OpenSubdiv/opensubdiv/far/loopPatchBuilder.cpp
Barry Fowler 810d7f671b Fix GCC warnings with current default flags:
- default flags include warnings enabled by -Wall and -Wextra
    - suppressed newer warnings in public headers and internal files
      (-Wclass-memaccess, -Wcast-function-type, -Wdeprecated-copy)
    - suppressed -Wunused-function from internal source files
2022-08-30 12:13:44 -07:00

1891 lines
69 KiB
C++

//
// Copyright 2018 DreamWorks Animation LLC.
//
// 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/loopPatchBuilder.h"
#include "../vtr/stackBuffer.h"
#include "../sdc/loopScheme.h"
#include <cassert>
#include <cmath>
#include <cstdio>
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
using Vtr::Array;
using Vtr::ConstArray;
using Vtr::internal::StackBuffer;
namespace Far {
//
// A simple struct with methods to compute Loop limit points (following
// the pattern established for Catmull-Clark limit points)
//
// Unlike the corresponding Catmull-Clark struct, Loop limit points are
// computed using the limit masks provided by the Sdc Scheme for Loop.
//
template <typename REAL>
struct LoopLimits {
public:
//
// Local classes to fulfill the interface requirements of template
// arguments to the Sdc::Scheme methods
//
// Class fulfilling <typename VERTEX>:
//
class LimitVertex {
public:
LimitVertex() : _nFaces(0), _nEdges(0) { }
LimitVertex(int faces, int edges) : _nFaces(faces), _nEdges(edges) { }
void Assign(int faces, int edges) { _nFaces = faces; _nEdges = edges; }
int GetNumEdges() const { return _nEdges; }
int GetNumFaces() const { return _nFaces; }
void GetSharpnessPerEdge(float sharpness[]) const {
sharpness[0] = Sdc::Crease::SHARPNESS_INFINITE;
for (int i = 1; i < _nEdges - 1; ++i) {
sharpness[i] = Sdc::Crease::SHARPNESS_SMOOTH;
}
sharpness[_nEdges - 1] = Sdc::Crease::SHARPNESS_INFINITE;
}
private:
int _nFaces;
int _nEdges;
};
//
// Class fulfilling <typename MASK>:
//
class LimitMask {
public:
typedef REAL Weight; // Also part of the expected interface
public:
LimitMask(Weight* w) : _weights(w), _valence(0) { }
~LimitMask() { }
public: // Generic interface expected of <typename MASK>:
int GetNumVertexWeights() const { return 1; }
int GetNumEdgeWeights() const { return _valence; }
int GetNumFaceWeights() const { return 0; }
void SetNumVertexWeights(int) { }
void SetNumEdgeWeights(int count) { _valence = count; }
void SetNumFaceWeights(int) { }
Weight const& VertexWeight(int) const { return _weights[0]; }
Weight const& EdgeWeight(int index) const { return _weights[1 + index]; }
Weight const& FaceWeight(int) const { return _weights[0]; }
Weight& VertexWeight(int) { return _weights[0]; }
Weight& EdgeWeight( int index) { return _weights[1 + index]; }
Weight& FaceWeight( int) { return _weights[0]; }
bool AreFaceWeightsForFaceCenters() const { return false; }
void SetFaceWeightsForFaceCenters(bool) { }
private:
Weight* _weights;
int _valence;
};
public:
typedef Sdc::Scheme<Sdc::SCHEME_LOOP> SchemeLoop;
static void ComputeInteriorPointWeights(int valence, int faceInRing,
REAL* pWeights, REAL* epWeights, REAL* emWeights);
static void ComputeBoundaryPointWeights(int valence, int faceInRing,
REAL* pWeights, REAL* epWeights, REAL* emWeights);
};
template <typename REAL>
void
LoopLimits<REAL>::ComputeInteriorPointWeights(int valence, int faceInRing,
REAL* pWeights, REAL* epWeights, REAL* emWeights) {
int ringSize = valence + 1;
LimitVertex vertex(valence, valence);
bool computeTangentPoints = epWeights && emWeights;
if (!computeTangentPoints) {
//
// The interior position mask is symmetric -- no need to rotate
// or otherwise account for orientation:
//
LimitMask pMask(pWeights);
SchemeLoop().ComputeVertexLimitMask(vertex, pMask,
Sdc::Crease::RULE_SMOOTH);
} else {
//
// The interior tangent masks will be directed along the first
// two edges (the second a rotation of the first). Adjust the
// tangent weights for a point along the tangent, then rotate
// according to the face within the ring:
//
int weightWidth = valence + 1;
StackBuffer<REAL, 32, true> tWeights(2 * weightWidth);
REAL * t1Weights = &tWeights[0];
REAL * t2Weights = t1Weights + ringSize;
LimitMask pMask(pWeights);
LimitMask t1Mask(t1Weights);
LimitMask t2Mask(t2Weights);
SchemeLoop().ComputeVertexLimitMask(vertex, pMask, t1Mask, t2Mask,
Sdc::Crease::RULE_SMOOTH);
//
// Use the subdominant eigenvalue to scale the limit tangent t1:
//
// e = (3 + cos(2*PI/valence)) / 8
//
// Combine it with a normalizing factor of (2 / valence) to account
// for the scale inherent in the tangent weights, and (2 / 3) to
// match desired placement of the cubic point in the regular case.
//
// The weights for t1 can simply be rotated around the ring to yield
// t2. Combine the weights for the point in a single set for t2 and
// then copy it into the appropriate orientation for ep and em:
//
double theta = 2.0 * M_PI / (double) valence;
REAL tanScale = (REAL) ((3.0 + 2.0 * std::cos(theta)) / (6.0 * valence));
for (int i = 0; i < ringSize; ++i) {
t2Weights[i] = pWeights[i] + t1Weights[i] * tanScale;
}
int n1 = faceInRing;
int n2 = valence - n1;
epWeights[0] = t2Weights[0];
std::memcpy(epWeights + 1, t2Weights + 1 + n2, n1 * sizeof(REAL));
std::memcpy(epWeights + 1 + n1, t2Weights + 1, n2 * sizeof(REAL));
n1 = (faceInRing + 1) % valence;
n2 = valence - n1;
emWeights[0] = t2Weights[0];
std::memcpy(emWeights + 1, t2Weights + 1 + n2, n1 * sizeof(REAL));
std::memcpy(emWeights + 1 + n1, t2Weights + 1, n2 * sizeof(REAL));
}
}
template <typename REAL>
void
LoopLimits<REAL>::ComputeBoundaryPointWeights(int valence, int faceInRing,
REAL* pWeights, REAL* epWeights, REAL* emWeights) {
LimitVertex vertex(valence - 1, valence);
bool computeTangentPoints = epWeights && emWeights;
if (!computeTangentPoints) {
//
// The boundary position mask will be assigned non-zero weights
// for the vertex and its first and last edges:
//
LimitMask pMask(pWeights);
SchemeLoop().ComputeVertexLimitMask(vertex, pMask,
Sdc::Crease::RULE_CREASE);
} else {
//
// The boundary tangent masks need more explicit handling than
// the interior. One of the tangents will be along the boundary
// and the other towards the interior, but one or both edge
// points may be along interior edges. A boundary edge point is
// easy to deal with once identified, but interior edge points
// need a numerical rotation of the interior tangent to orient it
// along the desired edge.
//
int weightWidth = valence + 1;
StackBuffer<REAL, 32, true> tWeights(2 * weightWidth);
REAL * t1Weights = &tWeights[0];
REAL * t2Weights = t1Weights + weightWidth;
REAL t1Leading = (REAL) (1.0 / 6.0);
REAL t1Trailing = -(REAL) (1.0 / 6.0);
REAL t2Scale = (REAL) (1.0 / 24.0);
LimitMask pMask(pWeights);
LimitMask t1Mask(t1Weights);
LimitMask t2Mask(t2Weights);
SchemeLoop().ComputeVertexLimitMask(vertex, pMask, t1Mask, t2Mask,
Sdc::Crease::RULE_CREASE);
bool epOnLeadingEdge = (faceInRing == 0);
bool emOnTrailingEdge = (faceInRing == (valence - 1));
if (epOnLeadingEdge) {
std::memset(&epWeights[0], 0, weightWidth * sizeof(REAL));
epWeights[0] = (REAL) (2.0 / 3.0);
epWeights[1] = (REAL) (1.0 / 3.0);
} else {
int iEdgeNext = faceInRing;
REAL faceAngle = (REAL) (M_PI / (double)(valence - 1));
REAL faceAngleNext = faceAngle * (REAL)iEdgeNext;
REAL cosAngleNext = std::cos(faceAngleNext);
REAL sinAngleNext = std::sin(faceAngleNext);
for (int i = 0; i < weightWidth; ++i) {
epWeights[i] = t2Scale * t2Weights[i] * sinAngleNext;
}
epWeights[0] += pWeights[0];
epWeights[1] += pWeights[1] + t1Leading * cosAngleNext;
epWeights[valence] += pWeights[valence] + t1Trailing * cosAngleNext;
}
if (emOnTrailingEdge) {
std::memset(&emWeights[0], 0, weightWidth * sizeof(REAL));
emWeights[0] = (REAL) (2.0 / 3.0);
emWeights[valence] = (REAL) (1.0 / 3.0);
} else {
int iEdgePrev = (faceInRing + 1) % valence;
REAL faceAngle = (REAL) (M_PI / (double)(valence - 1));
REAL faceAnglePrev = faceAngle * (REAL)iEdgePrev;
REAL cosAnglePrev = std::cos(faceAnglePrev);
REAL sinAnglePrev = std::sin(faceAnglePrev);
for (int i = 0; i < weightWidth; ++i) {
emWeights[i] = t2Scale * t2Weights[i] * sinAnglePrev;
}
emWeights[0] += pWeights[0];
emWeights[1] += pWeights[1] + t1Leading * cosAnglePrev;
emWeights[valence] += pWeights[valence] + t1Trailing * cosAnglePrev;
}
}
}
//
// SparseMatrixRow
//
// This was copied from the CatmarkPatchBuilder as a starting point, so
// comments below relate to the state of CatmarkPatchBuilder...
//
// This is a utility class representing a row of a SparseMatrix -- which
// in turn corresponds to a point of a resulting patch. Instances of this
// class are intended to encapsulate the contributions of a point and be
// passed to functions as such.
//
// (Consider moving this to PatchBuilder as a protected class or maybe a
// public class within SparseMatrix itself, e.g. SparseMatrix<REAL>::Row.)
//
namespace {
template <typename REAL>
class SparseMatrixRow {
public:
SparseMatrixRow(SparseMatrix<REAL> & matrix, int row) :
_size(matrix.GetRowSize(row)),
_indices(matrix.SetRowColumns(row).begin()),
_weights(matrix.SetRowElements(row).begin()) { }
int GetSize() const { return _size; }
void SetWeight(int i, REAL weight) { _weights[i] = weight; }
void Assign(int rowEntry, Index index, REAL weight) {
_indices[rowEntry] = index;
_weights[rowEntry] = weight;
}
void Copy(SparseMatrixRow<REAL> const & other) {
assert(GetSize() == other.GetSize());
std::memcpy(_indices, other._indices, _size * sizeof(Index));
std::memcpy(_weights, other._weights, _size * sizeof(REAL));
}
public:
int _size;
Index * _indices;
REAL * _weights;
};
} // end namespace
//
// Simple utility functions for dealing with SparseMatrix:
//
namespace {
#ifdef __INTEL_COMPILER
#pragma warning (push)
#pragma warning disable 1572
#endif
template <typename REAL>
inline bool _isZero(REAL w) { return (w == (REAL)0.0); }
#ifdef __INTEL_COMPILER
#pragma warning (pop)
#endif
template <typename REAL>
void
_initializeFullMatrix(SparseMatrix<REAL> & M, int nRows, int nColumns) {
M.Resize(nRows, nColumns, nRows * nColumns);
// Fill row 0 with index for every column:
M.SetRowSize(0, nColumns);
Array<int> row0Columns = M.SetRowColumns(0);
for (int i = 0; i < nColumns; ++i) {
row0Columns[i] = i;
}
// Copy row 0's indices into all other rows:
for (int row = 1; row < nRows; ++row) {
M.SetRowSize(row, nColumns);
Array<int> dstRowColumns = M.SetRowColumns(row);
std::memcpy(&dstRowColumns[0], &row0Columns[0], nColumns * sizeof(int));
}
}
template <typename REAL>
void
_resizeMatrix(SparseMatrix<REAL> & matrix,
int numRows, int numColumns, int numElements,
int const rowSizes[]) {
matrix.Resize(numRows, numColumns, numElements);
for (int i = 0; i < numRows; ++i) {
matrix.SetRowSize(i, rowSizes[i]);
}
assert(matrix.GetNumElements() == numElements);
}
template <typename REAL>
void
_addSparsePointToFullRow(REAL * fullRow,
SparseMatrixRow<REAL> const & p,
REAL s, int * indexMask) {
for (int i = 0; i < p.GetSize(); ++i) {
int index = p._indices[i];
fullRow[index] += s * p._weights[i];
indexMask[index] = 1 + index;
}
}
template <typename REAL>
void
_combineSparsePointsInFullRow(SparseMatrixRow<REAL> & p,
REAL aCoeff, SparseMatrixRow<REAL> const & a,
REAL bCoeff, SparseMatrixRow<REAL> const & b,
int rowSize, REAL * rowBuffer, int * maskBuffer) {
std::memset(maskBuffer, 0, rowSize * sizeof(int));
std::memset(rowBuffer, 0, rowSize * sizeof(REAL));
_addSparsePointToFullRow(rowBuffer, a, aCoeff, maskBuffer);
_addSparsePointToFullRow(rowBuffer, b, bCoeff, maskBuffer);
int nWeights = 0;
for (int i = 0; i < rowSize; ++i) {
if (maskBuffer[i]) {
p.Assign(nWeights++, maskBuffer[i] - 1, rowBuffer[i]);
}
}
assert(nWeights <= p.GetSize());
for (int i = nWeights; i < p.GetSize(); ++i, ++nWeights) {
p.Assign(i, 0, 0.0f);
}
}
template <typename REAL>
void
_addSparseRowToFull(REAL * fullRow,
SparseMatrix<REAL> const & M, int sparseRow, REAL s) {
ConstArray<int> indices = M.GetRowColumns(sparseRow);
ConstArray<REAL> weights = M.GetRowElements(sparseRow);
for (int i = 0; i < indices.size(); ++i) {
fullRow[indices[i]] += s * weights[i];
}
}
template <typename REAL>
void
_combineSparseMatrixRowsInFull(SparseMatrix<REAL> & dstMatrix, int dstRowIndex,
SparseMatrix<REAL> const & srcMatrix, int numSrcRows,
int const srcRowIndices[], REAL const * srcRowWeights) {
REAL * dstRow = &dstMatrix.SetRowElements(dstRowIndex)[0];
std::memset(dstRow, 0, dstMatrix.GetNumColumns() * sizeof(REAL));
for (int i = 0; i < numSrcRows; ++i) {
if (!_isZero(srcRowWeights[i])) {
_addSparseRowToFull(dstRow, srcMatrix, srcRowIndices[i], srcRowWeights[i]);
}
}
}
template <typename REAL>
void
_matrixPrintDensity(const char* prefix, SparseMatrix<REAL> const & M) {
int fullSize = M.GetNumRows() * M.GetNumColumns();
int sparseSize = M.GetNumElements();
int nonZeroSize = 0;
for (int i = 0; i < M.GetNumRows(); ++i) {
ConstArray<REAL> elements = M.GetRowElements(i);
for (int j = 0; j < elements.size(); ++j) {
nonZeroSize += (elements[j] != 0);
}
}
printf("%s(%dx%d = %d): elements = %d, non-zero = %d, density = %.1f\n",
prefix, M.GetNumRows(), M.GetNumColumns(), fullSize,
sparseSize, nonZeroSize, (REAL)nonZeroSize * 100.0f / (REAL)fullSize);
}
//
// The valence-2 interior case poses problems for the way patch points
// are computed as combinations of source points and stored as a row in
// a SparseMatrix. An interior vertex of valence-2 causes duplicate
// vertices to appear in the 1-rings of its neighboring vertices and we
// want the entries of a SparseMatrix row to be unique.
//
// For the most part, this does not pose a problem while the matrix (set
// of patch points) is being constructed, so we leave those duplicate
// entries in place and deal with them as a post-process here.
//
// The SourcePatch is also sensitive to the presence of such valence-2
// vertices for its own reasons (it needs to identifiy a unique set of
// source points from a set of corner rings), so a simple query of its
// corners indicates when this post-process is necessary. (And since
// this case is a rare occurrence, efficiency is not a major concern.)
//
template <typename REAL>
void _removeValence2Duplicates(SparseMatrix<REAL> & M) {
// This will later be determined by the PatchBuilder member:
int regFaceSize = 4;
SparseMatrix<REAL> T;
T.Resize(M.GetNumRows(), M.GetNumColumns(), M.GetNumElements());
int nRows = M.GetNumRows();
for (int row = 0; row < nRows; ++row) {
int srcRowSize = M.GetRowSize(row);
int const * srcIndices = M.GetRowColumns(row).begin();
REAL const * srcWeights = M.GetRowElements(row).begin();
// Scan the entries to see if there are duplicates -- copy
// the row if not, otherwise, need to compress it:
bool cornerUsed[4] = { false, false, false, false };
int srcDupCount = 0;
for (int i = 0; i < srcRowSize; ++i) {
int srcIndex = srcIndices[i];
if (srcIndex < regFaceSize) {
srcDupCount += (int) cornerUsed[srcIndex];
cornerUsed[srcIndex] = true;
}
}
// Size this row for the destination and copy or compress:
T.SetRowSize(row, srcRowSize - srcDupCount);
int* dstIndices = T.SetRowColumns(row).begin();
REAL* dstWeights = T.SetRowElements(row).begin();
if (srcDupCount) {
REAL * cornerDstPtr[4] = { 0, 0, 0, 0 };
for (int i = 0; i < srcRowSize; ++i) {
int srcIndex = *srcIndices++;
REAL srcWeight = *srcWeights++;
if (srcIndex < regFaceSize) {
if (cornerDstPtr[srcIndex]) {
*cornerDstPtr[srcIndex] += srcWeight;
continue;
} else {
cornerDstPtr[srcIndex] = dstWeights;
}
}
*dstIndices++ = srcIndex;
*dstWeights++ = srcWeight;
}
} else {
std::memcpy(&dstIndices[0], &srcIndices[0], srcRowSize * sizeof(Index));
std::memcpy(&dstWeights[0], &srcWeights[0], srcRowSize * sizeof(REAL));
}
}
M.Swap(T);
}
} // end namespace for SparseMatrix utilities
//
// GregoryTriConverter
//
// The GregoryTriConverter class provides a change-of-basis matrix from source
// vertices in a Loop mesh to the 18 control points of a quartic Gregory triangle.
//
// The quartic triangle is first constructed as a cubic/quartic hybrid -- with
// cubic boundary curves and cross-boundary continuity formulated in terms of
// cubics. The result is then raised to a full quartic once continuity across
// all boundaries is achieved. In most cases 2 of the 3 boundaries will be
// cubic (though now represented as quartic) and only one boundary need be a
// true quartic to meet a regular Box-spline patch.
//
// Control points are labeled using the convention adopted for quads, with
// Ep and Em referring to the "plus" and "minus" edge points and similarly
// for the face points Fp and Fm. The additional quartic "mid-edge" points
// associated with each boundary are referred to as M.
//
template <typename REAL>
class GregoryTriConverter {
public:
typedef REAL Weight;
typedef SparseMatrix<Weight> Matrix;
typedef SparseMatrixRow<Weight> Point;
public:
GregoryTriConverter() : _numSourcePoints(0) { }
GregoryTriConverter(SourcePatch const & sourcePatch);
GregoryTriConverter(SourcePatch const & sourcePatch, Matrix & sparseMatrix);
void Initialize(SourcePatch const & sourcePatch);
bool IsIsolatedInteriorPatch() const { return _isIsolatedInteriorPatch; }
bool HasVal2InteriorCorner() const { return _hasVal2InteriorCorner; }
int GetIsolatedInteriorCorner() const { return _isolatedCorner; }
int GetIsolatedInteriorValence() const { return _isolatedValence; }
void Convert(Matrix & sparseMatrix) const;
private:
//
// Local nested class for GregoryTriConverter to cache information for
// the corners of the source patch. It copies some information from the
// SourcePatch so that we don't have to keep it around, but it contains
// additional information relevant to the determination of the Gregory
// points -- most notably classifications of the face-points and the
// cosines of angles for the face corners that are used repeatedly.
//
struct CornerTopology {
// Basic flags copied from the SourcePatch
unsigned int isBoundary : 1;
unsigned int isSharp : 1;
unsigned int isDart : 1;
unsigned int isRegular : 1;
unsigned int isVal2Int : 1;
unsigned int isCorner : 1;
// Flags for edge- and face-points relating to adjacent corners:
unsigned int epOnBoundary : 1;
unsigned int emOnBoundary : 1;
unsigned int fpIsRegular : 1;
unsigned int fmIsRegular : 1;
unsigned int fpIsCopied : 1;
unsigned int fmIsCopied : 1;
// Other values stored for repeated use:
int valence;
int numFaces;
int faceInRing;
REAL faceAngle;
REAL cosFaceAngle;
// Its useful to have the ring for each corner immediately available:
StackBuffer<int, 30, true> ringPoints;
};
//
// Methods to resize the matrix before populating it:
//
void resizeMatrixUnisolated(Matrix & matrix) const;
void resizeMatrixIsolatedIrregular(Matrix & matrix, int irregCornerIndex,
int irregValence) const;
//
// Methods to compute the various rows of points in the matrix:
//
void assignRegularEdgePoints(int cornerIndex, Matrix & matrix) const;
void computeIrregularEdgePoints(int cornerIndex, Matrix & matrix,
Weight *weightBuffer) const;
void assignRegularFacePoints(int cornerIndex, Matrix & matrix) const;
void computeIrregularFacePoints(int cornerIndex, Matrix & matrix,
Weight *weightBuffer, int *indexBuffer) const;
void computeIrregularInteriorEdgePoints(int cornerIndex,
Point & P, Point & Ep, Point & Em,
Weight *weightBuffer) const;
void computeIrregularBoundaryEdgePoints(int cornerIndex,
Point & P, Point & Ep, Point & Em,
Weight *weightBuffer) const;
int getIrregularFacePointSize(int cornerNear, int cornerFar) const;
void computeIrregularFacePoint(
int cornerNear, int edgeInNearRing, int cornerFar,
Point const & p, Point const & eNear, Point const & eFar,
Point & fNear, REAL signForSideOfEdge /* -1.0 or 1.0 */,
Weight *rowWeights, int *columnMask) const;
void assignRegularMidEdgePoint(int edgeIndex, Matrix & matrix) const;
void computeIrregularMidEdgePoint(int edgeIndex, Matrix & matrix,
Weight *rowWeights, int *columnMask) const;
void promoteCubicEdgePointsToQuartic(Matrix & matrix,
Weight *rowWeights, int *columnMask) const;
private:
int _numSourcePoints;
int _maxValence;
bool _isIsolatedInteriorPatch;
bool _hasVal2InteriorCorner;
int _isolatedCorner;
int _isolatedValence;
CornerTopology _corners[3];
};
//
// GregoryTriConverter
//
// Construction and initialization/computation of the change-of-basis
// matrix to a Gregory patch.
//
template <typename REAL>
GregoryTriConverter<REAL>::GregoryTriConverter(
SourcePatch const & sourcePatch) {
Initialize(sourcePatch);
}
template <typename REAL>
GregoryTriConverter<REAL>::GregoryTriConverter(
SourcePatch const & sourcePatch, Matrix & sparseMatrix) {
Initialize(sourcePatch);
Convert(sparseMatrix);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::Initialize(SourcePatch const & sourcePatch) {
//
// Allocate and gather the 1-rings for the corner vertices and other
// topological information for more immediate access:
//
int width = sourcePatch.GetNumSourcePoints();
_numSourcePoints = width;
_maxValence = sourcePatch.GetMaxValence();
int boundaryCount = 0;
int irregularCount = 0;
int irregularCorner = -1;
int irregularValence = -1;
int sharpCount = 0;
int val2IntCount = 0;
for (int cIndex = 0; cIndex < 3; ++cIndex) {
SourcePatch::Corner srcCorner = sourcePatch._corners[cIndex];
CornerTopology& corner = _corners[cIndex];
corner.isBoundary = srcCorner._boundary;
corner.isSharp = srcCorner._sharp;
corner.isDart = srcCorner._dart;
corner.isCorner = (srcCorner._numFaces == 1);
corner.numFaces = srcCorner._numFaces;
corner.faceInRing = srcCorner._patchFace;
corner.isVal2Int = srcCorner._val2Interior;
corner.valence = corner.numFaces + corner.isBoundary;
corner.isRegular = ((corner.numFaces << corner.isBoundary) == 6)
&& !corner.isSharp;
if (corner.isRegular) {
corner.faceAngle = (REAL)(M_PI / 3.0);
corner.cosFaceAngle = 0.5f;
} else {
corner.faceAngle =
(corner.isBoundary ? REAL(M_PI) : REAL(2.0 * M_PI))
/ REAL(corner.numFaces);
corner.cosFaceAngle = std::cos(corner.faceAngle);
}
corner.ringPoints.SetSize(sourcePatch.GetCornerRingSize(cIndex));
sourcePatch.GetCornerRingPoints(cIndex, corner.ringPoints);
// Accumulate topology information to categorize the patch as a whole:
boundaryCount += corner.isBoundary;
if (!corner.isRegular) {
irregularCount ++;
irregularCorner = cIndex;
irregularValence = corner.valence;
}
sharpCount += corner.isSharp;
val2IntCount += corner.isVal2Int;
}
// Make a second pass to assign tags dependent on adjacent corners
for (int cIndex = 0; cIndex < 3; ++cIndex) {
CornerTopology& corner = _corners[cIndex];
int cNext = (cIndex + 1) % 3;
int cPrev = (cIndex + 2) % 3;
corner.epOnBoundary = false;
corner.emOnBoundary = false;
//
// Identify if the face points are regular or shared/copied from
// one of the pair:
//
corner.fpIsRegular = corner.isRegular && _corners[cNext].isRegular;
corner.fmIsRegular = corner.isRegular && _corners[cPrev].isRegular;
corner.fpIsCopied = false;
corner.fmIsCopied = false;
if (corner.isBoundary) {
corner.epOnBoundary = (corner.faceInRing == 0);
corner.emOnBoundary = (corner.faceInRing == (corner.numFaces - 1));
// Both face points are same when one of the two corners' edges
// is discontinuous -- one is then copied from the other (unless
// regular)
if (corner.numFaces > 1) {
if (corner.epOnBoundary) {
corner.fpIsRegular = corner.fmIsRegular;
corner.fpIsCopied = !corner.fpIsRegular;
}
if (corner.emOnBoundary) {
corner.fmIsRegular = corner.fpIsRegular;
corner.fmIsCopied = !corner.fmIsRegular;
}
} else {
// The case of a corner patch is always regular
corner.fpIsRegular = true;
corner.fmIsRegular = true;
}
}
}
_isIsolatedInteriorPatch = (irregularCount == 1) && (boundaryCount == 0) &&
(irregularValence > 2) && (sharpCount == 0);
if (_isIsolatedInteriorPatch) {
_isolatedCorner = irregularCorner;
_isolatedValence = irregularValence;
}
_hasVal2InteriorCorner = (val2IntCount > 0);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::Convert(Matrix & matrix) const {
//
// Initialize the sparse matrix to accomodate the coefficients for each
// row/point -- identify common topological cases to treat more easily
// (and note that specializing the population of the matrix may also be
// worthwhile in such cases)
//
if (_isIsolatedInteriorPatch) {
resizeMatrixIsolatedIrregular(matrix, _isolatedCorner, _isolatedValence);
} else {
resizeMatrixUnisolated(matrix);
}
//
// Compute the corner and edge points P, Ep and Em first. Since face
// points Fp and Fm involve edge points for two adjacent corners, their
// computation must follow:
//
int maxRingSize = 1 + _maxValence;
int weightBufferSize = std::max(3 * maxRingSize, 2 * _numSourcePoints);
StackBuffer<Weight, 128, true> weightBuffer(weightBufferSize);
StackBuffer<int, 128, true> indexBuffer(weightBufferSize);
for (int cIndex = 0; cIndex < 3; ++cIndex) {
if (_corners[cIndex].isRegular) {
assignRegularEdgePoints(cIndex, matrix);
} else {
computeIrregularEdgePoints(cIndex, matrix, weightBuffer);
}
}
for (int cIndex = 0; cIndex < 3; ++cIndex) {
if (_corners[cIndex].fpIsRegular || _corners[cIndex].fmIsRegular) {
assignRegularFacePoints(cIndex, matrix);
}
if (!_corners[cIndex].fpIsRegular || !_corners[cIndex].fmIsRegular) {
computeIrregularFacePoints(cIndex, matrix, weightBuffer, indexBuffer);
}
}
for (int eIndex = 0; eIndex < 3; ++eIndex) {
CornerTopology const & c0 = _corners[eIndex];
CornerTopology const & c1 = _corners[(eIndex + 1) % 3];
bool isBoundaryEdge = c0.epOnBoundary && c1.emOnBoundary;
bool isDartEdge = c0.epOnBoundary != c1.emOnBoundary;
if (isBoundaryEdge || (c0.isRegular && c1.isRegular && !isDartEdge)) {
assignRegularMidEdgePoint(eIndex, matrix);
} else {
computeIrregularMidEdgePoint(eIndex, matrix, weightBuffer, indexBuffer);
}
}
promoteCubicEdgePointsToQuartic(matrix, weightBuffer, indexBuffer);
if (_hasVal2InteriorCorner) {
_removeValence2Duplicates(matrix);
}
}
template <typename REAL>
void
GregoryTriConverter<REAL>::resizeMatrixIsolatedIrregular(
Matrix & matrix, int cornerIndex, int cornerValence) const {
int irregRingSize = 1 + cornerValence;
int irregCorner = cornerIndex;
int irregPlus = (cornerIndex + 1) % 3;
int irregMinus = (cornerIndex + 2) % 3;
int rowSizes[18];
int * rowSizePtr = 0;
rowSizePtr = rowSizes + irregCorner * 5;
*rowSizePtr++ = irregRingSize;
*rowSizePtr++ = irregRingSize;
*rowSizePtr++ = irregRingSize;
*rowSizePtr++ = 3 + irregRingSize;
*rowSizePtr++ = 3 + irregRingSize;
rowSizePtr = rowSizes + irregPlus * 5;
*rowSizePtr++ = 7;
*rowSizePtr++ = 7;
*rowSizePtr++ = 7;
*rowSizePtr++ = 5;
*rowSizePtr++ = 3 + irregRingSize;
rowSizePtr = rowSizes + irregMinus * 5;
*rowSizePtr++ = 7;
*rowSizePtr++ = 7;
*rowSizePtr++ = 7;
*rowSizePtr++ = 3 + irregRingSize;
*rowSizePtr++ = 5;
// The 3 quartic mid-edge points are not grouped with corners:
rowSizes[15 + irregCorner] = 3 + irregRingSize;
rowSizes[15 + irregPlus] = 4;
rowSizes[15 + irregMinus] = 3 + irregRingSize;
int numElements = 9*irregRingSize + 74;
_resizeMatrix(matrix, 18, _numSourcePoints, numElements, rowSizes);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::resizeMatrixUnisolated(Matrix & matrix) const {
int rowSizes[18];
int numElements = 0;
for (int cIndex = 0; cIndex < 3; ++cIndex) {
int * rowSize = rowSizes + cIndex*5;
CornerTopology const & corner = _corners[cIndex];
// First, the corner and pair of edge points:
if (corner.isRegular) {
if (! corner.isBoundary) {
rowSize[0] = 7;
rowSize[1] = 7;
rowSize[2] = 7;
} else {
rowSize[0] = 3;
rowSize[1] = corner.epOnBoundary ? 3 : 5;
rowSize[2] = corner.emOnBoundary ? 3 : 5;
}
} else {
if (corner.isSharp) {
rowSize[0] = 1;
rowSize[1] = 2;
rowSize[2] = 2;
} else if (! corner.isBoundary) {
int ringSize = 1 + corner.valence;
rowSize[0] = ringSize;
rowSize[1] = ringSize;
rowSize[2] = ringSize;
} else if (corner.numFaces > 1) {
int ringSize = 1 + corner.valence;
rowSize[0] = 3;
rowSize[1] = corner.epOnBoundary ? 3 : ringSize;
rowSize[2] = corner.emOnBoundary ? 3 : ringSize;
} else {
rowSize[0] = 3;
rowSize[1] = 3;
rowSize[2] = 3;
}
}
numElements += rowSize[0] + rowSize[1] + rowSize[2];
// Second, the pair of face points:
rowSize[3] = 5 - corner.epOnBoundary - corner.emOnBoundary;
rowSize[4] = 5 - corner.epOnBoundary - corner.emOnBoundary;
if (!corner.fpIsRegular || !corner.fmIsRegular) {
int cNext = (cIndex + 1) % 3;
int cPrev = (cIndex + 2) % 3;
if (!corner.fpIsRegular) {
rowSize[3] = getIrregularFacePointSize(cIndex,
corner.fpIsCopied ? cPrev : cNext);
}
if (!corner.fmIsRegular) {
rowSize[4] = getIrregularFacePointSize(cIndex,
corner.fmIsCopied ? cNext : cPrev);
}
}
numElements += rowSize[3] + rowSize[4];
// Third, the quartic mid-edge boundary point (edge following corner):
int cNext = (cIndex + 1) % 3;
CornerTopology const & cornerNext = _corners[cNext];
int & midEdgeSize = rowSizes[15 + cIndex];
if (corner.epOnBoundary && cornerNext.emOnBoundary) {
midEdgeSize = 2;
} else if (corner.isRegular && cornerNext.isRegular &&
(corner.epOnBoundary == cornerNext.emOnBoundary)) {
midEdgeSize = 4;
} else {
midEdgeSize = getIrregularFacePointSize(cIndex, cNext);
}
numElements += midEdgeSize;
}
_resizeMatrix(matrix, 18, _numSourcePoints, numElements, rowSizes);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::assignRegularEdgePoints(int cIndex, Matrix & matrix) const {
Point p (matrix, 5*cIndex + 0);
Point ep(matrix, 5*cIndex + 1);
Point em(matrix, 5*cIndex + 2);
CornerTopology const & corner = _corners[cIndex];
int const * cRing = corner.ringPoints;
if (! corner.isBoundary) {
REAL const pScale = (REAL) (1.0 / 12.0);
p.Assign(0, cIndex, 0.5f);
p.Assign(1, cRing[0], pScale);
p.Assign(2, cRing[1], pScale);
p.Assign(3, cRing[2], pScale);
p.Assign(4, cRing[3], pScale);
p.Assign(5, cRing[4], pScale);
p.Assign(6, cRing[5], pScale);
assert(p.GetSize() == 7);
// Identify the edges along Ep and Em and those opposite them:
REAL const eWeights[6] = { 7.0f, 5.0f, 1.0f, -1.0f, 1.0f, 5.0f };
REAL const eScale = (REAL) (1.0 / 36.0);
int iEdgeEp = corner.faceInRing;
int iEdgeEm = (corner.faceInRing + 1) % 6;
ep.Assign(0, cIndex, 0.5f);
ep.Assign(1, cRing[iEdgeEp], eScale * eWeights[0]);
ep.Assign(2, cRing[(iEdgeEp + 1) % 6], eScale * eWeights[1]);
ep.Assign(3, cRing[(iEdgeEp + 2) % 6], eScale * eWeights[2]);
ep.Assign(4, cRing[(iEdgeEp + 3) % 6], eScale * eWeights[3]);
ep.Assign(5, cRing[(iEdgeEp + 4) % 6], eScale * eWeights[4]);
ep.Assign(6, cRing[(iEdgeEp + 5) % 6], eScale * eWeights[5]);
assert(ep.GetSize() == 7);
em.Assign(0, cIndex, 0.5f);
em.Assign(1, cRing[iEdgeEm], eScale * eWeights[0]);
em.Assign(2, cRing[(iEdgeEm + 1) % 6], eScale * eWeights[1]);
em.Assign(3, cRing[(iEdgeEm + 2) % 6], eScale * eWeights[2]);
em.Assign(4, cRing[(iEdgeEm + 3) % 6], eScale * eWeights[3]);
em.Assign(5, cRing[(iEdgeEm + 4) % 6], eScale * eWeights[4]);
em.Assign(6, cRing[(iEdgeEm + 5) % 6], eScale * eWeights[5]);
assert(em.GetSize() == 7);
} else {
REAL oneThird = (REAL) (1.0 / 3.0);
REAL twoThirds = (REAL) (2.0 / 3.0);
REAL oneSixth = (REAL) (1.0 / 6.0);
p.Assign(0, cIndex, twoThirds);
p.Assign(1, cRing[0], oneSixth);
p.Assign(2, cRing[3], oneSixth);
assert(p.GetSize() == 3);
//
// We have three triangles here, and the two edge points may be along two
// of four edges -- two of which are interior and require weights adjusted
// from above to account for phantom points (yielding {1/2, 1/6, 1/6, 1/6})
//
if (corner.epOnBoundary) {
ep.Assign(0, cIndex, twoThirds);
ep.Assign(1, cRing[0], oneThird);
ep.Assign(2, cRing[3], 0.0f);
assert(ep.GetSize() == 3);
} else {
ep.Assign(0, cIndex, 0.5f);
ep.Assign(1, cRing[1], oneSixth);
ep.Assign(2, cRing[2], oneSixth);
ep.Assign(3, cRing[corner.emOnBoundary ? 3 : 0], oneSixth);
ep.Assign(4, cRing[corner.emOnBoundary ? 0 : 3], 0.0f);
assert(ep.GetSize() == 5);
}
if (corner.emOnBoundary) {
em.Assign(0, cIndex, twoThirds);
em.Assign(1, cRing[3], oneThird);
em.Assign(2, cRing[0], 0.0f);
assert(em.GetSize() == 3);
} else {
em.Assign(0, cIndex, 0.5f);
em.Assign(1, cRing[1], oneSixth);
em.Assign(2, cRing[2], oneSixth);
em.Assign(3, cRing[corner.epOnBoundary ? 0 : 3], oneSixth);
em.Assign(4, cRing[corner.epOnBoundary ? 3 : 0], 0.0f);
assert(em.GetSize() == 5);
}
}
}
template <typename REAL>
void
GregoryTriConverter<REAL>::computeIrregularEdgePoints(int cIndex,
Matrix & matrix, Weight *weightBuffer) const {
Point p (matrix, 5*cIndex + 0);
Point ep(matrix, 5*cIndex + 1);
Point em(matrix, 5*cIndex + 2);
//
// The corner and edge points P, Ep and Em are completely determined
// by the 1-ring of vertices around (and including) the corner vertex.
// We combine full sets of coefficients for the vertex and its 1-ring.
//
CornerTopology const & corner = _corners[cIndex];
if (corner.isSharp) {
//
// The sharp case -- both interior and boundary...
//
p.Assign(0, cIndex, 1.0f);
assert(p.GetSize() == 1);
// Approximating these for now, pending future investigation...
ep.Assign(0, cIndex, (REAL) (2.0 / 3.0));
ep.Assign(1, (cIndex+1) % 3, (REAL) (1.0 / 3.0));
assert(ep.GetSize() == 2);
em.Assign(0, cIndex, (REAL) (2.0 / 3.0));
em.Assign(1, (cIndex+2) % 3, (REAL) (1.0 / 3.0));
assert(em.GetSize() == 2);
} else if (! corner.isBoundary) {
//
// The irregular interior case:
//
computeIrregularInteriorEdgePoints(cIndex, p, ep, em, weightBuffer);
} else if (corner.numFaces > 1) {
//
// The irregular boundary case:
//
computeIrregularBoundaryEdgePoints(cIndex, p, ep, em, weightBuffer);
} else {
//
// The irregular/smooth corner case:
//
p.Assign(0, cIndex, (REAL) (4.0 / 6.0));
p.Assign(1, (cIndex+1) % 3, (REAL) (1.0 / 6.0));
p.Assign(2, (cIndex+2) % 3, (REAL) (1.0 / 6.0));
assert(p.GetSize() == 3);
ep.Assign(0, cIndex, (REAL) (2.0 / 3.0));
ep.Assign(1, (cIndex+1) % 3, (REAL) (1.0 / 3.0));
ep.Assign(2, (cIndex+2) % 3, 0.0f);
assert(ep.GetSize() == 3);
em.Assign(0, cIndex, (REAL) (2.0 / 3.0));
em.Assign(1, (cIndex+2) % 3, (REAL) (1.0 / 3.0));
em.Assign(2, (cIndex+1) % 3, 0.0f);
assert(em.GetSize() == 3);
}
}
template <typename REAL>
void
GregoryTriConverter<REAL>::computeIrregularInteriorEdgePoints(
int cIndex,
Point& p, Point& ep, Point& em,
Weight *ringWeights) const {
CornerTopology const & corner = _corners[cIndex];
int valence = corner.valence;
int weightWidth = 1 + valence;
Weight* pWeights = &ringWeights[0];
Weight* epWeights = pWeights + weightWidth;
Weight* emWeights = pWeights + weightWidth * 2;
//
// The interior (smooth) case -- invoke the public static method that
// computes pre-allocated ring weights for P, Ep and Em:
//
LoopLimits<REAL>::ComputeInteriorPointWeights(valence, corner.faceInRing,
pWeights, epWeights, emWeights);
//
// Transer the weights for the ring into the stencil form of the required
// Point type. The limit mask for position involves all ring weights, and
// since Ep and Em depend on it, there should be no need to filter weights
// with value 0:
//
p.Assign( 0, cIndex, pWeights[0]);
ep.Assign(0, cIndex, epWeights[0]);
em.Assign(0, cIndex, emWeights[0]);
for (int i = 1; i < weightWidth; ++i) {
int pRingPoint = corner.ringPoints[i-1];
p.Assign( i, pRingPoint, pWeights[i]);
ep.Assign(i, pRingPoint, epWeights[i]);
em.Assign(i, pRingPoint, emWeights[i]);
}
assert(p.GetSize() == weightWidth);
assert(ep.GetSize() == weightWidth);
assert(em.GetSize() == weightWidth);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::computeIrregularBoundaryEdgePoints(
int cIndex,
Point& p, Point& ep, Point& em,
Weight *ringWeights) const {
CornerTopology const & corner = _corners[cIndex];
int valence = corner.valence;
int weightWidth = 1 + corner.valence;
Weight* pWeights = &ringWeights[0];
Weight* epWeights = pWeights + weightWidth;
Weight* emWeights = pWeights + weightWidth * 2;
//
// The boundary (smooth) case -- invoke the public static method that
// computes pre-allocated ring weights for P, Ep and Em:
//
LoopLimits<REAL>::ComputeBoundaryPointWeights(valence, corner.faceInRing,
pWeights, epWeights, emWeights);
//
// Transfer ring weights into points -- exploiting cases where they
// are known to be non-zero only along the two boundary edges:
//
int N = weightWidth - 1;
int p0 = cIndex;
int p1 = corner.ringPoints[0];
int pN = corner.ringPoints[valence-1];
p.Assign(0, p0, pWeights[0]);
p.Assign(1, p1, pWeights[1]);
p.Assign(2, pN, pWeights[N]);
assert(p.GetSize() == 3);
// If Ep is on the boundary edge, it has only two non-zero weights along
// that edge:
ep.Assign(0, p0, epWeights[0]);
if (corner.epOnBoundary) {
ep.Assign(1, p1, epWeights[1]);
ep.Assign(2, pN, 0.0f);
assert(ep.GetSize() == 3);
} else {
for (int i = 1; i < weightWidth; ++i) {
ep.Assign(i, corner.ringPoints[i-1], epWeights[i]);
}
assert(ep.GetSize() == weightWidth);
}
// If Em is on the boundary edge, it has only two non-zero weights along
// that edge:
em.Assign(0, p0, emWeights[0]);
if (corner.emOnBoundary) {
em.Assign(1, pN, emWeights[N]);
em.Assign(2, p1, 0.0f);
assert(em.GetSize() == 3);
} else {
for (int i = 1; i < weightWidth; ++i) {
em.Assign(i, corner.ringPoints[i-1], emWeights[i]);
}
assert(em.GetSize() == weightWidth);
}
}
template <typename REAL>
int
GregoryTriConverter<REAL>::getIrregularFacePointSize(
int cIndexNear, int cIndexFar) const {
CornerTopology const & nearCorner = _corners[cIndexNear];
CornerTopology const & farCorner = _corners[cIndexFar];
if (nearCorner.isSharp && farCorner.isSharp) return 2;
int nearSize = nearCorner.ringPoints.GetSize() - 3;
int farSize = farCorner.ringPoints.GetSize() - 3;
return 4 + (((nearSize > 0) && !nearCorner.isSharp) ? nearSize : 0)
+ (((farSize > 0) && !farCorner.isSharp) ? farSize : 0);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::computeIrregularFacePoint(
int cIndexNear, int edgeInNearCornerRing, int cIndexFar,
Point const & p, Point const & eNear, Point const & eFar, Point & fNear,
REAL signForSideOfEdge, Weight *rowWeights, int *columnMask) const {
CornerTopology const & cornerNear = _corners[cIndexNear];
CornerTopology const & cornerFar = _corners[cIndexFar];
int valence = cornerNear.valence;
Weight cosNear = cornerNear.cosFaceAngle;
Weight cosFar = cornerFar.cosFaceAngle;
//
// From Loop, Schaefer et al, a face point F is computed as:
//
// F = (1/d) * (c0 * P0 + (d - 2*c0 - c1) * E0 + 2*c1 * E1 + R)
//
// where d = 3 for quads and d = 4 for triangles, and R is:
//
// R = 1/3 (Mm + Mp) + 2/3 (Cm + Cp)
//
// where Mm and Mp are the midpoints of the two adjacent edges
// and Cm and Cp are the midpoints of the two adjacent faces.
//
Weight pCoeff = cosFar / 4.0f;
Weight eNearCoeff = (4.0f - 2.0f * cosNear - cosFar) / 4.0f;
Weight eFarCoeff = 2.0f * cosNear / 4.0f;
int fullRowSize = _numSourcePoints;
std::memset(&columnMask[0], 0, fullRowSize * sizeof(int));
std::memset(&rowWeights[0], 0, fullRowSize * sizeof(Weight));
_addSparsePointToFullRow(rowWeights, p, pCoeff, columnMask);
_addSparsePointToFullRow(rowWeights, eNear, eNearCoeff, columnMask);
_addSparsePointToFullRow(rowWeights, eFar, eFarCoeff, columnMask);
// Remember that R is to be computed about an interior edge and is
// comprised of the two pairs of points opposite the interior edge
//
int iEdgeInterior = edgeInNearCornerRing;
int iEdgePrev = (iEdgeInterior + valence - 1) % valence;
int iEdgeNext = (iEdgeInterior + 1) % valence;
Weight rScale = (REAL) (0.25 * (7.0 / 18.0));
rowWeights[cornerNear.ringPoints[iEdgePrev]] += -signForSideOfEdge * rScale;
rowWeights[cornerNear.ringPoints[iEdgeNext]] += signForSideOfEdge * rScale;
int nWeights = 0;
for (int i = 0; i < fullRowSize; ++i) {
if (columnMask[i]) {
fNear.Assign(nWeights++, columnMask[i] - 1, rowWeights[i]);
}
}
// Complete the expected row size when val-2 corners induce duplicates:
if (_hasVal2InteriorCorner && (nWeights < fNear.GetSize())) {
while (nWeights < fNear.GetSize()) {
fNear.Assign(nWeights++, cIndexNear, 0.0f);
}
}
assert(fNear.GetSize() == nWeights);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::assignRegularFacePoints(int cIndex, Matrix & matrix) const {
CornerTopology const & corner = _corners[cIndex];
int cNext = (cIndex+1) % 3;
int cPrev = (cIndex+2) % 3;
int const * cRing = corner.ringPoints;
//
// Regular face-points are computed the same for both face-points of a
// a corner (fp and fm), so iterate through both and make appropriate
// assignments when tagged as regular:
//
for (int fIsFm = 0; fIsFm < 2; ++fIsFm) {
bool fIsRegular = fIsFm ? corner.fmIsRegular : corner.fpIsRegular;
if (!fIsRegular) continue;
Point f(matrix, 5*cIndex + 3 + fIsFm);
if (corner.isCorner) {
f.Assign(0, cIndex, 0.5f);
f.Assign(1, cNext, 0.25f);
f.Assign(2, cPrev, 0.25f);
assert(f.GetSize() == 3);
} else if (corner.epOnBoundary) {
// Face is the first/leading face of the boundary ring:
f.Assign(0, cIndex, (REAL) (11.0 / 24.0));
f.Assign(1, cRing[0], (REAL) ( 7.0 / 24.0));
f.Assign(2, cRing[1], (REAL) ( 5.0 / 24.0));
f.Assign(3, cRing[2], (REAL) ( 1.0 / 24.0));
assert(f.GetSize() == 4);
} else if (corner.emOnBoundary) {
// Face is the last/trailing face of the boundary ring:
f.Assign(0, cIndex, (REAL) (11.0 / 24.0));
f.Assign(1, cRing[3], (REAL) ( 7.0 / 24.0));
f.Assign(2, cRing[2], (REAL) ( 5.0 / 24.0));
f.Assign(3, cRing[1], (REAL) ( 1.0 / 24.0));
assert(f.GetSize() == 4);
} else {
// Face is interior or the middle face of the boundary:
int eNext = corner.isBoundary ? 0 : ((corner.faceInRing + 5) % 6);
int ePrev = corner.isBoundary ? 3 : ((corner.faceInRing + 2) % 6);
f.Assign(0, cIndex, (REAL) (10.0 / 24.0));
f.Assign(1, cPrev, 0.25f);
f.Assign(2, cNext, 0.25f);
f.Assign(3, cRing[ePrev], (REAL) ( 1.0 / 24.0));
f.Assign(4, cRing[eNext], (REAL) ( 1.0 / 24.0));
assert(f.GetSize() == 5);
}
}
}
template <typename REAL>
void
GregoryTriConverter<REAL>::computeIrregularFacePoints(int cIndex,
Matrix & matrix, Weight *rowWeights, int *columnMask) const {
// Identify neighboring corners:
CornerTopology const & corner = _corners[cIndex];
int cNext = (cIndex+1) % 3;
int cPrev = (cIndex+2) % 3;
Point epPrev(matrix, 5*cPrev + 1);
Point em (matrix, 5*cIndex + 2);
Point p (matrix, 5*cIndex + 0);
Point ep (matrix, 5*cIndex + 1);
Point emNext(matrix, 5*cNext + 2);
Point fp(matrix, 5*cIndex + 3);
Point fm(matrix, 5*cIndex + 4);
//
// Compute the face points Fp and Fm in terms of the corner (P) and edge
// points (Ep and Em) previously computed. The caller provides a buffer
// of the appropriate size (twice the width of the matrix) to use for
// combining weights, along with an integer buffer used to identify
// non-zero weights and preserve the sparsity of the combinations (note
// they use index + 1 to detect index 0 when cleared with 0 entries).
//
if (!corner.fpIsRegular && !corner.fpIsCopied) {
int iEdgeP = corner.faceInRing;
computeIrregularFacePoint(cIndex, iEdgeP, cNext,
p, ep, emNext, fp, 1.0, rowWeights, columnMask);
}
if (!corner.fmIsRegular && !corner.fmIsCopied) {
int iEdgeM = (corner.faceInRing + 1) % corner.valence;
computeIrregularFacePoint(cIndex, iEdgeM, cPrev,
p, em, epPrev, fm, -1.0, rowWeights, columnMask);
}
// Copy Fp or Fm now that any shared values were computed above:
if (corner.fpIsCopied) {
fp.Copy(fm);
}
if (corner.fmIsCopied) {
fm.Copy(fp);
}
if (!corner.fpIsRegular) assert(matrix.GetRowSize(5*cIndex + 3) == fp.GetSize());
if (!corner.fmIsRegular) assert(matrix.GetRowSize(5*cIndex + 4) == fm.GetSize());
}
template <typename REAL>
void
GregoryTriConverter<REAL>::assignRegularMidEdgePoint(int edgeIndex,
Matrix & matrix) const {
Point M(matrix, 15 + edgeIndex);
CornerTopology const & corner = _corners[edgeIndex];
if (corner.epOnBoundary) {
// Trivial boundary edge case -- midway between two corners
M.Assign(0, edgeIndex, 0.5f);
M.Assign(1, (edgeIndex + 1) % 3, 0.5f);
assert(M.GetSize() == 2);
} else {
// Regular case -- two corners and two vertices opposite the edge
int oppositeInRing = corner.isBoundary ?
(corner.faceInRing - 1) : ((corner.faceInRing + 5) % 6);
int oppositeVertex = corner.ringPoints[oppositeInRing];
M.Assign(0, edgeIndex, (REAL) (1.0 / 3.0));
M.Assign(1, (edgeIndex + 1) % 3, (REAL) (1.0 / 3.0));
M.Assign(2, (edgeIndex + 2) % 3, (REAL) (1.0 / 6.0));
M.Assign(3, oppositeVertex, (REAL) (1.0 / 6.0));
assert(M.GetSize() == 4);
}
}
template <typename REAL>
void
GregoryTriConverter<REAL>::computeIrregularMidEdgePoint(int edgeIndex, Matrix & matrix,
Weight * rowWeights, int * columnMask) const {
//
// General case -- interpolate midway between cubic edge points E0 and E1:
//
int cIndex0 = edgeIndex;
int cIndex1 = (edgeIndex + 1) % 3;
Point E0p(matrix, 5 * (cIndex0) + 1);
Point E1m(matrix, 5 * (cIndex1) + 2);
Point M(matrix, 15 + edgeIndex);
_combineSparsePointsInFullRow(M, (REAL)0.5f, E0p, (REAL)0.5f, E1m,
_numSourcePoints, rowWeights, columnMask);
}
template <typename REAL>
void
GregoryTriConverter<REAL>::promoteCubicEdgePointsToQuartic(Matrix & matrix,
Weight * rowWeights, int * columnMask) const {
//
// Re-assign all regular edge-point weights with quartic coefficients,
// so only perform general combinations for the irregular case.
//
REAL const onBoundaryWeights[3] = { 16, 7, 1 };
REAL const regBoundaryWeights[5] = { 13, 3, 3, 4, 1 };
REAL const regInteriorWeights[7] = { 12, 4, 3, 1, 0, 1, 3 };
REAL const oneOver24 = (REAL) (1.0 / 24.0);
for (int cIndex = 0; cIndex < 3; ++cIndex) {
CornerTopology const & corner = _corners[cIndex];
//
// Ordering of weight values for symmetric ep and em is the same, so
// we can re-assign in a loop of 2 for {ep, em}
//
Point P(matrix, 5 * cIndex);
for (int ePair = 0; ePair < 2; ++ePair) {
Point E(matrix, 5 * cIndex + 1 + ePair);
REAL const * weightsToReassign = 0;
bool eOnBoundary = ePair ? corner.emOnBoundary : corner.epOnBoundary;
if (eOnBoundary && !corner.isSharp) {
assert(E.GetSize() == 3);
weightsToReassign = onBoundaryWeights;
} else if (corner.isRegular) {
if (corner.isBoundary) {
assert(E.GetSize() == 5);
weightsToReassign = regBoundaryWeights;
} else {
assert(E.GetSize() == 7);
weightsToReassign = regInteriorWeights;
}
}
if (weightsToReassign) {
for (int i = 0; i < E.GetSize(); ++i) {
E.SetWeight(i, weightsToReassign[i] * oneOver24);
}
} else {
_combineSparsePointsInFullRow(E, (REAL)0.25f, P, (REAL)0.75f, E,
_numSourcePoints, rowWeights, columnMask);
}
}
}
}
namespace {
template <typename REAL>
void
_printPoint(SparseMatrixRow<REAL> const & p, bool printIndices = true,
bool printWeights = true) {
printf(" Point size = %d:\n", p._size);
if (printIndices) {
printf(" Indices: ");
for (int j = 0; j < p._size; ++j) {
printf("%6d ", p._indices[j]);
}
printf("\n");
}
if (printWeights) {
printf(" Weights: ");
for (int j = 0; j < p._size; ++j) {
printf("%6.3f ", (REAL)p._weights[j]);
}
printf("\n");
}
}
template <typename REAL>
void
_printMatrix(SparseMatrix<REAL> const & matrix, bool printIndices = true,
bool printWeights = true) {
printf("Matrix %d x %d, %d elements:\n",
matrix.GetNumRows(), matrix.GetNumColumns(), matrix.GetNumElements());
for (int i = 0; i < matrix.GetNumRows(); ++i) {
int rowSize = matrix.GetRowSize(i);
printf(" Row %d (size = %d):\n", i, rowSize);
if (printIndices) {
ConstArray<int> indices = matrix.GetRowColumns(i);
printf(" Indices: ");
for (int j = 0; j < rowSize; ++j) {
printf("%6d ", indices[j]);
}
printf("\n");
}
if (printWeights) {
ConstArray<REAL> weights = matrix.GetRowElements(i);
printf(" Weights: ");
for (int j = 0; j < rowSize; ++j) {
printf("%6.3f ", (REAL)weights[j]);
}
printf("\n");
}
}
}
#ifdef FAR_DEBUG_LOOP_PATCH_BUILDER
void
_printSourcePatch(SourcePatch const & patch, bool printCornerInfo = true,
bool printRingPoints = true) {
printf("SoucePatch - %d corners, %d points:\n",
patch._numCorners, patch._numSourcePoints);
if (printCornerInfo) {
printf(" Corner info:\n");
for (int i = 0; i < patch._numCorners; ++i) {
printf("%6d: boundary = %d, sharp = %d, numFaces = %d, in-ring = %d, ringSize = %d\n", i,
patch._corners[i]._boundary, patch._corners[i]._sharp, patch._corners[i]._numFaces,
patch._corners[i]._patchFace, patch._ringSizes[i]);
}
}
if (printRingPoints) {
StackBuffer<Index,64,true> ringPoints;
printf(" Ring points:\n");
for (int i = 0; i < patch._numCorners; ++i) {
int ringSize = patch._ringSizes[i];
ringPoints.SetSize(ringSize);
patch.GetCornerRingPoints(i, ringPoints);
printf("%6d: ", i);
for (int j = 0; j < ringSize; ++j) {
printf("%d ", ringPoints[j]);
}
printf("\n");
}
}
}
#endif
}
//
// Not using the same "Converter" pattern used above and in the Catmark scheme,
// since the two remaining conversions are fairly trivial.
//
template <typename REAL>
void
convertToLinear(SourcePatch const & sourcePatch, SparseMatrix<REAL> & matrix) {
typedef REAL Weight;
StackBuffer<Index,64,true> indexBuffer(1 + sourcePatch.GetMaxRingSize());
StackBuffer<Weight,64,true> weightBuffer(1 + sourcePatch.GetMaxRingSize());
int numElements = sourcePatch.GetCornerRingSize(0) +
sourcePatch.GetCornerRingSize(1) +
sourcePatch.GetCornerRingSize(2);
matrix.Resize(3, sourcePatch.GetNumSourcePoints(), numElements);
bool hasVal2InteriorCorner = false;
for (int cIndex = 0; cIndex < 3; ++cIndex) {
SourcePatch::Corner const & sourceCorner = sourcePatch._corners[cIndex];
int ringSize = sourcePatch.GetCornerRingSize(cIndex);
if (sourceCorner._sharp) {
matrix.SetRowSize(cIndex, 1);
} else if (sourceCorner._boundary) {
matrix.SetRowSize(cIndex, 3);
} else {
matrix.SetRowSize(cIndex, 1 + ringSize);
}
Array<Index> rowIndices = matrix.SetRowColumns(cIndex);
Array<Weight> rowWeights = matrix.SetRowElements(cIndex);
indexBuffer[0] = cIndex;
sourcePatch.GetCornerRingPoints(cIndex, &indexBuffer[1]);
if (sourceCorner._sharp) {
rowIndices[0] = cIndex;
rowWeights[0] = 1.0f;
} else if (sourceCorner._boundary) {
LoopLimits<REAL>::ComputeBoundaryPointWeights(
1 + sourceCorner._numFaces, sourceCorner._patchFace,
&weightBuffer[0], 0, 0);
rowIndices[0] = indexBuffer[0];
rowIndices[1] = indexBuffer[1];
rowIndices[2] = indexBuffer[ringSize];
rowWeights[0] = weightBuffer[0];
rowWeights[1] = weightBuffer[1];
rowWeights[2] = weightBuffer[ringSize];
} else {
LoopLimits<REAL>::ComputeInteriorPointWeights(
sourceCorner._numFaces, sourceCorner._patchFace,
&weightBuffer[0], 0, 0);
std::memcpy(&rowIndices[0], indexBuffer, rowIndices.size() * sizeof(Index));
std::memcpy(&rowWeights[0], weightBuffer, rowWeights.size() * sizeof(Weight));
}
hasVal2InteriorCorner |= sourceCorner._val2Interior;
}
if (hasVal2InteriorCorner) {
_removeValence2Duplicates(matrix);
}
}
template <typename REAL>
void
convertToGregory(SourcePatch const & sourcePatch, SparseMatrix<REAL> & matrix) {
GregoryTriConverter<REAL> gregoryConverter(sourcePatch);
gregoryConverter.Convert(matrix);
}
template <typename REAL>
void
convertToLoop(SourcePatch const & sourcePatch, SparseMatrix<REAL> & matrix) {
//
// Unlike quads, there are not enough degrees of freedom in the regular patch
// to enforce interpolation of the limit point and tangent at the corner while
// preserving the two adjoining boundary curves. Since we end up destroying
// neighboring conintuity in doing so, we use a fully constructed Gregory
// patch here for the isolated corner case as well as the general case.
//
// Unfortunately, the regular patch here -- a quartic Box-spline triangle --
// is not as flexible as the BSpline patches for Catmark. Unlike BSplines
// and Bezier patches, the Box-splines do not span the full space of possible
// shapes (only 12 control points in a space spanned by 15 polynomials for
// the quartic case). So it is possible to construct shapes with a Gregory
// or Bezier triangle that cannot be represented by the Box-spline.
//
// The solution fits a Box-spline patch to the constructed Gregory patch with
// a set of constraints. With quartic boundary curves, 12 constraints on the
// boundary curve make this tightly constrained. Such a set of constraints
// is rank deficient (11 instead of 12) so an additional constraint on the
// midpoint of the patch is included and a conversion matrix is constructed
// from the pseudo-inverse of the 13 constraints.
//
// For the full 12x15 conversion matrix from 15-point quartic Bezier patch
// back to a Box spline patch, the matrix rows and columns are ordered
// according to control point orientations used elsewhere. Correllation of
// points between the Bezier and Gregory points is as follows:
//
// Q0 Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14
// G0 G1 G15 G7 G5 G2 G3,4 G8,9 G6 G17 G13,14 G16 G11 G12 G10
//
// As with conversion from Gregory to BSpline for Catmark, one of the face
// points is chosen as a Bezier point in the conversion rather than combining
// the pair (which would avoid slight asymmetric artefacts of the choice).
// And given the solution now depends primarily on the boundary, its not
// necessary to construct a full Gregory patch with enforced continuity.
//
REAL const gregoryToLoopMatrix[12][15] = {
{ 8.214411f, 7.571190f, -7.690082f, 2.237840f, -1.118922f,-16.428828f, 0.666666f, 0.666666f,
2.237835f, 6.309870f, 0.666666f, -1.690100f, -0.428812f, -0.428805f, 0.214407f },
{ -0.304687f, 0.609374f, 6.752593f, 0.609374f, -0.304687f, 0.609378f, -3.333333f, -3.333333f,
0.609378f, -1.247389f, -3.333333f, -1.247389f, 3.276037f, 3.276037f, -1.638020f },
{ -1.118922f, 2.237840f, -7.690082f, 7.571190f, 8.214411f, 2.237835f, 0.666666f, 0.666666f,
-16.428828f, -1.690100f, 0.666666f, 6.309870f, -0.428805f, -0.428812f, 0.214407f },
{ 8.214411f,-16.428828f, 6.309870f, -0.428812f, 0.214407f, 7.571190f, 0.666666f, 0.666666f,
-0.428805f, -7.690082f, 0.666666f, -1.690100f, 2.237840f, 2.237835f, -1.118922f },
{ -0.813368f, 1.626735f, -0.773435f, -1.039929f, 0.519965f, 1.626735f, 0.666666f, 0.666666f,
-1.039930f, -0.773435f, 0.666666f, 1.226558f, -1.039929f, -1.039930f, 0.519965f },
{ 0.519965f, -1.039929f, -0.773435f, 1.626735f, -0.813368f, -1.039930f, 0.666666f, 0.666666f,
1.626735f, 1.226558f, 0.666666f, -0.773435f, -1.039930f, -1.039929f, 0.519965f },
{ 0.214407f, -0.428812f, 6.309870f,-16.428828f, 8.214411f, -0.428805f, 0.666666f, 0.666666f,
7.571190f, -1.690100f, 0.666666f, -7.690082f, 2.237835f, 2.237840f, -1.118922f },
{ -0.304687f, 0.609378f, -1.247389f, 3.276037f, -1.638020f, 0.609374f, -3.333333f, -3.333333f,
3.276037f, 6.752593f, -3.333333f, -1.247389f, 0.609374f, 0.609378f, -0.304687f },
{ 0.519965f, -1.039930f, 1.226558f, -1.039930f, 0.519965f, -1.039929f, 0.666666f, 0.666666f,
-1.039929f, -0.773435f, 0.666666f, -0.773435f, 1.626735f, 1.626735f, -0.813368f },
{ -1.638020f, 3.276037f, -1.247389f, 0.609378f, -0.304687f, 3.276037f, -3.333333f, -3.333333f,
0.609374f, -1.247389f, -3.333333f, 6.752593f, 0.609378f, 0.609374f, -0.304687f },
{ -1.118922f, 2.237835f, -1.690100f, -0.428805f, 0.214407f, 2.237840f, 0.666666f, 0.666666f,
-0.428812f, -7.690082f, 0.666666f, 6.309870f, 7.571190f,-16.428828f, 8.214411f },
{ 0.214407f, -0.428805f, -1.690100f, 2.237835f, -1.118922f, -0.428812f, 0.666666f, 0.666666f,
2.237840f, 6.309870f, 0.666666f, -7.690082f,-16.428828f, 7.571190f, 8.214411f }
};
int const gRowIndices[15] = { 0,1,15,7,5, 2,4,8,6, 17,14,16, 11,12, 10 };
SparseMatrix<REAL> G;
convertToGregory<REAL>(sourcePatch, G);
_initializeFullMatrix(matrix, 12, G.GetNumColumns());
for (int i = 0; i < 12; ++i) {
REAL const * gRowWeights = gregoryToLoopMatrix[i];
_combineSparseMatrixRowsInFull(matrix, i, G, 15, gRowIndices, gRowWeights);
}
}
//
// Internal utilities more relevant to the LoopPatchBuilder:
//
namespace {
//
// The patch type associated with each basis for Loop -- quickly
// indexed from an array. The patch type here is essentially the
// triangle form of each basis.
//
PatchDescriptor::Type patchTypeFromBasisArray[] = {
PatchDescriptor::NON_PATCH, // undefined
PatchDescriptor::LOOP, // regular
PatchDescriptor::GREGORY_TRIANGLE, // Gregory
PatchDescriptor::TRIANGLES, // linear
PatchDescriptor::NON_PATCH }; // Bezier -- for future use
};
LoopPatchBuilder::LoopPatchBuilder(
TopologyRefiner const& refiner, Options const& options) :
PatchBuilder(refiner, options) {
_regPatchType = patchTypeFromBasisArray[_options.regBasisType];
_irregPatchType = (_options.irregBasisType == BASIS_UNSPECIFIED)
? _regPatchType
: patchTypeFromBasisArray[_options.irregBasisType];
_nativePatchType = PatchDescriptor::LOOP;
_linearPatchType = PatchDescriptor::TRIANGLES;
}
LoopPatchBuilder::~LoopPatchBuilder() {
}
PatchDescriptor::Type
LoopPatchBuilder::patchTypeFromBasis(BasisType basis) const {
return patchTypeFromBasisArray[(int)basis];
}
template <typename REAL>
int
LoopPatchBuilder::convertSourcePatch(SourcePatch const & sourcePatch,
PatchDescriptor::Type patchType,
SparseMatrix<REAL> & matrix) const {
assert(_schemeType == Sdc::SCHEME_LOOP);
if (patchType == PatchDescriptor::LOOP) {
convertToLoop<REAL>(sourcePatch, matrix);
} else if (patchType == PatchDescriptor::TRIANGLES) {
convertToLinear<REAL>(sourcePatch, matrix);
} else if (patchType == PatchDescriptor::GREGORY_TRIANGLE) {
convertToGregory<REAL>(sourcePatch, matrix);
} else {
assert("Unknown or unsupported patch type" == 0);
}
return matrix.GetNumRows();
}
int
LoopPatchBuilder::convertToPatchType(SourcePatch const & sourcePatch,
PatchDescriptor::Type patchType,
SparseMatrix<float> & matrix) const {
return convertSourcePatch(sourcePatch, patchType, matrix);
}
int
LoopPatchBuilder::convertToPatchType(SourcePatch const & sourcePatch,
PatchDescriptor::Type patchType,
SparseMatrix<double> & matrix) const {
return convertSourcePatch(sourcePatch, patchType, matrix);
}
} // end namespace Far
} // end namespace OPENSUBDIV_VERSION
} // end namespace OpenSubdiv