C++ Allegro 5 Made Easy Tutorial 35 - Loading Tile Maps [Hard] Video Lecture | Allegro: A Complete Guide - Game Development

hello everybody and welcome to your 35th
a level 5 tutorial and in this tutorial
we're going to be expanding on what
we've learned last tutorial so I've
already got the code written out just
because it'll be easier there's a lot to
explain and instead of me typing and
explaining it'll be a lot easier for me
to just explain our experiments going on
the source code is on the website on my
website coding mini GTA so if you don't
feel like typing this all out then you
can download the source code so how we
got rid of the algorithm include and now
we have the vector and we have the edge
trim now so for those of you who don't
own a vector is a vector is a resizable
array so basically we can add value to
it delete values it's basically a good
dynamic array right yeah and it's a
collection and if you guys don't know
about vectors I highly advise you to
learn about them because sometime in the
future you're going to need to know
about done what do you like it or not so
in order to create a two-dimensional
vector we're going to take in the SE we
make a vector it's basically about a two
dimensional vectors of vector vectors
okay so with this cold right here with
our map any length we can make any part
of the map any length right they don't
all have to be the same uniform or width
or whatever right there could all be
different widths and the reason why is
because when we have an array like a 10
by 10 array it's set that there tends on
that they have to be maximum 10 spaces
wide and maximum 10 spaces down when we
have vectors when we have a vector of
vector each row each roll is a separate
vector ok so it's on its own separate
instance so for example this row can
contain 10 elements this row could
contain five elements if you want this
row could contain as a seven elements
this real quick a 10100 element
it doesn't really matter because each
each vector of vector vectors resizable
array so when we have a vector of
vectors and our multi dimensional vector
each of these are this own individual
vector so imagine these elements is as
your own arrays so imagine say we added
like 20 right here imagine this line is
an array of 12 and this line is an array
of 10 etc etc right so each of the each
of the lines of their own vectors okay
so and and for those of you who don't
know about vectors it might be on that
explanation might be kind of vague so I
advise you go and look into vectors more
so i put the ampersand over there's
because we're going to be changing the
value of it so we open our file if the
file is open let me create these
variables right here so all we have a
while loop right here and then we get
the line so we get a line in the file
but what we want what we need to do is
be able to put the odds separate them
and be able to put them into our our
vector so what we do is we create a
string stream and i'll rename it str i
mean put our line in the string stream
and we create a temporary vector because
our map as a vector of vectors but we
need to in order for us to put something
into a map file we need to put in a
vector sense of vector are vectors we
need a place on a vector fall in there
so we create a integer type vector
called 10 vector so we loop till we
reach the end of the string and I took
the end of the string stream and I think
you can also do a while str I'm not
really sure you could test that out boy
at so we're going to we say that if it's
not the end of the it was not the end of
the file then we do we do this right so
then we use the get the line function
again and this is a hidden or there
isn't different overload weather with
getline so basically we have our string
and we want to store the value into
right here and our delimiter is what
we're going to separate each instance by
so remember in the first map tutorial
the first two when we just let me just
did open file we just did open file
colon colon I think I mean are the two
right stream operators what that did is
that it treated each space of the
delimiter so then when it reached a
space is put that has returned this
value and I want to return this value
etc etc right so what a delimiter is is
that it basically takes tools in the
video when it sees this value right here
then it will will store the all the
values up until that point into this
variable and after it will just continue
until it reaches the end of that string
that string stream ok just like it's
reading to a file but it's going to read
till the end of the string stream so we
say that if the value dot length is
greater than 0 then we add that value to
the 10 vector now since our temperature
takes integers you just have to change
it to an integer from a string to an
integer we do this by doing a atoi and
we put the value C underscores a string
because there should be a constant char
believe so ah so yeah so why do why do I
have if valued at length is greater than
0 I have that there in case for whatever
reason say the person accidentally put a
space there or accidentally hash
trailing spaces if you have trailing
spaces uh even though the length of the
string if the length of the string is
equal to null so even if in our string
and our value is going to be eat when i
sees a space like that r-value is going
to be equal to that right then be equal
to no but when we convert it to an
integer it's going to convert the null
value equal to 0 and therefore it's
going to add in some things to our map
which we don't want so to prevent that
we just say that if the value is
the length of the value is not greater
than 0 then we don't add it if it is
greater than 0 then we add it towards a
temp vector right and if you don't want
to do it that way there's other our
methods that you can use in order to
trim it before you do things with like
you could do fine last night of and find
first of whatever i'm not going to get
into that but you could search those
search up those functions on the
internet but you could trim it before
but what this it makes it easier so once
we do this we add this to our vent
vector and when we use a function
pushback is basically adding it to the
vector so for example set vector size is
0 right now so there's nothing in our
vector so when do push back say we add
in the value zero right then our vector
size becomes one so then to identify
that vector or be ten victor zero right
just like an erase it starts at the
element 0 and so on and so forth so
we're just basically adding value to
temperature after we've done that and
we've added all the vectors affect the
10 vector then we have to add these this
to the multi dimensional vector to the
2d vector which is the vector vectors so
we add in that line of the vector into
our map vector so for so what this is
how it's going to work so the what
what's going to happen is that we're
going to get this line we're going to
store all the values within the 10
vector and once you start an intemperate
to let me put it into a map vector so
our map vector 0 matt vector 0 is going
to represent the first element in the
map vector in our entire map the first
element is going to represent the line
number right gonna represent line number
and then the second element is going to
represent the number within that line ok
so it's going to represent this number
right here and it's important to know
that because before when we had our map
we had our all the X values that we have
very low counter x or whatever our x
value was in here and our Y value were
in here so for example
arm like if we for example if our ex was
say two or whatever if our X is equal to
one now is equal to one will be drawing
this value over here and this one if our
X is equal to two this is going to be
this is good or if it's equal to one
it's representing line number one the
second line I mean and then it's going
to go across so it draws it differently
so in reality is going Y X instead of X
Y and I know that might sound a bit
confusing but what we'll get more into
that that arm once you start drawing so
basically let me get this line we store
the slide within our map vector and we
get a new one and then we stir with that
and when i'm at vector etc etc so that
is it for the loan map so if we go down
to the draw map don't forget to change
this so i'm going to go to draw a map or
what we need to do is we don't have a
map size x on the map' sighs why the
good thing about the vector class that
they have a size so first of all we say
that I loops from I to less than the
size of it and then we say J loop 2 j's
attend map I doubt sighs so what is this
saying so the map that size is
representing how many lines numbers
there are or how many columns there are
and map i dot size is how many elements
are within that row right so for example
i'm like i was saying before if I get on
my map file this one a map that size is
representing these numbers 1 2 3 4 this
the column numbers or the row number or
whatever and then the map saw the map i
dot size is representing which number it
within that row okay so the reason so
now now now that we do that we need to
switch around how we dry so we have to
switch before this was I tongues block
size and j times block size I x box has
and j times block size we have to change
it to j times block size I 10 box IJ
times block size plus block size and I
times block size plus block size why do
we have to do this
because the way we're drawing is
different the Jays now are representing
the x coordinate and the y and the eyes
now are representing the i coordinate
the eyes representing the column number
and the Jays are representing the the
the rope um the element within that row
right so so yeah so we have to switch
that around if you don't do it then it
would draw if we don't do this way with
drought inverted but just to see what we
get if you run this program so we get
our map and we have the attitude wise at
the end that we've added so it doesn't
they don't all have to be uniform with
and just before we end this tutorial I
never showed you creating my map but
here's the the multi dimensional vector
right here so we created put into loan
map and we put it into our draw function
and we run it statuses so that is it for
this tutorial hope you enjoyed it thanks
for watching and bye