FGFS-4.1/OpenSceneGraph
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Improved the cluster culling computation so that it now accounts for

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the local elevations.
This commit is contained in:
Robert Osfield
2004-05-04 14:02:53 +00:00
parent 55162d0c7c
commit ecaf3c1587
1 changed files with 35 additions and 21 deletions
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56
src/osgTerrain/DataSet.cpp
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@@ -1995,6 +1995,9 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
osg::Vec3 center_position(0.0f,0.0f,0.0f);
osg::Vec3 center_normal(0.0f,0.0f,1.0f);
osg::Vec3 transformed_center_normal(0.0f,0.0f,1.0f);
double globe_radius = et ? et->getRadiusPolar() : 1.0;
bool useClusterCullingCallback = mapLatLongsToXYZ;
if (useLocalToTileTransform)
{
@@ -2009,10 +2012,10 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
double minLat = grid->getOrigin().y();
double minX,minY,minZ;
et->convertLatLongHeightToXYZ(osg::DegreesToRadians(minLat),osg::DegreesToRadians(minLong),midZ,minX,minY,minZ);
et->convertLatLongHeightToXYZ(osg::DegreesToRadians(minLat),osg::DegreesToRadians(minLong),midZ, minX,minY,minZ);
double midX,midY;
et->convertLatLongHeightToXYZ(osg::DegreesToRadians(midLat),osg::DegreesToRadians(midLong),midZ,midX,midY,midZ);
et->convertLatLongHeightToXYZ(osg::DegreesToRadians(midLat),osg::DegreesToRadians(midLong),midZ, midX,midY,midZ);
double length = sqrt((midX-minX)*(midX-minX) + (midY-minY)*(midY-minY));
@@ -2070,6 +2073,7 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
float min_dot_product = 1.0f;
float max_cluster_culling_height = 0.0f;
for(r=0;r<numRows;++r)
{
@@ -2078,6 +2082,7 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
double X = orig_X + delta_X*(double)c;
double Y = orig_Y + delta_Y*(double)r;
double Z = orig_Z + grid->getHeight(c,r);
double height = Z;
if (mapLatLongsToXYZ)
{
@@ -2085,12 +2090,6 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
X,Y,Z);
}
// upadate the cluster culling data.
osg::Vec3 local_normal(X,Y,Z);
local_normal.normalize();
float local_dot_product = center_normal * local_normal;
min_dot_product = osg::minimum(min_dot_product, local_dot_product);
if (useLocalToTileTransform)
{
v[vi] = computeLocalPosition(worldToLocal,X,Y,Z);
@@ -2100,6 +2099,31 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
v[vi].set(X,Y,Z);
}
if (useClusterCullingCallback)
{
osg::Vec3 dv = v[vi] - center_position;
double d = sqrt(dv.x()*dv.x() + dv.y()*dv.y() + dv.z()*dv.z());
double theta = acos( globe_radius/ (globe_radius + fabs(height)) );
double phi = 2.0 * asin (d*0.5/globe_radius); // d/globe_radius;
double beta = theta+phi;
double cutoff = osg::PI_2 - 0.1;
//std::cout<<"theta="<<theta<<"\tphi="<<phi<<" beta "<<beta<<std::endl;
if (phi<cutoff && beta<cutoff)
{
float local_dot_product = -sin(theta + phi);
float local_m = globe_radius*( 1.0/ cos(theta+phi) - 1.0);
min_dot_product = osg::minimum(min_dot_product, local_dot_product);
max_cluster_culling_height = osg::maximum(max_cluster_culling_height,local_m);
}
else
{
//std::cout<<"Turning off cluster culling for wrap around tile."<<std::endl;
useClusterCullingCallback = false;
}
}
// note normal will need rotating.
if (n.valid()) (*(n.get()))[vi] = grid->getNormal(c,r);
@@ -2175,25 +2199,15 @@ osg::Node* DataSet::DestinationTile::createPolygonal()
#endif
bool useClusterCullingCallback = mapLatLongsToXYZ;
if (useClusterCullingCallback)
{
// set up cluster cullling,
osg::ClusterCullingCallback* ccc = new osg::ClusterCullingCallback;
float angle = acosf(min_dot_product)+osg::PI*0.5f;
float deviation = (angle<osg::PI) ? cos(angle) : -1.0f;
std::cout<<" center_position="<<center_position<<" center_normal="<<center_normal<<" min_dot_product="<<min_dot_product<<std::endl;
ccc->set(center_position, transformed_center_normal, deviation);
ccc->set(center_position + transformed_center_normal*max_cluster_culling_height ,
transformed_center_normal,
min_dot_product);
geometry->setCullCallback(ccc);
std::cout<<"manual ccc->getControlPoint()==\t"<<ccc->getControlPoint()<<"\t"<<ccc->getNormal()<<"\t"<<ccc->getDeviation()<<std::endl;
#if 0
ccc->computeFrom(geometry);
std::cout<<"computeFrom ccc->getControlPoint()==\t"<<ccc->getControlPoint()<<"\t"<<ccc->getNormal()<<"\t"<<ccc->getDeviation()<<std::endl;
#endif
}
osgUtil::Simplifier::IndexList pointsToProtectDuringSimplification;