Can anyone help with this vector maths to get normal?

Game Engine Game Engine Support and Discussion
1

After all the help i’ve had, here is my reflection script - shows the normal, and then the angle of incidence and angle of reflection. Only ‘bounces’ once

import bge
from mathutils import*
from math import*
from bge import render as Rasterizer
c= bge.logic.getCurrentController()
o = c.owner
range = 50
ob = o.position + (Vector([0,range,0])*o.orientation)

#first ray

ray = o.rayCast(ob,o, ob.magnitude, "", 0,0,1)

point = ray[1]
normal = ray[2]
start = o.position
color = [ 1.0, 0.0, 0.0]
Rasterizer.drawLine( start, point, color)

def get_reflection(v,n):
    N=Vector(n).normalize()
   
    V = Vector(v)
    R = []
    
    
       #print(v)
    dotS = V[0]*N[0] + V[1]*N[1] + V[2]*N[2]
    r1 = -2*dotS*N[0] + V[0]
    r2 = -2*dotS*N[1] + V[1]
    r3 = -2*dotS*N[2] + V[2]
    R.append(r1)
    R.append(r2)
    R.append(r3)
    return(Vector(R))    

v = o.getVectTo(point)[1]
Rasterizer.drawLine(point,point+normal*3, [0.0,1.0,0.0])
end = get_reflection(v,normal)
end.magnitude = Vector(point - o.position).magnitude
print(end.magnitude,sqrt(v[0]**2+v[1]**2+v[2]**2))
last = point+end


Rasterizer.drawLine(point,last, color)
2

Look at the reflect() method on vectors in mathutils.

3

I had a test:

In 2.49b reflect() is broken and returns incorrect values. In 2.57 it is fine.
You can normalize your vectors with normalize().

4

Just checked my game AI script. Didn’t find reflect() so that’s good. I seem to remember I couldn’t get it to work well.

5 
import bge
from mathutils import*
from math import*
from bge import render as Rasterizer
c= bge.logic.getCurrentController()
o = c.owner
ob = bge.logic.getCurrentScene().objects["Empty"]

#first ray
ray = o.rayCast(o,ob, 203.0, "", 0,0,1)
point = ray[1]
normal = ray[2]
start = o.position
end = point
color = [ 1.0, 0.0, 0.0]
Rasterizer.drawLine( start, end, color)

v = o.getVectTo(point)
n = normal.normalize()

poi = v.reflect(n)

Rasterizer.drawLine(point,poi, color)

#what i am basically looking for is to take the data from the normal, and use that to reflect
6

Second drawLine should be:

Rasterizer.drawLine(point, point+poi, color)

And possible You want to change length of poi with poi.magnitude(length) first.

7

WOW, thanks LAH!