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2D Vector bullshit

Name: Anonymous 2008-11-14 6:04

I've got 2 points (ie. X,Y vectors), and I need to find out the angle (degrees°) between them, so I can move an object which is at one of the points towards the other point.

How do I calculate the degrees plz???

Name: Anonymous 2008-11-15 15:35


void Object_t::Move()
{
     Accel.x = thrust * cos(DEG2RAD(headingDegs)); ?? OMG SO FUCKING OPTIMZIED!!!!!!!!!
     Accel.y = thrust * sin(DEG2RAD(headingDegs));

     Vector += Velocity;
}

Name: Anonymous 2008-11-15 16:17

>>41
I KNOW RIGHT

I also forgot the Velocity += Accel;  line but eh, I only pasted what's necessary.

So how the piss do I calculate the headingDegs?

Name: Anonymous 2008-11-15 19:13

>>31
POLYNOMINALS
lolwat

Name: Anonymous 2008-11-15 19:35

>>42
Here's what you do. Fuck that pansy ass cosine shit.

cos(x) = dot(X, Y)/(length(X)*length(Y))
x = arccos(dot(X, Y)/(length(X)*length(Y)))

There is the angle between the points. Blam. Read SICP.

Name: Anonymous 2008-11-15 19:37

BTW if you dont know what dot and length are:

dot(X, Y) = X[1]*Y[1] + X[2]*Y[2]
length(X) = sqrt(X[1]*X[1] + X[2]*X[2])

Good day.

Name: Anonymous 2008-11-16 9:14

OP here, finally got this shit working, thx guize l00l

Name: noobular 2008-11-17 8:02

WAIT NO

It doesn't work when the target vector is to the left of my current position vector.

/** Move ()
 *
 * Move the object towards its vector.
 *
 */
void Object_t::Move()
{
     Velocity.x = thrust * cos(headingDegs);
     Velocity.y = thrust * sin(headingDegs);

     Vector += Velocity;
}



/** GetDegrees ()
 *
 * Set headingDegs based on Target vector.
 *
 */

void Object_t::GetDegrees()
{
     float dx, dy;

     if (Target.y > Vector.y)
        dy = Target.y - Vector.y;
     else
        dy = Vector.y - Target.y;

     if (Target.x > Vector.x)
        dx = Target.x - Vector.x;
     else
        dx = Vector.x - Target.x;


     headingDegs = atan(dy / dx);
}


If I add this part to the end:

if (Target.x < Vector.x)
   headingDegs -= DEG2RAD(180);

it will work for targets that are left & up, but not left & down.  WHAT DO I DO LOL?

Name: Anonymous 2008-11-17 8:08

>>47
This is why we DONT HELP HIM!!! ;)

Name: fairX the haxxor 2008-11-17 13:07

>>48
;)

Name: Anonymous 2008-11-17 13:36

>>45
amerifag

Name: Anonymous 2008-11-17 15:20

>>50
explain nao

Name: Anonymous 2008-11-18 5:05

get atan2 up all in that ho for the sign of your life

Name: Anonymous 2008-11-18 5:33

>>47
See http://hyperphysics.phy-astr.gsu.edu/Hbase/ttrig.html#c2, that explains the problem and solution quite well.

Name: Anonymous 2008-11-18 8:02

Why the fuck do you want the angle for this?  Just normalize the delta between the two points to the speed you want.

P.S. And you still need 3 points to calculate an angle, saying the "angle between 2 points" is a fucking meaningless statement.

Name: Anonymous 2008-11-18 9:28

>>54
Obviously, he meant the angle between two vectors, dipshit.

Name: Anonymous 2008-11-18 13:17

This problem is trivial given a mathematician.

Name: Anonymous 2008-11-19 1:36

>>56
Not the useless ones I'm working with.

Name: Anonymous 2009-03-06 7:49

Responder client closed ClientSock.

Name: Anonymous 2010-11-26 13:19

Name: Anonymous 2011-02-04 18:00

Name: Anonymous 2013-06-18 19:47

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Name: Anonymous 2013-06-18 20:01

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Name: Anonymous 2013-06-18 20:23

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Name: Anonymous 2013-06-18 20:37

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Name: Anonymous 2013-06-18 21:05

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Name: Anonymous 2013-06-18 21:20

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Name: Anonymous 2013-06-18 21:27

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Name: Anonymous 2013-06-18 21:34

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