Android Application Development Tutorial - 174 - Creating Draw method for OpenGL Video Lecture | Android Application Development (Mobile App) - Software Development

what's up guys welcome to your hundred
in 74th Android tutorial for the new
boss in and what we're gonna do is
basically finish up or you know for the
most part finish up our triangle class
here I bet some of you guys like finally
I don't think it'd be so like
complicated drawl triangle but yeah
we're almost done guys so don't worry
about that
and what we're gonna do is we need to
call or create a method that's basically
gonna draw to our GL 10 object and so
it's gonna be pretty simple all we're
gonna do is create a new a new method
within this class called public void
draw and it's going to take a GL ten
object within it and we're gonna call it
GL just for simplicity and then we're
just gonna you know add our imports and
let's get into it basically we can
define certain things we can define how
we want to draw our triangle you know
which side of the triangle we want to
display we can disable the back side or
something like that so that's what we're
gonna do within this draw method is just
get everything set up and this is the
method that we're gonna call within our
render class because again our
constructor is going to set up basically
you know the base stuff that we need the
buffers and then we're gonna access
something through this draw method so
the first thing that we're going to do
is we're going to relate pretty much to
our GL object that's being passed in of
our draw here the whole time so what
we're going to do is we're going to say
GL and first we need to connect all of
our points so what we're going to do is
we're going to say we want to refer to
the GL front face that's the face of
that's facing the front you know I mean
we got to tell it how we want to connect
these points again we started at the top
of the triangle second points over to
the right third points to the left and
that's how we're going to connect our
triangle is clockwise so what we're
going to do is we're going to relate to
the GL ten class dot GL C and we have
counterclockwise or just CW for
clockwise and that's how we're going to
connect ours that's just again just
telling
which face we want to face front
obviously if we did counterclockwise
then the back would be facing us if that
makes sense
but we want to do the front facing us
and that's what's going to render to the
screen so there we go we have our
clockwise connection and all that good
stuff setup and now what we need to do
is we need to basically relate to the
client state and able it for vertice
arrays because again we're working with
this float buffer that's basically you
know a vertice array type thing because
you know we have float values within
that buffer so what we're going to do is
we're going to say GL dot GL an able
client state and as you can see it takes
an int array within it but again we're
just gonna relate to the GL 10 class and
you're gonna get familiar with relating
to this class when when you guys start
programming in GL or OpenGL and all
we're gonna do is say dot GL underscore
vertex array and that's just gonna allow
us again to use a vertex array and it
more than just an abling the the client
state and all we're also going to do is
give us a couple lines here I'm just
gonna say our GL object GL disabled
clients save because anytime we enable
we want to disable it again we're just
gonna say GL ten dot GL underscore
vertex array because that's what we're
disabling now and we're gonna write some
code in here obviously but again just to
make note you guys want to enable the
client state for a vertex array and also
disable it and again I told you guys
we're gonna relate to a pointer of some
sort that's why again we had to use this
line of code that is a native order so a
garbage collector won't you know throw
it away so what we're going to do is
we're going to say GL again pretty
pretty basic here and then just that
deep whoops
GL lower case like that sorry and then
we're just gonna say vertex pointer
again the pointer is what we need fix in
for things with s parameters we have the
size which is how many dimensions were
working with again we're just working
with X and the y value so that's
to be equal to to the type the stride
and the the buffer so again that's the
buffer we set up and so first again for
this for the size we're working with two
two-dimensional objects so we're just
gonna say two there for the type we need
to say it's a float because again if you
guys remember our vert buff is a float
type buffer so we're gonna relate to the
GL 10 class again and just say GL
underscore float and the stride we're
gonna set to zero and what the stride is
let's zoom back up to our vertices array
here if we had something else like
another dimension maybe or like a color
or something some other kind of
reference in here for example we wanted
to skip out one of these things
basically you use use the stride to you
know skip over this third and then start
our new vertices but since we don't have
anything we want to skip over we're
gonna set our stride to zero our pointer
is going to be our vert off or vertice
buffer and so we're just gonna say vert
buff so there we go now we can't have
reference to again our vert buffer that
we set up and all those coordinates that
we put within the buffer and all that
good stuff and we have to add one more
line but you know I can't want to
explain that last sign it's pretty
important for actually drawing our
triangle so I'll probably in this
tutorial now and I'll catch you guys in
the next tutorial where we're gonna
basically finish this triangle class for
the most part we might come back and do
texturing and all that good stuff but
we'll get our basic triangle set up and
I'll catch you guys in I hope you have a
good one
and see you later