Android Application Development Tutorial - 178 - Using GLU to set up

what's up guys welcome to your 170
eighth Android tutorial for the new boss
in or your new in this tutorial we're
basically gonna draw or triangle to the
screen well we're actually gonna look at
our triangle because it's already drawn
there we just have to find it and in
last tutorial again all we did is we
just set up our viewport we set up like
you know what where we want it to be
visible and all that good stuff and now
we're actually going to basically tell
our camera to look at a specific point
and we also want to set it to model mode
so what we're gonna do within our on
draw frame is after we you know call the
clear method we're just gonna say GL dot
GL matrix mode again oops GL matrix mode
and this time we're gonna set it equal
to the GL 10 class dot GL on your score
model mode and then what we're gonna do
is we're just gonna again gonna call
that load identity method so we're just
gonna say GL load identity and now what
we have to do is we have to tell our
camera where we want it to be in 3d
space and which direction we want to
look so how we're gonna do that is we
refer to a class called Glu and we're
just gonna say dot Glu Glu look at and
the first parameter it just takes in
which GL object we're looking at GL tin
object again that's what's being passed
into our class and then we have to set
where we want the camera where the eye
level is going to be so what we're gonna
do is we're going to say we want to be
on the x-axis so we're just gonna set
that equal to be 0 the y axis 0 the z
axis we're gonna pull the camera back
into basically us you know not into the
screen but away from the screen so we're
gonna say like negative 5 or something
like that then we have to tell where we
want to look at again our triangle was
pretty much in the center so we're just
going to say 0 0 0 basically the origin
of our 3d space and then what we're
going to do is we're going to set our up
values to 0 then like 2 and 0
something like that and now when we
render it it's basically setting our
camera up again at this position zero
zero negative five and it's looking in
this direction and you know that's how
we kind of set it up and then we're
gonna draw our triangle so let's make
sure it works real quickly so as you can
see it kind of looks kind of looks a
little bit off but that's fine for now
and I kind of wanted to show you guys
that example because we set up a frustum
a little bit differently than we should
be right here we have we've kind of
skewed our bottom and our top a little
bit so just to change that we're going
to change this to one so we have a
negative one bottom and a neg or plus
one top and now let's render and see how
that looks
so again G open GL you can kind of
render stuff pretty much however you'd
like you can set up the camera you can
set up you know the perspectives that's
at all that good stuff and it's pretty
you know pretty impressive and there we
go we have a better rendered triangle
where it's not kind of skewed and it's
not you know up higher it's kind of more
balanced in the center so there we go it
looks a little bit better so I'd
recommend you guys just playing around
with some of the values that we set up
and see if you can get look in the way
that you want again we can move our or
let's say we want to move our Z value
back to negative ten they'll kind of
look like it's scaled down or you know
we're further away and just quickly I
want to show you one more render for
this tutorial
and then we'll either get into texturing
this triangle or we'll get into 3d
programming with the square of some sort
as you can see again we're zoomed
further back out before we are a
negative five and now we're at negative
ten and again we set up this Z value to
refer to anywhere from you know one away
to 25 away so if we went up to like
negative 24 or you know even let's let's
go to negative 30
it won't even appear on our screen and
as you can see when we're at negative 30
it's not even appearing on your screen
because that's of the frustum that we
set up we only had it within you know 25
away so if we we did something more like
you know 23 negative 23 it's gonna be
really small but at least we can still
see it but if we move further than that
frustum value that we set up in our Z
Direction Z far then you know it's not
gonna render if we go further than that
distance so there's a little bit more
explanation on the frustum and see that
now we can still see the triangle as far
away but if it goes any further back or
you know actually could probably go one
further back but if it goes further than
that it's just gonna not even render
that triangle we aren't gonna worry
about it so that's kind of what the
frustum did that we set up in the last
tutorial again we're just setting our
camera here so we can even change
perspectives you know like moving up
five as well or something like that
again I just play around with the values
get comfortable with these commands and
these methods that we set up and try and
render it the way that you'd like but
we'll get into some more methods what we
can do how we can like rotate around
this object and all that good stuff as
for now we're probably done and we're
gonna start building our cube I'm
guessing so I'll see you guys then have
a good one