public CollideDemo(CollideType primOne, CollideType primTwo)
: base()
{
// Turn this on to keep a reference to all contacts with both bodies
CaptureBodyContacts = false;
Restitution = 0.2f;
Friction = 0.0f;// 1f;
int positionIterations = 5;
int velocityIterations = 5;
float penetrationEpsilon = 0.0001f;// 26f;
float velocityEpisilon = 0.0001f;// 01f;
ContactResolver = new ContactResolver(
positionIterations, velocityIterations,
penetrationEpsilon, velocityEpisilon);
primOneCollideType = primOne;
primTwoCollideType = primTwo;
DefaultSphereMass = 1f;
DefaultSphereRadius = 1f;
DefaultSpawnPosOne = new Vector3(-DefaultSphereRadius * 3.51f, 10.001f, 0.001f);
DefaultSpawnPosTwo = new Vector3(DefaultSphereRadius * 3.51f, 10.001f, 0.001f);
DefaultSpawnPosOne = new Vector3(0f, 10f, 0f);
DefaultSpawnPosTwo = new Vector3(-0.5f, 15f, 0f);
LastContact = new Contact();
}
public void Contact_XAxis()
{
NoBody bodyZero = new NoBody(Vector3.Right);
bodyZero.Velocity = Vector3.Left;
bodyZero.Mass = 1f;
bodyZero.calculateDerivedData();
NoBody bodyOne = new NoBody(Vector3.Left * .9f);
bodyOne.Velocity = Vector3.Right;
bodyOne.Mass = 1f;
bodyOne.calculateDerivedData();
Contact contact = new Contact();
contact.Bodies[0] = bodyZero;
contact.Bodies[1] = bodyOne;
contact.Point = Vector3.Zero;
contact.Penetration = 0.1f;
contact.Restitution = 1f;
contact.Friction = 0f;
contact.Normal = Vector3.Right;
contact.ReCalc(1f);
Assert.AreEqual(Vector3.Left, contact.CalcLocalVelocity(0, 1f));
Assert.AreEqual(Vector3.Right, contact.CalcLocalVelocity(1, 1f));
Assert.AreEqual(Vector3.Left, contact.RelativeContactPositions[0]);
Assert.AreEqual(Vector3.Right * 0.9f, contact.RelativeContactPositions[1]);
Assert.AreEqual(new Vector3(-2f, 0f, 0f), contact.ContactVelocity);
// Position Change
Vector3[] linearChange = new Vector3[2];
Vector3[] angularChange = new Vector3[2];
contact.ApplyPositionChange(
ref linearChange, ref angularChange, contact.Penetration);
Assert.AreEqual(Vector3.Zero, angularChange[0], "Zero angular change for object 0");
Assert.AreEqual(Vector3.Zero, angularChange[1], "Zero angular change for object 1");
Assert.AreEqual(new Vector3(0.05f, 0f, 0f), linearChange[0],
"Body 0 is pushed right by half penetration");
Assert.AreEqual(new Vector3(-0.05f, 0f, 0f), linearChange[1],
"Body 1 is pushed left by half penetration");
//Velocity Change
Vector3[] velocityChange = new Vector3[2];
Vector3[] rotationChange = new Vector3[2];
contact.ApplyVelocityChange(ref velocityChange, ref rotationChange);
Assert.AreEqual(
Vector3.Zero,
rotationChange[0],
"Zero rotation change for object 0");
Assert.AreEqual(
Vector3.Zero,
rotationChange[1],
"Zero rotation change for object 1");
Assert.AreEqual(
Vector3.Right * 2f,
velocityChange[0],
"Counter velocity applied to body 0");
Assert.AreEqual(
Vector3.Left * 2f,
velocityChange[1],
"Counter velocity applied to body 1");
Assert.AreEqual(
Vector3.Right,
bodyZero.Velocity);
Assert.AreEqual(Vector3.Zero, bodyZero.Rotation);
Assert.AreEqual(
Vector3.Left,
bodyOne.Velocity);
Assert.AreEqual(Vector3.Zero, bodyOne.Rotation);
}
void saveLastContact(Contact contact)
{
LastContact.DiscoveryHint = contact.DiscoveryHint;
LastContact.Bodies = contact.Bodies;
LastContact.Normal = contact.Normal;
LastContact.Point = contact.Point;
LastContact.Friction = contact.Friction;
LastContact.Penetration = contact.Penetration;
LastContact.Restitution = contact.Restitution;
LastContact.DesiredDeltaVelocity = contact.DesiredDeltaVelocity;
LastContact.ContactVelocity = contact.ContactVelocity;
}
private static void fillPointFaceBoxBox(Box one, Box two, Vector3 toCenter, CollisionData data, int best, float penetration)
{
Contact contact = new Contact();
Vector3 normal = one.getAxis(best);
if (Vector3.Dot(normal, toCenter) > 0)
{
normal *= -1f;
}
Vector3 vertex = two.HalfSizes;
float oneDot = Vector3.Dot(two.getAxis(0), normal);
if (oneDot < 0)
{
vertex *= new Vector3(-1f, 0f, 0f);
}
float twoDot = Vector3.Dot(two.getAxis(1), normal);
if (twoDot < 0)
{
vertex *= new Vector3(0f, -1f, 0f);
}
float threeDot = Vector3.Dot(two.getAxis(2), normal);
if (threeDot < 0)
{
vertex *= new Vector3(0f, 0f, -1f);
}
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnBox_Point_Face;
contact.Normal = normal;
contact.Penetration = penetration;
contact.Point = Vector3.Transform(vertex, two.Transform);
contact.Bodies[0] = one.Body;
contact.Bodies[1] = two.Body;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
}
public void Contact_BoxSpinningOnYAxisFallsOnToXZPlane()
{
// X-Z plane
NoBody planeBody = new NoBody(Vector3.Zero);
planeBody.InverseMass = 0f; //infinite mass
Forever.Physics.Collide.Plane plane = new Forever.Physics.Collide.Plane(planeBody, Vector3.Zero, Vector3.Up);
planeBody.calculateDerivedData();
// Spinning box colliding with the plane
NoBody boxBody = new NoBody(Vector3.Up * 0.95f);
boxBody.Mass = 1f;
boxBody.Rotation = new Vector3(0f, 0.01f, 0f);
boxBody.Velocity = new Vector3(0f, -1f, 0f);
boxBody.calculateDerivedData();
Box box = new Box(boxBody, Matrix.Identity, new Vector3(1f, 1f, 1f));
Contact contact = new Contact();
contact.Bodies[0] = planeBody;
contact.Bodies[1] = boxBody;
contact.Point = Vector3.Zero;
contact.Penetration = 0.05f;
contact.Restitution = 1f;
contact.Friction = 0f;
contact.Normal = Vector3.Up;
contact.ReCalc(1f);
Assert.AreEqual(Vector3.Zero, contact.CalcLocalVelocity(0, 1f));
Assert.AreEqual(Vector3.Left, contact.CalcLocalVelocity(1, 1f));
Assert.AreEqual(Vector3.Zero, contact.RelativeContactPositions[0]);
Assert.AreEqual(Vector3.Down * 0.95f, contact.RelativeContactPositions[1]);
Assert.AreEqual(Vector3.Right, contact.ContactVelocity);
// Position Change
Vector3[] linearChange = new Vector3[2];
Vector3[] angularChange = new Vector3[2];
contact.ApplyPositionChange(
ref linearChange, ref angularChange, contact.Penetration);
Assert.AreEqual(Vector3.Zero, angularChange[0], "Zero angular change for object 0");
Assert.AreEqual(Vector3.Zero, angularChange[1], "Zero angular change for object 1");
Assert.AreEqual(new Vector3(0.0f, 0f, 0f), linearChange[0],
"Body 0 is not pushed at all because it has infinite mass");
Assert.AreEqual(new Vector3(0f, -0.05f, 0f), linearChange[1],
"Body 1 is pushed up (forward in contact direction) by half penetration");
//Velocity Change
Vector3[] velocityChange = new Vector3[2];
Vector3[] rotationChange = new Vector3[2];
contact.ApplyVelocityChange(ref velocityChange, ref rotationChange);
Assert.AreEqual(
Vector3.Zero,
rotationChange[0],
"Zero rotation change for object 0");
Assert.AreEqual(
Vector3.Zero,
rotationChange[1],
"Zero rotation change for object 1");
Assert.AreEqual(
Vector3.Zero,
velocityChange[0],
"Zero velocity applied to body 0");
Assert.AreEqual(
Vector3.Up * 2f,
velocityChange[1],
"Counter velocity applied to body 1");
}
public static int sphereAndHalfSpace(Sphere sphere, Plane plane, CollisionData data)
{
Vector3 pos = sphere.Body.Position;
//d = p * L - l
float ballDist = Vector3.Dot(plane.Normal, pos) - (sphere.Radius - plane.Offset);
if (ballDist > 0) return 0;
Contact contact = new Contact();
contact.Normal = plane.Normal;
contact.Penetration = -ballDist;
contact.Point = pos - (plane.Normal * (ballDist + sphere.Radius));
contact.Bodies[0] = sphere.Body;
contact.Bodies[1] = null;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
public static int sphereAndSphere(Sphere one, Sphere two, CollisionData data)
{
//make sure we have contacts
if (data.contactsLeft <= 0) return 0;
// Cache the sphere positions
Vector3 positionOne = one.Body.Position;
Vector3 positionTwo = two.Body.Position;
if (positionOne == positionTwo)
{
throw new ArgumentException("Two bodies with the same position are unsupported....TODO");
}
// find the vector between the objects
Vector3 midline = positionOne - positionTwo;
float size = midline.Length();
//see if it is large enough
if (size <= 0.0f || size > one.Radius + two.Radius)
{
return 0;
}
// we manually create the normal, because we have the size at hand;
Vector3 normal = midline * (1f / size);
Contact contact = new Contact();
contact.Normal = normal;
contact.Point = positionTwo + midline * 0.5f;
contact.Penetration = (one.Radius + two.Radius - size);
//write the appropriate data
contact.Bodies[0] = one.Body;
contact.Bodies[1] = two.Body;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
public static int edgeAndEdge(
Box left, Vector3 leftEdgeOne, Vector3 leftEdgeTwo,
Box right, Vector3 rightEdgeOne, Vector3 rightEdgeTwo,
CollisionData data)
{
//return 0; //TODO
Vector3 leftCenter = left.Body.Position;
Vector3 rightCenter = right.Body.Position;
Vector3 midLineRight = rightCenter - leftCenter;
float distCenters = midLineRight.Length();
Vector3 projectedLeftEdge = TrickyMath.Project(leftEdgeOne - leftCenter, midLineRight);
float distLeftCenterToEdge = projectedLeftEdge.Length();
Vector3 projectedRightEdge = TrickyMath.Project(rightEdgeOne - rightCenter, -midLineRight);
float distRightCenterToEdge = projectedRightEdge.Length();
if (distCenters > (distLeftCenterToEdge + distRightCenterToEdge))
{
return 0;
}
float distEdges = (distLeftCenterToEdge + distRightCenterToEdge) - distCenters;
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnBox_Edge_Edge;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
contact.Bodies[0] = left.Body;
contact.Bodies[1] = right.Body;
contact.Penetration = (distLeftCenterToEdge + distRightCenterToEdge) - distCenters;
contact.Point = leftCenter + (midLineRight * 0.5f);
Vector3 x = leftEdgeOne - leftEdgeTwo; ;
x.Normalize();
Vector3 y, z;
TrickyMath.MakeOrthonormalBasis(x, out y, out z);
Vector3 realY = y;
Vector3 normal = TrickyMath.VectorProduct(x, realY);
normal.Normalize();
contact.Normal = normal;
data.contacts.Add(contact);
return 1;
}
public static int boxAndSphere(Box box, Sphere sph, CollisionData data)
{
Vector3 center = sph.Body.Position;
Vector3 relCenter = Vector3.Transform(center, Matrix.Invert(box.Transform));
double x = relCenter.X;
double y = relCenter.Y;
double z = relCenter.Z;
if (Math.Abs(x) - sph.Radius > box.HalfSizes.X
|| Math.Abs(y) - sph.Radius > box.HalfSizes.Y
|| Math.Abs(z) - sph.Radius > box.HalfSizes.Z)
{
return 0;
}
Vector3 closest = Vector3.Zero;
float dist;
dist = relCenter.X;
if (dist > box.HalfSizes.X) dist = box.HalfSizes.X;
if (dist < -box.HalfSizes.X) dist = -box.HalfSizes.X;
closest.X = dist;
dist = relCenter.Y;
if (dist > box.HalfSizes.Y) dist = box.HalfSizes.Y;
if (dist < -box.HalfSizes.Y) dist = -box.HalfSizes.Y;
closest.Y = dist;
dist = relCenter.Z;
if (dist > box.HalfSizes.Z) dist = box.HalfSizes.Z;
if (dist < -box.HalfSizes.Z) dist = -box.HalfSizes.Z;
closest.Z = dist;
dist = (closest - relCenter).Length();
if (dist > sph.Radius && !TrickyMath.AlmostEquals(0f, dist - sph.Radius)) return 0;
Vector3 closestWorld = Vector3.Transform(closest, box.Transform);
Contact contact = new Contact();
Vector3 normal = closestWorld - center;// (center - closestWorld);
normal.Normalize();
contact.Normal = normal;
Debug.Sanity(contact.Normal);
contact.Point = closestWorld;
contact.Penetration = sph.Radius - dist;// (float)Math.Sqrt((float)dist);
contact.Bodies[0] = box.Body;
contact.Bodies[1] = sph.Body;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
//TODO - write unit tests!!!!!!
public static int boxAndPoint(Box box, Vector3 pointWorld, CollisionData data)
{
Vector3 pointLocal = Vector3.Transform(pointWorld, Matrix.Invert(box.Body.World * box.OffsetMatrix));
Vector3 halfSizes = box.HalfSizes;
Vector3 absPoint = new Vector3(
TrickyMath.Abs(pointLocal.X),
TrickyMath.Abs(pointLocal.Y),
TrickyMath.Abs(pointLocal.Z)
);
Vector3 check = halfSizes - absPoint;
if (check.X < 0 || check.Y < 0 || check.Z < 0)
{
return 0;
}
Vector3 depth = new Vector3(
TrickyMath.Abs(absPoint.X - halfSizes.X),
TrickyMath.Abs(absPoint.Y - halfSizes.Y),
TrickyMath.Abs(absPoint.Z - halfSizes.Z)
);
depth = new Vector3(
depth.X != 0f ? depth.X : float.MaxValue,
depth.Y != 0f ? depth.Y : float.MaxValue,
depth.Z != 0f ? depth.Z : float.MaxValue
);
if (depth.X <= depth.Y && depth.X <= depth.Z)
{
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnBox_Point_Face;
Vector3 boxAxis = box.getAxis(0);
contact.Normal = boxAxis * (pointLocal.X > 0 ? -1f : 1f);
contact.Point = pointWorld;
contact.Penetration = TrickyMath.Abs(absPoint.X - halfSizes.X);
contact.Bodies[0] = box.Body;
contact.Bodies[1] = null;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
else if (depth.Y <= depth.X && depth.Y <= depth.Z)
{
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnBox_Point_Face;
Vector3 boxAxis = box.getAxis(1);
contact.Normal = boxAxis * (pointLocal.Y > 0 ? -1f : 1f);
contact.Point = pointWorld;
contact.Penetration = TrickyMath.Abs(absPoint.Y - halfSizes.Y);
contact.Bodies[0] = box.Body;
contact.Bodies[1] = null;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
else if (depth.Z <= depth.X && depth.Z <= depth.Y)
{
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnBox_Point_Face;
Vector3 boxAxis = box.getAxis(2);
contact.Normal = boxAxis * (pointLocal.Z > 0 ? -1f : 1f);
contact.Point = pointWorld;
contact.Penetration = TrickyMath.Abs(absPoint.Z - halfSizes.Z);
contact.Bodies[0] = box.Body;
contact.Bodies[1] = null;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
else
{
return 0;
}
}
/// <summary>
/// danger! This works for ContactDemo, but there is one hang up. The call to Math.Abs() should not
/// be needed. It isn't in the orange book text. However, we only get negative numbers from that Dot.
/// </summary>
/// <param name="box"></param>
/// <param name="plane"></param>
/// <param name="data"></param>
/// <returns></returns>
public static int boxAndPlane(Box box, Plane plane, CollisionData data)
{
if (data.contactsLeft <= 0) return 0;
int contacts_found = 0;
// p dot L < l
Vector3[] verts = box.WorldVerts();
foreach (Vector3 vert in verts)
{
//float vertexDist = (float)Math.Abs( (double)Vector3.Dot(plane.Normal, vert));
float vertexDist = Vector3.Dot(-plane.Normal, vert);
if (vertexDist >= plane.Offset + data.tolerance)
{
// the contact point is halfway between the vertex and the plane
// we multiply the direction by half the spearation distance
// and add the vertex location
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnPlane_Corner;
contact.Bodies[0] = box.Body;
contact.Bodies[1] = null;
contact.Point = plane.ClosestPoint(vert);
contact.Normal = plane.Normal;
contact.Penetration = vertexDist - plane.Offset;//TrickyMathHelper.Abs(plane.Offset - vertexDist);
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
contacts_found++;
}
}
return contacts_found;
}
public static int boxAndBox(Box one, Box two, CollisionData data)
{
Vector3 toCenter = two.Body.Position - one.Body.Position;
float pen = float.MaxValue;
int best = int.MaxValue;
if (!tryAxis(one, two, one.getAxis(0), toCenter, 0, ref pen, ref best)) return 0;
if (!tryAxis(one, two, one.getAxis(1), toCenter, 1, ref pen, ref best)) return 0;
if (!tryAxis(one, two, one.getAxis(2), toCenter, 2, ref pen, ref best)) return 0;
if (!tryAxis(one, two, one.getAxis(0), toCenter, 3, ref pen, ref best)) return 0;
if (!tryAxis(one, two, one.getAxis(1), toCenter, 4, ref pen, ref best)) return 0;
if (!tryAxis(one, two, one.getAxis(2), toCenter, 5, ref pen, ref best)) return 0;
int bestSingleAxis = best;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(0), two.getAxis(0)), toCenter, 6, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(0), two.getAxis(1)), toCenter, 7, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(0), two.getAxis(2)), toCenter, 8, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(1), two.getAxis(0)), toCenter, 9, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(1), two.getAxis(1)), toCenter, 10, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(1), two.getAxis(2)), toCenter, 11, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(2), two.getAxis(0)), toCenter, 12, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(2), two.getAxis(1)), toCenter, 13, ref pen, ref best)) return 0;
if (!tryAxis(one, two, TrickyMath.VectorProduct(one.getAxis(2), two.getAxis(2)), toCenter, 14, ref pen, ref best)) return 0;
if (best == int.MaxValue)
{
throw new Exception("Found no good axis");
}
if (best < 3)
{
fillPointFaceBoxBox(one, two, toCenter, data, best, pen);
return 1;
}
else if (best < 6)
{
// We've got a vertex of box one on a face of box two.
// We use the same algorithm as above, but swap around
// one and two (and therefore also the vector between their
// centres).
fillPointFaceBoxBox(two, one, toCenter * -1.0f, data, best - 3, pen);
return 1;
}
else
{
best -= 6; //move this back to talk about a cardinal axis
int oneAxisIndex = best / 3;
int twoAxisIndex = best % 3;
Vector3 oneAxis = one.getAxis(oneAxisIndex);
Vector3 twoAxis = two.getAxis(twoAxisIndex);
Vector3 axis = TrickyMath.VectorProduct(oneAxis, twoAxis);
axis.Normalize();
if (Vector3.Dot(axis, toCenter) > 0)
{
axis *= -1f;
}
float[] ptOnOneEdge = TrickyMath.Vector3ToFloatArray(one.HalfSizes);
float[] ptOnTwoEdge = TrickyMath.Vector3ToFloatArray(two.HalfSizes);
for (int i = 0; i < 3; i++)
{
if (i == oneAxisIndex)
{
ptOnOneEdge[i] = 0f;
}
else if (Vector3.Dot(one.getAxis(i), axis) > 0)
{
ptOnOneEdge[i] *= -1f;
}
if (i == twoAxisIndex)
{
ptOnTwoEdge[i] = 0;
}
else if (Vector3.Dot(two.getAxis(i), axis) < 0)
{
ptOnTwoEdge[i] *= -1f;
}
}
Vector3 vertexOnOneEdge = Vector3.Transform(
TrickyMath.FloatArrayToVector3(ptOnOneEdge),
one.Transform
);
Vector3 vertexOnTwoEdge = Vector3.Transform(
TrickyMath.FloatArrayToVector3(ptOnTwoEdge),
two.Transform
);
float[] oneHalfSizes = TrickyMath.Vector3ToFloatArray(one.HalfSizes);
float[] twoHalfSizes = TrickyMath.Vector3ToFloatArray(two.HalfSizes);
Vector3 vertex = contactPoint(
vertexOnOneEdge, oneAxis, oneHalfSizes[oneAxisIndex],
vertexOnTwoEdge, twoAxis, twoHalfSizes[twoAxisIndex],
bestSingleAxis > 2
);
Contact contact = new Contact();
contact.DiscoveryHint = ContactDiscoveryHint.BoxOnBox_Edge_Edge;
contact.Penetration = pen;
contact.Normal = axis;
contact.Point = vertex;
contact.Bodies[0] = one.Body;
contact.Bodies[1] = two.Body;
contact.Restitution = data.restitution;
contact.Friction = data.friction;
data.contacts.Add(contact);
return 1;
}
return 0;
}
