[jME Tutorial 1-2] Vector math with the jMonkeyEngine Video Lecture | jMonkeyEngine Math: An Ultimate Guide - Game Development

drawing the three axis Z Y and X a
vector is a point in space with
magnitude and direction
so change the color
so I can have a vector here
at points to five just two points along
the x-axis
five points along the Y and one along
the Zed Zed been towards you so I can
have another vector I'll say this is a
point seven two Nichols appear one
so to call this vector a this vector B
so I can add vectors together this would
then create a vector 9 7 2
which would be
solo okay
- which can also be visualized as going
up to a and taking this vector B and
moving it upwards and then joining it's
not to scale oops
and then you can also do the same going
to be and then moving on taking vector a
and adding back on to get to there and
already beginning to make a mess
vector subtraction it's probably one of
the more useful or killer both useful
but this is very useful as it can give
you the vector between two vectors
you
that's looks scribbled I nodes so I'm
just gonna use the same two vectors for
simplicity and decrease the size of this
one so if we want to find the vector
between this point a and this point
B
and depending on which direction Li once
we can either subtract a from B which
will give you this direction we can
subtract B from a so this direction
would be B minus a can visualize it as
having to turn this arrow the other way
around on so you're going from minus a
plus B and then the other way around
it's a minus B so this gives you this
factor here depend on which direction
wards I'm going to stay New Age and talk
to you about unit vectors and the
distance length or magnitude of a vector
so if I have a vector a 3-5-2 then its
magnitude or length denoted by two bars
alongside the one by 2020 so in two
equal the square root of x squared plus
y squared plus Z squared or the
Pythagorean theorem of evolution and a
unit vector with a little hat above it
it's the same as the vector divided by
the magnitude of the vector which this
gives a length of one which is very
useful and I will show you why right now
okay back in the j-money engine going to
control N and to go to one of my
templates I'm going to call this vector
meth click enter all this does is create
some changes in the move speed and the
rotation speed of the default fly care
and create a material because I get sick
of having to create it all the time so
now going to show you how to use vectors
in J monkey engine there's a new
shortcut PR tab going to create a
spatial
don't always us Joseph died and I need
to add the test data product properties
libraries compile and add life so now I
can use loads of assets that JME gives
for me for free
ok first of all I'm going to change the
color of the viewport to pink because it
is manly not dark grey pink color RBG a
you've never let me down before and you
never will so now I'm going to create a
new facial using the asset massive asset
messenger asset manager load model and I
hope I don't screw this up sindbad
sindbad and to the blue load
and hopefully it works no it won't
Wow no not you again it's because I need
to shift f6 justice pink
but where's my model gun needs to add a
light like sunlight I drag this over
there's a little pallet over there that
you can steal control shift I yes
that'll do
Oh shift f4 format shift f6 this time
yes we have a log in bird but this isn't
back to math at all I haven't done any
vector math yet here's what I'm going to
do now I'm going to add another one
because I can me lazy I'm just going to
copy and paste these two what are you
going to change lefty s1 and don't
forget to change this to s 1 also and
I'm going to link bit 5 units right 5
units up I'm not going to change this
head shift F 6
yes so now these two Sinbad's are at
different positions to move around with
the fly cannon you can see them in their
full glory
yes fine enough so now what can I
actually do I can find the distance
between them both which if I remember
correctly yes I will no not set get get
the local translation and find the
distance yes there is a function already
there for me that's too low there's nice
- it's just s and I want fill system out
this with s out V could have also just
type this out what am i doing v f6
so you can't even see it what am i doing
seriously
they're 7.07
units which in Jamie corresponds to
meters okay so got the distance let's
find the vector between the mir so I
talked about that so let me go back to
this
like trusty pen so now you imagine to
have a line like these this Sinbad is at
zero zero zero because I didn't move him
for this one is that five five zero so
he has a vector here this one don't know
how to really draw nothing so I won't do
anything and oh this is gonna be hard to
draw simplicity because I don't what
else to do I'm going to move him a
little bit set this up to zero one zero
they go back here
so now now he's moved a little
so now he is at zero one zero and this
one's at five five zero
so now I can find the vector between
these two if I want the direction to
face this way then I have to - the first
vector and add the second one and that
will get me the vector between them and
the direction so I want to - the first
one from the second ones or do s1 get
local translation dot subtract
the first one and I will normalize this
which is the same as saying that the
applied unit that they turned it into a
unit vector singleton the unit vector
Amnon horse direction that's what I'm
going to be using it as now so that's
the direction I want it to face in and
now I'm going to move the first model in
the direction of the second one and I
shall do this I'm going to first of all
move this as a class attribute so that I
can use it in different methods I'm
going to move it
how'd I do this again I want to see the
direction back there go to x time per
frame
so hopefully oh yes look at him go he
should exactly go over him yes I shall
try to explain what just happened so I
have so we had he was here the other guy
was here and now new direction is like
this it has a length of 1 so in 1 second
using time per frame he would be at this
direct he will be at this position