OpenSubdiv/opensubdiv/hbr/subdivision.h
2012-06-08 11:18:20 -07:00

295 lines
12 KiB
C++

//
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#ifndef HBRSUBDIVISION_H
#define HBRSUBDIVISION_H
template <class T> class HbrFace;
template <class T> class HbrVertex;
template <class T> class HbrHalfedge;
template <class T> class HbrMesh;
template <class T> class HbrSubdivision {
public:
HbrSubdivision<T>()
: creaseSubdivision(k_CreaseNormal) {}
virtual ~HbrSubdivision<T>() {}
virtual HbrSubdivision<T>* Clone() const = 0;
// How to subdivide a face
virtual void Refine(HbrMesh<T>* mesh, HbrFace<T>* face) = 0;
// Subdivide a face only at a particular vertex (creating one child)
virtual HbrFace<T>* RefineFaceAtVertex(HbrMesh<T>* mesh, HbrFace<T>* face, HbrVertex<T>* vertex) = 0;
// Refine all faces around a particular vertex
virtual void RefineAtVertex(HbrMesh<T>* mesh, HbrVertex<T>* vertex);
// Given an edge, try to ensure the edge's opposite exists by
// forcing refinement up the hierarchy
virtual void GuaranteeNeighbor(HbrMesh<T>* mesh, HbrHalfedge<T>* edge) = 0;
// Given an vertex, ensure all faces in the ring around it exist
// by forcing refinement up the hierarchy
virtual void GuaranteeNeighbors(HbrMesh<T>* mesh, HbrVertex<T>* vertex) = 0;
// Returns true if the vertex, edge, or face has a limit point,
// curve, or surface associated with it
virtual bool HasLimit(HbrMesh<T>* /* mesh */, HbrFace<T>* /* face */) { return true; }
virtual bool HasLimit(HbrMesh<T>* /* mesh */, HbrHalfedge<T>* /* edge */) { return true; }
virtual bool HasLimit(HbrMesh<T>* /* mesh */, HbrVertex<T>* /* vertex */) { return true; }
// How to turn faces, edges, and vertices into vertices
virtual HbrVertex<T>* Subdivide(HbrMesh<T>* mesh, HbrFace<T>* face) = 0;
virtual HbrVertex<T>* Subdivide(HbrMesh<T>* mesh, HbrHalfedge<T>* edge) = 0;
virtual HbrVertex<T>* Subdivide(HbrMesh<T>* mesh, HbrVertex<T>* vertex) = 0;
// Returns true if the vertex is extraordinary in the subdivision scheme
virtual bool VertexIsExtraordinary(HbrMesh<T>* /* mesh */, HbrVertex<T>* /* vertex */) { return false; }
// Crease subdivision rules. When subdividing a edge with a crease
// strength, we get two child subedges, and we need to determine
// what weights to assign these subedges. The "normal" rule
// is to simply assign the current edge's crease strength - 1
// to both of the child subedges. The "Chaikin" rule looks at the
// current edge and incident edges to the current edge's end
// vertices, and weighs them; for more information consult
// the Geri's Game paper.
enum CreaseSubdivision {
k_CreaseNormal,
k_CreaseChaikin
};
CreaseSubdivision GetCreaseSubdivisionMethod() const { return creaseSubdivision; }
void SetCreaseSubdivisionMethod(CreaseSubdivision method) { creaseSubdivision = method; }
// Figures out how to assign a crease weight on an edge to its
// subedge. The subedge must be a child of the parent edge
// (either subedge->GetOrgVertex() or subedge->GetDestVertex()
// == edge->Subdivide()). The vertex supplied must NOT be
// a parent of the subedge; it is either the origin or
// destination vertex of edge.
void SubdivideCreaseWeight(HbrHalfedge<T>* edge, HbrVertex<T>* vertex, HbrHalfedge<T>* subedge);
// Returns the expected number of children faces after subdivision
// for a face with the given number of vertices.
virtual int GetFaceChildrenCount(int nvertices) const = 0;
protected:
CreaseSubdivision creaseSubdivision;
// Helper routine for subclasses: for a given vertex, sums
// contributions from surrounding vertices
void AddSurroundingVerticesWithWeight(HbrMesh<T>* mesh, HbrVertex<T>* vertex, float weight, T* data);
// Helper routine for subclasses: for a given vertex with a crease
// mask, adds contributions from the two crease edges
void AddCreaseEdgesWithWeight(HbrMesh<T>* mesh, HbrVertex<T>* vertex, bool next, float weight, T* data);
private:
// Helper class used by AddSurroundingVerticesWithWeight
class SmoothSubdivisionVertexOperator : public HbrVertexOperator<T> {
public:
SmoothSubdivisionVertexOperator(T* data, bool meshHasEdits, float weight)
: m_data(data),
m_meshHasEdits(meshHasEdits),
m_weight(weight)
{
}
virtual void operator() (HbrVertex<T> &vertex) {
// Must ensure vertex edits have been applied
if (m_meshHasEdits) {
vertex.GuaranteeNeighbors();
}
m_data->AddWithWeight(vertex.GetData(), m_weight);
}
private:
T* m_data;
const bool m_meshHasEdits;
const float m_weight;
};
// Helper class used by AddCreaseEdgesWithWeight
class CreaseSubdivisionHalfedgeOperator : public HbrHalfedgeOperator<T> {
public:
CreaseSubdivisionHalfedgeOperator(HbrVertex<T> *vertex, T* data, bool meshHasEdits, bool next, float weight)
: m_vertex(vertex),
m_data(data),
m_meshHasEdits(meshHasEdits),
m_next(next),
m_weight(weight),
m_count(0)
{
}
virtual void operator() (HbrHalfedge<T> &edge) {
if (m_count < 2 && edge.IsSharp(m_next)) {
HbrVertex<T>* a = edge.GetDestVertex();
if (a == m_vertex) a = edge.GetOrgVertex();
// Must ensure vertex edits have been applied
if (m_meshHasEdits) {
a->GuaranteeNeighbors();
}
m_data->AddWithWeight(a->GetData(), m_weight);
m_count++;
}
}
private:
HbrVertex<T>* m_vertex;
T* m_data;
const bool m_meshHasEdits;
const bool m_next;
const float m_weight;
int m_count;
};
private:
// Helper class used by RefineAtVertex.
class RefineFaceAtVertexOperator : public HbrFaceOperator<T> {
public:
RefineFaceAtVertexOperator(HbrSubdivision<T>* subdivision, HbrMesh<T>* mesh, HbrVertex<T> *vertex)
: m_subdivision(subdivision),
m_mesh(mesh),
m_vertex(vertex)
{
}
virtual void operator() (HbrFace<T> &face) {
m_subdivision->RefineFaceAtVertex(m_mesh, &face, m_vertex);
}
private:
HbrSubdivision<T>* const m_subdivision;
HbrMesh<T>* const m_mesh;
HbrVertex<T>* const m_vertex;
};
};
template <class T>
void
HbrSubdivision<T>::RefineAtVertex(HbrMesh<T>* mesh, HbrVertex<T>* vertex) {
GuaranteeNeighbors(mesh, vertex);
RefineFaceAtVertexOperator op(this, mesh, vertex);
vertex->ApplyOperatorSurroundingFaces(op);
}
template <class T>
void
HbrSubdivision<T>::SubdivideCreaseWeight(HbrHalfedge<T>* edge, HbrVertex<T>* vertex, HbrHalfedge<T>* subedge) {
float sharpness = edge->GetSharpness();
// In all methods, if the parent edge is infinitely sharp, the
// child edge is also infinitely sharp
if (sharpness >= HbrHalfedge<T>::k_InfinitelySharp) {
subedge->SetSharpness(HbrHalfedge<T>::k_InfinitelySharp);
}
// Chaikin's curve subdivision: use 3/4 of the parent sharpness,
// plus 1/4 of crease sharpnesses incident to vertex
else if (creaseSubdivision == HbrSubdivision<T>::k_CreaseChaikin) {
float childsharp = 0.0f;
// Add 1/4 of the sharpness of all crease edges incident to
// the vertex (other than this crease edge)
std::list<HbrHalfedge<T>*> edges;
vertex->GuaranteeNeighbors();
vertex->GetSurroundingEdges(edges);
int n = 0;
for (typename std::list<HbrHalfedge<T>*>::iterator ei = edges.begin(); ei != edges.end(); ++ei) {
if (*ei == edge) continue;
if ((*ei)->GetSharpness() > HbrHalfedge<T>::k_Smooth) {
childsharp += (*ei)->GetSharpness();
n++;
}
}
if (n) {
childsharp = childsharp * 0.25f / n;
}
// Add 3/4 of the sharpness of this crease edge
childsharp += sharpness * 0.75f;
childsharp -= 1.0f;
if (childsharp < (float) HbrHalfedge<T>::k_Smooth) {
childsharp = (float) HbrHalfedge<T>::k_Smooth;
}
subedge->SetSharpness(childsharp);
} else {
sharpness -= 1.0f;
if (sharpness < (float) HbrHalfedge<T>::k_Smooth) {
sharpness = (float) HbrHalfedge<T>::k_Smooth;
}
subedge->SetSharpness(sharpness);
}
}
template <class T>
void
HbrSubdivision<T>::AddSurroundingVerticesWithWeight(HbrMesh<T>* mesh, HbrVertex<T>* vertex, float weight, T* data) {
SmoothSubdivisionVertexOperator op(data, mesh->HasVertexEdits(), weight);
vertex->ApplyOperatorSurroundingVertices(op);
}
template <class T>
void
HbrSubdivision<T>::AddCreaseEdgesWithWeight(HbrMesh<T>* mesh, HbrVertex<T>* vertex, bool next, float weight, T* data) {
CreaseSubdivisionHalfedgeOperator op(vertex, data, mesh->HasVertexEdits(), next, weight);
vertex->ApplyOperatorSurroundingEdges(op);
}
#endif /* HBRSUBDIVISION_H */