<CMath>Getting angles between 2 3d points.

[kajgies]

I need to get a cannon to schoot on my target.
It is a 3d game.

I need to get 2 angles between the x,y and z of the cannon, and the target.

I can calculate 1 of the angles:

float getAngle2 (float x1,float y1,float z1,float x2,float y2,float z2)
{
    float dist=sqrt(pow(x1 - x2,2) + pow(y1 - y2,2) + pow(z1 - z2,2));
    float dist2=sqrt(pow(x1 - x2,2) + pow(z1 - z2,2));
    return acos(dist2/dist)*180/3.1415926;
}

That's the angle on the y-plane.

But now I need to get the angles of the x-z plane.

Does anyone know how to do that?

Thanks in advance.

[naraku9333]

It looks like your are getting the angle on xz-plane, try using asin

[ne555]

v_j w_j = |v| |w| cos \theta

> I need to get 2 angles between the x,y and z of the cannon, and the target.
¿2 angles?

[kajgies]

Thanks for your answers.
@ne555
Yes I need 2 angles, because it's 3d.
See this image, to understand it.
http://updo.nl/file/ba07bcbe.png

@naraku9333
I tried that, but because the target moves, I cant get the opposite.

[ne555]

Three not aligned points define a plane.
The angle between the vectors is in that plane.

As I see in your drawing, you want to compute the angle of the projections.
So simply project your vector.
w_j = v_j - v_k n_k n_j where `n_j' is the normal of the plane.

[kajgies]

Thanks for your help I the code I now have is:

float getAngle (float x1,float y1,float z1,float x2,float y2,float z2)
{
    float theta = atan2(z1-z2,x1-x2);
    return -theta*180/3.1415926;
}
float getAngle2 (float x1,float y1,float z1,float x2,float y2,float z2)
{
    float dist=sqrt(pow(x1 - x2,2) + pow(y1 - y2,2) + pow(z1 - z2,2));
    float dist2=sqrt(pow(x1 - x2,2) + pow(z1 - z2,2));
    return acos(dist2/dist)*180/3.1415926;
}