Mesh::Mesh(const HalfedgeMesh& mesh, BSDF* bsdf) {
unordered_map<const Vertex *, int> vertexLabels;
vector<const Vertex *> verts;
size_t vertexI = 0;
for (VertexCIter it = mesh.verticesBegin(); it != mesh.verticesEnd(); it++) {
const Vertex *v = &*it;
verts.push_back(v);
vertexLabels[v] = vertexI;
vertexI++;
}
positions = new Vector3D[vertexI];
normals = new Vector3D[vertexI];
for (int i = 0; i < vertexI; i++) {
positions[i] = verts[i]->position;
normals[i] = verts[i]->normal;
}
for (FaceCIter f = mesh.facesBegin(); f != mesh.facesEnd(); f++) {
HalfedgeCIter h = f->halfedge();
indices.push_back(vertexLabels[&*h->vertex()]);
indices.push_back(vertexLabels[&*h->next()->vertex()]);
indices.push_back(vertexLabels[&*h->next()->next()->vertex()]);
}
this->bsdf = bsdf;
}
Vector3D Face::normal(void) const {
Vector3D N(0., 0., 0.);
HalfedgeCIter h = halfedge();
do {
Vector3D pi = h->vertex()->position;
Vector3D pj = h->next()->vertex()->position;
N += cross(pi, pj);
h = h->next();
} while (h != halfedge());
return N.unit();
}
Vector3D Vertex::normal( void ) const
// TODO Returns an approximate unit normal at this vertex, computed by
// TODO taking the area-weighted average of the normals of neighboring
// TODO triangles, then normalizing.
{
// TODO Compute and return the area-weighted unit normal.
//no boundary polygon
HalfedgeCIter h = this->halfedge();
Vector3D nrm(0, 0, 0);
double totalarea = 0;
do
{
h = h->twin();
FaceCIter f = h->face();
if(!f->isBoundary())
{
VertexCIter v1 = h->vertex();
VertexCIter v2 = h->next()->twin()->vertex();
Vector3D out = cross(v1->position - position, v2->position - position);
nrm += out;
totalarea += out.norm();
}
h = h->next();
}
while(h != this->halfedge());
nrm /= totalarea;
nrm.normalize();
return nrm;
}
