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From Wojciech Lewandowski, "----1----

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Attached is a fixed version of OverlayNode.cpp. I fixed CustomPolytope::cut( osg::Plane ) method.  Bug was apparent in such scenario:
 
Let P1 be some random frustum polytope
Let P2 be the polytope that was created from P1 bounding box (P2 contains P1 entirely)
 
Then ignoring precision errors: P1.cut( P2 ) == P2.cut( P1 ) == P1.  But this condition was not always met. Cut failed when some of the polytope reference points happened to lie exactly on some intersecting planes in both P1 & P2  (plane distance was = 0).
 
I only use CustomPolytope for my shadowing stuff so I did not test how this affects rest of OverlayNode.cpp.
 
----2----
 
Also attached is a minor precision improvement for osg::Plane intersect method (double version). 
 
----3----
 
I have also one observation regarding osg::Plane - There are two intersect vertices methods (float and double flavour):
 
inline int intersect(const std::vector<Vec3>& vertices) const
inline int intersect(const std::vector<Vec3d>& vertices) const
 
I guess osg::Plane won't compile when someone changes default vec3 typedef to vec3d. Shouldn't the first method be changed to use vec3f explicitly ? Ie:
 
inline int intersect(const std::vector<Vec3f>& vertices) const"
This commit is contained in:
Robert Osfield 2008-02-25 14:15:27 +00:00
parent adbc15b5a1
commit 55de8b03d9
2 changed files with 8 additions and 5 deletions
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10
include/osg/Plane
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@ -189,14 +189,14 @@ class OSG_EXPORT Plane
return 1 if the bs is completely above plane,
return 0 if the bs intersects the plane,
return -1 if the bs is completely below the plane.*/
inline int intersect(const std::vector<Vec3>& vertices) const
inline int intersect(const std::vector<Vec3f>& vertices) const
{
if (vertices.empty()) return -1;
int noAbove = 0;
int noBelow = 0;
int noOn = 0;
for(std::vector<Vec3>::const_iterator itr=vertices.begin();
for(std::vector<Vec3f>::const_iterator itr=vertices.begin();
itr != vertices.end();
++itr)
{
@ -229,9 +229,9 @@ class OSG_EXPORT Plane
itr != vertices.end();
++itr)
{
float d = distance(*itr);
if (d>0.0f) ++noAbove;
else if (d<0.0f) ++noBelow;
double d = distance(*itr);
if (d>0.0) ++noAbove;
else if (d<0.0) ++noBelow;
else ++noOn;
}

3
src/osgSim/OverlayNode.cpp
View File

@ -641,6 +641,9 @@ public:
// is first edge point inside plane?
if (distance_a>=0.0) newVertices.push_back(vertices[i]);
// add point to new face if point exactly on a plane
if (distance_a==0.0) newFace.vertices.push_back(vertices[i]);
// does edge intersect plane
if (distance_a * distance_b<0.0)
{