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https://github.com/PixarAnimationStudios/OpenSubdiv
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815e54edd0
Although valence 2 gregory patch is not well supported yet, this fix mitigates artifacts around such a vertex. Adding a shape catmark_gregory_test8 to see this issue.
452 lines
15 KiB
C++
452 lines
15 KiB
C++
//
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// Copyright 2013 Pixar
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//
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// Licensed under the Apache License, Version 2.0 (the "Apache License")
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// with the following modification; you may not use this file except in
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// compliance with the Apache License and the following modification to it:
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// Section 6. Trademarks. is deleted and replaced with:
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//
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// 6. Trademarks. This License does not grant permission to use the trade
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// names, trademarks, service marks, or product names of the Licensor
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// and its affiliates, except as required to comply with Section 4(c) of
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// the License and to reproduce the content of the NOTICE file.
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//
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// You may obtain a copy of the Apache License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the Apache License with the above modification is
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// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the Apache License for the specific
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// language governing permissions and limitations under the Apache License.
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//
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#include "../far/gregoryBasis.h"
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#include "../far/error.h"
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#include "../far/stencilTableFactory.h"
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#include "../far/topologyRefiner.h"
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#include "../vtr/stackBuffer.h"
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#include <cassert>
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#include <cmath>
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#include <cstring>
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namespace OpenSubdiv {
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namespace OPENSUBDIV_VERSION {
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namespace Far {
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// Builds a table of local indices pairs for each vertex of the patch.
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//
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// o
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// N0 |
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// | ....
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// | .... : Gregory patch
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// o ------ o ------ o ....
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// N1 V | .... M3
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// | .......
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// | .......
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// o .......
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// N2
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//
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// [...] [N2 - N3] [...]
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//
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// Each value pair is composed of 2 index values in range [0-4[ pointing
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// to the 2 neighbor vertices of the vertex 'V' belonging to the Gregory patch.
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// Neighbor ordering is valence CCW and must match the winding of the 1-ring
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// vertices.
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//
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static void
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getQuadOffsets(Vtr::internal::Level const & level, Vtr::Index fIndex,
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Vtr::Index offsets[], int fvarChannel=-1) {
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Far::ConstIndexArray fPoints = (fvarChannel<0) ?
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level.getFaceVertices(fIndex) :
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level.getFaceFVarValues(fIndex, fvarChannel);
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assert(fPoints.size()==4);
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for (int i = 0; i < 4; ++i) {
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Vtr::Index vIndex = fPoints[i];
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Vtr::ConstIndexArray vFaces = level.getVertexFaces(vIndex),
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vEdges = level.getVertexEdges(vIndex);
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int thisFaceInVFaces = -1;
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for (int j = 0; j < vFaces.size(); ++j) {
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if (fIndex == vFaces[j]) {
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thisFaceInVFaces = j;
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break;
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}
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}
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assert(thisFaceInVFaces != -1);
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// we have to use the number of incident edges to modulo the local index
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// because there could be 2 consecutive edges in the face belonging to
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// the Gregory patch.
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offsets[i*2+0] = thisFaceInVFaces;
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offsets[i*2+1] = (thisFaceInVFaces + 1)%vEdges.size();
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}
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}
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int
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GregoryBasis::ProtoBasis::GetNumElements() const {
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int nelems=0;
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for (int vid=0; vid<4; ++vid) {
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nelems += P[vid].GetSize();
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nelems += Ep[vid].GetSize();
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nelems += Em[vid].GetSize();
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nelems += Fp[vid].GetSize();
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nelems += Fm[vid].GetSize();
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}
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return nelems;
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}
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void
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GregoryBasis::ProtoBasis::Copy(int * sizes, Index * indices, float * weights) const {
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for (int vid=0; vid<4; ++vid) {
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P[vid].Copy(&sizes, &indices, &weights);
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Ep[vid].Copy(&sizes, &indices, &weights);
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Em[vid].Copy(&sizes, &indices, &weights);
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Fp[vid].Copy(&sizes, &indices, &weights);
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Fm[vid].Copy(&sizes, &indices, &weights);
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}
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}
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void
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GregoryBasis::ProtoBasis::Copy(GregoryBasis * dest) const {
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int nelems = GetNumElements();
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dest->_indices.resize(nelems);
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dest->_weights.resize(nelems);
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Copy(dest->_sizes, &dest->_indices[0], &dest->_weights[0]);
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}
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inline float csf(Index n, Index j) {
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if (j%2 == 0) {
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return cosf((2.0f * float(M_PI) * float(float(j-0)/2.0f))/(float(n)+3.0f));
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} else {
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return sinf((2.0f * float(M_PI) * float(float(j-1)/2.0f))/(float(n)+3.0f));
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}
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}
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inline float computeCoefficient(int valence) {
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// precomputed coefficient table up to valence 29
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static float efTable[] = {
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0, 0, 0,
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0.812816f, 0.500000f, 0.363644f, 0.287514f,
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0.238688f, 0.204544f, 0.179229f, 0.159657f,
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0.144042f, 0.131276f, 0.120632f, 0.111614f,
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0.103872f, 0.09715f, 0.0912559f, 0.0860444f,
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0.0814022f, 0.0772401f, 0.0734867f, 0.0700842f,
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0.0669851f, 0.0641504f, 0.0615475f, 0.0591488f,
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0.0569311f, 0.0548745f, 0.0529621f
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};
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assert(valence > 0);
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if (valence < 30) return efTable[valence];
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float t = 2.0f * float(M_PI) / float(valence);
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return 1.0f / (valence * (cosf(t) + 5.0f +
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sqrtf((cosf(t) + 9) * (cosf(t) + 1)))/16.0f);
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}
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GregoryBasis::ProtoBasis::ProtoBasis(
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Vtr::internal::Level const & level, Index faceIndex,
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int levelVertOffset, int fvarChannel) {
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Vtr::ConstIndexArray facePoints = (fvarChannel<0) ?
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level.getFaceVertices(faceIndex) :
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level.getFaceFVarValues(faceIndex, fvarChannel);
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assert(facePoints.size()==4);
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int maxvalence = level.getMaxValence(),
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valences[4],
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zerothNeighbors[4];
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Vtr::internal::StackBuffer<Index,40> manifoldRing((maxvalence+2)*2);
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Vtr::internal::StackBuffer<Point,16> f(maxvalence);
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Vtr::internal::StackBuffer<Point,64> r(maxvalence*4);
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Point e0[4], e1[4], org[4];
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for (int vid=0; vid<4; ++vid) {
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org[vid] = facePoints[vid];
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// save for varying stencils
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V[vid] = facePoints[vid];
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int ringSize =
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level.gatherQuadRegularRingAroundVertex(
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facePoints[vid], manifoldRing, fvarChannel);
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int valence;
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if (ringSize & 1) {
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// boundary vertex
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manifoldRing[ringSize] = manifoldRing[ringSize-1];
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++ringSize;
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valence = -ringSize/2;
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} else {
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valence = ringSize/2;
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}
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int ivalence = abs(valence);
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valences[vid] = valence;
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Index boundaryEdgeNeighbors[2],
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currentNeighbor = 0,
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zerothNeighbor=0,
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ibefore=0;
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Point pos(facePoints[vid]);
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for (int i=0; i<ivalence; ++i) {
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Index im = (i+ivalence-1)%ivalence,
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ip = (i+1)%ivalence;
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Index idx_neighbor = (manifoldRing[2*i + 0]),
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idx_diagonal = (manifoldRing[2*i + 1]),
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idx_neighbor_p = (manifoldRing[2*ip + 0]),
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idx_neighbor_m = (manifoldRing[2*im + 0]),
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idx_diagonal_m = (manifoldRing[2*im + 1]);
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bool boundaryNeighbor = (level.getVertexEdges(idx_neighbor).size() >
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level.getVertexFaces(idx_neighbor).size());
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if (fvarChannel>=0) {
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// XXXX manuelk need logic to check for boundary in fvar
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boundaryNeighbor = false;
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}
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if (boundaryNeighbor) {
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if (currentNeighbor<2) {
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boundaryEdgeNeighbors[currentNeighbor] = idx_neighbor;
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}
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++currentNeighbor;
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if (currentNeighbor==1) {
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ibefore = zerothNeighbor = i;
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} else {
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if (i-ibefore==1) {
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std::swap(boundaryEdgeNeighbors[0], boundaryEdgeNeighbors[1]);
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zerothNeighbor = i;
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}
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}
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}
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Point neighbor(idx_neighbor),
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diagonal(idx_diagonal),
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neighbor_p(idx_neighbor_p),
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neighbor_m(idx_neighbor_m),
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diagonal_m(idx_diagonal_m);
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f[i] = (pos*float(ivalence) + (neighbor_p+neighbor)*2.0f + diagonal) / (float(ivalence)+5.0f);
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P[vid] += f[i];
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r[vid*maxvalence+i] = (neighbor_p-neighbor_m)/3.0f + (diagonal-diagonal_m)/6.0f;
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}
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P[vid] /= float(ivalence);
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zerothNeighbors[vid] = zerothNeighbor;
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if (currentNeighbor == 1) {
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boundaryEdgeNeighbors[1] = boundaryEdgeNeighbors[0];
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}
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for (int i=0; i<ivalence; ++i) {
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int im = (i+ivalence-1)%ivalence;
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Point e = (f[i]+f[im])*0.5f;
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e0[vid] += e * csf(ivalence-3, 2*i);
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e1[vid] += e * csf(ivalence-3, 2*i+1);
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}
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float ef = computeCoefficient(ivalence);
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e0[vid] *= ef;
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e1[vid] *= ef;
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if (valence<0) {
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Point b0(boundaryEdgeNeighbors[0]),
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b1(boundaryEdgeNeighbors[1]);
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if (ivalence>2) {
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P[vid] = (b0 + b1 + pos*4.0f)/6.0f;
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} else {
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P[vid] = pos;
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}
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float k = float(float(ivalence) - 1.0f); //k is the number of faces
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float c = cosf(float(M_PI)/k);
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float s = sinf(float(M_PI)/k);
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float gamma = -(4.0f*s)/(3.0f*k+c);
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float alpha_0k = -((1.0f+2.0f*c)*sqrtf(1.0f+c))/((3.0f*k+c)*sqrtf(1.0f-c));
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float beta_0 = s/(3.0f*k + c);
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Point diagonal(manifoldRing[2*zerothNeighbor + 1]);
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e0[vid] = (b0 - b1)/6.0f;
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e1[vid] = pos*gamma + diagonal*beta_0 + (b0 + b1)*alpha_0k;
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for (int x=1; x<ivalence-1; ++x) {
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Index curri = ((x + zerothNeighbor)%ivalence);
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float alpha = (4.0f*sinf((float(M_PI) * float(x))/k))/(3.0f*k+c),
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beta = (sinf((float(M_PI) * float(x))/k) + sinf((float(M_PI) * float(x+1))/k))/(3.0f*k+c);
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Index idx_neighbor = manifoldRing[2*curri + 0],
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idx_diagonal = manifoldRing[2*curri + 1];
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Point p_neighbor(idx_neighbor),
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p_diagonal(idx_diagonal);
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e1[vid] += p_neighbor*alpha + p_diagonal*beta;
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}
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e1[vid] /= 3.0f;
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}
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}
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Index quadOffsets[8];
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getQuadOffsets(level, faceIndex, quadOffsets, fvarChannel);
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for (int vid=0; vid<4; ++vid) {
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int n = abs(valences[vid]),
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ivalence = n;
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int ip = (vid+1)%4,
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im = (vid+3)%4,
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np = abs(valences[ip]),
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nm = abs(valences[im]);
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Index start = quadOffsets[vid*2+0],
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prev = quadOffsets[vid*2+1],
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start_m = quadOffsets[im*2],
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prev_p = quadOffsets[ip*2+1];
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Point Em_ip, Ep_im;
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if (valences[ip]<-2) {
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Index j = (np + prev_p - zerothNeighbors[ip]) % np;
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Em_ip = P[ip] + e0[ip]*cosf((float(M_PI)*j)/float(np-1)) + e1[ip]*sinf((float(M_PI)*j)/float(np-1));
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} else {
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Em_ip = P[ip] + e0[ip]*csf(np-3,2*prev_p) + e1[ip]*csf(np-3,2*prev_p+1);
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}
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if (valences[im]<-2) {
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Index j = (nm + start_m - zerothNeighbors[im]) % nm;
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Ep_im = P[im] + e0[im]*cosf((float(M_PI)*j)/float(nm-1)) + e1[im]*sinf((float(M_PI)*j)/float(nm-1));
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} else {
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Ep_im = P[im] + e0[im]*csf(nm-3,2*start_m) + e1[im]*csf(nm-3,2*start_m+1);
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}
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if (valences[vid] < 0) {
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n = (n-1)*2;
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}
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if (valences[im] < 0) {
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nm = (nm-1)*2;
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}
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if (valences[ip] < 0) {
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np = (np-1)*2;
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}
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Point const * rp = &r[vid*maxvalence];
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if (valences[vid] >= 2) {
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float s1 = 3.0f - 2.0f*csf(n-3,2)-csf(np-3,2),
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s2 = 2.0f*csf(n-3,2),
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s3 = 3.0f -2.0f*cosf(2.0f*float(M_PI)/float(n)) - cosf(2.0f*float(M_PI)/float(nm));
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Ep[vid] = P[vid] + e0[vid]*csf(n-3, 2*start) + e1[vid]*csf(n-3, 2*start +1);
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Em[vid] = P[vid] + e0[vid]*csf(n-3, 2*prev ) + e1[vid]*csf(n-3, 2*prev + 1);
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Fp[vid] = (P[vid]*csf(np-3,2) + Ep[vid]*s1 + Em_ip*s2 + rp[start])/3.0f;
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Fm[vid] = (P[vid]*csf(nm-3,2) + Em[vid]*s3 + Ep_im*s2 - rp[prev])/3.0f;
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} else if (valences[vid] < -2) {
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Index jp = (ivalence + start - zerothNeighbors[vid]) % ivalence,
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jm = (ivalence + prev - zerothNeighbors[vid]) % ivalence;
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float s1 = 3-2*csf(n-3,2)-csf(np-3,2),
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s2 = 2*csf(n-3,2),
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s3 = 3.0f-2.0f*cosf(2.0f*float(M_PI)/n)-cosf(2.0f*float(M_PI)/nm);
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Ep[vid] = P[vid] + e0[vid]*cosf((float(M_PI)*jp)/float(ivalence-1)) + e1[vid]*sinf((float(M_PI)*jp)/float(ivalence-1));
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Em[vid] = P[vid] + e0[vid]*cosf((float(M_PI)*jm)/float(ivalence-1)) + e1[vid]*sinf((float(M_PI)*jm)/float(ivalence-1));
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Fp[vid] = (P[vid]*csf(np-3,2) + Ep[vid]*s1 + Em_ip*s2 + rp[start])/3.0f;
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Fm[vid] = (P[vid]*csf(nm-3,2) + Em[vid]*s3 + Ep_im*s2 - rp[prev])/3.0f;
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if (valences[im]<0) {
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s1=3-2*csf(n-3,2)-csf(np-3,2);
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Fp[vid] = Fm[vid] = (P[vid]*csf(np-3,2) + Ep[vid]*s1 + Em_ip*s2 + rp[start])/3.0f;
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} else if (valences[ip]<0) {
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s1 = 3.0f-2.0f*cosf(2.0f*float(M_PI)/n)-cosf(2.0f*float(M_PI)/nm);
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Fm[vid] = Fp[vid] = (P[vid]*csf(nm-3,2) + Em[vid]*s1 + Ep_im*s2 - rp[prev])/3.0f;
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}
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} else if (valences[vid]==-2) {
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Ep[vid] = (org[vid]*2.0f + org[ip])/3.0f;
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Em[vid] = (org[vid]*2.0f + org[im])/3.0f;
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Fp[vid] = Fm[vid] = (org[vid]*4.0f + org[((vid+2)%n)] + org[ip]*2.0f + org[im]*2.0f)/9.0f;
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}
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}
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// offset stencil indices.
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// These stencils are created relative to the level. Adding levelVertOffset,
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// we get stencils with absolute indices
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// (starts from the coarse level if the leveVertOffset includes level 0)
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for (int i = 0; i < 4; ++i) {
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P[i].OffsetIndices(levelVertOffset);
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Ep[i].OffsetIndices(levelVertOffset);
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Em[i].OffsetIndices(levelVertOffset);
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Fp[i].OffsetIndices(levelVertOffset);
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Fm[i].OffsetIndices(levelVertOffset);
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V[i].OffsetIndices(levelVertOffset);
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}
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}
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/*static*/
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StencilTable *
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GregoryBasis::CreateStencilTable(PointsVector const &stencils) {
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int nStencils = (int)stencils.size();
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if (nStencils == 0) return NULL;
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int nElements = 0;
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for (int i = 0; i < nStencils; ++i) {
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nElements += stencils[i].GetSize();
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}
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// allocate destination
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StencilTable *stencilTable = new StencilTable();
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// XXX: do we need numControlVertices in stencilTable?
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stencilTable->_numControlVertices = 0;
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stencilTable->resize(nStencils, nElements);
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int * sizes = &stencilTable->_sizes[0];
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Index * indices = &stencilTable->_indices[0];
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float * weights = &stencilTable->_weights[0];
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for (int i = 0; i < nStencils; ++i) {
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GregoryBasis::Point const &src = stencils[i];
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int size = src.GetSize();
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memcpy(indices, src.GetIndices(), size*sizeof(Index));
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memcpy(weights, src.GetWeights(), size*sizeof(float));
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*sizes = size;
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indices += size;
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weights += size;
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|
++sizes;
|
|
}
|
|
stencilTable->generateOffsets();
|
|
|
|
return stencilTable;
|
|
}
|
|
|
|
} // end namespace Far
|
|
|
|
} // end namespace OPENSUBDIV_VERSION
|
|
} // end namespace OpenSubdiv
|