public override void CheckForCollisions(List <LPhysicsObject2D> objs, float deltaTime)
{
base.CheckForCollisions(objs, deltaTime);
for (int i = objs.Count - 1; i >= 1; i--)
{
for (int j = i - 1; j >= 0; j--)
{
LPhysicsObject2D objA = objs[i];
LPhysicsObject2D objB = objs[j];
if (objA.collider != null &&
objB.collider != null &&
objA.collider.bounds.Intersects(objB.collider.bounds))
{
simplex.Clear();
direction = Vector2.one;
epa.Clear();
closestFace = null;
safety.Clear();
LContactConstraint2D constraint = CollisionDetect(objA, objB);
if (constraint != null)
{
contactConstraints.Add(constraint);
}
}
}
}
}
/// <summary>
/// <para>GJK判断是否碰撞</para>
/// <para>1.找direction方向的最远点</para>
/// <para>2.判断最远点是否与原点在同一方向(是否比原点还远)，如果不是则未碰撞</para>
/// <para>3.将最远点置入simplex，判断simplex是否包围了原点，如果是则碰撞，否则以离原点最近的simplex上的点到原点作为direction回到步骤1</para>
/// </summary>
/// <param name="objA"></param>
/// <param name="objB"></param>
private LContactConstraint2D CollisionDetect(LPhysicsObject2D objA, LPhysicsObject2D objB)
{
Vector2 a = objA.collider.GetFurtherPointInDirection(direction);
Vector2 b = objB.collider.GetFurtherPointInDirection(-direction);
SimplexPoint2D sp = new SimplexPoint2D(a, b);
if (simplex.IsSameDirectionWithOrigin(sp, direction))
{
simplex.Add(sp);
if (simplex.DoSimplex2D())
{
epa.Add(new EPAFace2D(simplex[0], simplex[1]));
epa.Add(new EPAFace2D(simplex[1], simplex[2]));
epa.Add(new EPAFace2D(simplex[2], simplex[0]));
PenetrationDetect(objA, objB);
return(ContactConstraintGenerate(objA, objB));
}
else
{
direction = simplex.FindClosestPointToOriginDirection();
return(CollisionDetect(objA, objB));
}
}
else
{
return(null);
}
}
/// <summary>
/// <para>EPA判断渗透方向和深度</para>
/// <para>1.找到list中离原点最近的face</para>
/// <para>2.如果与上一次找到的相同，直接返回</para>
/// <para>3.否则找face.normal的最远点A</para>
/// <para>4.移除使A看不到的原点的face，将(A, face.A)和(A, face.B)构建为新的face添加到list中，返回第一步</para>
/// </summary>
/// <returns></returns>
private void PenetrationDetect(LPhysicsObject2D objA, LPhysicsObject2D objB)
{
EPAFace2D face = epa.FindClosestFace();
if (closestFace == null ||
Mathf.Abs(closestFace.sqrMagnitude - face.sqrMagnitude) > EPAFace2D.Threshold)
{
closestFace = face;
safety.Add(closestFace);
Vector2 a = objA.collider.GetFurtherPointInDirection(closestFace.direction);
Vector2 b = objB.collider.GetFurtherPointInDirection(-closestFace.direction);
SimplexPoint2D sp = new SimplexPoint2D(a, b);
epa.ImportNewSupportPoint(sp);
PenetrationDetect(objA, objB);
}
}
private LContactConstraint2D ContactConstraintGenerate(LPhysicsObject2D objA, LPhysicsObject2D objB)
{
LContactConstraint2D constraint = null;
Vector2 contactPointsA = LGeometryUtil2D.CalcBarycentric(closestFace.sp1.a, closestFace.sp2.a);
Vector2 contactPointsB = LGeometryUtil2D.CalcBarycentric(closestFace.sp1.b, closestFace.sp2.b);
if (closestFace.sqrMagnitude > LPhysicsStatic2D.DistanceSqrtThreshold)
{
float penetration = Mathf.Sqrt(closestFace.sqrMagnitude);
Vector2 normal = closestFace.direction / penetration;
if (objA.rigidBody != null ||
objB.rigidBody != null)
{
constraint = new LContactConstraint2D(objA, objB);
constraint.anchorA = contactPointsA;
constraint.anchorB = contactPointsB;
constraint.normal = normal;
constraint.penetration = penetration;
}
}
return(constraint);
}
public void Update(Transform trans)
{
int instanceID = trans.GetInstanceID();
int index = physicsIndexes.IndexOf(instanceID);
LPhysicsObject2D physicsObj = null;
if (index == -1)
{
physicsObj = new LPhysicsObject2D(trans);
physicsIndexes.Add(instanceID);
physicsObjs.Add(physicsObj);
}
else
{
physicsObj = physicsObjs[index];
}
physicsObj.Refresh();
if (physicsObj.collider == null &&
physicsObj.rigidBody == null)
{
physicsObjs.Remove(physicsObj);
}
}
public LContactConstraint2D(LPhysicsObject2D objA, LPhysicsObject2D objB)
: base(objA, objB)
{
}
public LConstraint2D(LPhysicsObject2D objA, LPhysicsObject2D objB)
{
mObjA = objA;
mObjB = objB;
}
public LGeneralConstraint2D(LPhysicsObject2D objA, LPhysicsObject2D objB)
: base(objA, objB)
{
}
