private BulletShape CreatePhysicalHull(string objName, ulong newHullKey, PrimitiveBaseShape pbs, OMV.Vector3 size, float lod)
{
IntPtr hullPtr;
HullDesc hullDesc;
if (Hulls.TryGetValue(newHullKey, out hullDesc))
{
// If the hull shape already is created, just use it.
hullPtr = hullDesc.ptr;
}
else
{
// Build a new hull in the physical world
// Pass false for physicalness as this creates some sort of bounding box which we don't need
IMesh meshData = PhysicsScene.mesher.CreateMesh(objName, pbs, size, lod, false);
int[] indices = meshData.getIndexListAsInt();
List <OMV.Vector3> vertices = meshData.getVertexList();
//format conversion from IMesh format to DecompDesc format
List <int> convIndices = new List <int>();
List <float3> convVertices = new List <float3>();
for (int ii = 0; ii < indices.GetLength(0); ii++)
{
convIndices.Add(indices[ii]);
}
foreach (OMV.Vector3 vv in vertices)
{
convVertices.Add(new float3(vv.X, vv.Y, vv.Z));
}
// setup and do convex hull conversion
m_hulls = new List <ConvexResult>();
DecompDesc dcomp = new DecompDesc();
dcomp.mIndices = convIndices;
dcomp.mVertices = convVertices;
ConvexBuilder convexBuilder = new ConvexBuilder(HullReturn);
// create the hull into the _hulls variable
convexBuilder.process(dcomp);
// Convert the vertices and indices for passing to unmanaged.
// The hull information is passed as a large floating point array.
// The format is:
// convHulls[0] = number of hulls
// convHulls[1] = number of vertices in first hull
// convHulls[2] = hull centroid X coordinate
// convHulls[3] = hull centroid Y coordinate
// convHulls[4] = hull centroid Z coordinate
// convHulls[5] = first hull vertex X
// convHulls[6] = first hull vertex Y
// convHulls[7] = first hull vertex Z
// convHulls[8] = second hull vertex X
// ...
// convHulls[n] = number of vertices in second hull
// convHulls[n+1] = second hull centroid X coordinate
// ...
//
// TODO: is is very inefficient. Someday change the convex hull generator to return
// data structures that do not need to be converted in order to pass to Bullet.
// And maybe put the values directly into pinned memory rather than marshaling.
int hullCount = m_hulls.Count;
int totalVertices = 1; // include one for the count of the hulls
foreach (ConvexResult cr in m_hulls)
{
totalVertices += 4; // add four for the vertex count and centroid
totalVertices += cr.HullIndices.Count * 3; // we pass just triangles
}
float[] convHulls = new float[totalVertices];
convHulls[0] = (float)hullCount;
int jj = 1;
foreach (ConvexResult cr in m_hulls)
{
// copy vertices for index access
float3[] verts = new float3[cr.HullVertices.Count];
int kk = 0;
foreach (float3 ff in cr.HullVertices)
{
verts[kk++] = ff;
}
// add to the array one hull's worth of data
convHulls[jj++] = cr.HullIndices.Count;
convHulls[jj++] = 0f; // centroid x,y,z
convHulls[jj++] = 0f;
convHulls[jj++] = 0f;
foreach (int ind in cr.HullIndices)
{
convHulls[jj++] = verts[ind].x;
convHulls[jj++] = verts[ind].y;
convHulls[jj++] = verts[ind].z;
}
}
// create the hull data structure in Bullet
hullPtr = BulletSimAPI.CreateHullShape2(PhysicsScene.World.ptr, hullCount, convHulls);
}
BulletShape newShape = new BulletShape(hullPtr, ShapeData.PhysicsShapeType.SHAPE_HULL);
newShape.shapeKey = newHullKey;
return(newShape); // 'true' means a new shape has been added to this prim
}