// Handles collision with disk (usually player or bullet)
public void Collide(Disk disk)
{
// closest point on the segment to the player
Vector2 closePoint = ClosePoint(disk);
// closePoint is the one to do all the collision
Disk temp = new Disk(closePoint, Vector2.Zero, radius, Color.Transparent);
temp.Collide(disk);
}
//public void DeterministicMove(float elapsed)
//{
// if ((velocity + accel * elapsed).Length() > maxSpeed)
// {
// float elapsed1 = 0;
// if (velocity.Length() < maxSpeed)
// {
// float dotProduct = Vector2.Dot(velocity, accel);
// elapsed1 = (-dotProduct + (float)Math.Sqrt(dotProduct * dotProduct - accel.LengthSquared() * (velocity.LengthSquared() - maxSpeed * maxSpeed))) / accel.LengthSquared();
// position += velocity * elapsed1 + accel * elapsed1 * elapsed1 / 2;
// velocity += accel * elapsed1;
// }
// velocity.Normalize();
// velocity *= maxSpeed;
// position += velocity * (elapsed - elapsed1);
// }
// else
// {
// position += velocity * elapsed + accel * elapsed * elapsed / 2;
// velocity += accel * elapsed;
// }
//}
public void Collide(Disk disk, int colCount = 1)
{
if (!IfIntersects(disk) || !ifCollides || !disk.ifCollides)
{
return;
}
Vector2 direction = position - disk.position;
direction.Normalize();
if (mass == float.PositiveInfinity)
{
if (disk.mass != float.PositiveInfinity)
{
disk.position = position - direction * (disk.radius + radius);
disk.velocity -= 2 * Vector2.Dot(disk.velocity - velocity, direction) * direction;
}
}
else
{
if (disk.mass == float.PositiveInfinity)
{
position = disk.position + direction * (disk.radius + radius);
velocity -= 2 * Vector2.Dot(velocity - disk.velocity, direction) * direction;
}
else
{
//Vector2 center = (position * mass + disk.position * disk.mass) / (mass + disk.mass);
//float reducedMass = mass * disk.mass / (mass + disk.mass);
//Vector2 positionExchange = (reducedMass * (radius + disk.radius)) * direction;
//position = center + positionExchange / mass;
//disk.position = center - positionExchange / disk.mass;
//float impSpeed = Vector2.Dot(direction, velocity), diskImpSpeed = Vector2.Dot(direction, disk.velocity);
//Vector2 finalVel = direction * (mass * impSpeed + disk.mass * diskImpSpeed) / (mass + disk.mass);
//force += (-direction * impSpeed + finalVel) * mass / colCount;
//disk.force += (-direction * diskImpSpeed + finalVel) * disk.mass / colCount;
Vector2 center = (position * mass + disk.position * disk.mass) / (mass + disk.mass);
float reducedMass = mass * disk.mass / (mass + disk.mass);
Vector2 positionExchange = reducedMass * (radius + disk.radius) * direction;
position = center + positionExchange / mass;
disk.position = center - positionExchange / disk.mass;
float impSpeed = Vector2.Dot(direction, velocity), diskImpSpeed = Vector2.Dot(direction, disk.velocity);
Vector2 momentumExchange = reducedMass * 2 * (diskImpSpeed - impSpeed) * direction;
force += momentumExchange / colCount;
disk.force -= momentumExchange / colCount;
}
}
Collide();
disk.Collide();
}
