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Improvements to the plane clipping code.

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This commit is contained in:
Robert Osfield 2002-06-14 11:27:34 +00:00
parent d7760fbbd4
commit c71bf35152
1 changed files with 18 additions and 37 deletions
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55
src/osg/ShadowVolumeOccluder.cpp
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@ -9,7 +9,7 @@ using namespace osg;
typedef std::pair<bool,Vec3> Point; // bool=true signifies a newly created point, false indicates original point.
typedef std::pair<unsigned int,Vec3> Point; // bool=true signifies a newly created point, false indicates original point.
typedef std::vector<Point> PointList;
typedef std::vector<Vec3> VertexList;
@ -22,13 +22,13 @@ void convert(const VertexList& in,PointList& out)
itr!=in.end();
++itr)
{
out.push_back(Point(false,*itr));
out.push_back(Point(0,*itr));
}
}
// clip the convex hull 'in' to plane to generate a clipped convex hull 'out'
// return true if points remain after clipping.
unsigned int clip(const Plane& plane,const PointList& in, PointList& out)
unsigned int clip(const Plane& plane,const PointList& in, PointList& out,unsigned int planeMask)
{
std::vector<float> distance;
distance.reserve(in.size());
@ -49,17 +49,20 @@ unsigned int clip(const Plane& plane,const PointList& in, PointList& out)
{
out.push_back(in[i]);
if (distance[i_1]<0.0f)
{
unsigned int mask = (in[i].first & in[i_1].first) | planeMask;
float r = distance[i_1]/(distance[i_1]-distance[i]);
out.push_back(Point(true,in[i].second*r+in[i_1].second*(1.0f-r)));
out.push_back(Point(mask,in[i].second*r+in[i_1].second*(1.0f-r)));
}
}
else if (distance[i_1]>0.0f)
{
unsigned int mask = (in[i].first & in[i_1].first) | planeMask;
float r = distance[i_1]/(distance[i_1]-distance[i]);
out.push_back(Point(true,in[i].second*r+in[i_1].second*(1.0f-r)));
out.push_back(Point(mask,in[i].second*r+in[i_1].second*(1.0f-r)));
}
}
@ -73,12 +76,14 @@ unsigned int clip(const Polytope::PlaneList& planeList,const VertexList& vin,Poi
PointList in;
convert(vin,in);
unsigned int planeMask = 0x1;
for(Polytope::PlaneList::const_iterator itr=planeList.begin();
itr!=planeList.end();
++itr)
{
if (!clip(*itr,in,out)) return false;
if (!clip(*itr,in,out,planeMask)) return false;
in.swap(out);
planeMask <<= 1;
}
in.swap(out);
@ -112,9 +117,7 @@ void pushToFarPlane(PointList& points)
itr!=points.end();
++itr)
{
// std::cout << "itr->second "<< itr->second<< " after ";
itr->second.z() += 1.0f;
// std::cout << itr->second<< std::endl;
itr->second.z() = 1.0f;
}
}
@ -123,7 +126,7 @@ void computePlanes(const PointList& front, const PointList& back, Polytope::Plan
for(unsigned int i=0;i<front.size();++i)
{
unsigned int i_1 = (i+1)%front.size(); // do the mod to wrap the index round back to the start.
if (!front[i].first || !front[i_1].first)
if (!(front[i].first & front[i_1].first))
{
planeList.push_back(Plane(front[i].second,front[i_1].second,back[i].second));
}
@ -211,25 +214,9 @@ bool ShadowVolumeOccluder::computeOccluder(const NodePath& nodePath,const Convex
Matrix invP;
invP.invert(P);
// std::cout<<"P "<<P<<std::endl;
// std::cout<<"invP "<<invP<<std::endl;
//
// Vec3 v1(0,0,1000);
// std::cout<<"v1 "<<v1<<std::endl;
// Vec3 v2 = v1*P;
// std::cout<<"v2 "<<v2<<std::endl;
// Vec3 v3 = v2*invP;
// std::cout<<"v3 "<<v3<<std::endl;
//
// Vec3 v4(0,0,1);
// std::cout<<"v4 "<<v4<<std::endl;
// Vec3 v5=v4*invP;
// std::cout<<"v5 "<<v5<<std::endl;
// compute the transformation matrix which takes form local coords into clip space.
Matrix MVP(MV*P);
//MVP *= P;
// for the occluder polygon and each of the holes do
// first transform occluder polygon into clipspace by multiple it by c[i] = v[i]*(MV*P)
@ -255,13 +242,15 @@ bool ShadowVolumeOccluder::computeOccluder(const NodePath& nodePath,const Convex
// move the occlude points into projection space.
transform(points,MV);
// create the sides of the occluder
computePlanes(points,farPoints,_occluderVolume.getPlaneList());
// create the front face of the occluder
Plane occludePlane = computeFrontPlane(points);
_occluderVolume.add(occludePlane);
// create the sides of the occluder
computePlanes(points,farPoints,_occluderVolume.getPlaneList());
_occluderVolume.setupMask();
// if the front face is pointing away from the eye point flip the whole polytope.
if (occludePlane[3]>0.0f)
{
@ -280,13 +269,6 @@ bool ShadowVolumeOccluder::computeOccluder(const NodePath& nodePath,const Convex
transform(points,invMV);
transform(farPoints,invMV);
// Vec3 v6=v5*invMV;
// std::cout<<"******************"<<std::endl;
// std::cout<<"MV "<<MV<<std::endl;
// std::cout<<"invMV "<<invMV<<std::endl;
// std::cout<<"MV*invMV "<<MV*invMV<<std::endl;
// std::cout<<"v6 "<<v6<<std::endl;
osg::Geode* geode = osgNew osg::Geode;
group->addChild(geode);
geode->addDrawable(createOccluderDrawable(points,farPoints));
@ -298,7 +280,6 @@ bool ShadowVolumeOccluder::computeOccluder(const NodePath& nodePath,const Convex
}
else
{
std::cout << " occluder clipped out of frustum."<<points.size()<<std::endl;
return false;
}
}