//------------------------------------------------------------------------------------------
// BallSegmentCollisionDetection()
//------------------------------------------------------------------------------------------
private void BallSegmentCollisionDetection(ref GameObject current, ref Vec2 currentNormal)
{
for (int i = 0; i < myGame.GetNumberOfLines(); i++)
{
LineSegment line = myGame.GetLine(i);
if (Input.GetKey(Key.S) && line.parent is Stairs)
{
continue;
}
Vec2 differenceVector = _oldPosition - line.start;
float ballDistance = differenceVector.Dot((line.end - line.start).Normal());
Vec2 normal = (line.end - line.start).Normal();
Vec2 dist = position + (-ballDistance + radius) * normal;
float difference = (dist - position).Magnitude();
float b = -velocity.Dot(normal);
float a = ballDistance - radius;
if (b > 0)
{
float t = 3f;
if (a >= 0)
{
t = a / b;
}
else if (a >= -radius)
{
t = 0;
}
else
{
continue;
}
if (t <= 1f)
{
Vec2 POI = _oldPosition + t * velocity;
float d = (POI - line.start).Dot((line.end - line.start).Normalized());
if (0 <= d && d <= (line.end - line.start).Magnitude())
{
if (t < smallestToi)
{
smallestToi = t;
current = line;
currentNormal = normal;
currentline = (Platform)line;
}
}
}
}
}
}
CollisionInfo FindEarliestCollision()
{
GameObject current = null;
Vec2 currentNormal = new Vec2();
smallestToi = 2f;
MyGame myGame = (MyGame)game;
// Check other movers:
for (int i = 0; i < myGame.GetNumberOfMovers(); i++)
{
Ball mover = myGame.GetMover(i);
if (mover != this)
{
Vec2 relativePosition = position - mover.position;
//if (relativePosition.Magnitude() < radius + mover.radius)
//{
// TODO: compute correct normal and time of impact, and
// return *earliest* collision instead of *first detected collision*:
Vec2 u = _oldPosition - mover.position;
float a = velocity.Magnitude() * velocity.Magnitude();
float b = 2 * u.Dot(velocity);
float c = u.Magnitude() * u.Magnitude() - (radius + mover.radius) * (radius + mover.radius);
float delta = b * b - 4 * a * c;
float t;
t = (-b - Mathf.Sqrt(delta)) / (2 * a);
if (c < 0)
{
if (b < 0)
{
t = 0;
//Vec2 normal = (_oldPosition - mover.position).Normalized();
//return new CollisionInfo(normal, mover, t);
}
else
{
continue;
}
}
if (a != 0)
//{
// return null;
//}
//else
{
if (delta >= 0)
//{
// return null;
//}
//else
{
Vec2 pointOfImpact = _oldPosition + velocity * t;
Vec2 normal = (pointOfImpact - mover.position).Normalized();
if (0 <= t && t < 1)
{
if (t < smallestToi)
{
smallestToi = t;
current = mover;
currentNormal = normal;
}
}
//else return null;
}
}
//Vec2 normal = relativePosition.Normalized();
//float overlap = radius + mover.radius - relativePosition.Magnitude();
//return new CollisionInfo(normal, mover, overlap);
//}
}
}
for (int i = 0; i < myGame.GetNumberOfLines(); i++)
{
NLineSegment line = myGame.GetLine(i);
Vec2 differenceVector = _oldPosition - line.start;
float ballDistance = differenceVector.Dot((line.end - line.start).Normal());
//if (ballDistance < radius)
//{
Vec2 normal = (line.end - line.start).Normal();
Vec2 dist = position + (-ballDistance + radius) * normal;
float difference = (dist - position).Magnitude();
float b = -velocity.Dot(normal);
//float a = b - difference;
float a = ballDistance - radius;
if (b > 0)
//{
// return null;
//}
//else
{
float t = 3f;
if (a >= 0)
//{
// return null;
//}
//else
{
t = a / b;
}
else if (a >= -radius)
{
t = 0;
}
else
{
continue;
}
if (t <= 1f)
{
Vec2 POI = _oldPosition + t * velocity;
float d = (POI - line.start).Dot((line.end - line.start).Normalized());
if (0 <= d && d <= (line.end - line.start).Magnitude())
{
if (t < smallestToi)
{
smallestToi = t;
current = line;
currentNormal = normal;
}
}
// else return null;
}
}
//}
}
if (current != null)
{
return(new CollisionInfo(currentNormal, current, smallestToi));
}
else
{
return(null);
}
// TODO: Check Line segments using myGame.GetLine();
// return null;
}