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Merge pull request #833 from barfowl/gregory_patch_cleanup2

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Clean up Gregory patch conversion in preparation for future work
This commit is contained in:
David G Yu 2016-08-23 22:14:00 -07:00 committed by GitHub
commit d3323e8cc7
2 changed files with 355 additions and 359 deletions
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665
opensubdiv/far/gregoryBasis.cpp
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@ -38,47 +38,6 @@ namespace OPENSUBDIV_VERSION {
namespace Far {
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);
}
}
void
GregoryBasis::ProtoBasis::Copy(GregoryBasis * dest) const {
int nelems = GetNumElements();
dest->_indices.resize(nelems);
dest->_weights.resize(nelems);
Copy(dest->_sizes, &dest->_indices[0], &dest->_weights[0]);
}
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));
}
}
inline float computeCoefficient(int valence) {
// precomputed coefficient table up to valence 29
static float efTable[] = {
@ -99,35 +58,45 @@ inline float computeCoefficient(int valence) {
sqrtf((cosf(t) + 9) * (cosf(t) + 1)))/16.0f);
}
//
// There is a long and unclear history to the details of the patch conversion here...
//
// The formulae for computing the Gregory patch points do not follow the more widely
// accepted work of Loop, Shaefer et al or Myles et al. The formulae for the limit
// points and tangents also ultimately need to be retrieved from Sdc::Scheme to
// ensure they conform, so future factoring of the formulae is still necessary.
//
// This implementation is in the process of iterative refactoring to adapt it for
// more general use. The method is currently divided into four stages -- some of
// which will eventually be moved externally and/or made into methods of their own:
//
// - gather complete topology information for all four corners of the patch
// - compute the vertex-points and intermediate values used below
// - compute the edge-points
// - compute the face-points (which depend on multiple edge-points)
//
GregoryBasis::ProtoBasis::ProtoBasis(
Vtr::internal::Level const & level, Index faceIndex,
Vtr::internal::Level::VSpan const cornerSpans[],
int levelVertOffset, int fvarChannel) {
// XXX: This function is subject to refactor in 3.1
//
// The first stage -- gather topology information for the entire patch:
//
// This stage is intentionally separated from any computation as the information
// gathered here for each corner vertex (one-ring, valence, etc.) will eventually
// be passed to this function in a more general and compact form. We have to
// be careful with face-varying channels to query the topology from the vertices
// of the level, while computing the patch basis from the points (fvar values).
//
Vtr::ConstIndexArray faceVerts = level.getFaceVertices(faceIndex);
Vtr::ConstIndexArray facePoints = (fvarChannel < 0)
? faceVerts
: level.getFaceFVarValues(faceIndex, fvarChannel);
Vtr::ConstIndexArray facePoints = (fvarChannel<0) ?
level.getFaceVertices(faceIndex) :
level.getFaceFVarValues(faceIndex, fvarChannel);
assert(facePoints.size()==4);
int maxvalence = level.getMaxValence(),
valences[4];
// XXX: a temporary hack for the performance issue
// ensure Point has a capacity for the neighborhood of
// 2 extraordinary verts + 2 regular verts
// worse case: n-valence verts at a corner of n-gon.
int stencilCapacity =
4/*0-ring*/ + 2*(2*(maxvalence-2)/*1-ring around extraordinaries*/
+ 2/*1-ring around regulars, excluding shared ones*/);
Point e0[4], e1[4];
for (int i = 0; i < 4; ++i) {
P[i].Clear(stencilCapacity);
e0[i].Clear(stencilCapacity);
e1[i].Clear(stencilCapacity);
}
// Should be use a "local" max valence here in future
// A discontinuous edge in the fvar topology can increase the valence by one.
int maxvalence = level.getMaxValence() + int(fvarChannel>=0);
Vtr::internal::StackBuffer<Index, 40> manifoldRings[4];
manifoldRings[0].SetSize(maxvalence*2);
@ -135,290 +104,356 @@ GregoryBasis::ProtoBasis::ProtoBasis(
manifoldRings[2].SetSize(maxvalence*2);
manifoldRings[3].SetSize(maxvalence*2);
bool cornerBoundary[4];
int cornerValences[4];
int cornerNumFaces[4];
int cornerPatchFace[4];
float cornerFaceAngle[4];
// Sum the number of source vertices contributing to the patch, which define the
// size of the stencil for each "point" involved. We just want an upper bound
// here for now, so sum the vertices from the neighboring rings at each corner,
// but don't count the shared face points multiple times.
int stencilCapacity = 4;
for (int corner = 0; corner < 4; ++corner) {
// save for varying stencils
varyingIndex[corner] = faceVerts[corner] + levelVertOffset;
// Gather the (partial) one-ring around the corner vertex:
int ringSize = 0;
if (cornerSpans[corner]._numFaces == 0) {
ringSize = level.gatherQuadRegularRingAroundVertex( faceVerts[corner],
manifoldRings[corner], fvarChannel);
} else {
ringSize = level.gatherQuadRegularPartialRingAroundVertex( faceVerts[corner],
cornerSpans[corner],
manifoldRings[corner], fvarChannel);
}
stencilCapacity += ringSize - 3;
// Cache topology information about the corner for ease of use later:
if (ringSize & 1) {
cornerBoundary[corner] = true;
cornerNumFaces[corner] = (ringSize - 1) / 2;
cornerValences[corner] = cornerNumFaces[corner] + 1;
cornerFaceAngle[corner] = float(M_PI) / float(cornerNumFaces[corner]);
// Necessary to pad the ring to even size for the f[] and r[] computations...
manifoldRings[corner][ringSize] = manifoldRings[corner][ringSize-1];
} else {
cornerBoundary[corner] = false;
cornerNumFaces[corner] = ringSize / 2;
cornerValences[corner] = cornerNumFaces[corner];
cornerFaceAngle[corner] = 2.0f * float(M_PI) / float(cornerNumFaces[corner]);
}
// Identify the patch-face within the ring of faces for the corner (which
// will later be identified externally and specified directly):
int nEdgeVerts = cornerValences[corner];
Index vNext = facePoints[(corner + 1) % 4];
Index vPrev = facePoints[(corner + 3) % 4];
cornerPatchFace[corner] = -1;
for (int i = 0; i < nEdgeVerts; ++i) {
int iPrev = (i + 1) % nEdgeVerts;
if ((manifoldRings[corner][2*i] == vNext) && (manifoldRings[corner][2*iPrev] == vPrev)) {
cornerPatchFace[corner] = i;
break;
}
}
assert(cornerPatchFace[corner] != -1);
}
//
// The first computation pass...
//
// Compute vertex-point (P) and intermediate values (f[] and r[]) for each corner
//
Point e0[4], e1[4];
Vtr::internal::StackBuffer<Point, 10> f(maxvalence);
Vtr::internal::StackBuffer<Point, 40> r(maxvalence*4);
// the first phase
for (int corner = 0; corner < 4; ++corner) {
Index vCorner = facePoints[corner];
for (int vid=0; vid<4; ++vid) {
int cornerValence = cornerValences[corner];
// save for varying stencils
varyingIndex[vid] = facePoints[vid] + levelVertOffset;
//
// Compute intermediate f[] and r[] vectors:
//
// The f[] are used to compute position and limit tangents for the interior case,
// which should eventually be computed directly with Sdc::Scheme methods -- so
// these f[] will ultimately be made obsolete.
//
// The r[] are only used in computing face points Fp and Fm, and of the r[] that
// are allocated and computed for every edge of every corner vertex, only two are
// used for each corner vertex. Aside from only computing the subset of r[] needed,
// these can be deferred to direct computation as part of Fp and Fm as they serve
// no other purpose.
//
// Note also that the computations of each f[] and r[] do not take into account
// boundaries and relies on padding of the rings to provide an indexable value in
// these cases.
//
for (int i = 0; i < cornerValence; ++i) {
int ringSize = 0;
if (cornerSpans[vid]._numFaces == 0) {
ringSize = level.gatherQuadRegularRingAroundVertex( facePoints[vid],
manifoldRings[vid], fvarChannel);
} else {
ringSize = level.gatherQuadRegularPartialRingAroundVertex( facePoints[vid],
cornerSpans[vid],
manifoldRings[vid], fvarChannel);
}
int iPrev = (i+cornerValence-1)%cornerValence;
int iNext = (i+1)%cornerValence;
// when the corner vertex is on a boundary (ring-size is odd), valence is
// negated and the ring is padded to replicate the last entry
if (ringSize & 1) {
manifoldRings[vid][ringSize] = manifoldRings[vid][ringSize-1];
++ringSize;
valences[vid] = -ringSize/2;
} else {
valences[vid] = ringSize/2;
}
// Identify the vertex at the end of each edge along with the previous and
// next face- and edge-vertex in the ring:
Index vEdge = (manifoldRings[corner][2*i]);
Index vFaceNext = (manifoldRings[corner][2*i + 1]);
Index vEdgeNext = (manifoldRings[corner][2*iNext]);
Index vEdgePrev = (manifoldRings[corner][2*iPrev]);
Index vFacePrev = (manifoldRings[corner][2*iPrev + 1]);
int valence = valences[vid];
int ivalence = abs(valence);
for (int i=0; i<ivalence; ++i) {
Index im = (i+ivalence-1)%ivalence,
ip = (i+1)%ivalence;
Index idx_neighbor = (manifoldRings[vid][2*i + 0]),
idx_diagonal = (manifoldRings[vid][2*i + 1]),
idx_neighbor_p = (manifoldRings[vid][2*ip + 0]),
idx_neighbor_m = (manifoldRings[vid][2*im + 0]),
idx_diagonal_m = (manifoldRings[vid][2*im + 1]);
float d = float(ivalence)+5.0f;
float denom = 1.0f / (float(cornerValence) + 5.0f);
f[i].Clear(4);
f[i].AddWithWeight(facePoints[vid], float(ivalence)/d);
f[i].AddWithWeight(idx_neighbor_p, 2.0f/d);
f[i].AddWithWeight(idx_neighbor, 2.0f/d);
f[i].AddWithWeight(idx_diagonal, 1.0f/d);
f[i].AddWithWeight(vCorner, float(cornerValence) * denom);
f[i].AddWithWeight(vEdgeNext, 2.0f * denom);
f[i].AddWithWeight(vEdge, 2.0f * denom);
f[i].AddWithWeight(vFaceNext, denom);
P[vid].AddWithWeight(f[i], 1.0f/float(ivalence));
int rid = vid * maxvalence + i;
int rid = corner * maxvalence + i;
r[rid].Clear(4);
r[rid].AddWithWeight(idx_neighbor_p, 1.0f/3.0f);
r[rid].AddWithWeight(idx_neighbor_m, -1.0f/3.0f);
r[rid].AddWithWeight(idx_diagonal, 1.0f/6.0f);
r[rid].AddWithWeight(idx_diagonal_m, -1.0f/6.0f);
r[rid].AddWithWeight(vEdgeNext, 1.0f / 3.0f);
r[rid].AddWithWeight(vEdgePrev, -1.0f / 3.0f);
r[rid].AddWithWeight(vFaceNext, 1.0f / 6.0f);
r[rid].AddWithWeight(vFacePrev, -1.0f / 6.0f);
}
for (int i=0; i<ivalence; ++i) {
int im = (i+ivalence-1)%ivalence;
float c0 = 0.5f * csf(ivalence-3, 2*i);
float c1 = 0.5f * csf(ivalence-3, 2*i+1);
e0[vid].AddWithWeight(f[i ], c0);
e0[vid].AddWithWeight(f[im], c0);
e1[vid].AddWithWeight(f[i ], c1);
e1[vid].AddWithWeight(f[im], c1);
}
//
// Compute the vertex point P[] and intermediate limit tangents e0 and e1:
//
// The limit tangents e0 and e1 should be computed from Sdc::Scheme methods.
// But these explicit limit tangents vectors are not needed as intermediate
// results as the Ep and Em can be computed more directly from the limit
// masks for the tangent vectors.
//
if (! cornerBoundary[corner]) {
float theta = cornerFaceAngle[corner];
float posScale = 1.0f / float(cornerValence);
float tanScale = computeCoefficient(cornerValence);
float ef = computeCoefficient(ivalence);
e0[vid] *= ef;
e1[vid] *= ef;
P[corner].Clear(stencilCapacity);
e0[corner].Clear(stencilCapacity);
e1[corner].Clear(stencilCapacity);
// Boundary gregory case:
if (valence < 0) {
Index boundaryEdgeNeighbors[2] = { manifoldRings[vid][0],
manifoldRings[vid][ringSize-1] };
for (int i=0; i<cornerValence; ++i) {
int iPrev = (i+cornerValence-1) % cornerValence;
P[vid].Clear(stencilCapacity);
P[vid].AddWithWeight(boundaryEdgeNeighbors[0], 1.0f/6.0f);
P[vid].AddWithWeight(boundaryEdgeNeighbors[1], 1.0f/6.0f);
P[vid].AddWithWeight(facePoints[vid], 4.0f/6.0f);
P[corner].AddWithWeight(f[i], posScale);
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);
float c0 = tanScale * 0.5f * cosf(float(i) * theta);
e0[corner].AddWithWeight(f[i], c0);
e0[corner].AddWithWeight(f[iPrev], c0);
int idx_diagonal = manifoldRings[vid][1];
e0[vid].Clear(stencilCapacity);
e0[vid].AddWithWeight(boundaryEdgeNeighbors[0], 1.0f/6.0f);
e0[vid].AddWithWeight(boundaryEdgeNeighbors[1], -1.0f/6.0f);
e1[vid].Clear(stencilCapacity);
e1[vid].AddWithWeight(facePoints[vid], gamma);
e1[vid].AddWithWeight(idx_diagonal, beta_0);
e1[vid].AddWithWeight(boundaryEdgeNeighbors[0], alpha_0k);
e1[vid].AddWithWeight(boundaryEdgeNeighbors[1], alpha_0k);
for (int x=1; x<ivalence-1; ++x) {
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 = manifoldRings[vid][2*x + 0],
idx_diagonal = manifoldRings[vid][2*x + 1];
e1[vid].AddWithWeight(idx_neighbor, alpha);
e1[vid].AddWithWeight(idx_diagonal, beta);
float c1 = tanScale * 0.5f * sinf(float(i) * theta);
e1[corner].AddWithWeight(f[i], c1);
e1[corner].AddWithWeight(f[iPrev], c1);
}
e1[vid] *= 1.0f/3.0f;
} else {
Index vEdgeLeading = manifoldRings[corner][0];
Index vEdgeTrailing = manifoldRings[corner][2*cornerValence-1];
P[corner].Clear(stencilCapacity);
P[corner].AddWithWeight(vEdgeLeading, 1.0f / 6.0f);
P[corner].AddWithWeight(vEdgeTrailing, 1.0f / 6.0f);
P[corner].AddWithWeight(vCorner, 4.0f / 6.0f);
float k = float(cornerNumFaces[corner]);
float theta = cornerFaceAngle[corner];
float c = cosf(theta);
float s = sinf(theta);
float div3kc = 1.0f / (3.0f*k+c);
float gamma = -4.0f * s * div3kc;
float alpha_0k = -((1.0f+2.0f*c) * sqrtf(1.0f+c)) * div3kc / sqrtf(1.0f-c);
float beta_0 = s * div3kc;
Index vEdge = manifoldRings[corner][0];
Index vFace = manifoldRings[corner][1];
e0[corner].Clear(stencilCapacity);
e0[corner].AddWithWeight(vEdgeLeading, 1.0f / 6.0f);
e0[corner].AddWithWeight(vEdgeTrailing, -1.0f / 6.0f);
e1[corner].Clear(stencilCapacity);
e1[corner].AddWithWeight(vCorner, gamma);
e1[corner].AddWithWeight(vEdgeLeading, alpha_0k);
e1[corner].AddWithWeight(vFace, beta_0);
e1[corner].AddWithWeight(vEdgeTrailing, alpha_0k);
for (int i = 1; i < cornerValence - 1; ++i) {
float alpha = 4.0f * sinf(float(i)*theta) * div3kc;
float beta = (sinf(float(i)*theta) + sinf(float(i+1)*theta)) * div3kc;
vEdge = manifoldRings[corner][2*i + 0];
vFace = manifoldRings[corner][2*i + 1];
e1[corner].AddWithWeight(vEdge, alpha);
e1[corner].AddWithWeight(vFace, beta);
}
e1[corner] *= 1.0f / 3.0f;
}
}
// the second phase
//
// The second computation pass...
//
// Compute the edge points Ep and Em first. These can be computed local to the corner,
// unlike the face points, whose computation requires edge points from adjacent corners
// and so are computed in a final pass after all edge points are available.
//
// Consider merging this pass with the previous, now that face points have been deferred
// to a separate third pass.
//
// Note that computation of Ep and Em here use intermediate limit tangents e0 and e1 and
// compute rotations of these for Ep and Em. The masks for the limit tangents can be
// rotated topologically to avoid the explicit rotation here (at least for the interior
// case -- boundary case still warrants it until there is more flexibility in limit
// tangent masks orientation in Sdc)
//
for (int corner = 0; corner < 4; ++corner) {
for (int vid=0; vid<4; ++vid) {
// Identify edges in the ring pointing to the next and previous corner of the patch:
int iEdgeNext = cornerPatchFace[corner];
int iEdgePrev = (cornerPatchFace[corner] + 1) % cornerValences[corner];
int n = abs(valences[vid]);
int ivalence = n;
float faceAngle = cornerFaceAngle[corner];
int ip = (vid+1)%4,
im = (vid+3)%4,
np = abs(valences[ip]),
nm = abs(valences[im]);
float faceAngleNext = faceAngle * float(iEdgeNext);
float faceAnglePrev = faceAngle * float(iEdgePrev);
Index start = -1, prev = -1, start_m = -1, prev_p = -1;
for (int i = 0; i < n; ++i) {
if (manifoldRings[vid][i*2] == facePoints[ip])
start = i;
if (manifoldRings[vid][i*2] == facePoints[im])
prev = i;
}
for (int i = 0; i < np; ++i) {
if (manifoldRings[ip][i*2] == facePoints[vid]) {
prev_p = i;
break;
}
}
for (int i = 0; i < nm; ++i) {
if (manifoldRings[im][i*2] == facePoints[vid]) {
start_m = i;
break;
}
}
assert(start != -1 && prev != -1 && start_m != -1 && prev_p != -1);
if (! cornerBoundary[corner]) {
Ep[corner] = P[corner];
Ep[corner].AddWithWeight(e0[corner], cosf(faceAngleNext));
Ep[corner].AddWithWeight(e1[corner], sinf(faceAngleNext));
Point Em_ip = P[ip];
Point Ep_im = P[im];
Em[corner] = P[corner];
Em[corner].AddWithWeight(e0[corner], cosf(faceAnglePrev));
Em[corner].AddWithWeight(e1[corner], sinf(faceAnglePrev));
} else if (cornerNumFaces[corner] > 1) {
Ep[corner] = P[corner];
Ep[corner].AddWithWeight(e0[corner], cosf(faceAngleNext));
Ep[corner].AddWithWeight(e1[corner], sinf(faceAngleNext));
if (valences[ip]<-2) {
Index j = (np + prev_p) % np;
Em_ip.AddWithWeight(e0[ip], cosf((float(M_PI)*j)/float(np-1)));
Em_ip.AddWithWeight(e1[ip], sinf((float(M_PI)*j)/float(np-1)));
Em[corner] = P[corner];
Em[corner].AddWithWeight(e0[corner], cosf(faceAnglePrev));
Em[corner].AddWithWeight(e1[corner], sinf(faceAnglePrev));
} else {
Em_ip.AddWithWeight(e0[ip], csf(np-3, 2*prev_p));
Em_ip.AddWithWeight(e1[ip], csf(np-3, 2*prev_p+1));
}
// Edge points are on the control polygon here (with P midway between):
Ep[corner].Clear(stencilCapacity);
Ep[corner].AddWithWeight(facePoints[corner], 2.0f / 3.0f);
Ep[corner].AddWithWeight(facePoints[(corner+1)%4], 1.0f / 3.0f);
if (valences[im]<-2) {
Index j = (nm + start_m) % nm;
Ep_im.AddWithWeight(e0[im], cosf((float(M_PI)*j)/float(nm-1)));
Ep_im.AddWithWeight(e1[im], sinf((float(M_PI)*j)/float(nm-1)));
} else {
Ep_im.AddWithWeight(e0[im], csf(nm-3, 2*start_m));
Ep_im.AddWithWeight(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];
Ep[vid].AddWithWeight(e0[vid], csf(n-3, 2*start));
Ep[vid].AddWithWeight(e1[vid], csf(n-3, 2*start +1));
Em[vid] = P[vid];
Em[vid].AddWithWeight(e0[vid], csf(n-3, 2*prev ));
Em[vid].AddWithWeight(e1[vid], csf(n-3, 2*prev + 1));
Fp[vid].Clear(stencilCapacity);
Fp[vid].AddWithWeight(P[vid], csf(np-3, 2)/3.0f);
Fp[vid].AddWithWeight(Ep[vid], s1/3.0f);
Fp[vid].AddWithWeight(Em_ip, s2/3.0f);
Fp[vid].AddWithWeight(rp[start], 1.0f/3.0f);
Fm[vid].Clear(stencilCapacity);
Fm[vid].AddWithWeight(P[vid], csf(nm-3, 2)/3.0f);
Fm[vid].AddWithWeight(Em[vid], s3/3.0f);
Fm[vid].AddWithWeight(Ep_im, s2/3.0f);
Fm[vid].AddWithWeight(rp[prev], -1.0f/3.0f);
} else if (valences[vid] < -2) {
Index jp = (ivalence + start) % ivalence,
jm = (ivalence + prev) % 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];
Ep[vid].AddWithWeight(e0[vid], cosf((float(M_PI)*jp)/float(ivalence-1)));
Ep[vid].AddWithWeight(e1[vid], sinf((float(M_PI)*jp)/float(ivalence-1)));
Em[vid] = P[vid];
Em[vid].AddWithWeight(e0[vid], cosf((float(M_PI)*jm)/float(ivalence-1)));
Em[vid].AddWithWeight(e1[vid], sinf((float(M_PI)*jm)/float(ivalence-1)));
Fp[vid].Clear(stencilCapacity);
Fp[vid].AddWithWeight(P[vid], csf(np-3,2)/3.0f);
Fp[vid].AddWithWeight(Ep[vid], s1/3.0f);
Fp[vid].AddWithWeight(Em_ip, s2/3.0f);
Fp[vid].AddWithWeight(rp[start], 1.0f/3.0f);
Fm[vid].Clear(stencilCapacity);
Fm[vid].AddWithWeight(P[vid], csf(nm-3,2)/3.0f);
Fm[vid].AddWithWeight(Em[vid], s3/3.0f);
Fm[vid].AddWithWeight(Ep_im, s2/3.0f);
Fm[vid].AddWithWeight(rp[prev], -1.0f/3.0f);
if (valences[im]<0) {
s1=3-2*csf(n-3,2)-csf(np-3,2);
Fp[vid].Clear(stencilCapacity);
Fp[vid].AddWithWeight(P[vid], csf(np-3,2)/3.0f);
Fp[vid].AddWithWeight(Ep[vid], s1/3.0f);
Fp[vid].AddWithWeight(Em_ip, s2/3.0f);
Fp[vid].AddWithWeight(rp[start], 1.0f/3.0f);
Fm[vid] = Fp[vid];
} 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].Clear(stencilCapacity);
Fm[vid].AddWithWeight(P[vid], csf(nm-3,2)/3.0f);
Fm[vid].AddWithWeight(Em[vid], s1/3.0f);
Fm[vid].AddWithWeight(Ep_im, s2/3.0f);
Fm[vid].AddWithWeight(rp[prev], -1.0f/3.0f);
Fp[vid] = Fm[vid];
}
} else if (valences[vid]==-2) {
Ep[vid].Clear(stencilCapacity);
Ep[vid].AddWithWeight(facePoints[vid], 2.0f/3.0f);
Ep[vid].AddWithWeight(facePoints[ip], 1.0f/3.0f);
Em[vid].Clear(stencilCapacity);
Em[vid].AddWithWeight(facePoints[vid], 2.0f/3.0f);
Em[vid].AddWithWeight(facePoints[im], 1.0f/3.0f);
Fp[vid].Clear(stencilCapacity);
Fp[vid].AddWithWeight(facePoints[vid], 4.0f/9.0f);
Fp[vid].AddWithWeight(facePoints[((vid+2)%n)], 1.0f/9.0f);
Fp[vid].AddWithWeight(facePoints[ip], 2.0f/9.0f);
Fp[vid].AddWithWeight(facePoints[im], 2.0f/9.0f);
Fm[vid] = Fp[vid];
Em[corner].Clear(stencilCapacity);
Em[corner].AddWithWeight(facePoints[corner], 2.0f / 3.0f);
Em[corner].AddWithWeight(facePoints[(corner+3)%4], 1.0f / 3.0f);
}
}
// offset stencil indices.
// These stencils are created relative to the level. Adding levelVertOffset,
// we get stencils with absolute indices
// (starts from the coarse level if the leveVertOffset includes level 0)
for (int i = 0; i < 4; ++i) {
P[i].OffsetIndices(levelVertOffset);
Ep[i].OffsetIndices(levelVertOffset);
Em[i].OffsetIndices(levelVertOffset);
Fp[i].OffsetIndices(levelVertOffset);
Fm[i].OffsetIndices(levelVertOffset);
//
// The third pass...
//
// Compute the face points Fp and Fm in terms of the vertex (P) and edge points (Ep and
// Em) previously computed.
//
for (int corner = 0; corner < 4; ++corner) {
int cornerNext = (corner+1) % 4;
int cornerOpp = (corner+2) % 4;
int cornerPrev = (corner+3) % 4;
// Identify edges in the ring pointing to the next and previous corner of the
// patch and the intermediate r[] associated with each:
Point const * rp = &r[corner*maxvalence];
Point const & rEdgeNext = rp[cornerPatchFace[corner]];
Point const & rEdgePrev = rp[(cornerPatchFace[corner] + 1) % cornerValences[corner]];
// Coefficients to arrange the face points for tangent continuity across edges:
float cosCorner = cosf(cornerFaceAngle[corner]);
float cosPrev = cosf(cornerFaceAngle[cornerPrev]);
float cosNext = cosf(cornerFaceAngle[cornerNext]);
float s1 = 3.0f - 2.0f * cosCorner - cosNext;
float s2 = 2.0f * cosCorner;
float s3 = 3.0f - 2.0f * cosCorner - cosPrev;
if (! cornerBoundary[corner]) {
Fp[corner].Clear(stencilCapacity);
Fp[corner].AddWithWeight(P[corner], cosNext / 3.0f);
Fp[corner].AddWithWeight(Ep[corner], s1 / 3.0f);
Fp[corner].AddWithWeight(Em[cornerNext], s2 / 3.0f);
Fp[corner].AddWithWeight(rEdgeNext, 1.0f / 3.0f);
Fm[corner].Clear(stencilCapacity);
Fm[corner].AddWithWeight(P[corner], cosPrev / 3.0f);
Fm[corner].AddWithWeight(Em[corner], s3 / 3.0f);
Fm[corner].AddWithWeight(Ep[cornerPrev], s2 / 3.0f);
Fm[corner].AddWithWeight(rEdgePrev, -1.0f / 3.0f);
} else if (cornerNumFaces[corner] > 1) {
Fp[corner].Clear(stencilCapacity);
Fp[corner].AddWithWeight(P[corner], cosNext / 3.0f);
Fp[corner].AddWithWeight(Ep[corner], s1 / 3.0f);
Fp[corner].AddWithWeight(Em[cornerNext], s2 / 3.0f);
Fp[corner].AddWithWeight(rEdgeNext, 1.0f / 3.0f);
Fm[corner].Clear(stencilCapacity);
Fm[corner].AddWithWeight(P[corner], cosPrev / 3.0f);
Fm[corner].AddWithWeight(Em[corner], s3 / 3.0f);
Fm[corner].AddWithWeight(Ep[cornerPrev], s2 / 3.0f);
Fm[corner].AddWithWeight(rEdgePrev, -1.0f / 3.0f);
if (cornerBoundary[cornerPrev]) {
Fp[corner].Clear(stencilCapacity);
Fp[corner].AddWithWeight(P[corner], cosNext / 3.0f);
Fp[corner].AddWithWeight(Ep[corner], s1 / 3.0f);
Fp[corner].AddWithWeight(Em[cornerNext], s2 / 3.0f);
Fp[corner].AddWithWeight(rEdgeNext, 1.0f / 3.0f);
Fm[corner] = Fp[corner];
} else if (cornerBoundary[cornerNext]) {
Fm[corner].Clear(stencilCapacity);
Fm[corner].AddWithWeight(P[corner], cosPrev / 3.0f);
Fm[corner].AddWithWeight(Em[corner], s3 / 3.0f);
Fm[corner].AddWithWeight(Ep[cornerPrev], s2 / 3.0f);
Fm[corner].AddWithWeight(rEdgePrev, -1.0f / 3.0f);
Fp[corner] = Fm[corner];
}
} else {
Fp[corner].Clear(stencilCapacity);
Fp[corner].AddWithWeight(facePoints[corner], 4.0f / 9.0f);
Fp[corner].AddWithWeight(facePoints[cornerOpp], 1.0f / 9.0f);
Fp[corner].AddWithWeight(facePoints[cornerNext], 2.0f / 9.0f);
Fp[corner].AddWithWeight(facePoints[cornerPrev], 2.0f / 9.0f);
Fm[corner] = Fp[corner];
}
}
//
// Offset stencil indices...
//
// These stencils are currently created relative to the level and have levelVertOffset
// to make them absolute indices. But we will be localizing these to the patch itself
// and so any association/mapping with vertices or face-varying values in a Level will
// be handled externally.
//
for (int corner = 0; corner < 4; ++corner) {
P[corner].OffsetIndices(levelVertOffset);
Ep[corner].OffsetIndices(levelVertOffset);
Em[corner].OffsetIndices(levelVertOffset);
Fp[corner].OffsetIndices(levelVertOffset);
Fm[corner].OffsetIndices(levelVertOffset);
}
}

49
opensubdiv/far/gregoryBasis.h
View File

@ -38,40 +38,15 @@ namespace Far {
class TopologyRefiner;
/// \brief Container for gregory basis stencils
/// \brief Container for utilities relating to Gregory patch construction
///
/// XXXtakahito: Currently these classes are being used by EndPatch factories.
/// These classes will likely go away once we get limit masks
/// from SchemeWorker.
/// The GregoryBasis class has been reduced to a simple container of subclasses and
/// utilities (static methods) used by the EndCap Factories. It remains a class as
/// its methods to support stencil construction currently require it to be a friend
/// of the StencilTable class.
///
class GregoryBasis {
public:
/// \brief Updates point values based on the control values
///
/// \note The destination buffers are assumed to have allocated at least
/// \c GetNumStencils() elements.
///
/// @param controlValues Buffer with primvar data for the control vertices
///
/// @param values Destination buffer for the interpolated primvar
/// data
///
template <class T, class U>
void Evaluate(T const & controlValues, U values[20]) const {
Vtr::Index const * indices = &_indices.at(0);
float const * weights = &_weights.at(0);
for (int i=0; i<20; ++i) {
values[i].Clear();
for (int j=0; j<_sizes[i]; ++j, ++indices, ++weights) {
values[i].AddWithWeight(controlValues[*indices], *weights);
}
}
}
//
// Basis point
//
@ -193,11 +168,6 @@ public:
int levelVertOffset,
int fvarChannel);
int GetNumElements() const;
void Copy(int * sizes, Vtr::Index * indices, float * weights) const;
void Copy(GregoryBasis* dest) const;
// Control Vertices based on :
// "Approximating Subdivision Surfaces with Gregory Patches for Hardware
// Tessellation" Loop, Schaefer, Ni, Castano (ACM ToG Siggraph Asia
@ -229,8 +199,6 @@ public:
Vtr::Index varyingIndex[4];
};
typedef std::vector<GregoryBasis::Point> PointsVector;
// for basis point stencil
static void AppendToStencilTable(GregoryBasis::Point const &p,
StencilTable *table) {
@ -248,13 +216,6 @@ public:
table->_indices.push_back(index);
table->_weights.push_back(1.f);
}
private:
int _sizes[20];
std::vector<Vtr::Index> _indices;
std::vector<float> _weights;
};
} // end namespace Far