How to use AGS Part 27 (Using Inventory Items on Objects) Video Lecture

hi and welcome back to the AES tutorial
in this video we're going to talk about
using inventory items on objects in the
room how to do that I've got a couple of
emails and messages from people asking
how to do that so that's what we're
gonna cover in this video what we're
gonna do is we're gonna if you remember
in the main hall we have a clothes
closet door mr. Donatello is in there so
we're gonna let him out I'm gonna give
Sammy a key that he can use on the door
to unlock the door and open the door so
let's let's start by creating the open
door object and this in the main hall we
have a closed door which must be gonna
tell us that it's in but we need to have
another object the open door and and so
we'll just right-click in the room say
new object here the image that I'm going
to use is 470 and that creates say an
open door image now I'm gonna drag it
into place and it looks kind of strange
in the editor to have both a closed door
in an open door but in the game we're
only going to have one of these objects
visible at any one time so the game
you're not gonna see them both at the
same time I'm gonna initially when you
start the game this closed door should
be visible but the open door should not
be visible at all so I'm gonna set the
initial visible property of this open
door to false and the properties window
visible is false so that way when we run
the game and I'll go ahead and do that
I'm gonna change Sammy starting room to
the main hall I'm gonna set his X&Y
coordinates just very quickly somewhere
in the middle of the room so if I run
the game now you'll see that the closed
door is not visible in the room we just
have this this I'm sorry to close the
door is it visible but the open door is
not so what we want to do now is to give
Sammy a way to open this door and then
we'll hide this closed door and we'll
make this open door visible so let's do
that now
there's if you created a default game
like I did if you look up in the
inventories items you'll have one that's
already built for you called a key and
since that's exactly what we want we'll
just use that one for right now so if I
double click on inventory item key I'm
gonna go down to the properties of the
key
and there's a item here that says
there's a property that says player
starts with item right now that's set to
false meaning the player doesn't start
with the item but I'm gonna change that
to true so so that Sam you will start
the game with that item already in his
inventory and we don't have to worry
about giving it to him and then we can
use that key then to open the door so
how do we do that well go back to the
room if Sammy uses the key on this
closed door then we want to make the
closed door invisible and the open door
visible so what we do is we select the
closed door object we go over to the
events of the object and then there's an
event called use inventory on object and
that's the event that we want to use
here we want to say when the player uses
an inventory item namely the key on this
object we want the object the door to
open so we click on the ellipsis and
that creates a function for us called a
closed door use inventory so what we
want to do is we want to say first of
all before I do this let me do one more
thing go back to the room I forgot to
name the the open door here so I'm gonna
click on the open door I'm gonna name it
open open and then I'm gonna name the
put the design and under design the name
of the object itself I'm gonna say o
opened the door just to give it a name
that way we can refer to it in a script
so going back to the script then when
the player uses an inventory item on the
door now at this point we don't know
what the inventory item was if the
player had 500 inventory items in their
inventory we don't we want to know which
one did they use on the door we want to
make sure it's the key so what we do is
we say if the active inventory item is
the item that the current that the user
is currently using from the inventory so
in other words when you play the game
and you select the key from your
inventory and use it on the door that
key then becomes the active inventory
item so we want to make sure that that
active inventory item is the key so what
we want to do is we want to say if C
Sammy got active inventory equals and
remember we use the double equals sign i
key now by default that key item was
called i key i standing for inventory
key so if the active inventory
is the key then we want to hide the
closed door so a closed door dot visible
equals false and show the open door o
opened door dot visible equals true okay
let's see how that works
I'm gonna run the game now the doors
closed right now and if we did
everything correctly I should have a key
in my inventory I do it's right there so
I'm gonna select the key I'm gonna use
it on the door okay and then what
happened was now we see that it happened
correctly the closed door disappeared in
the open door appeared but notice that
mr. Donatello is still yelling things
from the closet so we'd really like to
turn that off
another thing that we'd like to do is
have Sammy walk over to the door before
he opens it that sort of gives the
player you know the illusion that he
Sammy actually did open the door and
that he didn't just open it from
wherever he was in the room so let's do
those two things let's have send me walk
over to the to the door first and then
once he opens the door let's have mr.
Donatello stop saying things and maybe
you know say say thank you to Sammy or
something like that
so then in our closed door user
inventory item right before he we set
the visible properties of the doors
let's have said me walk over to the door
so let's say see Sammy don't walk now
once an x and a y location so let's go
back to our room we want Sammy to walk
about to this location here which is X
248 Y 118 so 2 4 8 118 a blocking style
will be block and walk on the walkable
areas so that will have sent me walk
over there and then the end now we need
to have away from mr. Donatello to stop
saying whatever he was saying before we
couldn't do this with global variables
which I'll get into later but for now
we'll just do it with a variable defined
in the room what I'll do
and so I'll go up to the top of the room
script and now define a variable I'll
make it a true or a false variable now
and true a true or a false variable is
called a boolean so I'll type bool which
is short for boolean and I'll say is
donatello in closet and this will be
true if don't if mr. Donatella is in the
closet or false if he's not it's a way
for the game to know whether mr.
Donatello is and is stuck in the closet
or not so it's done it's hello in closet
will make this default to true because
when you start the game that mr.
Donatello is in the closet so we go back
down to our user inventory item function
and after we set the visible properties
on the doors we want to say mr.
Donatello is no longer stuck in the
closet so is Donatello in closet is
false now we need a way to use this
remember and are repeatedly execute this
is where mr. Donatello is saying things
in the background so here we want to
check before he says anything we want to
check to make sure that mr. Donatello is
in the closet before we actually have
him say something so here where we check
the timer remember we created this timer
we say it's timer expired
if timer has expired and is Donatello in
closet in other words and mr. Donatello
is in the closet then we want to do this
if mr. dontel is not in the closet we
don't even want to have him say anything
so let's run that and see how that works
ok so right now mr. Donatello should be
in the closet and he should be saying
something and we have to wait 10 seconds
for him to do so ok so he says Sammy are
you still out there now if I use the key
on the door and let him out notice the
Sammy walks over there and now we let
him out and he shouldn't mr. uh mr.
Donatello shouldn't say anything anymore
I'll wait about 10 seconds I think it's
been about 10 seconds so we can see that
that work that mr. Donatello is no
longer I'm seeing anything another thing
to notice is that if I go to a different
room if I go upstairs to the party hall
and come back down to the main
all notice that the door is still open
and mr. Donatello still in the closet
and everything like that so the room
saves State it knows where it was what
what the state of all the objects and
everything were the last time you were
there and it keeps that it keeps that
same state for all the objects for every
time you enter the room so that's useful
you don't have to continually every time
the player enters the room you know to
figure out where was this door last time
and where was this closed door and where
was mr. Donatello all that stuff is
maintained by a GS in it it remembers
everything for you so that's really what
I wanted to talk about in this video in
the next video we'll do a couple of more
things like will make Sammy be able
right now Sammy can't walk into the
closet because we we limited him to not
being able to walk into the closet when
the clip when the door was closed so
we'll be able to do a couple little
things like that and then we'll have mr.
Donatello say something to Sammy as soon
as he opens the door saying you know
thank you for letting me out so join us
in the next video guys hope this was
helpful