/// <summary>
/// Normalizes the given vector.
/// </summary>
/// <param name="value">The vector which should be normalized.</param>
/// <returns>A normalized vector.</returns>
#region public static JVector Normalize(JVector value)
public static JVector Normalize(JVector value)
{
JVector result;
JVector.Normalize(ref value, out result);
return(result);
}
public static bool ClosestPoints(ISupportMappable support1, ISupportMappable support2, ref JMatrix orientation1,
ref JMatrix orientation2, ref JVector position1, ref JVector position2,
out JVector p1, out JVector p2, out JVector normal)
{
VoronoiSimplexSolver simplexSolver = simplexSolverPool.GetNew();
simplexSolver.Reset();
p1 = p2 = JVector.Zero;
JVector r = position1 - position2;
JVector w, v;
JVector supVertexA;
JVector rn, vn;
rn = JVector.Negate(r);
SupportMapTransformed(support1, ref orientation1, ref position1, ref rn, out supVertexA);
JVector supVertexB;
SupportMapTransformed(support2, ref orientation2, ref position2, ref r, out supVertexB);
v = supVertexA - supVertexB;
normal = JVector.Zero;
int iter = 0;
float distSq = v.LengthSquared();
float epsilon = 0.00001f;
while ((distSq > epsilon) && (iter++ < MaxIterations))
{
IterationsTaken = iter;
vn = JVector.Negate(v);
SupportMapTransformed(support1, ref orientation1, ref position1, ref vn, out supVertexA);
SupportMapTransformed(support2, ref orientation2, ref position2, ref v, out supVertexB);
w = supVertexA - supVertexB;
if (!simplexSolver.InSimplex(w)) simplexSolver.AddVertex(w, supVertexA, supVertexB);
if (simplexSolver.Closest(out v))
{
distSq = v.LengthSquared();
normal = v;
}
else distSq = 0.0f;
}
simplexSolver.ComputePoints(out p1, out p2);
if (normal.LengthSquared() > JMath.Epsilon * JMath.Epsilon)
normal.Normalize();
simplexSolverPool.GiveBack(simplexSolver);
return true;
}
internal static JVector Clamp(JVector v, float len)
{
return((JVector.Dot(v, v) > len * len) ? JVector.Multiply(JVector.Normalize(v), len) : v);
}
/// <summary>
/// Initializes a contact.
/// </summary>
/// <param name="body1">The first body.</param>
/// <param name="body2">The second body.</param>
/// <param name="point1">The collision point in worldspace</param>
/// <param name="point2">The collision point in worldspace</param>
/// <param name="n">The normal pointing to body2.</param>
/// <param name="penetration">The estimated penetration depth.</param>
public void Initialize(RigidBody body1, RigidBody body2, ref JVector point1, ref JVector point2, ref JVector n,
float penetration, bool newContact, ContactSettings settings)
{
this.body1 = body1; this.body2 = body2;
this.normal = n; normal.Normalize();
this.p1 = point1; this.p2 = point2;
this.newContact = newContact;
JVector.Subtract(ref p1, ref body1.position, out relativePos1);
JVector.Subtract(ref p2, ref body2.position, out relativePos2);
JMatrix o1 = JMatrix.CreateRotationZ(body1.invOrientation);
JMatrix o2 = JMatrix.CreateRotationZ(body2.invOrientation);
JVector.Transform(ref relativePos1, ref o1, out realRelPos1);
JVector.Transform(ref relativePos2, ref o2, out realRelPos2);
this.initialPen = penetration;
this.penetration = penetration;
body1IsMassPoint = body1.isParticle;
body2IsMassPoint = body2.isParticle;
// Material Properties
if (newContact)
{
treatBody1AsStatic = body1.isStatic;
treatBody2AsStatic = body2.isStatic;
accumulatedNormalImpulse = 0.0f;
accumulatedTangentImpulse = 0.0f;
lostSpeculativeBounce = 0.0f;
switch (settings.MaterialCoefficientMixing)
{
case ContactSettings.MaterialCoefficientMixingType.TakeMaximum:
staticFriction = JMath.Max(body1.material.staticFriction, body2.material.staticFriction);
dynamicFriction = JMath.Max(body1.material.kineticFriction, body2.material.kineticFriction);
restitution = JMath.Max(body1.material.restitution, body2.material.restitution);
break;
case ContactSettings.MaterialCoefficientMixingType.TakeMinimum:
staticFriction = JMath.Min(body1.material.staticFriction, body2.material.staticFriction);
dynamicFriction = JMath.Min(body1.material.kineticFriction, body2.material.kineticFriction);
restitution = JMath.Min(body1.material.restitution, body2.material.restitution);
break;
case ContactSettings.MaterialCoefficientMixingType.UseAverage:
staticFriction = (body1.material.staticFriction + body2.material.staticFriction) / 2.0f;
dynamicFriction = (body1.material.kineticFriction + body2.material.kineticFriction) / 2.0f;
restitution = (body1.material.restitution + body2.material.restitution) / 2.0f;
break;
}
}
this.settings = settings;
}
/// <summary>
/// Discrete Circle vs Circle test. Very fast. Generates contact info.
/// NOTE: check distance for collisions. If negative then a collision has occurred.
/// This is done to remove all branches from this test and leave it to the user to decide when to branch.
/// </summary>
public static void CircleCircleTest(JVector centerA, float radiusA, JVector centerB, float radiusB, out JVector pointA, out JVector pointB, out JVector normal, out float distance)
{
// ||A-B|| - (r1+r2) < 0
float d = JVector.DistanceSquared(centerA, centerB);
float r = (radiusA + radiusB);
r *= r;
distance = d - r;
normal = (centerA - centerB) / d;
normal.Normalize();
// calculate closest 2 points
pointA = JVector.Negate(normal) * radiusA + centerA;
pointB = normal * radiusB + centerB;
}
/// <summary>
/// Checks two shapes for collisions.
/// </summary>
/// <param name="support1">The SupportMappable implementation of the first shape to test.</param>
/// <param name="support2">The SupportMappable implementation of the seconds shape to test.</param>
/// <param name="orientation1">The orientation of the first shape.</param>
/// <param name="orientation2">The orientation of the second shape.</param>
/// <param name="position1">The position of the first shape.</param>
/// <param name="position2">The position of the second shape</param>
/// <param name="point">The pointin world coordinates, where collision occur.</param>
/// <param name="normal">The normal pointing from body2 to body1.</param>
/// <param name="penetration">Estimated penetration depth of the collision.</param>
/// <returns>Returns true if there is a collision, false otherwise.</returns>
public static bool Detect(ISupportMappable support1, ISupportMappable support2, ref JMatrix orientation1,
ref JMatrix orientation2, ref JVector position1, ref JVector position2,
out JVector point, out JVector normal, out float penetration)
{
// Used variables
JVector v01, v02, v0;
JVector v11, v12, v1;
JVector v21, v22, v2;
JVector v31, v32, v3;
JVector mn;
// Initialization of the output
point = normal = JVector.Zero;
penetration = 0.0f;
// Get the center of shape1 in world coordinates -> v01
support1.SupportCenter(out v01);
JVector.Transform(ref v01, ref orientation1, out v01);
JVector.Add(ref position1, ref v01, out v01);
// Get the center of shape2 in world coordinates -> v02
support2.SupportCenter(out v02);
JVector.Transform(ref v02, ref orientation2, out v02);
JVector.Add(ref position2, ref v02, out v02);
// v0 is the center of the minkowski difference
JVector.Subtract(ref v02, ref v01, out v0);
// Avoid case where centers overlap -- any direction is fine in this case
if (v0.IsNearlyZero()) v0 = new JVector(0.00001f, 0);
// v1 = support in direction of origin
mn = v0;
JVector.Negate(ref v0, out normal);
SupportMapTransformed(support1, ref orientation1, ref position1, ref mn, out v11);
SupportMapTransformed(support2, ref orientation2, ref position2, ref normal, out v12);
JVector.Subtract(ref v12, ref v11, out v1);
if (JVector.Dot(ref v1, ref normal) <= 0.0f) return false;
// v2 = support perpendicular to v1,v0
normal = OutsidePortal(v1, v0);
JVector.Negate(ref normal, out mn);
SupportMapTransformed(support1, ref orientation1, ref position1, ref mn, out v21);
SupportMapTransformed(support2, ref orientation2, ref position2, ref normal, out v22);
JVector.Subtract(ref v22, ref v21, out v2);
//LD.Draw(Conversion.ToXNAVector2(v1), Conversion.ToXNAVector2(v0), Color.Blue);
//LD.Draw(Conversion.ToXNAVector2(v2), Conversion.ToXNAVector2(v0), Color.Blue);
if (JVector.Dot(ref v2, ref normal) <= 0.0f) return false;
// phase two: portal refinement
int maxIterations = 0;
while (true)
{
// find normal direction
if (!IntersectPortal(v0, v2, v1))
normal = InsidePortal(v2, v1);
else
// origin ray crosses the portal
normal = OutsidePortal(v2, v1);
// obtain the next support point
JVector.Negate(ref normal, out mn);
SupportMapTransformed(support1, ref orientation1, ref position1, ref mn, out v31);
SupportMapTransformed(support2, ref orientation2, ref position2, ref normal, out v32);
JVector.Subtract(ref v32, ref v31, out v3);
//LD.Draw(Conversion.ToXNAVector2(v3), Conversion.ToXNAVector2(v0), Color.Green);
if (JVector.Dot(v3, normal) <= 0)
{
JVector ab = v3 - v2;
float t = -(JVector.Dot(v2, ab)) / (JVector.Dot(ab, ab));
normal = (v2 + (t * ab));
return false;
}
// Portal lies on the outside edge of the Minkowski Hull.
// Return contact information
if (JVector.Dot((v3 - v2), normal) <= CollideEpsilon || ++maxIterations > MaximumIterations)
{
JVector ab = v2 - v1;
float t = JVector.Dot(JVector.Negate(v1), ab);
if (t <= 0.0f)
{
t = 0.0f;
normal = v1;
}
else
{
float denom = JVector.Dot(ab, ab);
if (t >= denom)
{
normal = v2;
t = 1.0f;
}
else
{
t /= denom;
normal = v1 + t * ab;
}
}
float s = 1 - t;
point = s * v11 + t * v21;
var point2 = s * v12 + t * v22;
// this causes a sq root = bad!
penetration = normal.Length();
normal.Normalize();
return true;
}
// if origin is inside (v1, v0, v3), refine portal
if (OriginInTriangle(v0, v1, v3))
{
v2 = v3;
v21 = v31;
v22 = v32;
continue;
}
// if origin is inside (v3, v0, v2), refine portal
else if (OriginInTriangle(v0, v2, v3))
{
v1 = v3;
v11 = v31;
v12 = v32;
continue;
}
return false;
}
}
/// <summary>
/// SupportMapping. Finds the point in the shape furthest away from the given direction.
/// Imagine a plane with a normal in the search direction. Now move the plane along the normal
/// until the plane does not intersect the shape. The last intersection point is the result.
/// </summary>
/// <param name="direction">The direction.</param>
/// <param name="result">The result.</param>
public override void SupportMapping(ref JVector direction, out JVector result)
{
result = direction;
result.Normalize();
JVector.Multiply(ref result, radius, out result);
}
