Ejemplo n.º 1
0
        ///<summary>
        /// Constructs a new compound hierarchy.
        ///</summary>
        ///<param name="owner">Owner of the hierarchy.</param>
        public CompoundHierarchy(CompoundCollidable owner)
        {
            Owner = owner;
            CompoundChild[] children = new CompoundChild[owner.children.Count];
            Array.Copy(owner.children.Elements, children, owner.children.Count);
            //In order to initialize a good tree, the local space bounding boxes should first be computed.
            //Otherwise, the tree would try to create a hierarchy based on a bunch of zeroed out bounding boxes!
            for (int i = 0; i < children.Length; i++)
            {
                children[i].CollisionInformation.worldTransform = owner.Shape.shapes.Elements[i].LocalTransform;
                children[i].CollisionInformation.UpdateBoundingBoxInternal(0);
            }

            Tree = new BoundingBoxTree <CompoundChild>(children);
        }
Ejemplo n.º 2
0
        /// <summary>
        /// Constructs a compound collidable containing only the specified subset of children.
        /// </summary>
        /// <param name="shape">Shape to base the compound collidable on.</param>
        /// <param name="childIndices">Indices of child shapes from the CompoundShape to include in the compound collidable.</param>
        /// <returns>Compound collidable containing only the specified subset of children.</returns>
        public static CompoundCollidable CreatePartialCompoundCollidable(CompoundShape shape, IList <int> childIndices)
        {
            if (childIndices.Count == 0)
            {
                throw new ArgumentException("Cannot create a compound from zero shapes.");
            }

            CompoundCollidable compound = new CompoundCollidable();
            Vector3            center   = new Vector3();
            float totalWeight           = 0;

            for (int i = 0; i < childIndices.Count; i++)
            {
                //Create and add the child object itself.
                CompoundShapeEntry entry = shape.shapes[childIndices[i]];
                compound.children.Add(new CompoundChild(shape, entry.Shape.GetCollidableInstance(), childIndices[i]));
                //Grab its entry to compute the center of mass of this subset.
                Vector3 toAdd;
                Vector3.Multiply(ref entry.LocalTransform.Position, entry.Weight, out toAdd);
                Vector3.Add(ref center, ref toAdd, out center);
                totalWeight += entry.Weight;
            }

            if (totalWeight <= 0)
            {
                throw new ArgumentException("Compound has zero total weight; invalid configuration.");
            }

            Vector3.Divide(ref center, totalWeight, out center);
            //Our subset of the compound is not necessarily aligned with the shape's origin.
            //By default, an object will rotate around the center of the collision shape.
            //We can't modify the shape data itself since it could be shared, which leaves
            //modifying the local position of the collidable.
            //We have the subset position in shape space, so pull the collidable back into alignment
            //with the origin.
            //This approach matches the rest of the CompoundHelper's treatment of subsets.
            compound.LocalPosition = -center;

            //Recompute the hierarchy for the compound.
            compound.hierarchy.Tree.Reconstruct(compound.children);
            compound.Shape = shape;
            return(compound);
        }
Ejemplo n.º 3
0
        /// <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="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(Func <CompoundChild, bool> splitPredicate,
                                         Entity <CompoundCollidable> a, out Entity <CompoundCollidable> b,
                                         out ShapeDistributionInformation distributionInfoA, out ShapeDistributionInformation distributionInfoB)
        {
            CompoundCollidable bCollidable = new CompoundCollidable {
                Shape = a.CollisionInformation.Shape
            };

            b = null;


            float weightA, weightB;

            if (SplitCompound(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;
                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 (bCollidable.children.Count > 0)
                {
                    float newMassB = weightB / (weightA + weightB) * originalMass;
                    Matrix3x3.Multiply(ref distributionInfoB.VolumeDistribution,
                                       newMassB * InertiaHelper.InertiaTensorScale, out distributionInfoB.VolumeDistribution);
                    b = new Entity <CompoundCollidable>();
                    b.Initialize(bCollidable, newMassB, distributionInfoB.VolumeDistribution);
                }

                SplitReposition(a, b, ref distributionInfoA, ref distributionInfoB, weightA, weightB);
                return(true);
            }

            return(false);
        }
Ejemplo n.º 4
0
        /// <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.
                CompoundChild child = compound.children.Elements[i];
                if (removalPredicate(child))
                {
                    removalOccurred = true;
                    CompoundShapeEntry 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--)
            {
                CompoundChild                child        = compound.children.Elements[i];
                CompoundShapeEntry           entry        = child.Entry;
                ShapeDistributionInformation 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--)
            {
                CompoundChild      child = compound.children.Elements[i];
                CompoundShapeEntry entry = child.Entry;
                Vector3            transformedOffset;
                Quaternion         conjugate;
                Quaternion.Conjugate(ref entry.LocalTransform.Orientation, out conjugate);
                Quaternion.Transform(ref offset, ref conjugate, out transformedOffset);
                child.CollisionInformation.localPosition = transformedOffset;
                ShapeDistributionInformation 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);
        }
Ejemplo n.º 5
0
        /// <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="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(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.
                CompoundChild child = a.children.Elements[i];
                if (splitPredicate(child))
                {
                    splitOccurred = true;

                    a.children.FastRemoveAt(i);
                    b.children.Add(child);
                    //The child event handler must be unhooked from the old compound and given to the new one.
                    child.CollisionInformation.events.Parent = b.Events;
                }
            }

            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--)
            {
                CompoundChild      child = a.children.Elements[i];
                CompoundShapeEntry entry = child.Entry;
                Vector3            weightedCenter;
                Vector3.Multiply(ref entry.LocalTransform.Position, entry.Weight, out weightedCenter);
                Vector3.Add(ref weightedCenter, ref distributionInfoA.Center, out distributionInfoA.Center);
                distributionInfoA.Volume += entry.Shape.Volume;
                weightA += entry.Weight;
            }

            for (int i = b.children.Count - 1; i >= 0; i--)
            {
                CompoundChild      child = b.children.Elements[i];
                CompoundShapeEntry entry = child.Entry;
                Vector3            weightedCenter;
                Vector3.Multiply(ref entry.LocalTransform.Position, entry.Weight, out weightedCenter);
                Vector3.Add(ref weightedCenter, ref distributionInfoB.Center, out distributionInfoB.Center);
                distributionInfoB.Volume += entry.Shape.Volume;
                weightB += entry.Weight;
            }

            //Average the center out.
            if (weightA > 0)
            {
                Vector3.Divide(ref distributionInfoA.Center, weightA, out distributionInfoA.Center);
            }

            if (weightB > 0)
            {
                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--)
            {
                CompoundChild      child = a.children.Elements[i];
                CompoundShapeEntry entry = child.Entry;
                Vector3            transformedOffset;
                Quaternion         conjugate;
                Quaternion.Conjugate(ref entry.LocalTransform.Orientation, out conjugate);
                Quaternion.Transform(ref offsetA, ref conjugate, out transformedOffset);
                child.CollisionInformation.localPosition = transformedOffset;
                Matrix3x3 contribution;
                CompoundShape.TransformContribution(ref entry.LocalTransform, ref distributionInfoA.Center,
                                                    ref entry.Shape.volumeDistribution, entry.Weight, out contribution);
                Matrix3x3.Add(ref contribution, ref distributionInfoA.VolumeDistribution,
                              out distributionInfoA.VolumeDistribution);
            }

            for (int i = b.children.Count - 1; i >= 0; i--)
            {
                CompoundChild      child = b.children.Elements[i];
                CompoundShapeEntry entry = child.Entry;
                Vector3            transformedOffset;
                Quaternion         conjugate;
                Quaternion.Conjugate(ref entry.LocalTransform.Orientation, out conjugate);
                Quaternion.Transform(ref offsetB, ref conjugate, out transformedOffset);
                child.CollisionInformation.localPosition = transformedOffset;
                Matrix3x3 contribution;
                CompoundShape.TransformContribution(ref entry.LocalTransform, ref distributionInfoB.Center,
                                                    ref entry.Shape.volumeDistribution, entry.Weight, out contribution);
                Matrix3x3.Add(ref contribution, 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);
        }