osg::Node* makeLabelNode(const FilterContext& context,
const Feature* feature,
const std::string& value,
const TextSymbol* text,
NumericExpression& priorityExpr )
{
LabelNode* labelNode = new LabelNode(
context.getSession()->getMapInfo().getProfile()->getSRS(),
GeoPoint(feature->getSRS(), feature->getGeometry()->getBounds().center()),
value,
text );
if ( text->priority().isSet() )
{
AnnotationData* data = new AnnotationData();
data->setPriority( feature->eval(priorityExpr, &context) );
labelNode->setAnnotationData( data );
}
return labelNode;
}
void
GeodeticGraticule::initLabelPool(CameraData& cdata)
{
const osgEarth::SpatialReference* srs = osgEarth::SpatialReference::create("wgs84");
Style style;
TextSymbol* text = style.getOrCreateSymbol<TextSymbol>();
text->alignment() = TextSymbol::ALIGN_CENTER_CENTER;
text->fill()->color() = options().labelColor().get();
AltitudeSymbol* alt = style.getOrCreateSymbol<AltitudeSymbol>();
alt->clamping() = AltitudeSymbol::CLAMP_TO_TERRAIN;
unsigned int labelPoolSize = 8 * options().gridLines().get();
for (unsigned int i = 0; i < labelPoolSize; i++)
{
GeoPoint pt(srs, 0,0,0);
LabelNode* label = new LabelNode(_mapNode.get(), pt, "0,0");
label->setDynamic(true);
label->setStyle(style);
cdata._labelPool.push_back(label);
}
}
bool
GraticuleLabelingEngine::cullTraverse(osgUtil::CullVisitor& nv, CameraData& data)
{
osg::Camera* cam = nv.getCurrentCamera();
// Don't draw the labels if we are too far from North-Up:
double heading = getCameraHeading(cam->getViewMatrix());
if (osg::RadiansToDegrees(fabs(heading)) > 7.0)
return false;
// Initialize the label pool for this camera if we have not done so:
if (data.xLabels.empty())
{
for (unsigned i = 0; i < MAX_LABELS; ++i)
{
LabelNode* label = new LabelNode();
label->setDynamic(true);
label->setStyle(_xLabelStyle);
label->setHorizonCulling(false);
label->setOcclusionCulling(false);
data.xLabels.push_back(label);
}
for (unsigned i = 0; i < MAX_LABELS; ++i)
{
LabelNode* label = new LabelNode();
label->setDynamic(true);
label->setStyle(_yLabelStyle);
label->setHorizonCulling(false);
label->setOcclusionCulling(false);
data.yLabels.push_back(label);
}
}
// Start out with all labels off. We will then turn back on the ones we use:
for (unsigned i = 0; i < MAX_LABELS; ++i)
{
data.xLabels[i]->setNodeMask(0);
data.yLabels[i]->setNodeMask(0);
}
// Intersect the corners of the view frustum with the ellipsoid.
// This will yield the approximate geo-extent of the view.
// TODO: graduate this to the core if generally useful - could be helpful
// for displaying the extent of the current view.
// Calculate the "clip to world" matrix = MVPinv.
osg::Matrix MVP = (*nv.getModelViewMatrix()) * cam->getProjectionMatrix();
osg::Matrix MVPinv;
MVPinv.invert(MVP);
EllipsoidIntersector ellipsoid(_srs->getEllipsoid());
// For each corner, transform the clip coordinates at the near and far
// planes into world space and intersect that line with the ellipsoid:
osg::Vec3d p0, p1;
// find the lower-left corner of the frustum:
osg::Vec3d LL_world;
p0 = osg::Vec3d(-1, -1, -1) * MVPinv;
p1 = osg::Vec3d(-1, -1, +1) * MVPinv;
bool LL_ok = ellipsoid.intersectLine(p0, p1, LL_world);
if (!LL_ok)
return false;
// find the upper-left corner of the frustum:
osg::Vec3d UL_world;
p0 = osg::Vec3d(-1, +1, -1) * MVPinv;
p1 = osg::Vec3d(-1, +1, +1) * MVPinv;
bool UL_ok = ellipsoid.intersectLine(p0, p1, UL_world);
if (!UL_ok)
return false;
// find the lower-right corner of the frustum:
osg::Vec3d LR_world;
p0 = osg::Vec3d(+1, -1, -1) * MVPinv;
p1 = osg::Vec3d(+1, -1, +1) * MVPinv;
bool LR_ok = ellipsoid.intersectLine(p0, p1, LR_world);
if (!LR_ok)
return false;
// Use this for clamping geopoints to the edges of the frustum:
ClipSpace window(MVP, MVPinv);
return updateLabels(LL_world, UL_world, LR_world, window, data);
}
void
GeodeticGraticule::updateLabels()
{
const osgEarth::SpatialReference* srs = osgEarth::SpatialReference::create("wgs84");
Threading::ScopedMutexLock lock(_cameraDataMapMutex);
for (CameraDataMap::iterator i = _cameraDataMap.begin(); i != _cameraDataMap.end(); ++i)
{
CameraData& cdata = i->second;
std::vector< GeoExtent > extents;
if (cdata._viewExtent.crossesAntimeridian())
{
GeoExtent first, second;
cdata._viewExtent.splitAcrossAntimeridian(first, second);
extents.push_back(first);
extents.push_back(second);
}
else
{
extents.push_back( cdata._viewExtent );
}
double resDegrees = cdata._resolution * 180.0;
// We want half the resolution so the labels don't appear as often as the grid lines
resDegrees *= 2.0;
// Hide all the labels
for (unsigned int i = 0; i < cdata._labelPool.size(); i++)
{
cdata._labelPool[i]->setNodeMask(0);
}
// Approximate offset in degrees
double degOffset = cdata._metersPerPixel / 111000.0;
unsigned int labelIndex = 0;
bool done = false;
for (unsigned int extentIndex = 0; extentIndex < extents.size() && !done; extentIndex++)
{
GeoExtent extent = extents[extentIndex];
int minLonIndex = floor(((extent.xMin() + 180.0)/resDegrees));
int maxLonIndex = ceil(((extent.xMax() + 180.0)/resDegrees));
int minLatIndex = floor(((extent.yMin() + 90)/resDegrees));
int maxLatIndex = ceil(((extent.yMax() + 90)/resDegrees));
// Generate horizontal labels
for (int i = minLonIndex; i <= maxLonIndex && !done; i++)
{
GeoPoint point(srs, -180.0 + (double)i * resDegrees, cdata._lat + (_centerOffset.y() * degOffset), 0, ALTMODE_ABSOLUTE);
LabelNode* label = cdata._labelPool[labelIndex++].get();
label->setNodeMask(~0u);
label->setPosition(point);
std::string text = getText( point, false);
label->setText( text );
if (labelIndex == cdata._labelPool.size() - 1)
{
done = true;
}
}
// Generate the vertical labels
for (int i = minLatIndex; i <= maxLatIndex && !done; i++)
{
GeoPoint point(srs, cdata._lon + (_centerOffset.x() * degOffset), -90.0 + (double)i * resDegrees, 0, ALTMODE_ABSOLUTE);
// Skip drawing labels at the poles
if (osg::equivalent(osg::absolute( point.y()), 90.0, 0.1))
{
continue;
}
LabelNode* label = cdata._labelPool[labelIndex++].get();
label->setNodeMask(~0u);
label->setPosition(point);
std::string text = getText( point, true);
label->setText( text );
if (labelIndex == cdata._labelPool.size() - 1)
{
done = true;
}
}
}
}
}
