public TraceResult Trace(JVector origin, JVector direction, TraceOptions options)
{
if (direction.Length() < 0.1f)
{
return(null);
}
RaycastCallback callback = (b, n, f) =>
{
if ((b.IsStatic == true) && (options.HasFlag(TraceOptions.IgnoreStatic)))
{
return(false);
}
if ((b.IsStatic == false) && (options.HasFlag(TraceOptions.IgnoreDynamic)))
{
return(false);
}
return(true);
};
RigidBody body;
JVector normal;
float friction;
if (this.CollisionSystem.Raycast(
origin,
direction,
callback,
out body,
out normal,
out friction))
{
return(new TraceResult(body, friction, origin + friction * direction, normal));
}
return(null);
}
public override void PrepareForIteration(float timestep)
{
var delta = Target - Body1.Position;
var length = delta.Length();
if (length > 1f * Velocity)
{
if (Velocity > targetVelocity.Length())
{
targetVelocity = JVector.Normalize(delta) * (targetVelocity.Length() + Velocity * timestep);
}
else
{
targetVelocity = JVector.Normalize(delta) * Velocity;
}
}
else
{
targetVelocity = JVector.Normalize(delta) * (float)Math.Sqrt(length);
}
}
public virtual void SetScale(JVector p_scale, bool p_transform = true)
{
_scale = p_scale;
_boundingSphere.Radius = p_scale.Length() / 2.9f;
if (p_transform)
{
_matWorld = Matrix.CreateScale(p_scale.X, p_scale.Y, p_scale.Z)
* Matrix.CreateFromYawPitchRoll(_rotation.Y, _rotation.X, _rotation.Z)
* Matrix.CreateTranslation(_position.X, _position.Y, _position.Z);
}
}
public virtual void SetScaleRotationPosition(JVector p_scale, JVector p_rotation, JVector p_position, bool p_transform = true)
{
_scale = p_scale;
_rotation = p_rotation;
_position = p_position;
_boundingSphere.Radius = p_scale.Length() / 2.9f;
_boundingSphere.Center.X = p_position.X;
_boundingSphere.Center.Y = p_position.Y;
_boundingSphere.Center.Z = p_position.Z;
if (p_transform)
{
_matWorld = Matrix.CreateScale(_scale.X, _scale.Y, _scale.Z)
* Matrix.CreateFromYawPitchRoll(_rotation.Y, _rotation.X, _rotation.Z)
* Matrix.CreateTranslation(_position.X, _position.Y, _position.Z);
}
}
/// <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)
{
float sigma = (float)Math.Sqrt((float)(direction.X * direction.X + direction.Z * direction.Z));
if (direction.Y > direction.Length() * sina)
{
result.X = 0.0f;
result.Y = (2.0f / 3.0f) * height;
result.Z = 0.0f;
}
else if (sigma > 0.0f)
{
result.X = radius * direction.X / sigma;
result.Y = -(1.0f / 3.0f) * height;
result.Z = radius * direction.Z / sigma;
}
else
{
result.X = 0.0f;
result.Y = -(1.0f / 3.0f) * height;
result.Z = 0.0f;
}
}
// see: btSubSimplexConvexCast.cpp
/// <summary>
/// Checks if a ray definied through it's origin and direction collides
/// with a shape.
/// </summary>
/// <param name="support">The supportmap implementation representing the shape.</param>
/// <param name="orientation">The orientation of the shape.</param>
/// <param name="invOrientation">The inverse orientation of the shape.</param>
/// <param name="position">The position of the shape.</param>
/// <param name="origin">The origin of the ray.</param>
/// <param name="direction">The direction of the ray.</param>
/// <param name="fraction">The fraction which gives information where at the
/// ray the collision occured. The hitPoint is calculated by: origin+friction*direction.</param>
/// <param name="normal">The normal from the ray collision.</param>
/// <returns>Returns true if the ray hit the shape, false otherwise.</returns>
public static bool Raycast(ISupportMappable support, ref JMatrix orientation, ref JMatrix invOrientation,
ref JVector position, ref JVector origin, ref JVector direction, out float fraction, out JVector normal)
{
VoronoiSimplexSolver simplexSolver = simplexSolverPool.GetNew();
simplexSolver.Reset();
normal = JVector.Zero;
fraction = float.MaxValue;
float lambda = 0.0f;
JVector r = direction;
JVector x = origin;
JVector w, p, v;
JVector arbitraryPoint;
SupportMapTransformed(support, ref orientation, ref position, ref r, out arbitraryPoint);
JVector.Subtract(ref x, ref arbitraryPoint, out v);
int maxIter = MaxIterations;
float distSq = v.LengthSquared();
float epsilon = 0.000001f;
float VdotR;
while ((distSq > epsilon) && (maxIter-- != 0))
{
SupportMapTransformed(support, ref orientation, ref position, ref v, out p);
JVector.Subtract(ref x, ref p, out w);
float VdotW = JVector.Dot(ref v, ref w);
if (VdotW > 0.0f)
{
VdotR = JVector.Dot(ref v, ref r);
if (VdotR >= -JMath.Epsilon)
{
simplexSolverPool.GiveBack(simplexSolver);
return(false);
}
else
{
lambda = lambda - VdotW / VdotR;
JVector.Multiply(ref r, lambda, out x);
JVector.Add(ref origin, ref x, out x);
JVector.Subtract(ref x, ref p, out w);
normal = v;
}
}
if (!simplexSolver.InSimplex(w))
{
simplexSolver.AddVertex(w, x, p);
}
if (simplexSolver.Closest(out v))
{
distSq = v.LengthSquared();
}
else
{
distSq = 0.0f;
}
}
#region Retrieving hitPoint
// Giving back the fraction like this *should* work
// but is inaccurate against large objects:
// fraction = lambda;
JVector p1, p2;
simplexSolver.ComputePoints(out p1, out p2);
p2 = p2 - origin;
fraction = p2.Length() / direction.Length();
#endregion
if (normal.LengthSquared() > JMath.Epsilon * JMath.Epsilon)
{
normal.Normalize();
}
simplexSolverPool.GiveBack(simplexSolver);
return(true);
}
/// <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);
}
}
