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Added airport terrain check for random objects

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Random objects like lights and trees are not placed on airport terrain
anymore. This commit also refactors some of the existing code for clarity.
Discussion can be found here [1] and detailed history here [2].

[1] https://sourceforge.net/p/flightgear/simgear/merge-requests/102/
[2] https://sourceforge.net/u/fahimdalvi/simgear/ci/bugfix/ws30_random_objects_avoid_airports/~/tree/

Squashed commit of the following:

commit 643198f8d52da8d65a674b052c508f03d7f83ac0
Author: Fahim Imaduddin Dalvi <dalvifahim@gmail.com>
Date:   Tue Jan 4 09:57:34 2022 +0300

    Implemented corrected airport intersection logic

    We now convert the point into the correct coordinate system before
    checking for intersections with the airport geometry.

commit 7e0819e4f88992658301a2c15d890fc489cfe3b6
Author: Fahim Imaduddin Dalvi <dalvifahim@gmail.com>
Date:   Wed Nov 10 19:59:04 2021 +0300

    Added airport terrain check code for random objects

    This commit does not work as expected. The light-coverage check is disabled
    to amplify the bug.

commit eb21e8fd256dcf124857ac51afc0d7c3c90ae1c6
Author: Fahim Imaduddin Dalvi <dalvifahim@gmail.com>
Date:   Wed Nov 10 19:53:44 2021 +0300

    Refactored elevation constraint checking code

    This commit provides a separate elevation constraint function that does not
    displace the given point. The current function has been renamed to indicate
    the displacement side effect.
This commit is contained in:
Fahim Imaduddin Dalvi 2022-01-04 18:10:03 +03:00
parent d4b02d58d6
commit c4c5829d37
2 changed files with 22 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
simgear/scene/tgdb/VPBTechnique.cxx
View File

@ -541,7 +541,7 @@ void VertexNormalGenerator::populateCenter(osgTerrain::Layer* elevationLayer, os
_masterLocator->convertLocalToModel(osg::Vec3d(ndc.x(), ndc.y(), -1000), origin);
_masterLocator->convertLocalToModel(ndc, model);
model = VPBTechnique::checkAgainstElevationConstraints(origin, model, _constraint_vtx_gap);
model = VPBTechnique::checkAndDisplaceAgainstElevationConstraints(origin, model, _constraint_vtx_gap);
texcoords->push_back(osg::Vec2(ndc.x(), ndc.y()));
@ -1641,7 +1641,13 @@ void VPBTechnique::applyMaterials(BufferData& buffer, Locator* masterLocator)
D, ll_O, ll_x, ll_y, t_0, t_x, t_y, x_scale, y_scale, pointInTriangle)) {
// Check against constraints to stop lights on roads
const osg::Vec3 vp = v_x * pointInTriangle.x() + v_y * pointInTriangle.y() + v_0;
if (checkAgainstRandomObjectsConstraints(_randomObjectsConstraintGroup, vp - up * 100, vp + up * 100))
const osg::Vec3 upperPoint = vp + up * 100;
const osg::Vec3 lowerPoint = vp - up * 100;
if (checkAgainstRandomObjectsConstraints(_randomObjectsConstraintGroup, lowerPoint, upperPoint))
continue;
const osg::Matrixd localToGeocentricTransform = buffer._transform->getMatrix();
if (checkAgainstElevationConstraints(lowerPoint * localToGeocentricTransform, upperPoint * localToGeocentricTransform))
continue;
handler->placeObject(vp, up, n);
@ -2364,7 +2370,7 @@ void VPBTechnique::removeElevationConstraint(osg::ref_ptr<osg::Node> constraint)
// Check a given vertex against any elevation constraints E.g. to ensure the terrain mesh doesn't
// poke through any airport meshes. If such a constraint exists, the function will return a replacement
// vertex displaces such that it lies 1m below the contraint relative to the passed in origin.
osg::Vec3d VPBTechnique::checkAgainstElevationConstraints(osg::Vec3d origin, osg::Vec3d vertex, float vtx_gap)
osg::Vec3d VPBTechnique::checkAndDisplaceAgainstElevationConstraints(osg::Vec3d origin, osg::Vec3d vertex, float vtx_gap)
{
const std::lock_guard<std::mutex> lock(VPBTechnique::_elevationConstraintMutex); // Lock the _elevationConstraintGroup for this scope
osg::ref_ptr<osgUtil::LineSegmentIntersector> intersector;
@ -2382,6 +2388,17 @@ osg::Vec3d VPBTechnique::checkAgainstElevationConstraints(osg::Vec3d origin, osg
}
}
bool VPBTechnique::checkAgainstElevationConstraints(osg::Vec3d origin, osg::Vec3d vertex)
{
const std::lock_guard<std::mutex> lock(VPBTechnique::_elevationConstraintMutex); // Lock the _elevationConstraintGroup for this scope
osg::ref_ptr<osgUtil::LineSegmentIntersector> intersector;
intersector = new osgUtil::LineSegmentIntersector(origin, vertex);
osgUtil::IntersectionVisitor visitor(intersector.get());
_elevationConstraintGroup->accept(visitor);
return intersector->containsIntersections();
}
// Add an osg object representing a contraint on the terrain mesh. The generated
// terrain mesh will not include any random objects intersecting with the
// constraint model.

3
simgear/scene/tgdb/VPBTechnique.hxx
View File

@ -96,7 +96,8 @@ class VPBTechnique : public TerrainTechnique
// As airports are generated in a separate loading thread, these are static.
static void addElevationConstraint(osg::ref_ptr<osg::Node> constraint);
static void removeElevationConstraint(osg::ref_ptr<osg::Node> constraint);
static osg::Vec3d checkAgainstElevationConstraints(osg::Vec3d origin, osg::Vec3d vertex, float vertex_gap);
static osg::Vec3d checkAndDisplaceAgainstElevationConstraints(osg::Vec3d origin, osg::Vec3d vertex, float vertex_gap);
static bool checkAgainstElevationConstraints(osg::Vec3d origin, osg::Vec3d vertex);
static void clearConstraints();