public void Add(Joint joint)
{
Debug.Assert(_jointCount < _jointCapacity);
_joints[_jointCount++] = joint;
}
public GearJointDef()
{
type = JointType.Gear;
joint1 = null;
joint2 = null;
ratio = 1.0f;
}
/// Destroy a joint. This may cause the connected bodies to begin colliding.
/// @warning This function is locked during callbacks.
public void DestroyJoint(Joint j)
{
Debug.Assert(!IsLocked);
if (IsLocked)
{
return;
}
bool collideConnected = j._collideConnected;
// Remove from the doubly linked list.
if (j._prev != null)
{
j._prev._next = j._next;
}
if (j._next != null)
{
j._next._prev = j._prev;
}
if (j == _jointList)
{
_jointList = j._next;
}
// Disconnect from island graph.
Body bodyA = j._bodyA;
Body bodyB = j._bodyB;
// Wake up connected bodies.
bodyA.WakeUp();
bodyB.WakeUp();
// Remove from body 1.
if (j._edgeA.Prev != null)
{
j._edgeA.Prev.Next = j._edgeA.Next;
}
if (j._edgeA.Next != null)
{
j._edgeA.Next.Prev = j._edgeA.Prev;
}
if (j._edgeA == bodyA._jointList)
{
bodyA._jointList = j._edgeA.Next;
}
j._edgeA.Prev = null;
j._edgeA.Next = null;
// Remove from body 2
if (j._edgeB.Prev != null)
{
j._edgeB.Prev.Next = j._edgeB.Next;
}
if (j._edgeB.Next != null)
{
j._edgeB.Next.Prev = j._edgeB.Prev;
}
if (j._edgeB == bodyB._jointList)
{
bodyB._jointList = j._edgeB.Next;
}
j._edgeB.Prev = null;
j._edgeB.Next = null;
Debug.Assert(_jointCount > 0);
--_jointCount;
// If the joint prevents collisions, then flag any contacts for filtering.
if (collideConnected == false)
{
ContactEdge edge = bodyB.GetConactList();
while (edge != null)
{
if (edge.Other == bodyA)
{
// Flag the contact for filtering at the next time step (where either
// body is awake).
edge.Contact.FlagForFiltering();
}
edge = edge.Next;
}
}
}
void DrawJoint(Joint joint)
{
Body b1 = joint.GetBody1();
Body b2 = joint.GetBody2();
XForm xf1, xf2;
b1.GetXForm(out xf1);
b2.GetXForm(out xf2);
Vector2 x1 = xf1.Position;
Vector2 x2 = xf2.Position;
Vector2 p1 = joint.GetAnchor1();
Vector2 p2 = joint.GetAnchor2();
Color color = ColorEx.FromScRgb(0.5f, 0.8f, 0.8f);
switch (joint.JointType)
{
case JointType.Distance:
DebugDraw.DrawSegment(p1, p2, color);
break;
case JointType.Pulley:
{
PulleyJoint pulley = (PulleyJoint)joint;
Vector2 s1 = pulley.GetGroundAnchor1();
Vector2 s2 = pulley.GetGroundAnchor2();
DebugDraw.DrawSegment(s1, p1, color);
DebugDraw.DrawSegment(s2, p2, color);
DebugDraw.DrawSegment(s1, s2, color);
}
break;
case JointType.Mouse:
// don't draw this
break;
default:
DebugDraw.DrawSegment(x1, p1, color);
DebugDraw.DrawSegment(p1, p2, color);
DebugDraw.DrawSegment(x2, p2, color);
break;
}
}
/// Create a joint to rain bodies together. No reference to the definition
/// is retained. This may cause the connected bodies to cease colliding.
/// @warning This function is locked during callbacks.
public Joint CreateJoint(JointDef def)
{
Debug.Assert(!IsLocked);
if (IsLocked)
{
return null;
}
Joint j = Joint.Create(def);
// Connect to the world list.
j._prev = null;
j._next = _jointList;
if (_jointList != null)
{
_jointList._prev = j;
}
_jointList = j;
++_jointCount;
// Connect to the bodies' doubly linked lists.
j._edgeA.Joint = j;
j._edgeA.Other = j._bodyB;
j._edgeA.Prev = null;
j._edgeA.Next = j._bodyA._jointList;
if (j._bodyA._jointList != null)
j._bodyA._jointList.Prev = j._edgeA;
j._bodyA._jointList = j._edgeA;
j._edgeB.Joint = j;
j._edgeB.Other = j._bodyA;
j._edgeB.Prev = null;
j._edgeB.Next = j._bodyB._jointList;
if (j._bodyB._jointList != null)
j._bodyB._jointList.Prev = j._edgeB;
j._bodyB._jointList = j._edgeB;
Body bodyA = def.body1;
Body bodyB = def.body2;
bool staticA = bodyA.IsStatic;
bool staticB = bodyB.IsStatic;
// If the joint prevents collisions, then flag any contacts for filtering.
if (def.collideConnected == false && (staticA == false || staticB == false))
{
// Ensure we iterate over contacts on a dynamic body (usually have less contacts
// than a static body). Ideally we will have a contact count on both bodies.
if (staticB)
{
MathUtils.Swap(ref bodyA, ref bodyB);
}
ContactEdge edge = bodyB.GetConactList();
while (edge != null)
{
if (edge.Other == bodyA)
{
// Flag the contact for filtering at the next time step (where either
// body is awake).
edge.Contact.FlagForFiltering();
}
edge = edge.Next;
}
}
// Note: creating a joint doesn't wake the bodies.
return j;
}