public static float DistanceBetweenPointAndLineSegment(ref Vector2 point, ref Vector2 start, ref Vector2 end)
{
if (start == end)
{
return(Vector2.Distance(point, start));
}
Vector2 v = end - start;
Vector2 w = point - start;
float c1 = Vector2.Dot(w, v);
if (c1 <= 0)
{
return(Vector2.Distance(point, start));
}
float c2 = Vector2.Dot(v, v);
if (c2 <= c1)
{
return(Vector2.Distance(point, end));
}
float b = c1 / c2;
Vector2 pointOnLine = start + v * b;
return(Vector2.Distance(point, pointOnLine));
}
private void AdjustSprings(float timeStep)
{
foreach (var pair in _springs)
{
Spring spring = pair.Value;
spring.Update(timeStep, Definition.KSpring, Definition.InfluenceRadius);
if (spring.Active)
{
float L = spring.RestLength;
float distance;
Vector2.Distance(ref spring.P0.Position, ref spring.P1.Position, out distance);
if (distance > (L + (Definition.YieldRatioStretch * L)))
{
spring.RestLength += timeStep * Definition.Plasticity * (distance - L - (Definition.YieldRatioStretch * L));
}
else if (distance < (L - (Definition.YieldRatioCompress * L)))
{
spring.RestLength -= timeStep * Definition.Plasticity * (L - (Definition.YieldRatioCompress * L) - distance);
}
}
else
{
_springsToRemove.Add(pair.Key);
}
}
for (int i = 0; i < _springsToRemove.Count; ++i)
{
_springs.Remove(_springsToRemove[i]);
}
}
private void InitializePlasticity()
{
_isPlasticityInitialized = true;
_springs.Clear();
float q;
foreach (Particle pa in Particles)
{
foreach (Particle pb in Particles)
{
if (pa.GetHashCode() == pb.GetHashCode())
{
continue;
}
Vector2.Distance(ref pa.Position, ref pb.Position, out q);
Vector2.Subtract(ref pb.Position, ref pa.Position, out _rij);
_rij /= q;
if (q < RestLength)
{
_springs.Add(new Spring2(pa, pb, q));
}
}
pa.Velocity = Vector2.Zero;
}
}
/// <summary>
/// Activate the explosion at the specified position.
/// </summary>
/// <param name="pos">The position (center) of the explosion.</param>
/// <param name="radius">The radius of the explosion.</param>
/// <param name="force">The force applied</param>
/// <param name="maxForce">A maximum amount of force. When force gets over this value, it will be equal to maxForce</param>
/// <returns>A list of bodies and the amount of force that was applied to them.</returns>
public Dictionary <Body, Vector2> Activate(Vector2 pos, float radius, float force, float maxForce = float.MaxValue)
{
HashSet <Body> affectedBodies = new HashSet <Body>();
AABB aabb;
aabb.LowerBound = pos - new Vector2(radius);
aabb.UpperBound = pos + new Vector2(radius);
// Query the world for bodies within the radius.
World.QueryAABB(fixture =>
{
if (Vector2.Distance(fixture.Body.Position, pos) <= radius)
{
if (!affectedBodies.Contains(fixture.Body))
{
affectedBodies.Add(fixture.Body);
}
}
return(true);
}, ref aabb);
return(ApplyImpulse(pos, radius, force, maxForce, affectedBodies));
}
public static bool IsCollisionPossible(
PhysicalVector2 position1,
PhysicalVector2 position2
)
{
float distance = PhysicalVector2.Distance(position1, position2);
return(distance < 64.0f * 6);
}
public List <Vector3> SubdivideEvenly(int divisions)
{
List <Vector3> verts = new List <Vector3>();
float length = GetLength();
float deltaLength = length / divisions + 0.001f;
float t = 0.000f;
// we always start at the first control point
Vector2 start = ControlPoints[0];
Vector2 end = GetPosition(t);
// increment t until we are at half the distance
while (deltaLength * 0.5f >= Vector2.Distance(start, end))
{
end = GetPosition(t);
t += 0.0001f;
if (t >= 1f)
{
break;
}
}
start = end;
// for each box
for (int i = 1; i < divisions; i++)
{
Vector2 normal = GetPositionNormal(t);
float angle = (float)Math.Atan2(normal.Y, normal.X);
verts.Add(new Vector3(end.X, end.Y, angle));
// until we reach the correct distance down the curve
while (deltaLength >= Vector2.Distance(start, end))
{
end = GetPosition(t);
t += 0.00001f;
if (t >= 1f)
{
break;
}
}
if (t >= 1f)
{
break;
}
start = end;
}
return(verts);
}
public float GetLength()
{
List <Vector2> verts = GetVertices(ControlPoints.Count * 25);
float length = 0;
for (int i = 1; i < verts.Count; i++)
{
length += Vector2.Distance(verts[i - 1], verts[i]);
}
if (Closed)
{
length += Vector2.Distance(verts[ControlPoints.Count - 1], verts[0]);
}
return(length);
}
private Dictionary <Body, Vector2> ApplyImpulse(Vector2 pos, float radius, float force, float maxForce, HashSet <Body> overlappingBodies)
{
Dictionary <Body, Vector2> forces = new Dictionary <Body, Vector2>(overlappingBodies.Count);
foreach (Body overlappingBody in overlappingBodies)
{
if (IsActiveOn(overlappingBody))
{
float distance = Vector2.Distance(pos, overlappingBody.Position);
float forcePercent = GetPercent(distance, radius);
Vector2 forceVector = pos - overlappingBody.Position;
forceVector *= 1f / (float)Math.Sqrt(forceVector.X * forceVector.X + forceVector.Y * forceVector.Y);
forceVector *= Math.Min(force * forcePercent, maxForce);
forceVector *= -1;
overlappingBody.ApplyLinearImpulse(forceVector);
forces.Add(overlappingBody, forceVector);
}
}
return(forces);
}
public static float Distance(Vector2 a, Vector2 b)
{
return(MonoGameVector2.Distance(a.MonoGameVector, b.MonoGameVector));
}
public static float Distance(Vector2 v1, Vector2 v2)
{
return(Vector.Distance(v1, v2));
}
public void Update()
{
Vector2.Distance(ref PA.Position, ref PB.Position, out CurrentDistance);
}