// followed by variable sized convex hull data
#region Construction
// Create a convex collider from the given point cloud.
public static unsafe BlobAssetReference <Collider> Create(
NativeArray <float3> points, float convexRadius,
float3?scale = null, CollisionFilter?filter = null, Material?material = null)
{
if (convexRadius < 0.0f || !math.isfinite(convexRadius))
{
throw new ArgumentException("Tried to create ConvexCollider with invalid convex radius");
}
// Build convex hull
int verticesCapacity = points.Length;
int triangleCapacity = 2 * verticesCapacity;
var vertices = (ConvexHullBuilder.Vertex *)UnsafeUtility.Malloc(verticesCapacity * sizeof(ConvexHullBuilder.Vertex), 16, Allocator.Temp);
var triangles = (ConvexHullBuilder.Triangle *)UnsafeUtility.Malloc(triangleCapacity * sizeof(ConvexHullBuilder.Triangle), 16, Allocator.Temp);
var builder = new ConvexHullBuilder(vertices, verticesCapacity, triangles, triangleCapacity);
float3 s = scale ?? new float3(1);
// Build the points' AABB and validate them
var domain = new Aabb();
foreach (var point in points)
{
if (math.any(!math.isfinite(point)))
{
throw new ArgumentException("Tried to create ConvexCollider with invalid points");
}
domain.Include(point * s);
}
// Add points to the hull
builder.IntegerSpaceAabb = domain;
foreach (float3 point in points)
{
builder.AddPoint(point * s);
}
// TODO: shrink by convex radius
// Build face information
float maxAngle = 0.1f * (float)math.PI / 180.0f;
builder.BuildFaceIndices(maxAngle);
// Simplify the hull until it's under the max vertices requirement
// TODO.ma this is just a failsafe. We need to think about user-controlled simplification settings & how to warn the user if their shape is too complex.
{
const int maxVertices = 252; // as per Havok
float maxSimplificationError = 1e-3f;
int iterations = 0;
while (builder.Vertices.PeakCount > maxVertices)
{
if (iterations++ > 10) // don't loop forever
{
Assert.IsTrue(false);
return(new BlobAssetReference <Collider>());
}
builder.SimplifyVertices(maxSimplificationError);
builder.BuildFaceIndices();
maxSimplificationError *= 2.0f;
}
}
// Convert hull to compact format
var tempHull = new TempHull(ref builder);
// Allocate collider
int totalSize = UnsafeUtility.SizeOf <ConvexCollider>();
totalSize += tempHull.Vertices.Count * sizeof(float3);
totalSize = Math.NextMultipleOf16(totalSize); // planes currently must be aligned for Havok
totalSize += tempHull.Planes.Count * sizeof(Plane);
totalSize += tempHull.Faces.Count * sizeof(ConvexHull.Face);
totalSize += tempHull.FaceVertexIndices.Count * sizeof(short);
totalSize += tempHull.VertexEdges.Count * sizeof(ConvexHull.Edge);
totalSize += tempHull.FaceLinks.Count * sizeof(ConvexHull.Edge);
ConvexCollider *collider = (ConvexCollider *)UnsafeUtility.Malloc(totalSize, 16, Allocator.Temp);
// Initialize it
{
UnsafeUtility.MemClear(collider, totalSize);
collider->MemorySize = totalSize;
collider->m_Header.Type = ColliderType.Convex;
collider->m_Header.CollisionType = CollisionType.Convex;
collider->m_Header.Version = 0;
collider->m_Header.Magic = 0xff;
collider->m_Header.Filter = filter ?? CollisionFilter.Default;
collider->m_Header.Material = material ?? Material.Default;
ref var hull = ref collider->ConvexHull;
hull.ConvexRadius = convexRadius;
// Initialize blob arrays
{
byte *end = (byte *)collider + UnsafeUtility.SizeOf <ConvexCollider>();
hull.VerticesBlob.Offset = (int)(end - (byte *)UnsafeUtility.AddressOf(ref hull.VerticesBlob.Offset));
hull.VerticesBlob.Length = tempHull.Vertices.Count;
end += sizeof(float3) * tempHull.Vertices.Count;
end = (byte *)Math.NextMultipleOf16((ulong)end); // planes currently must be aligned for Havok
hull.FacePlanesBlob.Offset = (int)(end - (byte *)UnsafeUtility.AddressOf(ref hull.FacePlanesBlob.Offset));
hull.FacePlanesBlob.Length = tempHull.Planes.Count;
end += sizeof(Plane) * tempHull.Planes.Count;
hull.FacesBlob.Offset = (int)(end - (byte *)UnsafeUtility.AddressOf(ref hull.FacesBlob.Offset));
hull.FacesBlob.Length = tempHull.Faces.Count;
end += sizeof(ConvexHull.Face) * tempHull.Faces.Count;
hull.FaceVertexIndicesBlob.Offset = (int)(end - (byte *)UnsafeUtility.AddressOf(ref hull.FaceVertexIndicesBlob.Offset));
hull.FaceVertexIndicesBlob.Length = tempHull.FaceVertexIndices.Count;
end += sizeof(byte) * tempHull.FaceVertexIndices.Count;
hull.VertexEdgesBlob.Offset = (int)(end - (byte *)UnsafeUtility.AddressOf(ref hull.VertexEdgesBlob.Offset));
hull.VertexEdgesBlob.Length = tempHull.VertexEdges.Count;
end += sizeof(ConvexHull.Edge) * tempHull.VertexEdges.Count;
hull.FaceLinksBlob.Offset = (int)(end - (byte *)UnsafeUtility.AddressOf(ref hull.FaceLinksBlob.Offset));
hull.FaceLinksBlob.Length = tempHull.FaceLinks.Count;
end += sizeof(ConvexHull.Edge) * tempHull.FaceLinks.Count;
}
// Fill blob arrays
{
for (int i = 0; i < tempHull.Vertices.Count; i++)
{
hull.Vertices[i] = tempHull.Vertices[i];
hull.VertexEdges[i] = tempHull.VertexEdges[i];
}
for (int i = 0; i < tempHull.Faces.Count; i++)
{
hull.Planes[i] = tempHull.Planes[i];
hull.Faces[i] = tempHull.Faces[i];
}
for (int i = 0; i < tempHull.FaceVertexIndices.Count; i++)
{
hull.FaceVertexIndices[i] = tempHull.FaceVertexIndices[i];
hull.FaceLinks[i] = tempHull.FaceLinks[i];
}
}
// Fill mass properties
{
var massProperties = builder.ComputeMassProperties();
Math.DiagonalizeSymmetricApproximation(massProperties.InertiaTensor, out float3x3 orientation, out float3 inertia);
float maxLengthSquared = 0.0f;
foreach (float3 vertex in hull.Vertices)
{
maxLengthSquared = math.max(maxLengthSquared, math.lengthsq(vertex - massProperties.CenterOfMass));
}
collider->MassProperties = new MassProperties
{
MassDistribution = new MassDistribution
{
Transform = new RigidTransform(orientation, massProperties.CenterOfMass),
InertiaTensor = inertia
},
Volume = massProperties.Volume,
AngularExpansionFactor = math.sqrt(maxLengthSquared)
};
}
}