Direction of Velocity

heyas;


im doing a velocity check on the avatar by doing llvecmag on the... whats velocity, llgetvelocity? now, as i understand, the velocity gives me how fast the avatar is moving in all 3 directions, and llvecmag just dispenses with all that and gives me the absolute speed regardless of directionals.

that's good, but now i need to tell the difference between the avatar going forward, and the avatar going backward. can i get this from the velocity x bits if i'm using an attachment on an avatar? or is this world x?

llGetVel() returns the velocity in region coordinates, not relative to the avatar. You'll have to transform it to to the avatar's coordinate frame. There's an explanation and example in:

http://www.lslwiki.net/lslwiki/wakka.php?wakka=llGetVel

Alternately you could find the (unit) vector in region coordinates that points along the avatar's forward direction, compute a dot product, and use the sign of the result:

vector velocity = llGetVel();
vector fwd = llRot2Fwd(llGetRot());

float fwdVelocityComponent = velocity*fwd;  // Dot product

if (fwdVelocityComponent > 0.0)
{
   // Going forward
} else if (fwdVelocityComponent < 0.0)
{
   // Going backward
} else
{
   // Going neither forward nor backward; maybe sideways/up/down, maybe still
}

http://en.wikipedia.org/wiki/Dot_product

great!

thanks again, hewee :)