// The is the top-level collision detection function.
//
// The MovingObject doesn't intersect anything now; would it
// do so if the vector displacement is applied?
//
// If we do have a collision, we "creep up" on the object we collide
// with until we're within stepsize of the minimum dimension of the
// moving part
//
public bool TestCollision(MovingObject mo, float stepSize, ref Vector3 displacement, CollisionParms parms)
{
topLevelCalls++;
parms.Initialize();
if (mo.parts.Count == 0)
{
return(false);
}
// Remember where the first part started
Vector3 start = mo.parts[0].shape.center;
Vector3 originalDisplacement = displacement;
float len = displacement.Length;
//MaybeDumpSphereTree();
int nsteps = (int)Math.Ceiling(len / stepSize);
Vector3 step = (len <= stepSize ? displacement : displacement * (stepSize / len));
// Try to step the whole way
if (!StepTowardCollision(mo, displacement, nsteps, step, parms))
{
displacement = Vector3.Zero;
return(false);
}
// Otherwise, we hit something. Step toward it
// The minimum distance
float smallStepSize = Math.Min(MO.InchesToMeters(MinInchesToObstacle),
stepSize * MinFractionToObstacle);
len = step.Length;
nsteps = (int)Math.Ceiling(len / smallStepSize);
Vector3 smallStep = step * (smallStepSize / len);
bool hit = StepTowardCollision(mo, step, nsteps, smallStep, parms);
displacement = originalDisplacement - (mo.parts[0].shape.center - start);
return(hit);
}
