C++ Allegro 5 Made Easy Tutorial 27 - Bitmap Effects Video Lecture | Allegro: A Complete Guide - Game Development

hello everybody and welcome to your I
think 27 that I go 5 tutorial and in
this tutorial we're going to be learning
on how to learning on different bitmap
effects okay so the first effect is
we're going to be learning on how to
rotate sprites or bitmaps so the top of
our code or any way you want
we're gonna make a float variable called
degrees and we're gonna set that to zero
point zero you can set it to integer
float doesn't really matter
yeah so after this code right hand the
update what we're gonna do is when this
code is taken from the collision
tutorial we don't really need the
collision code so you can't take the
code from the sprite animation tutorial
if you want but yeah okay so right here
we're gonna check to for two key presses
so if they press the W key then you're
going to increase we're going to
increment degrees by one and we have a
elsif and if they press the S button
then we're going to increment degrees by
one okay so if we go so with another
sprite animation tutorial we cropped out
certain images right and yeah that's
that's really good bummer doing a
rotating a sprite we can't rotate a
spread and crop the image at the same
time that that function is not in there
so one of the bitmap effects that we're
going to be learning is we're going to
inner draw function we're going to make
a sub bitmap and that's gonna be equal
to ail underscore create sub bitmap and
what a sub bitmap is is that you put in
a name of a bitmap that you want to
I'll create a sub of or like I get a
region of and then you take that picture
and you make another bitmap from a
smaller one so this is the parent bitmap
that we're getting from and basically
we're creating a sub a map or a smaller
portion the bhimavaram were storing it
into our new variable so just like we
did a L drop bitmap region we're just
gonna player are our X sorry X is gonna
be our source X and our Y is gonna be
our source Y times 32 and our width and
height is gonna be 32 by 32 and then
after that what we're gonna do is we're
gonna say I'll draw rotated bitmap okay
so this time we're just gonna draw the
subway map and then for the CX and CY
that's what the center X and Center Y so
that's where it's gonna that point that
it's gonna be rotating around right so
if you want to rotate around the center
of the image since the image is 32 by 32
then half of the image is gonna be 16 by
16 so let's just see why in the CX and
CY for the X and YX and y coordinate and
for the angles the angle takes in a
Radian degree right not Radian measures
right so to change the degrees to
radians just do degrees times pi divided
by I divided by 180 so we'll just do the
point one point one four one five
divided by 180 and for the flags will
put null so if we run this program right
here if we look at our player we can
rotate our player in any direction we
need to right you might notice that
sometimes it might come out a bit grainy
when you're moving in the gutters
because it could be because of the
pictures quality cetera et cetera so you
might want to improve the quality if
that happens now one thing that we want
to know is that we know that this 350 is
due entrance sorry 60 degrees in the
circle right so we know that flow like
different integer types have
limit right and if we say we the person
kept on rotating it over and over and
over again eventually the degrees would
reach the limit so to avoid that what we
say is that we will say that if degrees
is we'll say that if it's equal to 360
or degrees is equal to negative 360 then
we'll set degrees equal to zero so and I
will just reset it so that it can only
go from zero to 360 and therefore we
won't run into any problems okay all
right so that is for rotating sprites
and that is one sprite effect okay so
the next spread effect is we're going to
be learning about cloning bitmaps so as
we noted that this when we draw the two
bitmaps they're from the same image
right so since we want to use multiple
images instead of our loading well they
are different images but so you want to
load the same image all we have to do is
just say that player 2 is equal to Al
clone bitmap I know you put in the
bitmap that we want to clone and in this
case when we draw it it's gonna draw the
clone bitmap to the screen so it draws
the exact same bit not to the screen
okay so that is another spread effect so
we learned about three we learned about
creating sub bitmaps we learned about
cloning bitmaps and we learned about
rotating bitmaps okay so after this what
we're gonna be learning is about tinting
bitmaps
okay so tinting bitmaps will take the
dig basically the color from that uh
color for that we specify a little tent
the bitmap to that color okay so if we
look at this we will say I'll draw
tinted bitmap okay so we're gonna take
the subway map and we're going to take
in a color L map RGB and will attend it
to a red color and the X&Y and we said
that this to null so if we draw if we
look at what we get when we run this
program
we see that it is a reddish color okay
so this was this is really really good
especially like they say you have a
somebody attacked the player right and
you want to show that the player got
damaged you listed out if they talked a
player the player turned red for like
one or two seconds or never sure
indicating that the player got hit or
something like that or if you just want
to tend to for any reason then you can't
right so another another thing with
tinting is that if we add an alpha
channel to that we can say we tint it to
like say 0.5 or something right I won't
meet into when we tint it we can set the
transparency or whatever when we tend to
it and therefore we can kind of like we
could set the image to be sort of
transparent so if I was to draw this
after so let me let me take this right
here and draw it after the after the
player after the enemy I mean so as you
can see it's the image of transparent
you can see through the image right we
could see the transparent area right
there cuz you could you could see the on
the underlying image over the the
regular image so with with that we can
we can change it so if we want if we
don't if we don't want to need
transparency then we can just set that
to one no sorry - what am I talking
about I was thinking we were doing an
RGB a float so if we didn't want any
transparency we wanted to be opaque I
think that's the thing that's an that's
a word then you can't see do it and if
you put a lower value then you can see
to it even more okay so that is it for
tinting bitmap so you can basically tint
and set if you could see through it as
well so last but not least we're going
to be learning about scaling right and
scaling is you can increase or decrease
size of it so for this we're going to we
would just use the degree set the
scaling factor right now it doesn't
really matter we were just gonna know
that the degrees is gonna represent
scaling right now so lastly we're gonna
take scale the bitmap and what we're
gonna take is this bitmap and D okay
okay so so we we have our sub bitmap and
then the next one we take the source X
and source Y and stuff like that so
since we already have our sub bitmap
then we we just hit that to zero zero
the source width and height
that's just 32 by 32 since our image is
32 by 32 the X&Y coordinate I'm the
player X&Y and for the width is the
width and height we want the image to be
so in this case we will just put 32 x
degrees and we'll put 32 x degrees so
since the grease is 0 32 times 0 0 so
we're not gonna see the image once we
start but once you press like W we're
gonna see it zoom in and press s it's
gonna zoom out ok so yeah so if you
notice one last thing so before we end
just to just let you know like if we
don't if we never created these sub
bitmap right to create that then this is
like draw a bitmap region so then with
the source X in the source why excetera
etc you could do that the cropper
section of the image so for example if I
if I said it's a 16 by 16 and I said the
width and height of that to 16 and 16
then if we draw the image to the screen
we only draw a half of the image right
so it's just like a drop in my region
but in this case you can scale it make
it larger or smaller depending on what
you need so that is it for this tutorial
hope you enjoyed it thanks for watching
and bye