OpenSubdiv/opensubdiv/far/gregoryBasis.cpp
Takahito Tejima 43aa2500c4 Refactor far factories.
This change moves all gregory patch generation from Far::PatchTablesFactory
so that we can construct patch tables without stencil tables as well as client
can chose any end patch strategies (we have 3 options for now: legacy 2.x style
gregory patch, gregory basis patch and experimental regular patch approximation).

Also Far::EndCapGregoryBasisPatchFactory provides index mapping from patch index
to vtr face index, which can be used for single gregory patch evaluation on top
of refined points, without involving heavier stencil tables generation.
2015-04-20 18:59:07 -07:00

397 lines
14 KiB
C++

//
// Copyright 2013 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#include "../far/gregoryBasis.h"
#include "../far/error.h"
#include "../far/stencilTablesFactory.h"
#include "../far/topologyRefiner.h"
#include <cassert>
#include <cmath>
#include <cstring>
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
namespace Far {
// Builds a table of local indices pairs for each vertex of the patch.
//
// o
// N0 |
// | ....
// | .... : Gregory patch
// o ------ o ------ o ....
// N1 V | .... M3
// | .......
// | .......
// o .......
// N2
//
// [...] [N2 - N3] [...]
//
// Each value pair is composed of 2 index values in range [0-4[ pointing
// to the 2 neighbor vertices of the vertex 'V' belonging to the Gregory patch.
// Neighbor ordering is valence CCW and must match the winding of the 1-ring
// vertices.
//
static void
getQuadOffsets(Vtr::Level const & level, Vtr::Index fIndex,
Vtr::Index offsets[], int fvarChannel=-1) {
Far::ConstIndexArray fPoints = (fvarChannel<0) ?
level.getFaceVertices(fIndex) :
level.getFVarFaceValues(fIndex, fvarChannel);
assert(fPoints.size()==4);
for (int i = 0; i < 4; ++i) {
Vtr::Index vIndex = fPoints[i];
Vtr::ConstIndexArray vFaces = level.getVertexFaces(vIndex),
vEdges = level.getVertexEdges(vIndex);
int thisFaceInVFaces = -1;
for (int j = 0; j < vFaces.size(); ++j) {
if (fIndex == vFaces[j]) {
thisFaceInVFaces = j;
break;
}
}
assert(thisFaceInVFaces != -1);
// we have to use the number of incident edges to modulo the local index
// because there could be 2 consecutive edges in the face belonging to
// the Gregory patch.
offsets[i*2+0] = thisFaceInVFaces;
offsets[i*2+1] = (thisFaceInVFaces + 1)%vEdges.size();
}
}
int
GregoryBasis::ProtoBasis::GetNumElements() const {
int nelems=0;
for (int vid=0; vid<4; ++vid) {
nelems += P[vid].GetSize();
nelems += Ep[vid].GetSize();
nelems += Em[vid].GetSize();
nelems += Fp[vid].GetSize();
nelems += Fm[vid].GetSize();
}
return nelems;
}
void
GregoryBasis::ProtoBasis::Copy(int * sizes, Index * indices, float * weights) const {
for (int vid=0; vid<4; ++vid) {
P[vid].Copy(&sizes, &indices, &weights);
Ep[vid].Copy(&sizes, &indices, &weights);
Em[vid].Copy(&sizes, &indices, &weights);
Fp[vid].Copy(&sizes, &indices, &weights);
Fm[vid].Copy(&sizes, &indices, &weights);
}
}
inline float csf(Index n, Index j) {
if (j%2 == 0) {
return cosf((2.0f * float(M_PI) * float(float(j-0)/2.0f))/(float(n)+3.0f));
} else {
return sinf((2.0f * float(M_PI) * float(float(j-1)/2.0f))/(float(n)+3.0f));
}
}
GregoryBasis::ProtoBasis::ProtoBasis(
Vtr::Level const & level, Index faceIndex, int fvarChannel) {
static float ef[MAX_VALENCE-3] = {
0.812816f, 0.500000f, 0.363644f, 0.287514f,
0.238688f, 0.204544f, 0.179229f, 0.159657f,
0.144042f, 0.131276f, 0.120632f, 0.111614f,
0.103872f, 0.09715f, 0.0912559f, 0.0860444f,
0.0814022f, 0.0772401f, 0.0734867f, 0.0700842f,
0.0669851f, 0.0641504f, 0.0615475f, 0.0591488f,
0.0569311f, 0.0548745f, 0.0529621f
};
Vtr::ConstIndexArray facePoints = (fvarChannel<0) ?
level.getFaceVertices(faceIndex) :
level.getFVarFaceValues(faceIndex, fvarChannel);
assert(facePoints.size()==4);
int maxvalence = level.getMaxValence(),
valences[4],
zerothNeighbors[4];
Index * manifoldRing = (int *)alloca((maxvalence+2)*2 * sizeof(int));
// Because MSVC does not support VLAs, we have to run alloca() in a macro and
// call in-place constructors - it's only been standardized for 15 years after
// all...
#define AllocaPointsArrays(variable, npoints) \
Point * variable = (Point *)alloca(npoints*sizeof(Point)); \
{ for (int i=0; i<npoints; ++i) { new (&variable[i]) Point; } }
AllocaPointsArrays(f, maxvalence);
AllocaPointsArrays(r, maxvalence*4);
Point e0[4], e1[4], org[4];
for (int vid=0; vid<4; ++vid) {
org[vid] = facePoints[vid];
// save for varying stencils
V[vid] = facePoints[vid];
int ringSize =
level.gatherQuadRegularRingAroundVertex(
facePoints[vid], manifoldRing, fvarChannel);
int valence;
if (ringSize & 1) {
// boundary vertex
manifoldRing[ringSize] = manifoldRing[ringSize-1];
++ringSize;
valence = -ringSize/2;
} else {
valence = ringSize/2;
}
int ivalence = abs(valence);
valences[vid] = valence;
Index boundaryEdgeNeighbors[2],
currentNeighbor = 0,
zerothNeighbor=0,
ibefore=0;
Point pos(facePoints[vid]);
for (int i=0; i<ivalence; ++i) {
Index im = (i+ivalence-1)%ivalence,
ip = (i+1)%ivalence;
Index idx_neighbor = (manifoldRing[2*i + 0]),
idx_diagonal = (manifoldRing[2*i + 1]),
idx_neighbor_p = (manifoldRing[2*ip + 0]),
idx_neighbor_m = (manifoldRing[2*im + 0]),
idx_diagonal_m = (manifoldRing[2*im + 1]);
bool boundaryNeighbor = (level.getVertexEdges(idx_neighbor).size() >
level.getVertexFaces(idx_neighbor).size());
if (fvarChannel>=0) {
// XXXX manuelk need logic to check for boundary in fvar
boundaryNeighbor = false;
}
if (boundaryNeighbor) {
if (currentNeighbor<2) {
boundaryEdgeNeighbors[currentNeighbor] = idx_neighbor;
}
++currentNeighbor;
if (currentNeighbor==1) {
ibefore = zerothNeighbor = i;
} else {
if (i-ibefore==1) {
std::swap(boundaryEdgeNeighbors[0], boundaryEdgeNeighbors[1]);
zerothNeighbor = i;
}
}
}
Point neighbor(idx_neighbor),
diagonal(idx_diagonal),
neighbor_p(idx_neighbor_p),
neighbor_m(idx_neighbor_m),
diagonal_m(idx_diagonal_m);
f[i] = (pos*float(ivalence) + (neighbor_p+neighbor)*2.0f + diagonal) / (float(ivalence)+5.0f);
P[vid] += f[i];
r[vid*maxvalence+i] = (neighbor_p-neighbor_m)/3.0f + (diagonal-diagonal_m)/6.0f;
}
P[vid] /= float(ivalence);
zerothNeighbors[vid] = zerothNeighbor;
if (currentNeighbor == 1) {
boundaryEdgeNeighbors[1] = boundaryEdgeNeighbors[0];
}
for (int i=0; i<ivalence; ++i) {
int im = (i+ivalence-1)%ivalence;
Point e = (f[i]+f[im])*0.5f;
e0[vid] += e * csf(ivalence-3, 2*i);
e1[vid] += e * csf(ivalence-3, 2*i+1);
}
e0[vid] *= ef[ivalence-3];
e1[vid] *= ef[ivalence-3];
if (valence<0) {
Point b0(boundaryEdgeNeighbors[0]),
b1(boundaryEdgeNeighbors[1]);
if (ivalence>2) {
P[vid] = (b0 + b1 + pos*4.0f)/6.0f;
} else {
P[vid] = pos;
}
float k = float(float(ivalence) - 1.0f); //k is the number of faces
float c = cosf(float(M_PI)/k);
float s = sinf(float(M_PI)/k);
float gamma = -(4.0f*s)/(3.0f*k+c);
float alpha_0k = -((1.0f+2.0f*c)*sqrtf(1.0f+c))/((3.0f*k+c)*sqrtf(1.0f-c));
float beta_0 = s/(3.0f*k + c);
Point diagonal(manifoldRing[2*zerothNeighbor + 1]);
e0[vid] = (b0 - b1)/6.0f;
e1[vid] = pos*gamma + diagonal*beta_0 + (b0 + b1)*alpha_0k;
for (int x=1; x<ivalence-1; ++x) {
Index curri = ((x + zerothNeighbor)%ivalence);
float alpha = (4.0f*sinf((float(M_PI) * float(x))/k))/(3.0f*k+c),
beta = (sinf((float(M_PI) * float(x))/k) + sinf((float(M_PI) * float(x+1))/k))/(3.0f*k+c);
Index idx_neighbor = manifoldRing[2*curri + 0],
idx_diagonal = manifoldRing[2*curri + 1];
Point p_neighbor(idx_neighbor),
p_diagonal(idx_diagonal);
e1[vid] += p_neighbor*alpha + p_diagonal*beta;
}
e1[vid] /= 3.0f;
}
}
Index quadOffsets[8];
getQuadOffsets(level, faceIndex, quadOffsets, fvarChannel);
for (int vid=0; vid<4; ++vid) {
int n = abs(valences[vid]),
ivalence = n;
int ip = (vid+1)%4,
im = (vid+3)%4,
np = abs(valences[ip]),
nm = abs(valences[im]);
Index start = quadOffsets[vid*2+0],
prev = quadOffsets[vid*2+1],
start_m = quadOffsets[im*2],
prev_p = quadOffsets[ip*2+1];
Point Em_ip, Ep_im;
if (valences[ip]<-2) {
Index j = (np + prev_p - zerothNeighbors[ip]) % np;
Em_ip = P[ip] + e0[ip]*cosf((float(M_PI)*j)/float(np-1)) + e1[ip]*sinf((float(M_PI)*j)/float(np-1));
} else {
Em_ip = P[ip] + e0[ip]*csf(np-3,2*prev_p) + e1[ip]*csf(np-3,2*prev_p+1);
}
if (valences[im]<-2) {
Index j = (nm + start_m - zerothNeighbors[im]) % nm;
Ep_im = P[im] + e0[im]*cosf((float(M_PI)*j)/float(nm-1)) + e1[im]*sinf((float(M_PI)*j)/float(nm-1));
} else {
Ep_im = P[im] + e0[im]*csf(nm-3,2*start_m) + e1[im]*csf(nm-3,2*start_m+1);
}
if (valences[vid] < 0) {
n = (n-1)*2;
}
if (valences[im] < 0) {
nm = (nm-1)*2;
}
if (valences[ip] < 0) {
np = (np-1)*2;
}
Point const * rp = &r[vid*maxvalence];
if (valences[vid] > 2) {
float s1 = 3.0f - 2.0f*csf(n-3,2)-csf(np-3,2),
s2 = 2.0f*csf(n-3,2),
s3 = 3.0f -2.0f*cosf(2.0f*float(M_PI)/float(n)) - cosf(2.0f*float(M_PI)/float(nm));
Ep[vid] = P[vid] + e0[vid]*csf(n-3, 2*start) + e1[vid]*csf(n-3, 2*start +1);
Em[vid] = P[vid] + e0[vid]*csf(n-3, 2*prev ) + e1[vid]*csf(n-3, 2*prev + 1);
Fp[vid] = (P[vid]*csf(np-3,2) + Ep[vid]*s1 + Em_ip*s2 + rp[start])/3.0f;
Fm[vid] = (P[vid]*csf(nm-3,2) + Em[vid]*s3 + Ep_im*s2 - rp[prev])/3.0f;
} else if (valences[vid] < -2) {
Index jp = (ivalence + start - zerothNeighbors[vid]) % ivalence,
jm = (ivalence + prev - zerothNeighbors[vid]) % ivalence;
float s1 = 3-2*csf(n-3,2)-csf(np-3,2),
s2 = 2*csf(n-3,2),
s3 = 3.0f-2.0f*cosf(2.0f*float(M_PI)/n)-cosf(2.0f*float(M_PI)/nm);
Ep[vid] = P[vid] + e0[vid]*cosf((float(M_PI)*jp)/float(ivalence-1)) + e1[vid]*sinf((float(M_PI)*jp)/float(ivalence-1));
Em[vid] = P[vid] + e0[vid]*cosf((float(M_PI)*jm)/float(ivalence-1)) + e1[vid]*sinf((float(M_PI)*jm)/float(ivalence-1));
Fp[vid] = (P[vid]*csf(np-3,2) + Ep[vid]*s1 + Em_ip*s2 + rp[start])/3.0f;
Fm[vid] = (P[vid]*csf(nm-3,2) + Em[vid]*s3 + Ep_im*s2 - rp[prev])/3.0f;
if (valences[im]<0) {
s1=3-2*csf(n-3,2)-csf(np-3,2);
Fp[vid] = Fm[vid] = (P[vid]*csf(np-3,2) + Ep[vid]*s1 + Em_ip*s2 + rp[start])/3.0f;
} else if (valences[ip]<0) {
s1 = 3.0f-2.0f*cosf(2.0f*float(M_PI)/n)-cosf(2.0f*float(M_PI)/nm);
Fm[vid] = Fp[vid] = (P[vid]*csf(nm-3,2) + Em[vid]*s1 + Ep_im*s2 - rp[prev])/3.0f;
}
} else if (valences[vid]==-2) {
Ep[vid] = (org[vid]*2.0f + org[ip])/3.0f;
Em[vid] = (org[vid]*2.0f + org[im])/3.0f;
Fp[vid] = Fm[vid] = (org[vid]*4.0f + org[((vid+2)%n)] + org[ip]*2.0f + org[im]*2.0f)/9.0f;
}
}
}
void
GregoryBasis::Point::FactorizeBasisVertex(StencilTables const * stencils,
ProtoStencil dst) {
// Use the Allocator to factorize the Gregory patch influence CVs with the
// supporting CVs from the stencil tables.
if (!stencils) return;
dst.Clear();
for (int j = 0; j < _size; ++j) {
dst.AddWithWeight(*stencils, _indices[j], _weights[j]);
}
}
} // end namespace Far
} // end namespace OPENSUBDIV_VERSION
} // end namespace OpenSubdiv