private void applyTo(Character Interactor, Entity Interactee)
{
double dx = Interactor.GetBoundingRectangle().X - Interactee.GetBoundingRectangle().X;
double dy = Interactor.GetY() - Interactee.GetY();
double yVel = ((Character)Interactor).YVel;
double xVel = ((Character)Interactor).XVel;
double interactorAngle = Math.Atan2(yVel, xVel);
double minimumReboundVelocity = 0.75;
double friction = Engine.MarioControl ? 0.8 : 0.75;
///
/// The collision mechanism will detect which side the collision has occurred on
/// by inferring that the axis with least distance between centres of objects will
/// therefore have been the first to collide. We then split each axis into the two
/// cases of the cardinal direction of approach, again inferred from the difference
/// in centres. Then, we apply a velocity and acceleration in the opposite direction
/// of that of the collision. We ensure that multiple collisions occuring in the same
/// interaction queue do not repeatedly flip the velocities and accelerations (i.e. by
/// repearatedly multiplying by -1) by using a ternary to ensure that the resultant direction
/// will always be opposite of the incoming collision direction. As the collisions are
/// proportional to the speed of the colliding entities, we need to make sure we have a
/// minimum possible ejection speed to avoid an entity appearing to be trapped in a collision
/// with very low speed.
///
/// Note also that in collisions between two characters, we apply the same collision to
/// both interactor and interactee. The asture reader will note this will apply the collision
/// ejection vectors twice to each character, which will nullify the apparent relative velocity
/// being twice as high as that of a vs. static collision.
///
if (Math.Abs(dx) > Math.Abs(dy))
{
Interactor.YVel *= friction; //Friction
if (dx > 0)
{
Interactor.PosX -= Math.Min(xVel, -minimumReboundVelocity);
Interactor.XVel *= 0.3 * (Interactor.XAcc < 0 ? -1 : 1);
Interactor.XAcc *= 0.3 * (this.Interactor.XAcc < 0 ? -1 : 1); //bounce a little
}
else
{
Interactor.PosX -= Math.Max(xVel, minimumReboundVelocity);
Interactor.XVel *= 0.3 * (Interactor.XAcc > 0 ? -1 : 1);
Interactor.XAcc *= 0.3 * (this.Interactor.XAcc > 0 ? -1 : 1); ; //bounce a little
}
if (SoundEffects.sounds["hurt"].State == SoundState.Stopped && Interactor is Player && Interactor.XVel >0.5)
{
SoundEffects.sounds["hurt"].Volume = 0.75f;
// soundInstance.IsLooped = False;
SoundEffects.sounds["hurt"].Play();
}
}
else
{
Interactor.XVel *= friction; //Apply a small friction coefficient
if (dy > 0)
{
Interactor.PosY -= Math.Min(yVel, -minimumReboundVelocity);
Interactor.YVel *= 0.3 * (Interactor.YVel > 0 ? -1 : 1);
Interactor.YAcc = 0.3 * Interactor.YAcc * (Interactor.YAcc < 0 ? -1 : 1); //bounce a little
}
else
{
Interactor.PosY -= yVel;
Interactor.YVel = 0;
Interactor.YAcc = 0.3 * Interactor.YAcc * (Interactor.YAcc > 0 ? -1 : 1); //bounce a little
Interactor.Jumping = false;
}
}
}
