Angle based bounce

Blitz3D Forums/Blitz3D Programming/Angle based bounce

AlternativeRealities

(Posted 2004) [#1]

I have a sphere which is moving at an angle towards a wall, when it hits the wall I need to know what the deflection angle will be in order to turn the Entity.

Any help would be greatfully appreciated.

AntonyWells

(Posted 2004) [#2]

if your walls are 'straight' you can use this,

with xi,yi,zi being the current inertia of the ball when it hits.

nx=collidedNx()
ny=collidedny()
nz=collidedNz() ;get the normals

if nx<>0 xi=-xi
if ny<>0 yi=-yi
if nz<>0 zi=-zi
;-

you could try nx=abs(collidednX())*x etc, for non straight angles.

AlternativeRealities

(Posted 2004) [#3]

Thanks for the quick response, but it didn't seem to work, let me elaborate a little, my ball object is being moved by:

MoveEntity balls(1)\obj,0,0,balls(1)\speed

then all I have to do to change its direction is to use:

TurnEntity balls(1)\obj,0,newAngle,0

I then check for collisions using:

Collisions SPHERE, POLY,2,2
CountColl = CountCollisions(balls(1)\obj)
If CountColl<>0 Then
For f=1 To countColl
If EntityCollided(balls(1)\obj,ground) Then
TurnEntity balls(1)\obj,0,bouncedAngle,0
End If
Next
End If

Its the bouncedAngle that I cannot get right.

DarkEagle

(Posted 2004) [#4]

bouncedAngle = ATan2(CollisionNX(balls(1),f),CollisionNZ(balls(1),f)) + offset

play with the offset, and the order of the arguments passed to ATan2, and the signs

AlternativeRealities

(Posted 2004) [#5]

With a little tweaking it worked, thatnks for your help.

Kanati

(Posted 2004) [#6]

the angle of incident = the angle of attack......