public static void ApplyCollisionData(CollisionData cdata)
{
if (cdata.TargetBody == null) return;
cdata.TargetBody.Position += cdata.dPos;
cdata.TargetBody.Velocity += cdata.dVel;
cdata.TargetBody.AngularVelocity += cdata.dAngVel;
}
public static CollisionData CalcCollision(Contact con)
{
var cdata = new CollisionData();
cdata.TargetBody = con.TargetBody;
cdata.dPos = Vector2.Zero;
cdata.dVel = Vector2.Zero;
cdata.dAngVel = 0;
var A = con.TargetBody;
var B = con.ImpactBody;
//penetration resolution
var totalInvMass = A.InvMass() + B.InvMass();
cdata.dPos = (con.Disp * A.InvMass() / (totalInvMass)) * con.Normal; //more massive-> less weight. objects in collision share burden of displacing proportional to 1/M.
//collision response
var sepVel = Vector2.Dot(B.Velocity - A.Velocity, con.Normal); //separating velocity: relative velocity of impact body along normal.
if (sepVel >= 0) return cdata; //return no change if bodies are separating
float rest = (A.Restitution+B.Restitution)/2;
float impulse = sepVel * (1 + rest) / (totalInvMass);
cdata.dVel = (impulse * A.InvMass()) * con.Normal;
return cdata;
}
public static CollisionData AggrCollisionData(List<CollisionData> cdata)
{
var aggr = new CollisionData();
if (cdata.Count > 0)
{
aggr.TargetBody = cdata.First().TargetBody;
foreach (var cd in cdata)
aggr += cd;
//aggr /= cdata.Count;
aggr.dPos *= HARDNESS;
}
return aggr;
}