public virtual void OnCollide(PhysicsBodyComponent with)
{
if (OnCollision != null)
{
OnCollision(this, with);
}
}
public void SimulateSingle(PhysicsBodyComponent ob, float deltaTime)
{
StepSingle(ob, deltaTime);
BroadphaseSingle(IntersectionType.Soft, ob, deltaTime);
CollisionResponse(deltaTime);
BroadphaseSingle(IntersectionType.Rigid, ob, deltaTime);
CollisionResponse(deltaTime);
ApplyDeltaSnapshot(ob, deltaTime);
}
void Step(float deltaTime)
{
// Step objects
for (int i = 0; i < physicsBodies.Count; i++)
{
PhysicsBodyComponent ob = physicsBodies[i];
StepSingle(ob, deltaTime);
}
}
void BroadphaseSingle(IntersectionType forType, PhysicsBodyComponent p1, float deltaTime)
{
broadIntersections.Clear();
Broadphase(forType, p1, deltaTime, 0);
// Sort the intersections by entry time, where first intersections are the first in the array.
intersections = new Intersection[broadIntersections.Count];
broadIntersections.CopyTo(intersections);
Array.Sort(intersections, CompareIntersection);
}
void StepSingle(PhysicsBodyComponent ob, float deltaTime)
{
if (!ob.IsStatic && ob.IsEnabled && ob.GameObject.IsEnabled)
{
ob.PreUpdate(deltaTime);
if (ob.IsAffectedByGravity)
{
ob.Velocity += Gravity * deltaTime;
}
ob.Step(deltaTime);
}
}
void CalculateMaxStep(PhysicsBodyComponent p1, PhysicsBodyComponent p2,
AxisAlignedBoundingBox p1Col, AxisAlignedBoundingBox?p1StepCol,
AxisAlignedBoundingBox p2Col, AxisAlignedBoundingBox?p2StepCol)
{
if (p2.IsStatic && p1StepCol.HasValue && p1StepCol.Value.Intersects(p2Col))
{
p1.Delta.MaxStep = 0;
}
else if (p1.IsStatic && p2StepCol.HasValue && p2StepCol.Value.Intersects(p1Col))
{
p2.Delta.MaxStep = 0;
}
}
void ApplyDeltaSnapshot(PhysicsBodyComponent ob, float deltaTime)
{
if (!ob.IsStatic)
{
// Apply all the changes to the physics objects from,
// the collision response and step
ob.Transform.Position = ob.Delta.FinalPosition;
ob.Velocity = ob.Delta.FinalVelocity;
ob.IsGrounded = ob.Delta.IsGrounded;
ob.Delta.Reset();
}
ob.PostUpdate(deltaTime);
}
public void RemovePhysicsBody(PhysicsBodyComponent body)
{
physicsBodies.Remove(body);
}
public void AddPhysicsBody(PhysicsBodyComponent body)
{
physicsBodies.Add(body);
}
void CollisionResponse(float deltaTime)
{
for (int i = 0; i < intersections.Length; i++)
{
Intersection intersection = intersections[i];
PhysicsBodyComponent p1 = intersection.Object1;
PhysicsBodyComponent p2 = intersection.Object2;
AxisAlignedBoundingBox p1Collider = p1.GetCollider();
AxisAlignedBoundingBox p1DeltaCollider = p1.GetColliderAt(p1.Delta.FinalPosition);
AxisAlignedBoundingBox p2Collider = p2.GetCollider();
AxisAlignedBoundingBox p2DeltaCollider = p2.GetColliderAt(p2.Delta.FinalPosition);
if (intersection.Type == IntersectionType.Rigid)
{
// Update the intersection data, so that previous updates for
// these objects are applied
intersection.UpdateFromDelta();
// If both entry times are invalid, the objects aren't intersecting anymore,
// so ignore the collision.
if (intersection.Object1EntryTime == 1 && intersection.Object2EntryTime == 1)
{
continue;
}
// Handle the collision based on static states
if (intersection.Object2.IsStatic)
{
// If we are past the first sweep pass for this object,
// and this intersection is no longer valid, then ignore it.
if (p1.Delta.DeltaPass > 0)
{
if (!p1DeltaCollider.Intersects(p2Collider))
{
continue;
}
}
// Gather intersection data
Vector3 surfaceNormal = intersection.Object2Normal;
float collisionTime = intersection.Object1EntryTime;
float remainingTime = 1f - collisionTime;
float stepDist = intersection.Resolver.StepDistance(p1DeltaCollider, p2Collider);
//if (surfaceNormal.Y == 0)
// Diagnostics.DashCMD.WriteLine("{0} | {1}", stepDist.ToString(), Math.Min(p1.Delta.MaxStep, p1.MaxStep));
//Diagnostics.DashCMD.WriteLine(surfaceNormal);
// Try to step on object
if (p1.CanStep && p2.CanBeSteppedOn && surfaceNormal.Y == 0 &&
stepDist >= 0 && stepDist <= Math.Min(p1.Delta.MaxStep, p1.MaxStep))
{
// Step onto object
p1.Delta.FinalPosition.Y += stepDist + 0.001f;
p1.Delta.FinalVelocity.Y = 0;
p1.Delta.IsGrounded = p1.Delta.IsGrounded || true;
p1.Delta.Stepped = true;
}
else // Normal collision resolve
{
// Calculate the compensation in position from the collision
Vector3 compensation = surfaceNormal * (Maths.Abs(p1.Delta.FinalVelocity * deltaTime)) * remainingTime;
p1.Delta.FinalPosition += compensation;
// If this normal moved the object anywhere upward,
// that object is now considered grounded
if (surfaceNormal.Y > 0)
{
p1.Delta.IsGrounded = p1.Delta.IsGrounded || true;
}
// Fix the velocity
if (p1.BounceOnWallCollision || p1.BounceOnVerticalCollision)
{
if ((surfaceNormal.X != 0 || surfaceNormal.Z != 0) && p1.BounceOnWallCollision)
{
if (surfaceNormal.X != 0)
{
p1.Delta.FinalVelocity.X *= -(1f - p1.HorizontalBounceFalloff);
}
if (surfaceNormal.Z != 0)
{
p1.Delta.FinalVelocity.Z *= -(1f - p1.HorizontalBounceFalloff);
}
}
else if (surfaceNormal.Y != 0 && p1.BounceOnVerticalCollision)
{
p1.Delta.FinalVelocity.Y *= -(1f - p1.VerticalBounceFalloff);
p1.Delta.FinalVelocity.X *= p1.InverseFriction;
p1.Delta.FinalVelocity.Z *= p1.InverseFriction;
}
else
{
intersection.Resolver.FixVelocity(ref p1.Delta.FinalVelocity, surfaceNormal);
}
}
else
{
intersection.Resolver.FixVelocity(ref p1.Delta.FinalVelocity, surfaceNormal);
}
}
// Another delta pass has occured
p1.Delta.DeltaPass++;
p1.OnCollide(p2);
p2.OnCollide(p1);
}
else if (intersection.Object1.IsStatic)
{
// If we are past the first sweep pass for this object,
// and this intersection is no longer valid, then ignore it.
if (p2.Delta.DeltaPass > 0)
{
if (!p2DeltaCollider.Intersects(p1Collider))
{
continue;
}
}
// Gather intersection data
Vector3 surfaceNormal = intersection.Object1Normal;
float collisionTime = intersection.Object2EntryTime;
float remainingTime = 1f - collisionTime;
float stepDist = intersection.Resolver.StepDistance(p2DeltaCollider, p1Collider);
// Try to step on object
if (p2.CanStep && p1.CanBeSteppedOn && surfaceNormal.Y == 0 &&
stepDist >= 0 && stepDist <= Math.Min(p2.Delta.MaxStep, p2.MaxStep))
{
// Step onto object
p2.Delta.FinalPosition.Y += stepDist + 0.001f;
p2.Delta.FinalVelocity.Y = 0;
p2.Delta.IsGrounded = p2.Delta.IsGrounded || true;
p2.Delta.Stepped = true;
}
else // Normal collision resolve
{
// Calculate the compensation in position from the collision
Vector3 compensation = surfaceNormal * (Maths.Abs(p2.Delta.FinalVelocity * deltaTime)) * remainingTime;
p2.Delta.FinalPosition += compensation;
// If this normal moved the object anywhere upward,
// that object is now considered grounded
if (surfaceNormal.Y > 0)
{
p2.Delta.IsGrounded = p2.Delta.IsGrounded || true;
}
// Fix the velocity
if (p2.BounceOnWallCollision || p2.BounceOnVerticalCollision)
{
if ((surfaceNormal.X != 0 || surfaceNormal.Z != 0) && p2.BounceOnWallCollision)
{
if (surfaceNormal.X != 0)
{
p2.Delta.FinalVelocity.X *= -(1f - p2.HorizontalBounceFalloff);
}
if (surfaceNormal.Z != 0)
{
p2.Delta.FinalVelocity.Z *= -(1f - p2.HorizontalBounceFalloff);
}
}
else if (surfaceNormal.Y != 0 && p2.BounceOnVerticalCollision)
{
p2.Delta.FinalVelocity.Y *= -(1f - p2.VerticalBounceFalloff);
p1.Delta.FinalVelocity.X *= p1.InverseFriction;
p1.Delta.FinalVelocity.Z *= p1.InverseFriction;
}
else
{
intersection.Resolver.FixVelocity(ref p2.Delta.FinalVelocity, surfaceNormal);
}
}
else
{
intersection.Resolver.FixVelocity(ref p2.Delta.FinalVelocity, surfaceNormal);
}
}
// Another delta pass has occured
p2.Delta.DeltaPass++;
p1.OnCollide(p2);
p2.OnCollide(p1);
}
}
else
{
// If we are past the first sweep pass for this object,
// and this intersection is no longer valid, then ignore it.
if ((!p1DeltaCollider.Intersects(p2Collider)) &&
(!p2DeltaCollider.Intersects(p1Collider)))
{
continue;
}
float p1DeltaMiddleX = p1.Delta.FinalPosition.X + p1.Size.X / 2f;
float p2DeltaMiddleX = p2.Delta.FinalPosition.X + p2.Size.X / 2f;
float p1DeltaMiddleZ = p1.Delta.FinalPosition.Z + p1.Size.Z / 2f;
float p2DeltaMiddleZ = p2.Delta.FinalPosition.Z + p2.Size.Z / 2f;
Vector3 p1Move = new Vector3((p2DeltaMiddleX - p1DeltaMiddleX), 0, (p2DeltaMiddleZ - p1DeltaMiddleZ));
Vector3 p2Move = new Vector3((p1DeltaMiddleX - p2DeltaMiddleX), 0, (p1DeltaMiddleZ - p2DeltaMiddleZ));
if (p1Move.X == p2Move.X)
{
p1Move.X += Maths.Random.Next((int)-p2.Size.X, (int)p2.Size.X) / deltaTime;
}
Vector2 masses = new Vector2((p2.Mass / p1.Mass), (p1.Mass / p2.Mass)) * 0.5f;
if (p1.CanBePushedBySoft)
{
p1.Delta.FinalVelocity -= p1Move * masses.X;
p1.Delta.FinalPosition = p1.Transform.Position + p1.Delta.FinalVelocity * deltaTime;
}
if (p2.CanBePushedBySoft)
{
p2.Delta.FinalVelocity -= p2Move * masses.Y;
p2.Delta.FinalPosition = p2.Transform.Position + p2.Delta.FinalVelocity * deltaTime;
}
p1.OnCollide(p2);
p2.OnCollide(p1);
}
}
}
void Broadphase(IntersectionType forType, PhysicsBodyComponent p1, float deltaTime, int start)
{
if (!p1.IsEnabled || !p1.GameObject.IsEnabled)
{
return;
}
if (!p1.CanCollide)
{
return;
}
// For every object, check if it CAN intersect with any other object
AxisAlignedBoundingBox p1Collider = p1.GetCollider();
AxisAlignedBoundingBox p1Broad = p1.GetBroadphase();
AxisAlignedBoundingBox?p1StepCollider = null;
if (p1.CanStep)
{
p1StepCollider = p1.GetColliderAt(p1.Delta.StepPosition);
}
if (RecordProcessedBoundingBoxes)
{
LastProcessedBoundingBoxes.Add(p1Collider);
LastProcessedBoundingBoxes.Add(p1Broad);
}
for (int k = start; k < physicsBodies.Count; k++)
{
PhysicsBodyComponent p2 = physicsBodies[k];
if (!p2.IsEnabled || !p2.GameObject.IsEnabled)
{
continue;
}
if (p2 == p1)
{
continue;
}
if (!p2.CanCollide)
{
continue;
}
// Get the type of intersection to determine how it should be handled
IntersectionType type = GetIntersectionType(p1.IsStatic, p2.IsStatic);
if (type != forType)
{
continue;
}
if (forType == IntersectionType.Soft && (!p2.CanCollideWithSoft || !p1.CanCollideWithSoft))
{
continue;
}
AxisAlignedBoundingBox p2Collider = p2.GetCollider();
AxisAlignedBoundingBox p2Broad = p2.GetBroadphase();
AxisAlignedBoundingBox?p2StepCollider = null;
if (p2.CanStep)
{
p2StepCollider = p2.GetColliderAt(p2.Delta.StepPosition);
}
if (RecordProcessedBoundingBoxes)
{
LastProcessedBoundingBoxes.Add(p2Collider);
LastProcessedBoundingBoxes.Add(p2Broad);
}
// Check if the objects CAN intersect
if (CanIntersect(p1.IsStatic, p1Collider, p1Broad, p2.IsStatic, p2Collider, p2Broad))
{
// Calculate max step
if (type == IntersectionType.Rigid)
{
CalculateMaxStep(p1, p2, p1Collider, p1StepCollider, p2Collider, p2StepCollider);
}
// Add the possible intersection
Intersection intersect = new Intersection(p1, p2, sweepResolver, deltaTime, type);
broadIntersections.Add(intersect);
}
}
// Let extensions run
foreach (IPhysicsEngineExtension ext in extensions)
{
if (!ext.IsActive || !ext.CanCheck(forType, p1.IsStatic))
{
continue;
}
// Get intersections from extensions
IEnumerable <PhysicsBodyComponent> intersections = ext.GetBroadphaseIntersections(p1Broad);
foreach (PhysicsBodyComponent physOb in intersections)
{
AxisAlignedBoundingBox?physObStepCollider = null;
if (physOb.CanStep)
{
physObStepCollider = physOb.GetColliderAt(physOb.Delta.StepPosition);
}
IntersectionType type = GetIntersectionType(p1.IsStatic, physOb.IsStatic);
// Calculate max step
if (type == IntersectionType.Rigid)
{
CalculateMaxStep(p1, physOb, p1Collider, p1StepCollider, physOb.GetCollider(), physObStepCollider);
}
// Add the possible intersection
Intersection intersection = new Intersection(p1, physOb, sweepResolver, deltaTime, IntersectionType.Rigid);
broadIntersections.Add(intersection);
}
}
}