[jME Tutorial 1-9] Reflections with the jMonkeyEngine (Part 3/3) Video Lecture | jMonkeyEngine Math: An Ultimate Guide - Game Development

should be equals so that access is going
to be I have the direction specified
anywhere I do not okay so I've messed up
quite a few important points so I need
to use the direction from the cam I'm
going to sing a 23 f direction because
can put Kate direction this should
already be normalized and so should the
contact normal so I don't need to do any
additional normalization so I'm going to
subside direction dot cross product of
the normal and I'll given the access
from which I need to rotate the quarter
nyan angle so I'm then going to find the
angle theta from the cross product
between these two so cause your products
a float into the dots equals direction
dot dot of the normal should i'm going
to come plus cos theta it's easier to
easy to visualize we're going to say
theta because fast mare empty cause of
cos theta and now i'm going to rotate
this court an in-control she died from
angle access rotate it by theta along
the axis I'm not sure if this is going
to be normalized or not i'm just going
to normalize it anyway my eyes locals it
doesn't create a new object
and then to rotate the normal vector
along this angle and then multiply the
vector the normal vector by this quarter
nyan i'm going to say reflection that's
going to equal the quaternion x the
vector which is the tumble to find the
normal vector so I'm
multiplying this vector here by the
quarter nyan which corresponds to this
angle here and that reminds me I need to
negate this direction because it's
facing towards the cam I wanted to be
facing away at 3f there and now I've got
the direction in which the reflection
should be looking lovely so then I'm
going to put a new quarterly turning not
going to give an extra big ones if I
smell something wrong I know you already
exist and then going to set q1 to look
at this direction so I'm going to create
a quarter nyan from a direction the acts
that up axis is why so unit why flexion
out the phone what am i doing seriously
and then I'm going to set the arrow
which is G to set its rotation to be
this core turnin i pray to god that this
works
k aiming tips I don't know their plus G
okay it's not what i was expecting the
no no that is completely wrong
okay come on fly cam well actually now
would be actually eat directions right I
need to move the arrow to that point
there let's set the local translation to
the contact points to close this not get
contact points try again like it have to
be white why did I need get rights
cannot really see its material setcolor
if I use blue yet don't think so try
again quickly gee probably quite hard to
to visualize this but I do believe that
is correct so if I can looks correct to
me let's find out five let's get rid of
the rotation should make it easier to
sin
so should point pretty much directly at
me
okay but is not once
wait no this is that is right you're not
shooting exactly a straight line okay
even better I
move this directly in front of law so to
set local translation three so quickly
by this one little one direction left
collection down will touch the sad
direction if I'm not going to move
anything depressed gee what's up facing
directly yes okay Brannon so I've
confirmed that that works so that's how
you do it with cult aliens so I'll go
over it once again so I've got a normal
yeah which you can get from either array
collider bull and then you can just use
the get contact normal we can use the
quad and get the vet to see the normal
vertices from that and so if I have a
direction try one to which i want to
reflect first negate it so i needed to
face the other way and they need to find
the angle here you can get from the dot
product I then need to find the axis
which I want to rotate so if i do the
cross product between these two axis i
will get the plane perpendicular which
which is the axis i need to rotate
around so then i simply find the core
turning around that axis using this
angle here and then i just multiply the
normal by that court an ian and then if
I want it to face this way now I simply
negate the direction so
I've done that they're probably better
if I do this reflection here now negate
this one let's get local oh I've already
rotated it again shift f6 to run it
SG and that is it reflected Oh through
the access rather than deflected away
from us okay so actually do it with
quarter nians and I should i'll show you
can I be bothered to show you how to do
it the other way that's why not I've
already here and I'm already over at the
time but who cares okay so i won't need
any of this oily commenter helps
probably need plant so okay so I've got
the normal got a direction collie buddz
remember how I did the other one okay
let's recap quickly so straight line
have the normal have the direction I
want to reflect
so I need to find the adjacent length
which I can do using the dot product and
then I can say that but this is n this
is a let's say using the dot product of
a and n assuming they're both unit
vectors which they r equals cos theta
and I know that to be the hypotenuse
this is the jason this is the opposite
but cos theta equals adjacent over
hypotenuse the our porn users of length
1 so it goes away and then cos theta
equal to the adjacent length which means
that the dot product of a and n is the
adjacent length and then if i multiply
that length by n i'll get the length in
that direction and if i multiply that by
2 i will get its game missing or then
get this length here and then if i if i
subtract that from vector a so i start
the origin I go to a I then down by two
times the dot product times by the
normal vector F a mouthful but let's
find it out quickly to the do or that
direction so the reflection should be
it's going to be a direction
subtract two x actually I do the normal
sub x to do local do that by going to
the dot product of the direction normal
so i'll just do direction dots normal
think that was it then i create a look
at and see if that squirt normal i
ce'tainly it's always good to have
directions as normalized analyze local
just f6
gee brilliant that looks right so
probably that way it was a bit more
easier to do in court aliens but you
know leave the choice up to you if
you've got court aliens you can do it
this way if you haven't do it that way
ok I think I'll blow it on for long
enough about reflection