bool
ElevationLayerVector::createHeightField(const TileKey& key,
bool fallback,
const Profile* haeProfile,
ElevationInterpolation interpolation,
ElevationSamplePolicy samplePolicy,
osg::ref_ptr<osg::HeightField>& out_result,
bool* out_isFallback,
ProgressCallback* progress ) const
{
unsigned lowestLOD = key.getLevelOfDetail();
bool hfInitialized = false;
//Get a HeightField for each of the enabled layers
GeoHeightFieldVector heightFields;
//The number of fallback heightfields we have
int numFallbacks = 0;
//Default to being fallback data.
if ( out_isFallback )
{
*out_isFallback = true;
}
// if the caller provided an "HAE map profile", he wants an HAE elevation grid even if
// the map profile has a vertical datum. This is the usual case when building the 3D
// terrain, for example. Construct a temporary key that doesn't have the vertical
// datum info and use that to query the elevation data.
TileKey keyToUse = key;
if ( haeProfile )
{
keyToUse = TileKey(key.getLevelOfDetail(), key.getTileX(), key.getTileY(), haeProfile );
}
// Generate a heightfield for each elevation layer.
unsigned defElevSize = 8;
for( ElevationLayerVector::const_iterator i = this->begin(); i != this->end(); i++ )
{
ElevationLayer* layer = i->get();
if ( layer->getVisible() )
{
GeoHeightField geoHF = layer->createHeightField( keyToUse, progress );
// if "fallback" is set, try to fall back on lower LODs.
if ( !geoHF.valid() && fallback )
{
TileKey hf_key = keyToUse.createParentKey();
while ( hf_key.valid() && !geoHF.valid() )
{
geoHF = layer->createHeightField( hf_key, progress );
if ( !geoHF.valid() )
hf_key = hf_key.createParentKey();
}
if ( geoHF.valid() )
{
if ( hf_key.getLevelOfDetail() < lowestLOD )
lowestLOD = hf_key.getLevelOfDetail();
//This HeightField is fallback data, so increment the count.
numFallbacks++;
}
}
if ( geoHF.valid() )
{
heightFields.push_back( geoHF );
}
}
}
//If any of the layers produced valid data then it's not considered a fallback
if ( out_isFallback )
{
*out_isFallback = (numFallbacks == heightFields.size());
//OE_NOTICE << "Num fallbacks=" << numFallbacks << " numHeightFields=" << heightFields.size() << " is fallback " << *out_isFallback << std::endl;
}
if ( heightFields.size() == 0 )
{
//If we got no heightfields but were requested to fallback, create an empty heightfield.
if ( fallback )
{
out_result = HeightFieldUtils::createReferenceHeightField( keyToUse.getExtent(), defElevSize, defElevSize );
return true;
}
else
{
//We weren't requested to fallback so just return.
return false;
}
}
else if (heightFields.size() == 1)
{
if ( lowestLOD == key.getLevelOfDetail() )
{
//If we only have on heightfield, just return it.
out_result = heightFields[0].takeHeightField();
}
else
{
GeoHeightField geoHF = heightFields[0].createSubSample( key.getExtent(), interpolation);
out_result = geoHF.takeHeightField();
hfInitialized = true;
}
}
else
{
//If we have multiple heightfields, we need to composite them together.
unsigned int width = 0;
unsigned int height = 0;
for (GeoHeightFieldVector::const_iterator i = heightFields.begin(); i < heightFields.end(); ++i)
{
if (i->getHeightField()->getNumColumns() > width)
width = i->getHeightField()->getNumColumns();
if (i->getHeightField()->getNumRows() > height)
height = i->getHeightField()->getNumRows();
}
out_result = new osg::HeightField();
out_result->allocate( width, height );
//Go ahead and set up the heightfield so we don't have to worry about it later
double minx, miny, maxx, maxy;
key.getExtent().getBounds(minx, miny, maxx, maxy);
double dx = (maxx - minx)/(double)(out_result->getNumColumns()-1);
double dy = (maxy - miny)/(double)(out_result->getNumRows()-1);
const SpatialReference* keySRS = keyToUse.getProfile()->getSRS();
//Create the new heightfield by sampling all of them.
for (unsigned int c = 0; c < width; ++c)
{
double x = minx + (dx * (double)c);
for (unsigned r = 0; r < height; ++r)
{
double y = miny + (dy * (double)r);
//Collect elevations from all of the layers. Iterate BACKWARDS because the last layer
// is the highest priority.
std::vector<float> elevations;
for( GeoHeightFieldVector::reverse_iterator itr = heightFields.rbegin(); itr != heightFields.rend(); ++itr )
{
const GeoHeightField& geoHF = *itr;
float elevation = 0.0f;
if ( geoHF.getElevation(keySRS, x, y, interpolation, keySRS, elevation) )
{
if (elevation != NO_DATA_VALUE)
{
elevations.push_back(elevation);
}
}
}
float elevation = NO_DATA_VALUE;
//The list of elevations only contains valid values
if (elevations.size() > 0)
{
if (samplePolicy == SAMPLE_FIRST_VALID)
{
elevation = elevations[0];
}
else if (samplePolicy == SAMPLE_HIGHEST)
{
elevation = -FLT_MAX;
for (unsigned int i = 0; i < elevations.size(); ++i)
{
if (elevation < elevations[i]) elevation = elevations[i];
}
}
else if (samplePolicy == SAMPLE_LOWEST)
{
elevation = FLT_MAX;
for (unsigned i = 0; i < elevations.size(); ++i)
{
if (elevation > elevations[i]) elevation = elevations[i];
}
}
else if (samplePolicy == SAMPLE_AVERAGE)
{
elevation = 0.0;
for (unsigned i = 0; i < elevations.size(); ++i)
{
elevation += elevations[i];
}
elevation /= (float)elevations.size();
}
}
out_result->setHeight(c, r, elevation);
}
}
}
// Replace any NoData areas with the reference value. This is zero for HAE datums,
// and some geoid height for orthometric datums.
if (out_result.valid())
{
const Geoid* geoid = 0L;
const VerticalDatum* vdatum = key.getProfile()->getSRS()->getVerticalDatum();
if ( haeProfile && vdatum )
{
geoid = vdatum->getGeoid();
}
HeightFieldUtils::resolveInvalidHeights(
out_result.get(),
key.getExtent(),
NO_DATA_VALUE,
geoid );
//ReplaceInvalidDataOperator o;
//o.setValidDataOperator(new osgTerrain::NoDataValue(NO_DATA_VALUE));
//o( out_result.get() );
}
//Initialize the HF values for osgTerrain
if (out_result.valid() && !hfInitialized )
{
//Go ahead and set up the heightfield so we don't have to worry about it later
double minx, miny, maxx, maxy;
key.getExtent().getBounds(minx, miny, maxx, maxy);
out_result->setOrigin( osg::Vec3d( minx, miny, 0.0 ) );
double dx = (maxx - minx)/(double)(out_result->getNumColumns()-1);
double dy = (maxy - miny)/(double)(out_result->getNumRows()-1);
out_result->setXInterval( dx );
out_result->setYInterval( dy );
out_result->setBorderWidth( 0 );
}
return out_result.valid();
}
