/// <summary>
/// Determines the drag vector on a CollisionObject.
/// </summary>
/// <param name="obj">The CollisionObject.</param>
/// <returns>A vector representing the drag-force.</returns>
public static Vector2 DragVector(CollisionObject obj)
{
float dragY = -0.5f * PhysicsConstants.airDensity * PhysicsConstants.dragCoeff * (float)Math.Pow(obj.GetCollisionBox().Width *PhysicsConstants.metersPerPixel, 2) * (float)Math.Pow(obj.GetSpeed().Y, 3) / Math.Abs(obj.GetSpeed().Y);
float dragX = -0.5f * PhysicsConstants.airDensity * PhysicsConstants.dragCoeff * (float)Math.Pow(obj.GetCollisionBox().Height *PhysicsConstants.metersPerPixel, 2) * (float)Math.Pow(obj.GetSpeed().X, 3) / Math.Abs(obj.GetSpeed().X);
#region check for NaN
if (float.IsNaN(dragY))
{
dragY = 0;
}
if (float.IsNaN(dragX))
{
dragX = 0;
}
#endregion
return(new Vector2(dragX / obj.GetMass(), dragY / obj.GetMass()) * (float)Globals.deltaTime.TotalSeconds * PhysicsConstants.metersPerPixel);
}
/// <summary>
/// Determines the gravity force on a CollisionObject.
/// </summary>
/// <param name="obj">The object to determine the gravity-force for.</param>
/// <returns>A vector representing the gravitational force.</returns>
public static Vector2 Gravity(CollisionObject obj)
{
return(new Vector2(0, PhysicsConstants.gravity * obj.GetMass()) * (float)Globals.deltaTime.TotalSeconds * PhysicsConstants.metersPerPixel);
}