static void
computeBestFitOBB(TheaArray<Vector3> const & points, Box3 & result, bool has_up, Vector3 const & up)
{
if (points.empty())
{
result = Box3();
return;
}
else if (points.size() == 1)
{
result = Box3(AxisAlignedBox3(points[0]));
return;
}
Vector3 centroid;
CoordinateFrame3 cframe;
if (has_up)
{
centroid = CentroidN<Vector3, 3>::compute(points.begin(), points.end());
Vector3 u, v;
up.createOrthonormalBasis(u, v);
cframe = CoordinateFrame3::_fromAffine(AffineTransform3(basisMatrix(u, v, up), centroid));
}
else
{
Plane3 plane;
LinearLeastSquares3<Vector3>::fitPlane(points.begin(), points.end(), plane, ¢roid);
planeToCFrame(plane, centroid, cframe);
}
OBB best_obb;
computeOBB(points, cframe, best_obb, true);
Matrix3 rot = Matrix3::rotationAxisAngle((has_up ? up : Vector3::unitY()), Math::degreesToRadians(10));
for (int a = 10; a < 180; a += 10)
{
cframe._setRotation(cframe.getRotation() * rot);
computeOBB(points, cframe, best_obb, false);
}
result = Box3(AxisAlignedBox3(best_obb.lo, best_obb.hi), best_obb.cframe);
}
void computeBestFitOBB(unsigned int vcount,const float *points,unsigned int pstride,float *sides,float *matrix)
{
float bmin[3];
float bmax[3];
fm_getAABB(vcount,points,pstride,bmin,bmax);
float center[3];
center[0] = (bmax[0]-bmin[0])*0.5f + bmin[0];
center[1] = (bmax[1]-bmin[1])*0.5f + bmin[1];
center[2] = (bmax[2]-bmin[2])*0.5f + bmin[2];
float ax = 0;
float ay = 0;
float az = 0;
float sweep = 45.0f; // 180 degree sweep on all three axes.
float steps = 8.0f; // 16 steps on each axis.
float bestVolume = 1e9;
float angle[3];
while ( sweep >= 1 )
{
bool found = false;
float stepsize = sweep / steps;
for (float x=ax-sweep; x<=ax+sweep; x+=stepsize)
{
for (float y=ay-sweep; y<=ay+sweep; y+=stepsize)
{
for (float z=az-sweep; z<=az+sweep; z+=stepsize)
{
float pmatrix[16];
fm_eulerMatrix( x*FM_DEG_TO_RAD, y*FM_DEG_TO_RAD, z*FM_DEG_TO_RAD, pmatrix );
pmatrix[3*4+0] = center[0];
pmatrix[3*4+1] = center[1];
pmatrix[3*4+2] = center[2];
float psides[3];
computeOBB( vcount, points, pstride, psides, pmatrix );
float volume = psides[0]*psides[1]*psides[2]; // the volume of the cube
if ( volume <= bestVolume )
{
bestVolume = volume;
sides[0] = psides[0];
sides[1] = psides[1];
sides[2] = psides[2];
angle[0] = ax;
angle[1] = ay;
angle[2] = az;
memcpy(matrix,pmatrix,sizeof(float)*16);
found = true; // yes, we found an improvement.
}
}
}
}
if ( found )
{
ax = angle[0];
ay = angle[1];
az = angle[2];
sweep*=0.5f; // sweep 1/2 the distance as the last time.
}
else
{
break; // no improvement, so just
}
}
}
