//
// Use the QuikGrid library to generate a grid from a set of 3D points.
//
bool vtElevLayer::CreateFromPoints(vtFeatureSet *set, const IPoint2 &size,
float fDistanceRatio)
{
#if SUPPORT_QUIKGRID
vtFeatureSetPoint3D *fsp3 = dynamic_cast<vtFeatureSetPoint3D *>(set);
if (!fsp3)
return false;
DRECT extent;
fsp3->ComputeExtent(extent);
int iMaxSize = fsp3->NumEntities();
ScatData sdata(iMaxSize);
DPoint3 p;
for (int i = 0; i < iMaxSize; i++)
{
fsp3->GetPoint(i, p);
sdata.SetNext(p.x, p.y, p.z);
}
// Make a SurfaceGrid to hold the results
DPoint2 spacing(extent.Width() / (size.x-1), extent.Height() / (size.y-1));
SurfaceGrid Zgrid(size.x, size.y);
for (int x = 0; x < size.x; x++)
Zgrid.xset(x, extent.left + spacing.x * x);
for (int y = 0; y < size.y; y++)
Zgrid.yset(y, extent.bottom + spacing.y * y);
// "When any new points will not contributed more than 1/(scan bandwidth cutoff)
// towards the value of a grid intersection scanning will cease in that
// direction. "
int x1 = XpandScanRatio(); // default 16, valid values 1..100
// "The Distance cutoff specifies a percent of the Density Distance"
int x2 = XpandDensityRatio(); // default 150, valid values 1..10000
int x3 = XpandEdgeFactor(); // default 100, valid values 1..10000
float x4 = XpandUndefinedZ();
long x5 = XpandSample();
XpandDensityRatio((int) (fDistanceRatio * 100));
// Do the expand operation, gradually so we get progress
XpandInit(Zgrid, sdata);
int count = 0, total = size.x * size.y;
while (XpandPoint( Zgrid, sdata))
{
if ((count % 100) == 0)
{
if (progress_callback(count * 99 / total))
{
// user cancelled
return false;
}
}
count++;
}
// copy the result to a ElevationGrid
m_pGrid = new vtElevationGrid(extent, size, true, set->GetAtProjection());
for (int x = 0; x < size.x; x++)
for (int y = 0; y < size.y; y++)
{
float value = Zgrid.z(x,y);
if (value == -99999)
m_pGrid->SetFValue(x, y, INVALID_ELEVATION);
else
m_pGrid->SetFValue(x, y, value);
}
m_pGrid->ComputeHeightExtents();
m_pGrid->SetupLocalCS();
return true;
#else
// No QuikGrid
return false;
#endif
}
//**************************************************************
// X p a n d
// Generate the entire grid in one call.
//*************************************************************
void Xpand( SurfaceGrid &Zgrid, ScatData &RandomData)
{
XpandInit( Zgrid, RandomData );
while( XpandPoint( Zgrid, RandomData) ) ;
}
