/// <summary>
/// Are ellipses colliding?
/// </summary>
/// <param name="v1">First ellipse center point</param>
/// <param name="size1">First ellipse size</param>
/// <param name="angle1">First ellipse angle</param>
/// <param name="v2">Second ellipse center point</param>
/// <param name="size2">Second ellipse size</param>
/// <param name="angle2">Second ellipse angle</param>
/// <param name="depth">Penetration depth (out)</param>
/// <param name="point1">First ellipse intersection point</param>
/// <param name="point2">Second ellipse intersection point</param>
/// <returns>True if colliding</returns>
public static bool IsEllipseCollision(
Vector v1, Vector size1, double angle1,
Vector v2, Vector size2, double angle2,
out CollisionState state)
{
// Direction vector from first ellipse center to second ellipse center
Vector direction = v2.MinusNew( v1 );
double angle = direction.Angle;
// Point of collision on first ellipse
state.Point1 = EllipsePoint( v1, size1, angle1, angle );
// Point of collision on second ellipse
state.Point2 = EllipsePoint( v2, size2, angle2, angle + Math.PI );
// Penetration depth
state.Depth = state.Point2.MinusNew( state.Point1 );
// If first ellipse radius (in direction of ray) + second ellipse radius is greater than the distance
// between the two ellipses, we have a collision
state.Colliding = ( v1.Distance( state.Point1 ) + v2.Distance( state.Point2 ) > v1.Distance( v2 ) );
return state.Colliding;
}
public virtual void ResolveRectangleCollision( RectangleParticle p, Engine engine, ref CollisionState state )
{
}
public virtual void ResolveCircleCollision( CircleParticle p, Engine engine, ref CollisionState state )
{
}
public virtual void CheckCollision( IParticle particle, Engine engine, ref CollisionState state )
{
}
public override void CheckCollision( IParticle particle, Engine engine, ref CollisionState state )
{
//particle.ResolveRectangleCollision( this, engine );
}
private void CheckCollisions()
{
collisions.Clear();
foreach ( ISurface surface in surfaces )
{
if ( surface.Active )
{
foreach ( Particle particle in particles )
{
particle.CheckCollision( surface, this );
}
}
}
Dictionary<string, object> compared = new Dictionary<string, object>();
foreach ( Particle particle1 in particles )
{
foreach ( Particle particle2 in particles )
{
if ( particle1 != particle2 )
{
string key = ( particle1.Index < particle2.Index )
? particle1.Index.ToString() + "," + particle2.Index.ToString()
: particle2.Index.ToString() + "," + particle1.Index.ToString();
if ( !compared.ContainsKey( key ) )
{
compared.Add( key, null );
CollisionState state = new CollisionState();
particle2.CheckCollision( particle1, this, ref state );
if ( state.Colliding ) collisions.Add( state );
}
}
}
}
}
public override void CheckCollision( IParticle particle, Engine engine, ref CollisionState state )
{
// HACK: here i need not to collide wheels with body particles
if (this is Wheel && !(particle is Wheel)) return;
if (particle is Wheel && !(this is Wheel)) return;
particle.ResolveCircleCollision(this, engine, ref state);
}
public override void ResolveRectangleCollision( RectangleParticle p, Engine engine, ref CollisionState state )
{
throw new Exception( "The method or operation is not implemented." );
}
public override void ResolveCircleCollision( CircleParticle p, Engine engine, ref CollisionState state )
{
if ( Collision.IsEllipseCollision( curr, Size, 0, p.curr, p.Size, 0, out state ) )
{
Vector normal = state.Depth.Clone().Normalize();
Vector vel1 = curr.MinusNew( prev );
Vector vel2 = p.curr.MinusNew( p.prev );
p.prev = p.curr.PlusNew( state.Depth );
prev = curr.MinusNew( state.Depth );
}
}
