protected virtual void Remove(int contactIndex)
{
Contact removing = contacts.Elements[contactIndex];
contacts.FastRemoveAt(contactIndex);
OnRemoved(removing);
unusedContacts.GiveBack(removing);
}
private static void MaintainEdge(int a, int b, RawList <int> edges)
{
bool contained = false;
int index = 0;
for (int k = 0; k < edges.Count; k += 2)
{
if ((edges[k] == a && edges[k + 1] == b) || (edges[k] == b && edges[k + 1] == a))
{
contained = true;
index = k;
}
}
//If it isn't present, add it to the edge list.
if (!contained)
{
edges.Add(a);
edges.Add(b);
}
else
{
//If it is present, that means both edge-connected triangles were deleted now, so get rid of it.
edges.FastRemoveAt(index + 1);
edges.FastRemoveAt(index);
}
}
/// <summary>
/// Removes redundant points. Two points are redundant if they occupy the same hash grid cell.
/// </summary>
/// <param name="points">List of points to prune.</param>
/// <param name="cellSize">Size of cells to determine redundancy.</param>
public static void RemoveRedundantPoints(RawList <Vector3> points, double cellSize)
{
var set = BlockedCellSets.Take();
for (int i = points.Count - 1; i >= 0; --i)
{
var element = points.Elements[i];
var cell = new BlockedCell
{
X = (int)Math.Floor(element.X / cellSize),
Y = (int)Math.Floor(element.Y / cellSize),
Z = (int)Math.Floor(element.Z / cellSize)
};
if (set.Contains(cell))
{
points.FastRemoveAt(i);
}
else
{
set.Add(cell);
//TODO: Consider adding adjacent cells to guarantee that a point on the border between two cells will still detect the presence
//of a point on the opposite side of that border.
}
}
set.Clear();
BlockedCellSets.GiveBack(set);
}
void DeactivateObjects()
{
//Deactivate only some objects each frame.
int numberOfEntitiesDeactivated = 0;
int numberOfIslandsChecked = 0;
int originalIslandCount = simulationIslands.Count;
while (numberOfEntitiesDeactivated < maximumDeactivationAttemptsPerFrame && simulationIslands.Count > 0 && numberOfIslandsChecked < originalIslandCount)
{
deactivationIslandIndex = (deactivationIslandIndex + 1) % simulationIslands.Count;
var island = simulationIslands.Elements[deactivationIslandIndex];
if (island.memberCount == 0)
{
//Found an orphan island left over from merge procedures or removal procedures.
//Shoo it on out.
simulationIslands.FastRemoveAt(deactivationIslandIndex);
GiveBackIsland(island);
}
else
{
island.TryToDeactivate();
numberOfEntitiesDeactivated += island.memberCount;
}
++numberOfIslandsChecked;
}
}
void RemoveStaleOverlaps()
{
//We don't need to do any synchronization or queueing here; just remove everything directly.
ApplySolverUpdateableChangesDirectly = true;
//Remove stale objects.
for (int i = narrowPhasePairs.count - 1; i >= 0; i--)
{
var pair = narrowPhasePairs.Elements[i];
//A stale overlap is a pair which has not been updated, but not because of inactivity.
//Pairs between two inactive shapes are not updated because the broad phase does not output overlaps
//between inactive entries. We need to keep such pairs around, otherwise when they wake up, lots of extra work
//will be needed and quality will suffer.
//The classic stale overlap is two objects which have moved apart. Because the bounding boxes no longer overlap,
//the broad phase does not generate an overlap for them. Obviously, we should get rid of such a pair.
//Any such pair will have at least one active member. Having velocity requires activity and teleportation will activate the object.
//There's another sneaky kind of stale overlap. Consider a sleeping dynamic object on a Terrain. The Terrain, being a static object,
//is considered inactive. The sleeping dynamic object is also inactive. Now, remove the sleeping dynamic object.
//Both objects are still considered inactive. But the pair is clearly stale- one of its members doesn't even exist anymore!
//This has nasty side effects, like retaining memory. To solve this, also check to see if either member does not belong to the simulation.
if (pair.NeedsUpdate && //If we didn't receive an update in the previous narrow phase run and...
(pair.broadPhaseOverlap.entryA.IsActive || pair.broadPhaseOverlap.entryB.IsActive || //one of us is active or..
pair.broadPhaseOverlap.entryA.BroadPhase == null || pair.broadPhaseOverlap.entryB.BroadPhase == null)) //one of us doesn't exist anymore...
{
//Get rid of the pair!
if (RemovingPair != null)
RemovingPair(pair);
narrowPhasePairs.FastRemoveAt(i);
overlapMapping.Remove(pair.BroadPhaseOverlap);
//The clean up will issue an order to get rid of the solver updateable if it is active.
//To avoid a situation where the solver updateable outlives the pair but is available for re-use
//because of the factory giveback here, the updateable is removed directly (ApplySolverUpdateableChangesDirectly = true).
pair.CleanUp();
pair.Factory.GiveBack(pair);
}
else
{
pair.NeedsUpdate = true;
}
}
ApplySolverUpdateableChangesDirectly = false;
}
///<summary>
/// Removes a connection reference from the member.
///</summary>
///<param name="connection">Reference to remove.</param>
///<param name="index">Index of the connection in this member's list</param>
internal void RemoveConnectionReference(SimulationIslandConnection connection, int index)
{
if (connections.Count > index)
{
connections.FastRemoveAt(index);
if (connections.Count > index)
{
connections.Elements[index].SetListIndex(this, index);
}
}
}
void RemoveStaleOverlaps()
{
//Remove stale objects.
for (int i = narrowPhasePairs.count - 1; i >= 0; i--)
{
var pair = narrowPhasePairs.Elements[i];
if (pair.NeedsUpdate &&
//Overlap will not be refreshed if entries are inactive, but shouldn't remove narrow phase pair.
(pair.BroadPhaseOverlap.entryA.IsActive || pair.BroadPhaseOverlap.entryB.IsActive))
{
narrowPhasePairs.FastRemoveAt(i);
OnRemovePair(pair);
}
else
{
pair.NeedsUpdate = true;
}
}
}
internal void RemovePair(CollidablePairHandler pair, ref int index)
{
if (pairs.count > index)
{
pairs.FastRemoveAt(index);
if (pairs.count > index)
{
var endPair = pairs.Elements[index];
if (endPair.CollidableA == this)
{
endPair.listIndexA = index;
}
else
{
endPair.listIndexB = index;
}
}
}
index = -1;
}
public override void Update(float dt)
{
for (int i = removedEntities.Count - 1; i >= 0; --i)
{
if (random.NextDouble() < 0.2)
{
var entity = removedEntities[i];
addedEntities.Add(entity);
Space.Add(entity);
removedEntities.FastRemoveAt(i);
}
}
for (int i = addedEntities.Count - 1; i >= 0; --i)
{
if (random.NextDouble() < 0.02)
{
var entity = addedEntities[i];
removedEntities.Add(entity);
Space.Remove(entity);
addedEntities.FastRemoveAt(i);
}
}
if (Game.MouseInput.MiddleButton != Microsoft.Xna.Framework.Input.ButtonState.Pressed)
{
for (int i = 0; i < 20; i++)
{
var entity = addedEntities[random.Next(addedEntities.Count)];
entity.Position = new Vector3(
(float)(random.NextDouble() - 0.5f) * width,
(float)(random.NextDouble() - 0.5f) * height,
(float)(random.NextDouble() - 0.5f) * length);
}
}
base.Update(dt);
}
private static void RemoveInsidePoints(RawList <Vector3> points, RawList <int> triangleIndices,
RawList <int> outsidePoints)
{
RawList <int> insidePoints = CommonResources.GetIntList();
//We're going to remove points from this list as we go to prune it down to the truly inner points.
insidePoints.AddRange(outsidePoints);
outsidePoints.Clear();
for (int i = 0; i < triangleIndices.Count && insidePoints.Count > 0; i += 3)
{
//Compute the triangle's plane in point-normal representation to test other points against.
Vector3 normal;
FindNormal(triangleIndices, points, i, out normal);
Vector3 p = points.Elements[triangleIndices.Elements[i]];
for (int j = insidePoints.Count - 1; j >= 0; --j)
{
//Offset from the triangle to the current point, tested against the normal, determines if the current point is visible
//from the triangle face.
Vector3 offset;
Vector3.Subtract(ref points.Elements[insidePoints.Elements[j]], ref p, out offset);
float dot;
Vector3.Dot(ref offset, ref normal, out dot);
//If it's visible, then it's outside!
if (dot > 0)
{
//This point is known to be on the outside; put it on the outside!
outsidePoints.Add(insidePoints.Elements[j]);
insidePoints.FastRemoveAt(j);
}
}
}
CommonResources.GiveBack(insidePoints);
}
/// <summary>
/// Constructs a new demo.
/// </summary>
/// <param name="game">Game owning this demo.</param>
public MutableStaticGroupTestDemo(DemosGame game)
: base(game)
{
//Creating a bunch of separate StaticMeshes or kinematic Entity objects for an environment can pollute the broad phase.
//This is because the broad phase implementation doesn't have guarantees about what elements can collide, so it has to
//traverse the acceleration structure all the way down to pairs to figure it out. That can get expensive!
//Individual objects, like StaticMeshes, can have very complicated geometry without hurting the broad phase because the broad phase
//has no knowledge of the thousands of triangles in the mesh. The StaticMesh itself knows that the triangles within the mesh
//never need to collide, so it never needs to test them against each other.
//Similarly, the StaticGroup can be given a bunch of separate collidables. The broad phase doesn't directly know about these child collidables-
//it only sees the StaticGroup. The StaticGroup knows that the things inside it can't ever collide with each other, so no tests are needed.
//This avoids the performance problem!
//To demonstrate, we'll be creating a set of static objects and giving them to a group to manage.
var collidables = new List<Collidable>();
//Start with a whole bunch of boxes. These are entity collidables, but without entities!
float xSpacing = 6;
float ySpacing = 6;
float zSpacing = 6;
//NOTE: You might notice this demo takes a while to start, especially on the Xbox360. Do not fear! That's due to the creation of the graphics data, not the physics.
//The physics can handle over 100,000 static objects pretty easily. The graphics, not so much :)
//Try disabling the game.ModelDrawer.Add() lines and increasing the number of static objects.
int xCount = 15;
int yCount = 7;
int zCount = 15;
var random = new Random(5);
for (int i = 0; i < xCount; i++)
{
for (int j = 0; j < yCount; j++)
{
for (int k = 0; k < zCount; k++)
{
//Create a transform and the instance of the mesh.
var collidable = new ConvexCollidable<BoxShape>(new BoxShape((float)random.NextDouble() * 6 + .5f, (float)random.NextDouble() * 6 + .5f, (float)random.NextDouble() * 6 + .5f));
//This EntityCollidable isn't associated with an entity, so we must manually tell it where to sit by setting the WorldTransform.
//This also updates its bounding box.
collidable.WorldTransform = new RigidTransform(
new Vector3(i * xSpacing - xCount * xSpacing * .5f, j * ySpacing + 3, k * zSpacing - zCount * zSpacing * .5f),
Quaternion.CreateFromAxisAngle(Vector3.Normalize(new Vector3((float)random.NextDouble(), (float)random.NextDouble(), (float)random.NextDouble())), (float)random.NextDouble() * 100));
collidables.Add(collidable);
}
}
}
//Now create a bunch of instanced meshes too.
xSpacing = 6;
ySpacing = 6;
zSpacing = 6;
xCount = 10;
yCount = 2;
zCount = 10;
Vector3[] vertices;
int[] indices;
ModelDataExtractor.GetVerticesAndIndicesFromModel(game.Content.Load<Model>("fish"), out vertices, out indices);
var meshShape = new InstancedMeshShape(vertices, indices);
for (int i = 0; i < xCount; i++)
{
for (int j = 0; j < yCount; j++)
{
for (int k = 0; k < zCount; k++)
{
//Create a transform and the instance of the mesh.
var transform = new AffineTransform(
new Vector3((float)random.NextDouble() * 6 + .5f, (float)random.NextDouble() * 6 + .5f, (float)random.NextDouble() * 6 + .5f),
Quaternion.CreateFromAxisAngle(Vector3.Normalize(new Vector3((float)random.NextDouble(), (float)random.NextDouble(), (float)random.NextDouble())), (float)random.NextDouble() * 100),
new Vector3(i * xSpacing - xCount * xSpacing * .5f, j * ySpacing + 50, k * zSpacing - zCount * zSpacing * .5f));
var mesh = new InstancedMesh(meshShape, transform);
//Making the triangles one-sided makes collision detection a bit more robust, since the backsides of triangles won't try to collide with things
//and 'pull' them back into the mesh.
mesh.Sidedness = TriangleSidedness.Counterclockwise;
collidables.Add(mesh);
}
}
}
var ground = new ConvexCollidable<BoxShape>(new BoxShape(200, 1, 200));
ground.WorldTransform = new RigidTransform(new Vector3(0, -3, 0), Quaternion.Identity);
collidables.Add(ground);
var group = new StaticGroup(collidables);
var removed = new RawList<Collidable>();
var contained = new RawList<Collidable>();
group.Shape.CollidableTree.CollectLeaves(contained);
for (int i = 0; i < 100000; ++i)
{
for (int collidableIndex = contained.Count - 1; collidableIndex >= 0; --collidableIndex)
{
if (random.NextDouble() < 0.6)
{
group.Shape.Remove(contained[collidableIndex]);
removed.Add(contained[collidableIndex]);
contained.FastRemoveAt(collidableIndex);
}
}
for (int collidableIndex = removed.Count - 1; collidableIndex >= 0; --collidableIndex)
{
if (random.NextDouble() < 0.4)
{
group.Shape.Add(removed[collidableIndex]);
contained.Add(removed[collidableIndex]);
removed.FastRemoveAt(collidableIndex);
}
}
}
for (int i = 0; i < contained.Count; ++i)
{
game.ModelDrawer.Add(contained[i]);
}
Space.Add(group);
//Create a bunch of dynamic boxes to drop on the staticswarm.
xCount = 8;
yCount = 3;
zCount = 8;
xSpacing = 3f;
ySpacing = 5f;
zSpacing = 3f;
for (int i = 0; i < xCount; i++)
for (int j = 0; j < zCount; j++)
for (int k = 0; k < yCount; k++)
{
Space.Add(new Box(new Vector3(
xSpacing * i - (xCount - 1) * xSpacing / 2f,
100 + k * (ySpacing),
2 + zSpacing * j - (zCount - 1) * zSpacing / 2f),
1, 1, 1, 10));
}
game.Camera.Position = new Vector3(0, 60, 90);
}
/// <summary>
/// Identifies the indices of points in a set which are on the outer convex hull of the set.
/// </summary>
/// <param name="points">List of points in the set.</param>
/// <param name="outputTriangleIndices">List of indices into the input point set composing the triangulated surface of the convex hull.
/// Each group of 3 indices represents a triangle on the surface of the hull.</param>
public static void GetConvexHull(RawList <Vector3> points, RawList <int> outputTriangleIndices)
{
if (points.Count == 0)
{
throw new ArgumentException("Point set must have volume.");
}
RawList <int> outsidePoints = CommonResources.GetIntList();
if (outsidePoints.Capacity < points.Count - 4)
{
outsidePoints.Capacity = points.Count - 4;
}
//Build the initial tetrahedron.
//It will also give us the location of a point which is guaranteed to be within the
//final convex hull. We can use this point to calibrate the winding of triangles.
//A set of outside point candidates (all points other than those composing the tetrahedron) will be returned in the outsidePoints list.
//That list will then be further pruned by the RemoveInsidePoints call.
Vector3 insidePoint;
ComputeInitialTetrahedron(points, outsidePoints, outputTriangleIndices, out insidePoint);
//Compute outside points.
RemoveInsidePoints(points, outputTriangleIndices, outsidePoints);
var edges = CommonResources.GetIntList();
var toRemove = CommonResources.GetIntList();
var newTriangles = CommonResources.GetIntList();
//We're now ready to begin the main loop.
while (outsidePoints.Count > 0)
{
//While the convex hull is incomplete...
for (int k = 0; k < outputTriangleIndices.Count; k += 3)
{
//Find the normal of the triangle
Vector3 normal;
FindNormal(outputTriangleIndices, points, k, out normal);
//Get the furthest point in the direction of the normal.
int maxIndexInOutsideList = GetExtremePoint(ref normal, points, outsidePoints);
int maxIndex = outsidePoints.Elements[maxIndexInOutsideList];
Vector3 maximum = points.Elements[maxIndex];
//If the point is beyond the current triangle, continue.
Vector3 offset;
Vector3.Subtract(ref maximum, ref points.Elements[outputTriangleIndices.Elements[k]], out offset);
float dot;
Vector3.Dot(ref normal, ref offset, out dot);
if (dot > 0)
{
//It's been picked! Remove the maximum point from the outside.
outsidePoints.FastRemoveAt(maxIndexInOutsideList);
//Remove any triangles that can see the point, including itself!
edges.Clear();
toRemove.Clear();
for (int n = outputTriangleIndices.Count - 3; n >= 0; n -= 3)
{
//Go through each triangle, if it can be seen, delete it and use maintainEdge on its edges.
if (IsTriangleVisibleFromPoint(outputTriangleIndices, points, n, ref maximum))
{
//This triangle can see it!
//TODO: CONSIDER CONSISTENT WINDING HAPPYTIMES
MaintainEdge(outputTriangleIndices[n], outputTriangleIndices[n + 1], edges);
MaintainEdge(outputTriangleIndices[n], outputTriangleIndices[n + 2], edges);
MaintainEdge(outputTriangleIndices[n + 1], outputTriangleIndices[n + 2], edges);
//Because fast removals are being used, the order is very important.
//It's pulling indices in from the end of the list in order, and also ensuring
//that we never issue a removal order beyond the end of the list.
outputTriangleIndices.FastRemoveAt(n + 2);
outputTriangleIndices.FastRemoveAt(n + 1);
outputTriangleIndices.FastRemoveAt(n);
}
}
//Create new triangles.
for (int n = 0; n < edges.Count; n += 2)
{
//For each edge, create a triangle with the extreme point.
newTriangles.Add(edges[n]);
newTriangles.Add(edges[n + 1]);
newTriangles.Add(maxIndex);
}
//Only verify the windings of the new triangles.
VerifyWindings(newTriangles, points, ref insidePoint);
outputTriangleIndices.AddRange(newTriangles);
newTriangles.Clear();
//Remove all points from the outsidePoints if they are inside the polyhedron
RemoveInsidePoints(points, outputTriangleIndices, outsidePoints);
//The list has been significantly messed with, so restart the loop.
break;
}
}
}
CommonResources.GiveBack(outsidePoints);
CommonResources.GiveBack(edges);
CommonResources.GiveBack(toRemove);
CommonResources.GiveBack(newTriangles);
}
public override void Update(float dt)
{
//Add previously removed characters.
for (int i = removedCharacters.Count - 1; i >= 0; --i)
{
if (random.NextDouble() < 0.2)
{
Space.Add(removedCharacters[i]);
removedCharacters.FastRemoveAt(i);
}
}
for (int i = removedSphereCharacters.Count - 1; i >= 0; --i)
{
if (random.NextDouble() < 0.2)
{
Space.Add(removedSphereCharacters[i]);
removedSphereCharacters.FastRemoveAt(i);
}
}
//Tell all the characters to run around randomly.
for (int i = 0; i < characters.Count; i++)
{
if (characters[i].Space != null)
{
if (random.NextDouble() < 0.02)
{
removedCharacters.Add(characters[i]);
Space.Remove(characters[i]);
}
else
{
characters[i].HorizontalMotionConstraint.MovementDirection = new Vector2((float)(random.NextDouble() * 2 - 1), (float)(random.NextDouble() * 2 - 1));
if (random.NextDouble() < .01f)
{
characters[i].Jump();
}
var next = random.NextDouble();
if (next < .01)
{
//Note: The character's graphic won't represent the crouching process properly since we're not remove/readding it.
if (next < .005f && characters[i].StanceManager.CurrentStance == Stance.Standing)
{
characters[i].StanceManager.DesiredStance = Stance.Crouching;
}
else
{
characters[i].StanceManager.DesiredStance = Stance.Standing;
}
}
}
}
}
//Tell the sphere characters to run around too.
for (int i = 0; i < sphereCharacters.Count; i++)
{
if (sphereCharacters[i].Space != null)
{
if (random.NextDouble() < 0.02)
{
removedSphereCharacters.Add(sphereCharacters[i]);
Space.Remove(sphereCharacters[i]);
}
else
{
sphereCharacters[i].HorizontalMotionConstraint.MovementDirection = new Vector2((float)(random.NextDouble() * 2 - 1), (float)(random.NextDouble() * 2 - 1));
if (random.NextDouble() < .01f)
{
sphereCharacters[i].Jump();
}
}
}
}
base.Update(dt);
}
private static void MaintainEdge(int a, int b, RawList<int> edges)
{
bool contained = false;
int index = 0;
for (int k = 0; k < edges.Count; k += 2)
{
if ((edges[k] == a && edges[k + 1] == b) || (edges[k] == b && edges[k + 1] == a))
{
contained = true;
index = k;
}
}
//If it isn't present, add it to the edge list.
if (!contained)
{
edges.Add(a);
edges.Add(b);
}
else
{
//If it is present, that means both edge-connected triangles were deleted now, so get rid of it.
edges.FastRemoveAt(index + 1);
edges.FastRemoveAt(index);
}
}
/// <summary>
/// Identifies the indices of points in a set which are on the outer convex hull of the set.
/// </summary>
/// <param name="points">List of points in the set.</param>
/// <param name="outputTriangleIndices">List of indices composing the triangulated surface of the convex hull.
/// Each group of 3 indices represents a triangle on the surface of the hull.</param>
public static void GetConvexHull(RawList<Vector3> points, RawList<int> outputTriangleIndices)
{
if (points.Count == 0)
{
throw new ArgumentException("Point set must have volume.");
}
RawList<int> outsidePoints = CommonResources.GetIntList();
if (outsidePoints.Capacity < points.Count - 4)
outsidePoints.Capacity = points.Count - 4;
//Build the initial tetrahedron.
//It will also give us the location of a point which is guaranteed to be within the
//final convex hull. We can use this point to calibrate the winding of triangles.
//A set of outside point candidates (all points other than those composing the tetrahedron) will be returned in the outsidePoints list.
//That list will then be further pruned by the RemoveInsidePoints call.
Vector3 insidePoint;
ComputeInitialTetrahedron(points, outsidePoints, outputTriangleIndices, out insidePoint);
//Compute outside points.
RemoveInsidePoints(points, outputTriangleIndices, outsidePoints);
var edges = CommonResources.GetIntList();
var toRemove = CommonResources.GetIntList();
var newTriangles = CommonResources.GetIntList();
//We're now ready to begin the main loop.
while (outsidePoints.Count > 0)
{
//While the convex hull is incomplete...
for (int k = 0; k < outputTriangleIndices.Count; k += 3)
{
//Find the normal of the triangle
Vector3 normal;
FindNormal(outputTriangleIndices, points, k, out normal);
//Get the furthest point in the direction of the normal.
int maxIndexInOutsideList = GetExtremePoint(ref normal, points, outsidePoints);
int maxIndex = outsidePoints.Elements[maxIndexInOutsideList];
Vector3 maximum = points.Elements[maxIndex];
//If the point is beyond the current triangle, continue.
Vector3 offset;
Vector3.Subtract(ref maximum, ref points.Elements[outputTriangleIndices.Elements[k]], out offset);
float dot;
Vector3.Dot(ref normal, ref offset, out dot);
if (dot > 0)
{
//It's been picked! Remove the maximum point from the outside.
outsidePoints.FastRemoveAt(maxIndexInOutsideList);
//Remove any triangles that can see the point, including itself!
edges.Clear();
toRemove.Clear();
for (int n = outputTriangleIndices.Count - 3; n >= 0; n -= 3)
{
//Go through each triangle, if it can be seen, delete it and use maintainEdge on its edges.
if (IsTriangleVisibleFromPoint(outputTriangleIndices, points, n, ref maximum))
{
//This triangle can see it!
//TODO: CONSIDER CONSISTENT WINDING HAPPYTIMES
MaintainEdge(outputTriangleIndices[n], outputTriangleIndices[n + 1], edges);
MaintainEdge(outputTriangleIndices[n], outputTriangleIndices[n + 2], edges);
MaintainEdge(outputTriangleIndices[n + 1], outputTriangleIndices[n + 2], edges);
//Because fast removals are being used, the order is very important.
//It's pulling indices in from the end of the list in order, and also ensuring
//that we never issue a removal order beyond the end of the list.
outputTriangleIndices.FastRemoveAt(n + 2);
outputTriangleIndices.FastRemoveAt(n + 1);
outputTriangleIndices.FastRemoveAt(n);
}
}
//Create new triangles.
for (int n = 0; n < edges.Count; n += 2)
{
//For each edge, create a triangle with the extreme point.
newTriangles.Add(edges[n]);
newTriangles.Add(edges[n + 1]);
newTriangles.Add(maxIndex);
}
//Only verify the windings of the new triangles.
VerifyWindings(newTriangles, points, ref insidePoint);
outputTriangleIndices.AddRange(newTriangles);
newTriangles.Clear();
//Remove all points from the outsidePoints if they are inside the polyhedron
RemoveInsidePoints(points, outputTriangleIndices, outsidePoints);
//The list has been significantly messed with, so restart the loop.
break;
}
}
}
CommonResources.GiveBack(outsidePoints);
CommonResources.GiveBack(edges);
CommonResources.GiveBack(toRemove);
CommonResources.GiveBack(newTriangles);
}
/// <summary>
/// Constructs a new demo.
/// </summary>
/// <param name="game">Game owning this demo.</param>
public MutableStaticGroupTestDemo(DemosGame game)
: base(game)
{
//Creating a bunch of separate StaticMeshes or kinematic Entity objects for an environment can pollute the broad phase.
//This is because the broad phase implementation doesn't have guarantees about what elements can collide, so it has to
//traverse the acceleration structure all the way down to pairs to figure it out. That can get expensive!
//Individual objects, like StaticMeshes, can have very complicated geometry without hurting the broad phase because the broad phase
//has no knowledge of the thousands of triangles in the mesh. The StaticMesh itself knows that the triangles within the mesh
//never need to collide, so it never needs to test them against each other.
//Similarly, the StaticGroup can be given a bunch of separate collidables. The broad phase doesn't directly know about these child collidables-
//it only sees the StaticGroup. The StaticGroup knows that the things inside it can't ever collide with each other, so no tests are needed.
//This avoids the performance problem!
//To demonstrate, we'll be creating a set of static objects and giving them to a group to manage.
var collidables = new List <Collidable>();
//Start with a whole bunch of boxes. These are entity collidables, but without entities!
Fix64 xSpacing = 6;
Fix64 ySpacing = 6;
Fix64 zSpacing = 6;
//NOTE: You might notice this demo takes a while to start, especially on the Xbox360. Do not fear! That's due to the creation of the graphics data, not the physics.
//The physics can handle over 100,000 static objects pretty easily. The graphics, not so much :)
//Try disabling the game.ModelDrawer.Add() lines and increasing the number of static objects.
int xCount = 15;
int yCount = 7;
int zCount = 15;
var random = new Random(5);
for (int i = 0; i < xCount; i++)
{
for (int j = 0; j < yCount; j++)
{
for (int k = 0; k < zCount; k++)
{
//Create a transform and the instance of the mesh.
var collidable = new ConvexCollidable <BoxShape>(new BoxShape((Fix64)random.NextDouble() * 6 + .5m, (Fix64)random.NextDouble() * 6 + .5m, (Fix64)random.NextDouble() * 6 + .5m));
//This EntityCollidable isn't associated with an entity, so we must manually tell it where to sit by setting the WorldTransform.
//This also updates its bounding box.
collidable.WorldTransform = new RigidTransform(
new Vector3(i * xSpacing - xCount * xSpacing * .5m, j * ySpacing + 3, k * zSpacing - zCount * zSpacing * .5m),
Quaternion.CreateFromAxisAngle(Vector3.Normalize(new Vector3((Fix64)random.NextDouble(), (Fix64)random.NextDouble(), (Fix64)random.NextDouble())), (Fix64)random.NextDouble() * 100));
collidables.Add(collidable);
}
}
}
//Now create a bunch of instanced meshes too.
xSpacing = 6;
ySpacing = 6;
zSpacing = 6;
xCount = 10;
yCount = 2;
zCount = 10;
Vector3[] vertices;
int[] indices;
ModelDataExtractor.GetVerticesAndIndicesFromModel(game.Content.Load <Model>("fish"), out vertices, out indices);
var meshShape = new InstancedMeshShape(vertices, indices);
for (int i = 0; i < xCount; i++)
{
for (int j = 0; j < yCount; j++)
{
for (int k = 0; k < zCount; k++)
{
//Create a transform and the instance of the mesh.
var transform = new AffineTransform(
new Vector3((Fix64)random.NextDouble() * 6 + .5m, (Fix64)random.NextDouble() * 6 + .5m, (Fix64)random.NextDouble() * 6 + .5m),
Quaternion.CreateFromAxisAngle(Vector3.Normalize(new Vector3((Fix64)random.NextDouble(), (Fix64)random.NextDouble(), (Fix64)random.NextDouble())), (Fix64)random.NextDouble() * 100),
new Vector3(i * xSpacing - xCount * xSpacing * .5m, j * ySpacing + 50, k * zSpacing - zCount * zSpacing * .5m));
var mesh = new InstancedMesh(meshShape, transform);
//Making the triangles one-sided makes collision detection a bit more robust, since the backsides of triangles won't try to collide with things
//and 'pull' them back into the mesh.
mesh.Sidedness = TriangleSidedness.Counterclockwise;
collidables.Add(mesh);
}
}
}
var ground = new ConvexCollidable <BoxShape>(new BoxShape(200, 1, 200));
ground.WorldTransform = new RigidTransform(new Vector3(0, -3, 0), Quaternion.Identity);
collidables.Add(ground);
var group = new StaticGroup(collidables);
var removed = new RawList <Collidable>();
var contained = new RawList <Collidable>();
group.Shape.CollidableTree.CollectLeaves(contained);
for (int i = 0; i < 100000; ++i)
{
for (int collidableIndex = contained.Count - 1; collidableIndex >= 0; --collidableIndex)
{
if (random.NextDouble() < 0.6)
{
group.Shape.Remove(contained[collidableIndex]);
removed.Add(contained[collidableIndex]);
contained.FastRemoveAt(collidableIndex);
}
}
for (int collidableIndex = removed.Count - 1; collidableIndex >= 0; --collidableIndex)
{
if (random.NextDouble() < 0.4)
{
group.Shape.Add(removed[collidableIndex]);
contained.Add(removed[collidableIndex]);
removed.FastRemoveAt(collidableIndex);
}
}
}
for (int i = 0; i < contained.Count; ++i)
{
game.ModelDrawer.Add(contained[i]);
}
Space.Add(group);
//Create a bunch of dynamic boxes to drop on the staticswarm.
xCount = 8;
yCount = 3;
zCount = 8;
xSpacing = 3;
ySpacing = 5;
zSpacing = 3;
for (int i = 0; i < xCount; i++)
{
for (int j = 0; j < zCount; j++)
{
for (int k = 0; k < yCount; k++)
{
Space.Add(new Box(new Vector3(
xSpacing * i - (xCount - 1) * xSpacing / 2,
100 + k * (ySpacing),
2 + zSpacing * j - (zCount - 1) * zSpacing / 2),
1, 1, 1, 10));
}
}
}
game.Camera.Position = new Vector3(0, 60, 90);
}