all of these enemies then I can
just easily restart the game and that
should restart to my enemies too and
inside of this if statement right up
here we're just gonna type in dot node
not that should prevent it like so now
let's build around and we can hit all of
our enemies like so and then I shall
start the game again as soon as the
enemies stopped coming and I can
continue on playing and as you can see
the enemies are falling through my
object as well and also as you can see
the enemies were still coming at my ball
but they weren't growing in the ball in
the middle wasn't growing in size so
let's head back over to our churches
began and right inside of this if
games started equals equals false we
want to say hits will be equal to zero
and now let's build a room and now I can
press play again and as soon as the
enemies start coming again I can get hit
again three times and voila there you
have it thank you all so much for
watching if you enjoyed this tutorial be
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a lot with scoring and labels so be sure
to subscribe for that anyway I will see
you in the next one