C++ Allegro 5 Made Easy Tutorial 20 - Creating and Saving Bitmaps Video Lecture | Allegro: A Complete Guide - Game Development

hello everybody and welcome to your next
level 5 tutorial so in this tutorial
we're going to be learning about
creating and saving bitmaps
now a lot of you might not think this is
important but it could real it really be
a good thing to incorporate in your
games especially if you want a group
have it I character creator or something
in your game then this is really really
really a good thing to look into ok so
first of all this is the code from the
sprite animation just wear your
spreadsheet animation tutorial not the
individual sprite the spreadsheet
animation tutorials 13 and 14 okay so
this code is exactly the same and if you
don't have this source code you can
download it off my website ok so right
now in my project folder I have two
different images okay a one called
person and one call here okay so I'm
going to be doing is joining the person
and the hair into one image and
displaying it to the screen that helps
and because if you you could easily draw
them as two different instances and you
could say draw the person then draw the
hair after but if you can combine them
into one bitmap it's less work for the
hardware or less work for the for the
computer or whatever and all you can
save it if you need it for later use
like say you say you have a character
create in your game and then you let
them create a person they played a
person like this with blue hair then you
can save it as its own separate instance
so when you load the when the person
loads the game again right then you can
just load in that image rather than
loading in these two different images
and having to join them again
you can just load the other image so I'm
going to be showing you how to do that
for now so right now we're going to get
rid of the load bitmap and we're gonna
say I'll create bitmap and for now we're
not gonna we're gonna leave that there
for now and what we're gonna do is gonna
do el underscore bitmap and we're going
to do person L load bitmap
and it's called person dot PNG and we're
gonna create another bitmap called hair
a little bit map and here dot PNG and
then as for the create bitmap when you
specify within the height so we're gonna
say I'll get bitmap with I'm gonna put
the person and I'll get bitmap height
and put the person in there okay so we
have okay so we have our bitmaps and
okay so we have everything set up like
so okay so now we created a bitmap for
our our player but we have to be able to
draw to the bitmap so you know our
display our display a kind of positive
bitmap it has a back buffer and what
happens is that we draw everything to
our back buffer and when we call al flip
display it switches like kind of flips
to display so it shows what happens on
the back buffer and then the the the
other screen becomes a back buffer and
so on and so forth so they see the back
buffer is like it's like a bitmap right
you drive you thing to it and you drive
to the screen so we want to do is that
we want to draw the player and the
person and stuff to the player bitmap so
then we store it we store whatever we
need into one bitmap so we need to do is
type in ail set underscore target bitmap
and then there we're gonna put the bit
back that we want to set as our target
render target so basically every single
thing that you every draw commander
everything you draw from now on is gonna
be drawn to the player bitmap not
display not the back buffer to the
player brain map so we're gonna do we're
going to do a la bit map and we're going
to put the person X&Y and no
and we're gonna put LLL draw bitmap here
XY or actually not we don't do XY just
put zero sorry sir I'm thinking that was
like drawing it to the screen sorry so
we just put zero zero and we put it on
the reason why we have zero zero is
because on our current our current
player bitmap is the width and height of
each of our images right so we're just
drawing it at the top corner of this
player bitmap so we're not drawing it
according to screen coordinates we're
just drawing it according to these
bitmaps coordinates so sorry if I
confuse you but just head to zero zero
so it it draws it on our bitmap
so once we drive it into our bitmap what
we want to do is we will go we're gonna
want to save the image okay so we'll do
al save bitmap and we'll save this as
player 1 dot PNG and the bitmap we want
to save is player okay so we stored all
that stuff into our player bitmap and
we're saving it as a PNG file called
player 1 okay so now we set our target
tool players will be drawing everything
to our player cloud or to our player
bitmap but we need to revert it back to
our display or our to our backboard
person and we can actually draw stuff to
the screen so what we're gonna do is
we're gonna do a let
target bitmap I'm gonna do a it back
buffer and then we put in the display in
there and then everything will be drawn
according to the display ok so that is
basically it
and oh for my images I'm just crunching
few things in the region before we use
this player image that was 3 by 4 this
image is 4 by 4 so I just gotta change
some stuff in here firstly I checked I
said this is 0 you might not have to do
this but I have to do it because of my
my image has changed Booya
so once we do that then
when we run this program notice it
combines the person with the hair rate
so combines this with this image and we
just created a new image called player 1
of a PNG file format so then if you want
to load this in and in another game or
when they load the game then you can
load it in rather than loading in these
two images so that is it for this
tutorial I hope you enjoyed it thanks
for watching and bye