// calulate all gravitational forces in game
// then will apply the force to the given object
public void ApplyGravityToObject(GameObject gameObject)
{
Vector2 netForce = new Vector2(0f, 0f);
Vector2 position = gameObject.position;
foreach (GameObject opposer in asteroids)
{
// find unit vector
Vector2 diffVect = opposer.position - position;
Vector2 unitVector;
if (diffVect.Length() == 0.0f) continue;
unitVector.X = diffVect.X / diffVect.Length();
unitVector.Y = diffVect.Y / diffVect.Length();
Vector2 currentForce;
currentForce.X = (opposer.mass / diffVect.LengthSquared()) * GRAVITATIONAL_CONSTANT * unitVector.X;
currentForce.Y = (opposer.mass / diffVect.LengthSquared()) * GRAVITATIONAL_CONSTANT * unitVector.Y;
netForce += currentForce;
}
netForce.X = netForce.X * gameObject.mass;
netForce.Y = netForce.Y * gameObject.mass;
gameObject.UpdateVelocityWithForce(netForce);
}
private bool IsCollision(GameObject asteroid, GameObject asteroid2)
{
asteroid.vertices.Add(asteroid.vertices.First());
asteroid2.vertices.Add(asteroid2.vertices.First());
for (int i = 0; i < asteroid.vertices.Count - 1; i++)
{
for (int j = 0; j < asteroid2.vertices.Count - 1; j++)
{
if (Intersects(asteroid.vertices.ElementAt(i), asteroid.vertices.ElementAt(i + 1),
asteroid2.vertices.ElementAt(j), asteroid2.vertices.ElementAt(j + 1)))
{
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
asteroid2.vertices.RemoveAt(asteroid2.vertices.Count - 1);
return true;
}
}
}
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
asteroid2.vertices.RemoveAt(asteroid2.vertices.Count - 1);
return false;
}
// calulate all collision forces in game
// then will apply the force to the given object
public void ApplyCollisionForceToObject(GameObject asteriod)
{
// woot
}
private void HandleObjectCollisions(Stack<Collision> collisions, GameObject asteroid)
{
foreach (GameObject asteroid2 in asteroids)
{
if (asteroid.Equals(asteroid2))
{
continue;
}
if (IsWithinRadius(asteroid, asteroid2))
{
//possible collision
if (IsCollision(asteroid, asteroid2))
{
collisions.Push(new Collision(asteroids.IndexOf(asteroid), asteroids.IndexOf(asteroid2)));
}
}
}
}
private void HandleEdgeCollisions(Stack<Collision> collisions, GameObject asteroid)
{
if (CollidesWithEdge(asteroid))
{
collisions.Push(new Collision(asteroids.IndexOf(asteroid), -1));
}
}
private bool CollidesWithEdge(GameObject asteroid)
{
//called when checking if an object collides with the border of the screen.
asteroid.vertices.Add(asteroid.vertices.First());
for (int i = 0; i < asteroid.vertices.Count - 1; i++)
{
Vector2 v1 = asteroid.vertices.ElementAt(i);
Vector2 v2 = asteroid.vertices.ElementAt(i + 1);
Vector2 topLeft = new Vector2(border.Left, border.Top);
Vector2 topRight = new Vector2(border.Right, border.Top);
Vector2 bottomRight = new Vector2(border.Right, border.Bottom);
Vector2 bottomLeft = new Vector2(border.Left, border.Bottom);
if (Intersects(v1, v2, topLeft, topRight))
{
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
return true;
}
else if (Intersects(v1, v2, topRight, bottomRight))
{
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
return true;
}
else if (Intersects(v1, v2, bottomRight, bottomLeft))
{
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
return true;
}
else if (Intersects(v1, v2, bottomLeft, topLeft))
{
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
return true;
}
}
asteroid.vertices.RemoveAt(asteroid.vertices.Count - 1);
return false;
}
private static bool IsWithinRadius(GameObject asteroid, GameObject asteroid2)
{
return Vector2.Distance(asteroid.position, asteroid2.position) <= asteroid.radius + asteroid2.radius;
}
private void DrawObject(GameObject asteroid)
{
foreach (Vector2 point1 in asteroid.vertices)
{
foreach (Vector2 point2 in asteroid.vertices)
{
DrawLine(point1, point2, asteroid.colour);
}
}
}
