C++ Allegro 5 Made Easy Tutorial 33 - Loading Tile Maps [Easy] Video Lecture | Allegro: A Complete Guide - Game Development

hello everybody and welcome to your 33rd
a level 5 tutorial so in this tutorial
we're gonna be learning on how to load
maps into our program ok so to start off
a lot of people when they teach you
tours on the on how to do this they
normally have their map array within
their program and they modify it and
they show you how to do it in your game
I mean I know they're just trying to
teach you the concepts and they're not
saying that's definitely the right way
but they're teaching you they're getting
you into bad habits really fast and I'm
gonna try and distinguish that right
it's not good to put your mouth Falls
and within your game fall even if it's a
little game it's really not good the
problem with that there's two problems
with that first of all every single time
you make one change to the game you're
gonna want you to the map or something
you're gonna have to recompile your code
it's gonna recompile matically and you
might be saying recompiling need to
expire to ten seconds but say you're
trying to to test something your code
and you have to keep on changing it over
and over again it kind of gets annoying
at times and also the amount of time do
you spend recompiling and adds up right
it takes a lot of time and if you're
working for a professional company or
something time is money you can't waste
time recompiling when you really don't
need to second reason is if you have a
designer working with you you don't want
your designer to look at your underlying
code this is for you to see and the
designer should be designing their own
code most designers a lot of designers
might not even know how to program so
they might not know how your core
functionality works so it's best to
separate the two so to start off we're
going to be creating an extreme and our
permanent we need to include the FG in
the pyrenees I'm gonna need our block
size so if we look at our code over here
our this is our 10 and map text file so
the top we're gonna specify the width
and height of our text how many elements
the basically the size of an array what
our race I should be and then the zeros
are gonna represent the sky and the ones
who can represent the ground so it's a
10 by 10
and each of these blocks is gonna be
equal to the block size so the burner
each each zero is gonna be representing
a block that's 40 40 pixels wider than
40 pixels high right so yeah so if we go
to our program we need to load in these
values right but first we need to add in
some variables so we need a load counter
x2 0 need load count of Y so that's 0
we need our map size X and I'm upsize
why last but not least you know map 100
by 100 now in our load map function yeah
we need to create an old map function
we're gonna create a constant char and
the file name so that's a fondant amount
probably gonna be loading in and
normally after that we normally do put a
point into the map or just do a
reference or whatever it's in the map to
the array but since since weren't using
a global variable which is about habit
but since you're using a global variable
and it's a before the load map then
we're just gonna use that map instance
but in most cases you're gonna want to
have the map that whatever the variable
you're gonna be storing the values in in
this function and yeah I say that global
versions are a bad idea but for the
since we're not using classes then we're
being excused but if you wanna kind of
do it the proper way then you can take
this map code and we can put it within
our we just put it within somewhere and
I mean when the main function and then
and the parameters we'll just put a
pointer to the map so to begin what we
need to do is we need to open the file
name where I'm at restored right so we
do open file and we're opening the file
name so we need to check to see if the
file is open cuz it was not open she's
not open you probably went on and do an
error message or something using the
native message box so if it is open then
we want to store the the map size X and
the amount size why
like so so if we look at our code we're
gonna get the width of the height and
the height of the map okay so after we
do that and then we want to loop we
wanna cycle throughout the text file so
we're gonna say while we're not at the
end of the file that means loop do it so
we're gonna be loading in map load
counter X load counter Y and what our
aim is to do is to resemble the layout
that resemble our array in the same
layout that is laid out in this file so
how are we gonna do this so we're gonna
increment little kind of X by one and
we're gonna say that if load counter X
is greater than or equal to map size X
then low counter X is equal to zero
and load counter Y plus plus so what's
going on here uh I don't know what the
problem is oh yeah cuz I already have
the function in down there don't worry
don't worry about the error for now okay
but if we if we look at it okay so a
little kind of XML counter Y is equal to
zero okay so first we use open file
we're gonna be getting this value right
here and we're gonna be storing it in
the map array 0 0 once you over here we
increment the load counter X by 1 so
that means this value is being stored in
the map array 1 0 and this is gonna be
stored in 2 0 3 0 etc etc once it
reaches here we reset little counter X
about to 0 and we increment a little
kind of Y by 1 so this body is gonna be
stored in the in the index 0 1 it's
gonna be in 1 1 2 1 do you want - et
cetera et cetera and therefore we're
gonna get the same layout in our mat
file as in the as in our map in our map
array as the same as I'm not file so if
we so once we do that then we're going
to we're going to need to draw the map
so we're just gonna make a
instance of the drawn map in here and
our mat file and it was a reason why
we're not doing it up here is because we
need to be able to draw perimeters but
the permanent add-on comes in after in
our main and our main function so we
won't be able to use a draw the permit
is if we if we draw the map up there so
we do draw map our mat file and we're
gonna do two for loops so for loop to
map size X and we're going to have a
nested for loop that's gonna loop to
this till map size Y so it's basically
gonna cycle through our whole map um do
our whole map file so once we do this so
we're gonna create an if statement so
we're gonna say that if map IJ it's
equal to zero so if that index of the
map is equal to zero then we're gonna
want to draw a filled rectangle and
we're gonna want to draw it in the
correct position so we do by this we say
I times block size J times block size
and we do I times block size plus block
size and J times block size plus block
size and for the color wheel set it to a
blue color since the sky okay so we got
that and we'll just say else since we're
only working with two numbers so if the
map IJ is equal to one and then we're
gonna draw a nice green color for the
ground okay so what is this thing right
here okay so for instance the the way we
the way we loaded in our map is not the
same way we're gonna draw it we're gonna
basically draw our map
column by column but doesn't matter how
we drop we just need to put each
individual element in the correct
position on the screen right so how do
we do this okay so for example so say is
equal to zero and J is equal to zero so
we know that we're gonna we're gonna map
I J's the first element in our map so
this this element in the map so we
needed to draw at the top left corner of
the screen so we do I times block size
so zero times 40 is equal to zero so we
start drying at a pixel zero and zero H
is equal to zero so zero times four is
equal to zero so we started trying homes
there on the y coordinate then zero
times zero plus 40 is equal to 40 so we
end drawing at the fortieth pixel and
zero plus 40 is equal to 40 so we end
drawing in the fortieth pixel in the y
position Y column and then we draw that
a certain color so then say I lose again
and J is equal to one so we know that if
J is equal to or map IJ oh sorry
map IJ is going to be equal to this
element right here right so we know that
I so equal to zero so we're going to
start drawing from the pixel zero and
end up drawing in the pixel forty but J
0 to 1 so 1 times 40 is equal to 40 so
we start drawing at the fortieth pixel
40 plus 40 equals 80 so we end drawing
on the idiots picture so and therefore
we get our whole image drawn how we need
it to be drawn so right before we flip
the display we're just gonna draw a knot
and we put in our map file in there and
for a load map and so after we create
our map I just said it a hundred by a
hundred just in case you're gonna
increase the size in that forever or
whatever forever reason but you could
set to 10 by 10 if you want but we're
gonna load map map 1 dot txt and we're
gonna put none that fall in there and oh
yeah I can't do that that should work
and yeah so I'm still getting some still
getting some errors okay so I just fixed
a problem by just doing a just putting
in map and then a hundred and the second
one and change that as well for the draw
map as well and when he changed that you
got a change at the bottom as well so if
we run this program we see that we get
the given map that we've gotten to the
zeros representing the blue and the ones
representing the green so I hope you
enjoyed this tutorial thanks for
watching and bye