/// <summary> /// Removes a child from a compound body. /// </summary> /// <param name="childContributions">List of distribution information associated with each child shape of the whole compound shape used by the compound being split.</param> /// <param name="removalPredicate">Delegate which determines if a child in the original compound should be moved to the new compound.</param> /// <param name="distributionInfo">Volume, volume distribution, and center information about the new form of the original compound collidable.</param> /// <param name="compound">Original compound to have a child removed.</param> /// <returns>Whether or not the predicate returned true for any element in the original compound and split the compound.</returns> public static bool RemoveChildFromCompound(Entity <CompoundCollidable> compound, Func <CompoundChild, bool> removalPredicate, IList <ShapeDistributionInformation> childContributions, out ShapeDistributionInformation distributionInfo) { float weight; float removedWeight; Vector3 removedCenter; if (RemoveChildFromCompound(compound.CollisionInformation, removalPredicate, childContributions, out distributionInfo, out weight, out removedWeight, out removedCenter)) { //Reconfigure the entities using the data computed in the split. //Only bother if there are any children left in the compound! if (compound.CollisionInformation.Children.Count > 0) { float originalMass = compound.mass; float newMass = (weight / (weight + removedWeight)) * originalMass; Matrix3X3.Multiply(ref distributionInfo.VolumeDistribution, newMass * InertiaHelper.InertiaTensorScale, out distributionInfo.VolumeDistribution); compound.Initialize(compound.CollisionInformation, newMass, distributionInfo.VolumeDistribution, distributionInfo.Volume); RemoveReposition(compound, ref distributionInfo, weight, removedWeight, ref removedCenter); } return(true); } else { return(false); } }
/// <summary> /// Splits a single compound collidable into two separate compound collidables and computes information needed by the simulation. /// </summary> /// <param name="childContributions">List of distribution information associated with each child shape of the whole compound shape used by the compound being split.</param> /// <param name="splitPredicate">Delegate which determines if a child in the original compound should be moved to the new compound.</param> /// <param name="a">Original compound to be split. Children in this compound will be removed and added to the other compound.</param> /// <param name="b">Compound to receive children removed from the original compound.</param> /// <param name="distributionInfoA">Volume, volume distribution, and center information about the new form of the original compound collidable.</param> /// <param name="distributionInfoB">Volume, volume distribution, and center information about the new compound collidable.</param> /// <returns>Whether or not the predicate returned true for any element in the original compound and split the compound.</returns> public static bool SplitCompound(IList <ShapeDistributionInformation> childContributions, Func <CompoundChild, bool> splitPredicate, Entity <CompoundCollidable> a, out Entity <CompoundCollidable> b, out ShapeDistributionInformation distributionInfoA, out ShapeDistributionInformation distributionInfoB) { CompoundCollidable bCollidable = new CompoundCollidable(); bCollidable.Shape = a.CollisionInformation.Shape; b = new Entity <CompoundCollidable>(); float weightA, weightB; if (SplitCompound(childContributions, splitPredicate, a.CollisionInformation, bCollidable, out distributionInfoA, out distributionInfoB, out weightA, out weightB)) { //Reconfigure the entities using the data computed in the split. float originalMass = a.mass; float newMassA = (weightA / (weightA + weightB)) * originalMass; Matrix3X3.Multiply(ref distributionInfoA.VolumeDistribution, newMassA * InertiaHelper.InertiaTensorScale, out distributionInfoA.VolumeDistribution); a.Initialize(a.CollisionInformation, newMassA, distributionInfoA.VolumeDistribution, distributionInfoA.Volume); float newMassB = (weightB / (weightA + weightB)) * originalMass; Matrix3X3.Multiply(ref distributionInfoB.VolumeDistribution, newMassB * InertiaHelper.InertiaTensorScale, out distributionInfoB.VolumeDistribution); b.Initialize(bCollidable, newMassB, distributionInfoB.VolumeDistribution, distributionInfoB.Volume); Reposition(a, b, ref distributionInfoA, ref distributionInfoB, weightA, weightB); return(true); } else { return(false); } }
static void RemoveReposition(Entity compound, ref ShapeDistributionInformation distributionInfo, float weight, float removedWeight, ref Vector3 removedCenter) { //The compounds are not aligned with the original's position yet. //In order to align them, first look at the centers the split method computed. //They are offsets from the center of the original shape in local space. //These can be used to reposition the objects in world space. Vector3 weightedA, weightedB; Vector3.Multiply(ref distributionInfo.Center, weight, out weightedA); Vector3.Multiply(ref removedCenter, removedWeight, out weightedB); Vector3 newLocalCenter; Vector3.Add(ref weightedA, ref weightedB, out newLocalCenter); Vector3.Divide(ref newLocalCenter, weight + removedWeight, out newLocalCenter); Vector3 localOffset; Vector3.Subtract(ref distributionInfo.Center, ref newLocalCenter, out localOffset); Vector3 originalPosition = compound.position; Vector3 offset = Vector3.Transform(localOffset, compound.orientation); compound.Position = originalPosition + offset; Vector3 originalLinearVelocity = compound.linearVelocity; Vector3 originalAngularVelocity = compound.angularVelocity; compound.AngularVelocity = originalAngularVelocity; compound.LinearVelocity = originalLinearVelocity + Vector3.Cross(originalAngularVelocity, offset); }
/// <summary> /// Splits a single compound collidable into two separate compound collidables and computes information needed by the simulation. /// </summary> /// <param name="splitPredicate">Delegate which determines if a child in the original compound should be moved to the new compound.</param> /// <param name="distributionInfoA">Volume, volume distribution, and center information about the new form of the original compound collidable.</param> /// <param name="distributionInfoB">Volume, volume distribution, and center information about the new compound collidable.</param> /// <param name="a">Original compound to be split. Children in this compound will be removed and added to the other compound.</param> /// <param name="b">Compound to receive children removed from the original compound.</param> /// <returns>Whether or not the predicate returned true for any element in the original compound and split the compound.</returns> public static bool SplitCompound(Func <CompoundChild, bool> splitPredicate, Entity <CompoundCollidable> a, Entity <CompoundCollidable> b, out ShapeDistributionInformation distributionInfoA, out ShapeDistributionInformation distributionInfoB) { float weightA, weightB; if (SplitCompound(splitPredicate, a.CollisionInformation, b.CollisionInformation, out distributionInfoA, out distributionInfoB, out weightA, out weightB)) { //Reconfigure the entities using the data computed in the split. float originalMass = a.mass; if (a.CollisionInformation.children.Count > 0) { float newMassA = (weightA / (weightA + weightB)) * originalMass; Matrix3x3.Multiply(ref distributionInfoA.VolumeDistribution, newMassA * InertiaHelper.InertiaTensorScale, out distributionInfoA.VolumeDistribution); a.Initialize(a.CollisionInformation, newMassA, distributionInfoA.VolumeDistribution); } if (b.CollisionInformation.children.Count > 0) { float newMassB = (weightB / (weightA + weightB)) * originalMass; Matrix3x3.Multiply(ref distributionInfoB.VolumeDistribution, newMassB * InertiaHelper.InertiaTensorScale, out distributionInfoB.VolumeDistribution); b.Initialize(b.CollisionInformation, newMassB, distributionInfoB.VolumeDistribution); } SplitReposition(a, b, ref distributionInfoA, ref distributionInfoB, weightA, weightB); return(true); } return(false); }
static void SplitReposition(Entity a, Entity b, ref ShapeDistributionInformation distributionInfoA, ref ShapeDistributionInformation distributionInfoB, float weightA, float weightB) { //The compounds are not aligned with the original's position yet. //In order to align them, first look at the centers the split method computed. //They are offsets from the center of the original shape in local space. //These can be used to reposition the objects in world space. System.Numerics.Vector3 weightedA, weightedB; Vector3Ex.Multiply(ref distributionInfoA.Center, weightA, out weightedA); Vector3Ex.Multiply(ref distributionInfoB.Center, weightB, out weightedB); System.Numerics.Vector3 newLocalCenter; Vector3Ex.Add(ref weightedA, ref weightedB, out newLocalCenter); Vector3Ex.Divide(ref newLocalCenter, weightA + weightB, out newLocalCenter); System.Numerics.Vector3 localOffsetA; System.Numerics.Vector3 localOffsetB; Vector3Ex.Subtract(ref distributionInfoA.Center, ref newLocalCenter, out localOffsetA); Vector3Ex.Subtract(ref distributionInfoB.Center, ref newLocalCenter, out localOffsetB); System.Numerics.Vector3 originalPosition = a.position; b.Orientation = a.Orientation; System.Numerics.Vector3 offsetA = QuaternionEx.Transform(localOffsetA, a.Orientation); System.Numerics.Vector3 offsetB = QuaternionEx.Transform(localOffsetB, a.Orientation); a.Position = originalPosition + offsetA; b.Position = originalPosition + offsetB; System.Numerics.Vector3 originalLinearVelocity = a.linearVelocity; System.Numerics.Vector3 originalAngularVelocity = a.angularVelocity; a.AngularVelocity = originalAngularVelocity; b.AngularVelocity = originalAngularVelocity; a.LinearVelocity = originalLinearVelocity + System.Numerics.Vector3.Cross(originalAngularVelocity, offsetA); b.LinearVelocity = originalLinearVelocity + System.Numerics.Vector3.Cross(originalAngularVelocity, offsetB); }
static void Reposition(Entity a, Entity b, ref ShapeDistributionInformation distributionInfoA, ref ShapeDistributionInformation distributionInfoB, float weightA, float weightB) { //The compounds are not aligned with the original's position yet. //In order to align them, first look at the centers the split method computed. //They are offsets from the center of the original shape in local space. //These can be used to reposition the objects in world space. Vector3 weightedA, weightedB; Vector3.Multiply(ref distributionInfoA.Center, weightA, out weightedA); Vector3.Multiply(ref distributionInfoB.Center, weightB, out weightedB); Vector3 newLocalCenter; Vector3.Add(ref weightedA, ref weightedB, out newLocalCenter); Vector3.Divide(ref newLocalCenter, weightA + weightB, out newLocalCenter); Vector3 localOffsetA; Vector3 localOffsetB; Vector3.Subtract(ref distributionInfoA.Center, ref newLocalCenter, out localOffsetA); Vector3.Subtract(ref distributionInfoB.Center, ref newLocalCenter, out localOffsetB); Vector3 originalPosition = a.position; b.Orientation = a.Orientation; //Imagine a split that does not occur right down the middle, but along a far side: (oo - (o - o)) //Both distributions will be positive. Only the first split works properly because there the position //was aligned with the local space origin. Vector3 offsetA = Vector3.Transform(localOffsetA, a.Orientation); Vector3 offsetB = Vector3.Transform(localOffsetB, a.Orientation); a.Position = originalPosition + offsetA; b.Position = originalPosition + offsetB; Vector3 originalLinearVelocity = a.linearVelocity; Vector3 originalAngularVelocity = a.angularVelocity; a.AngularVelocity = originalAngularVelocity; b.AngularVelocity = originalAngularVelocity; a.LinearVelocity = originalLinearVelocity + Vector3.Cross(originalAngularVelocity, offsetA); b.LinearVelocity = originalLinearVelocity + Vector3.Cross(originalAngularVelocity, offsetB); }
public override void ComputeDistributionInformation(out ShapeDistributionInformation shapeInfo) { shapeInfo.VolumeDistribution = ComputeVolumeDistribution(out shapeInfo.Volume); shapeInfo.Center = ComputeCenter(); }
/// <summary> /// Splits a single compound collidable into two separate compound collidables and computes information needed by the simulation. /// </summary> /// <param name="childContributions">List of distribution information associated with each child shape of the whole compound shape used by the compound being split.</param> /// <param name="splitPredicate">Delegate which determines if a child in the original compound should be moved to the new compound.</param> /// <param name="a">Original compound to be split. Children in this compound will be removed and added to the other compound.</param> /// <param name="b">Compound to receive children removed from the original compound.</param> /// <param name="distributionInfoA">Volume, volume distribution, and center information about the new form of the original compound collidable.</param> /// <param name="distributionInfoB">Volume, volume distribution, and center information about the new compound collidable.</param> /// <param name="weightA">Total weight associated with the new form of the original compound collidable.</param> /// <param name="weightB">Total weight associated with the new compound collidable.</param> /// <returns>Whether or not the predicate returned true for any element in the original compound and split the compound.</returns> public static bool SplitCompound(IList <ShapeDistributionInformation> childContributions, Func <CompoundChild, bool> splitPredicate, CompoundCollidable a, CompoundCollidable b, out ShapeDistributionInformation distributionInfoA, out ShapeDistributionInformation distributionInfoB, out float weightA, out float weightB) { bool splitOccurred = false; for (int i = a.children.count - 1; i >= 0; i--) { //The shape doesn't change during this process. The entity could, though. //All of the other collidable information, like the Tag, CollisionRules, Events, etc. all stay the same. var child = a.children.Elements[i]; if (splitPredicate(child)) { splitOccurred = true; a.children.FastRemoveAt(i); b.children.Add(child); } } if (!splitOccurred) { //No split occurred, so we cannot proceed. distributionInfoA = new ShapeDistributionInformation(); distributionInfoB = new ShapeDistributionInformation(); weightA = 0; weightB = 0; return(false); } //Compute the contributions from the original shape to the new form of the original collidable. distributionInfoA = new ShapeDistributionInformation(); weightA = 0; distributionInfoB = new ShapeDistributionInformation(); weightB = 0; for (int i = a.children.count - 1; i >= 0; i--) { var child = a.children.Elements[i]; var entry = child.Entry; var contribution = childContributions[child.shapeIndex]; Vector3.Add(ref contribution.Center, ref entry.LocalTransform.Position, out contribution.Center); Vector3.Multiply(ref contribution.Center, child.Entry.Weight, out contribution.Center); Vector3.Add(ref contribution.Center, ref distributionInfoA.Center, out distributionInfoA.Center); distributionInfoA.Volume += contribution.Volume; weightA += entry.Weight; } for (int i = b.children.count - 1; i >= 0; i--) { var child = b.children.Elements[i]; var entry = child.Entry; var contribution = childContributions[child.shapeIndex]; Vector3.Add(ref contribution.Center, ref entry.LocalTransform.Position, out contribution.Center); Vector3.Multiply(ref contribution.Center, child.Entry.Weight, out contribution.Center); Vector3.Add(ref contribution.Center, ref distributionInfoB.Center, out distributionInfoB.Center); distributionInfoB.Volume += contribution.Volume; weightB += entry.Weight; } //Average the center out. Vector3.Divide(ref distributionInfoA.Center, weightA, out distributionInfoA.Center); Vector3.Divide(ref distributionInfoB.Center, weightB, out distributionInfoB.Center); //Note that the 'entry' is from the Shape, and so the translations are local to the shape's center. //That is not technically the center of the new collidable- distributionInfoA.Center is. //Offset the child collidables by -distributionInfoA.Center using their local offset. Vector3 offsetA; Vector3.Negate(ref distributionInfoA.Center, out offsetA); Vector3 offsetB; Vector3.Negate(ref distributionInfoB.Center, out offsetB); //Compute the unscaled inertia tensor. for (int i = a.children.count - 1; i >= 0; i--) { var child = a.children.Elements[i]; child.CollisionInformation.localPosition = offsetA; var entry = child.Entry; var contribution = childContributions[child.shapeIndex]; CompoundShape.TransformContribution(ref entry.LocalTransform, ref distributionInfoA.Center, ref contribution.VolumeDistribution, entry.Weight, out contribution.VolumeDistribution); Vector3.Add(ref entry.LocalTransform.Position, ref offsetA, out entry.LocalTransform.Position); Matrix3X3.Add(ref contribution.VolumeDistribution, ref distributionInfoA.VolumeDistribution, out distributionInfoA.VolumeDistribution); } for (int i = b.children.count - 1; i >= 0; i--) { var child = b.children.Elements[i]; child.CollisionInformation.localPosition = offsetB; var entry = child.Entry; var contribution = childContributions[child.shapeIndex]; CompoundShape.TransformContribution(ref entry.LocalTransform, ref distributionInfoB.Center, ref contribution.VolumeDistribution, entry.Weight, out contribution.VolumeDistribution); Vector3.Add(ref entry.LocalTransform.Position, ref offsetB, out entry.LocalTransform.Position); Matrix3X3.Add(ref contribution.VolumeDistribution, ref distributionInfoB.VolumeDistribution, out distributionInfoB.VolumeDistribution); } //Normalize the volume distribution. Matrix3X3.Multiply(ref distributionInfoA.VolumeDistribution, 1 / weightA, out distributionInfoA.VolumeDistribution); Matrix3X3.Multiply(ref distributionInfoB.VolumeDistribution, 1 / weightB, out distributionInfoB.VolumeDistribution); //Update the hierarchies of the compounds. //TODO: Create a new method that does this quickly without garbage. Requires a new Reconstruct method which takes a pool which stores the appropriate node types. a.hierarchy.Tree.Reconstruct(a.children); b.hierarchy.Tree.Reconstruct(b.children); return(true); }
/// <summary> /// Removes a child from a compound collidable. /// </summary> /// <param name="compound">Compound collidable to remove a child from.</param> /// <param name="removalPredicate">Callback which analyzes a child and determines if it should be removed from the compound.</param> /// <param name="childContributions">Distribution contributions from all shapes in the compound shape. This can include shapes which are not represented in the compound.</param> /// <param name="distributionInfo">Distribution information of the new compound.</param> /// <param name="weight">Total weight of the new compound.</param> /// <param name="removedWeight">Weight removed from the compound.</param> /// <param name="removedCenter">Center of the chunk removed from the compound.</param> /// <returns>Whether or not any removal took place.</returns> public static bool RemoveChildFromCompound(CompoundCollidable compound, Func <CompoundChild, bool> removalPredicate, IList <ShapeDistributionInformation> childContributions, out ShapeDistributionInformation distributionInfo, out float weight, out float removedWeight, out Vector3 removedCenter) { bool removalOccurred = false; removedWeight = 0; removedCenter = new Vector3(); for (int i = compound.children.count - 1; i >= 0; i--) { //The shape doesn't change during this process. The entity could, though. //All of the other collidable information, like the Tag, CollisionRules, Events, etc. all stay the same. var child = compound.children.Elements[i]; if (removalPredicate(child)) { removalOccurred = true; var entry = child.Entry; removedWeight += entry.Weight; Vector3 toAdd; Vector3.Multiply(ref entry.LocalTransform.Position, entry.Weight, out toAdd); Vector3.Add(ref removedCenter, ref toAdd, out removedCenter); //The child event handler must be unhooked from the compound. child.CollisionInformation.events.Parent = null; compound.children.FastRemoveAt(i); } } if (!removalOccurred) { //No removal occurred, so we cannot proceed. distributionInfo = new ShapeDistributionInformation(); weight = 0; return(false); } if (removedWeight > 0) { Vector3.Divide(ref removedCenter, removedWeight, out removedCenter); } //Compute the contributions from the original shape to the new form of the original collidable. distributionInfo = new ShapeDistributionInformation(); weight = 0; for (int i = compound.children.count - 1; i >= 0; i--) { var child = compound.children.Elements[i]; var entry = child.Entry; var contribution = childContributions[child.shapeIndex]; Vector3.Add(ref contribution.Center, ref entry.LocalTransform.Position, out contribution.Center); Vector3.Multiply(ref contribution.Center, child.Entry.Weight, out contribution.Center); Vector3.Add(ref contribution.Center, ref distributionInfo.Center, out distributionInfo.Center); distributionInfo.Volume += contribution.Volume; weight += entry.Weight; } //Average the center out. Vector3.Divide(ref distributionInfo.Center, weight, out distributionInfo.Center); //Note that the 'entry' is from the Shape, and so the translations are local to the shape's center. //That is not technically the center of the new collidable- distributionInfo.Center is. //Offset the child collidables by -distributionInfo.Center using their local offset. Vector3 offset; Vector3.Negate(ref distributionInfo.Center, out offset); //Compute the unscaled inertia tensor. for (int i = compound.children.count - 1; i >= 0; i--) { var child = compound.children.Elements[i]; var entry = child.Entry; Vector3 transformedOffset; Quaternion conjugate; Quaternion.Conjugate(ref entry.LocalTransform.Orientation, out conjugate); Vector3.Transform(ref offset, ref conjugate, out transformedOffset); child.CollisionInformation.localPosition = transformedOffset; var contribution = childContributions[child.shapeIndex]; CompoundShape.TransformContribution(ref entry.LocalTransform, ref distributionInfo.Center, ref contribution.VolumeDistribution, entry.Weight, out contribution.VolumeDistribution); //Vector3.Add(ref entry.LocalTransform.Position, ref offsetA, out entry.LocalTransform.Position); Matrix3X3.Add(ref contribution.VolumeDistribution, ref distributionInfo.VolumeDistribution, out distributionInfo.VolumeDistribution); } //Normalize the volume distribution. Matrix3X3.Multiply(ref distributionInfo.VolumeDistribution, 1 / weight, out distributionInfo.VolumeDistribution); //Update the hierarchies of the compounds. //TODO: Create a new method that does this quickly without garbage. Requires a new Reconstruct method which takes a pool which stores the appropriate node types. compound.hierarchy.Tree.Reconstruct(compound.children); return(true); }