Polyhedron AABB::ToPolyhedron() const
{
// Note to maintainer: This function is an exact copy of OBB:ToPolyhedron() and Frustum::ToPolyhedron().
Polyhedron p;
// Populate the corners of this AABB.
// The will be in the order 0: ---, 1: --+, 2: -+-, 3: -++, 4: +--, 5: +-+, 6: ++-, 7: +++.
for(int i = 0; i < 8; ++i)
p.v.push_back(CornerPoint(i));
// Generate the 6 faces of this AABB.
const int faces[6][4] =
{
{ 0, 1, 3, 2 }, // X-
{ 4, 6, 7, 5 }, // X+
{ 0, 4, 5, 1 }, // Y-
{ 7, 6, 2, 3 }, // Y+
{ 0, 2, 6, 4 }, // Z-
{ 1, 5, 7, 3 }, // Z+
};
for(int f = 0; f < 6; ++f)
{
Polyhedron::Face face;
for(int v = 0; v < 4; ++v)
face.v.push_back(faces[f][v]);
p.f.push_back(face);
}
assume(p.IsClosed());
assume(p.IsConvex());
assume(p.EulerFormulaHolds());
assume(p.FaceIndicesValid());
assume(p.FacesAreNondegeneratePlanar());
assume(p.Contains(this->CenterPoint()));
return p;
}
Polyhedron Polyhedron::ConvexHull(const float3 *pointArray, int numPoints)
{
///\todo Check input ptr and size!
std::set<int> extremes;
const float3 dirs[] =
{
float3(1,0,0), float3(0,1,0), float3(0,0,1),
float3(1,1,0), float3(1,0,1), float3(0,1,1),
float3(1,1,1)
};
for(size_t i = 0; i < ARRAY_LENGTH(dirs); ++i)
{
int idx1, idx2;
OBB::ExtremePointsAlongDirection(dirs[i], pointArray, numPoints, idx1, idx2);
extremes.insert(idx1);
extremes.insert(idx2);
}
Polyhedron p;
assume(extremes.size() >= 4); ///\todo Fix this case!
int i = 0;
std::set<int>::iterator iter = extremes.begin();
for(; iter != extremes.end() && i < 4; ++iter, ++i)
p.v.push_back(pointArray[*iter]);
Face f;
f.v.resize(3);
f.v[0] = 0; f.v[1] = 1; f.v[2] = 2; p.f.push_back(f);
f.v[0] = 0; f.v[1] = 1; f.v[2] = 3; p.f.push_back(f);
f.v[0] = 0; f.v[1] = 2; f.v[2] = 3; p.f.push_back(f);
f.v[0] = 1; f.v[1] = 2; f.v[2] = 3; p.f.push_back(f);
p.OrientNormalsOutsideConvex(); // Ensure that the winding order of the generated tetrahedron is correct for each face.
// assert(p.IsClosed());
//assert(p.IsConvex());
assert(p.FaceIndicesValid());
assert(p.EulerFormulaHolds());
// assert(p.FacesAreNondegeneratePlanar());
CHullHelp hull;
for(int j = 0; j < (int)p.f.size(); ++j)
hull.livePlanes.push_back(j);
// For better performance, merge the remaining extreme points first.
for(; iter != extremes.end(); ++iter)
{
p.MergeConvex(pointArray[*iter]);
mathassert(p.FaceIndicesValid());
// mathassert(p.IsClosed());
// mathassert(p.FacesAreNondegeneratePlanar());
// mathassert(p.IsConvex());
}
// Merge all the rest of the points.
for(int j = 0; j < numPoints; ++j)
{
if (p.f.size() > 5000 && (j & 255) == 0)
printf("Mergeconvex %d/%d, #vertices %d, #faces %d\n", j, numPoints, (int)p.v.size(), (int)p.f.size());
p.MergeConvex(pointArray[i]);
mathassert(p.FaceIndicesValid());
// mathassert(p.IsClosed());
// mathassert(p.FacesAreNondegeneratePlanar());
//mathassert(p.IsConvex());
// if (p.f.size() > 5000)
// break;
}
return p;
}
