/*! Subdivides the face at faceindex into a vector of faces
*/
std::vector< std::vector<Vector3<float> > > LoopSubdivisionMesh::Subdivide(unsigned int faceIndex)
{
std::vector< std::vector<Vector3<float> > > faces;
EdgeIterator eit = GetEdgeIterator( f(faceIndex).edge );
// get the inner halfedges
unsigned int e0, e1, e2;
// and their vertex indices
unsigned int v0, v1, v2;
e0 = eit.GetEdgeIndex();
v0 = eit.GetEdgeVertexIndex();
eit.Next();
e1 = eit.GetEdgeIndex();
v1 = eit.GetEdgeVertexIndex();
eit.Next();
e2 = eit.GetEdgeIndex();
v2 = eit.GetEdgeVertexIndex();
// Compute positions of the vertices
Vector3<float> pn0 = VertexRule(v0);
Vector3<float> pn1 = VertexRule(v1);
Vector3<float> pn2 = VertexRule(v2);
// Compute positions of the edge vertices
Vector3<float> pn3 = EdgeRule(e0);
Vector3<float> pn4 = EdgeRule(e1);
Vector3<float> pn5 = EdgeRule(e2);
// add the four new triangles to new mesh
std::vector<Vector3<float> > verts;
verts.push_back(pn0); verts.push_back(pn3); verts.push_back(pn5);
faces.push_back(verts);
verts.clear();
verts.push_back(pn3); verts.push_back(pn4); verts.push_back(pn5);
faces.push_back(verts);
verts.clear();
verts.push_back(pn3); verts.push_back(pn1); verts.push_back(pn4);
faces.push_back(verts);
verts.clear();
verts.push_back(pn5); verts.push_back(pn4); verts.push_back(pn2);
faces.push_back(verts);
return faces;
}
float HalfEdgeMesh::FaceCurvature(unsigned int faceIndex) const
{
// NB Assumes vertex curvature already computed
unsigned int indx = f(faceIndex).edge;
const EdgeIterator it = GetEdgeIterator(indx);
const Vertex& v1 = v(it.GetEdgeVertexIndex());
const Vertex &v2 = v(it.Next().GetEdgeVertexIndex());
const Vertex &v3 = v(it.Next().GetEdgeVertexIndex());
return (v1.curvature + v2.curvature + v3.curvature) / 3.f;
}
/*! Subdivides the face at faceIndex given 3 not subdividable neighbors
or if subdividable for this face is false
*/
std::vector< std::vector<Vector3<float> > >
AdaptiveLoopSubdivisionMesh::Subdivide3(unsigned int faceIndex){
EdgeIterator eit = GetEdgeIterator( f(faceIndex).edge );
Vector3<float> v1 = VertexRule(eit.GetEdgeVertexIndex());
Vector3<float> v2 = VertexRule(eit.Next().GetEdgeVertexIndex());
Vector3<float> v3 = VertexRule(eit.Next().GetEdgeVertexIndex());
std::vector<Vector3<float> > face;
face.push_back(v1); face.push_back(v2); face.push_back(v3);
std::vector< std::vector<Vector3<float> > > faces;
faces.push_back(face);
return faces;
}
Vector3<float> HalfEdgeMesh::FaceNormal(unsigned int faceIndex) const
{
unsigned int indx = f(faceIndex).edge;
const EdgeIterator it = GetEdgeIterator(indx);
const Vector3<float> &p1 = v(it.GetEdgeVertexIndex()).pos;
const Vector3<float> &p2 = v(it.Next().GetEdgeVertexIndex()).pos;
const Vector3<float> &p3 = v(it.Next().GetEdgeVertexIndex()).pos;
const Vector3<float> e1 = p2-p1;
const Vector3<float> e2 = p3-p1;
return Cross(e1, e2).Normalize();
}
/*! Subdivides the face at faceIndex given 2 not subdividable neighbors
*/
std::vector< std::vector<Vector3<float> > >
AdaptiveLoopSubdivisionMesh::Subdivide2(unsigned int faceIndex){
// We know we have otwo false faces
// 1. Start by orienting the triangle so that we always have the same case
// We find the start edge as the edge who shares face with the _subdividable_ neighbor
EdgeIterator eit = GetEdgeIterator( f(faceIndex).edge );
unsigned int num = 0;
while( !Subdividable(eit.Pair().GetEdgeFaceIndex()) ){
eit.Pair().Next();
assert(num++ < 3);
}
// go back to inner edge
eit.Pair();
// 2. Now find the vertices
std::vector< std::vector<Vector3<float> > > faces;
// corner vertices, labeled from current edge's origin vertex
Vector3<float> v1 = VertexRule(eit.GetEdgeVertexIndex());
Vector3<float> v2 = VertexRule(eit.Next().GetEdgeVertexIndex());
Vector3<float> v3 = VertexRule(eit.Next().GetEdgeVertexIndex());
// edge vertices, labeled from start edge
Vector3<float> e1v = EdgeRule( eit.Next().GetEdgeIndex() );
// 3. Create the 2 faces and push them on the vector
std::vector<Vector3<float> > face;
face.push_back(v1); face.push_back(e1v); face.push_back(v3);
faces.push_back(face);
face.clear();
face.push_back(e1v); face.push_back(v2); face.push_back(v3);
faces.push_back(face);
face.clear();
// 4. Return
return faces;
}
