How do i find if an object is before or after a waypoint?
- by BoMann Andersen
Im working on a racing game for a school project.
Using Visual studio 10 pro, and Irrlicht.
Sorry for bad grammar ., and its my first question so not sure if its done right.
How i want it to work is that i make waypoints at different points on the track,
and then i run my waypoint check to see if a car is past its next waypoint (the next it "needs" to go past), if yes then it updates the next waypoint, else nothing.
The way i hope this will work is, i make a vector from n to n+1, then find the vector that is perpendicular to the first vector at n. Then i see if the object is in front or behind that vector.
I found a Gamedev.net forumpost that helped me make this function:
void Engine::checkWaypoint(Vehicle* vehicle)
{
btVector3 vector = waypoints[vehicle->nextWaypoint];
// n
btVector3 nextVector = waypoints[vehicle->nextWaypoint + 1];
// n+1
vector = nextVector - vector;
// First vector
btVector3 pos = btVector3(vehicle->position.X,vehicle->position.Y,vehicle->position.Z);
float product = vector.dot(pos - waypoints[vehicle->nextWaypoint]);
// positiv = before, negative = behind
if(product < 0)
vehicle->nextWaypoint += 1;
}
Current bugs with this is:
Updates the nextwaypoint more then ones without going past a new point.
When it gets to the end and resets, it stops triggering on the first waypoints.
So my questions:
Is this an good way to do this?
Did i do it right?
