mirror of
https://github.com/PixarAnimationStudios/OpenSubdiv
synced 2024-11-26 05:20:05 +00:00
770c8a45e2
This migrates a fix from the legacy GLSL shader code to improve consistency between the implementions.
374 lines
14 KiB
Metal
374 lines
14 KiB
Metal
#line 0 "osd/mtlPatchBoxSplineTriangle.metal"
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//
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// Copyright 2015-2019 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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// ----------------------------------------------------------------------------
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// Legacy Gregory
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// ----------------------------------------------------------------------------
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#if defined(OSD_PATCH_GREGORY) || defined(OSD_PATCH_GREGORY_BOUNDARY)
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// precomputed catmark coefficient table up to valence 29
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constant float OsdCatmarkCoefficient[30] = {
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0, 0, 0, 0.812816, 0.500000, 0.363644, 0.287514,
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0.238688, 0.204544, 0.179229, 0.159657,
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0.144042, 0.131276, 0.120632, 0.111614,
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0.103872, 0.09715, 0.0912559, 0.0860444,
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0.0814022, 0.0772401, 0.0734867, 0.0700842,
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0.0669851, 0.0641504, 0.0615475, 0.0591488,
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0.0569311, 0.0548745, 0.0529621
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};
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float
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OsdComputeCatmarkCoefficient(int valence)
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{
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#if OSD_MAX_VALENCE < 30
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return OsdCatmarkCoefficient[valence];
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#else
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if (valence < 30) {
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return OsdCatmarkCoefficient[valence];
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} else {
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float t = 2.0f / float(valence);
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return 1.0f / (valence * (cospi(t) + 5.0f +
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sqrt((cospi(t) + 9) * (cospi(t) + 1)))/16.0f);
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}
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#endif
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}
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float cosfn(int n, int j) {
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return cospi((2.0f * j)/float(n));
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}
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float sinfn(int n, int j) {
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return sinpi((2.0f * j)/float(n));
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}
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#ifndef OSD_MAX_VALENCE
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#define OSD_MAX_VALENCE 4
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#endif
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template<typename OsdVertexBuffer>
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float3 OsdReadVertex(int vertexIndex, OsdVertexBuffer osdVertexBuffer)
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{
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int index = (vertexIndex /*+ OsdBaseVertex()*/);
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return osdVertexBuffer[index].position;
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}
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template<typename OsdValenceBuffer>
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int OsdReadVertexValence(int vertexID, OsdValenceBuffer osdValenceBuffer)
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{
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int index = int(vertexID * (2 * OSD_MAX_VALENCE + 1));
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return osdValenceBuffer[index];
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}
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template<typename OsdValenceBuffer>
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int OsdReadVertexIndex(int vertexID, int valenceVertex, OsdValenceBuffer osdValenceBuffer)
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{
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int index = int(vertexID * (2 * OSD_MAX_VALENCE + 1) + 1 + valenceVertex);
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return osdValenceBuffer[index];
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}
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template<typename OsdQuadOffsetBuffer>
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int OsdReadQuadOffset(int primitiveID, int offsetVertex, OsdQuadOffsetBuffer osdQuadOffsetBuffer)
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{
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int index = int(4*primitiveID + offsetVertex);
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return osdQuadOffsetBuffer[index];
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}
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void OsdComputePerVertexGregory(unsigned vID, float3 P, threadgroup OsdPerVertexGregory& v, OsdPatchParamBufferSet osdBuffers)
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{
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v.clipFlag = short3(0,0,0);
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int ivalence = OsdReadVertexValence(vID, osdBuffers.valenceBuffer);
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v.valence = ivalence;
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int valence = abs(ivalence);
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float3 f[OSD_MAX_VALENCE];
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float3 pos = P;
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float3 opos = float3(0,0,0);
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#ifdef OSD_PATCH_GREGORY_BOUNDARY
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v.org = pos;
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int boundaryEdgeNeighbors[2];
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int currNeighbor = 0;
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int ibefore = 0;
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int zerothNeighbor = 0;
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#endif
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for (int i=0; i<valence; ++i) {
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int im = (i+valence-1)%valence;
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int ip = (i+1)%valence;
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int idx_neighbor = OsdReadVertexIndex(vID, 2*i, osdBuffers.valenceBuffer);
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#ifdef OSD_PATCH_GREGORY_BOUNDARY
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bool isBoundaryNeighbor = false;
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int valenceNeighbor = OsdReadVertexValence(idx_neighbor, osdBuffers.valenceBuffer);
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if (valenceNeighbor < 0) {
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isBoundaryNeighbor = true;
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if (currNeighbor<2) {
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boundaryEdgeNeighbors[currNeighbor] = idx_neighbor;
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}
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currNeighbor++;
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if (currNeighbor == 1) {
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ibefore = i;
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zerothNeighbor = i;
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} else {
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if (i-ibefore == 1) {
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int tmp = boundaryEdgeNeighbors[0];
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boundaryEdgeNeighbors[0] = boundaryEdgeNeighbors[1];
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boundaryEdgeNeighbors[1] = tmp;
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zerothNeighbor = i;
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}
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}
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}
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#endif
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float3 neighbor = OsdReadVertex(idx_neighbor, osdBuffers.vertexBuffer);
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int idx_diagonal = OsdReadVertexIndex(vID, 2*i + 1, osdBuffers.valenceBuffer);
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float3 diagonal = OsdReadVertex(idx_diagonal, osdBuffers.vertexBuffer);
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int idx_neighbor_p = OsdReadVertexIndex(vID, 2*ip, osdBuffers.valenceBuffer);
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float3 neighbor_p = OsdReadVertex(idx_neighbor_p, osdBuffers.vertexBuffer);
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int idx_neighbor_m = OsdReadVertexIndex(vID, 2*im, osdBuffers.valenceBuffer);
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float3 neighbor_m = OsdReadVertex(idx_neighbor_m, osdBuffers.vertexBuffer);
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int idx_diagonal_m = OsdReadVertexIndex(vID, 2*im + 1, osdBuffers.valenceBuffer);
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float3 diagonal_m = OsdReadVertex(idx_diagonal_m, osdBuffers.vertexBuffer);
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f[i] = (pos * float(valence) + (neighbor_p + neighbor)*2.0f + diagonal) / (float(valence)+5.0f);
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opos += f[i];
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v.r[i] = (neighbor_p-neighbor_m)/3.0f + (diagonal - diagonal_m)/6.0f;
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}
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opos /= valence;
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v.P = float4(opos, 1.0f).xyz;
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float3 e;
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v.e0 = float3(0,0,0);
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v.e1 = float3(0,0,0);
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for(int i=0; i<valence; ++i) {
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int im = (i + valence -1) % valence;
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e = 0.5f * (f[i] + f[im]);
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v.e0 += cosfn(valence, i)*e;
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v.e1 += sinfn(valence, i)*e;
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}
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float ef = OsdComputeCatmarkCoefficient(valence);
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v.e0 *= ef;
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v.e1 *= ef;
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#ifdef OSD_PATCH_GREGORY_BOUNDARY
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v.zerothNeighbor = zerothNeighbor;
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if (currNeighbor == 1) {
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boundaryEdgeNeighbors[1] = boundaryEdgeNeighbors[0];
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}
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if (ivalence < 0) {
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if (valence > 2) {
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v.P = (OsdReadVertex(boundaryEdgeNeighbors[0], osdBuffers.vertexBuffer) +
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OsdReadVertex(boundaryEdgeNeighbors[1], osdBuffers.vertexBuffer) +
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4.0f * pos)/6.0f;
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} else {
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v.P = pos;
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}
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v.e0 = (OsdReadVertex(boundaryEdgeNeighbors[0], osdBuffers.vertexBuffer) -
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OsdReadVertex(boundaryEdgeNeighbors[1], osdBuffers.vertexBuffer))/6.0;
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float k = float(float(valence) - 1.0f); //k is the number of faces
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float c = cospi(1.0/k);
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float s = sinpi(1.0/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)*sqrt(1.0f+c))/((3.0f*k+c)*sqrt(1.0f-c));
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float beta_0 = s/(3.0f*k + c);
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int idx_diagonal = OsdReadVertexIndex(vID, 2*zerothNeighbor + 1, osdBuffers.valenceBuffer);
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float3 diagonal = OsdReadVertex(idx_diagonal, osdBuffers.vertexBuffer);
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v.e1 = gamma * pos +
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alpha_0k * OsdReadVertex(boundaryEdgeNeighbors[0], osdBuffers.vertexBuffer) +
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alpha_0k * OsdReadVertex(boundaryEdgeNeighbors[1], osdBuffers.vertexBuffer) +
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beta_0 * diagonal;
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for (int x=1; x<valence - 1; ++x) {
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int curri = ((x + zerothNeighbor)%valence);
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float alpha = (4.0f*sinpi((float(x))/k))/(3.0f*k+c);
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float beta = (sinpi((float(x))/k) + sinpi((float(x+1))/k))/(3.0f*k+c);
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int idx_neighbor = OsdReadVertexIndex(vID, 2*curri, osdBuffers.valenceBuffer);
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float3 neighbor = OsdReadVertex(idx_neighbor, osdBuffers.vertexBuffer);
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idx_diagonal = OsdReadVertexIndex(vID, 2*curri + 1, osdBuffers.valenceBuffer);
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diagonal = OsdReadVertex(idx_diagonal, osdBuffers.vertexBuffer);
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v.e1 += alpha * neighbor + beta * diagonal;
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}
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v.e1 /= 3.0f;
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}
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#endif
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}
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void
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OsdComputePerPatchVertexGregory(int3 patchParam, unsigned ID, unsigned primitiveID,
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threadgroup OsdPerVertexGregory* v,
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device OsdPerPatchVertexGregory& result,
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OsdPatchParamBufferSet osdBuffers)
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{
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result.P = v[ID].P;
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int i = ID;
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int ip = (i+1)%4;
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int im = (i+3)%4;
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int valence = abs(v[i].valence);
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int n = valence;
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int start = OsdReadQuadOffset(primitiveID, i, osdBuffers.quadOffsetBuffer) & 0xff;
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int prev = (OsdReadQuadOffset(primitiveID, i, osdBuffers.quadOffsetBuffer) >> 8) & 0xff;
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int start_m = OsdReadQuadOffset(primitiveID, im, osdBuffers.quadOffsetBuffer) & 0xff;
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int prev_p = (OsdReadQuadOffset(primitiveID, ip, osdBuffers.quadOffsetBuffer) >> 8) & 0xff;
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int np = abs(v[ip].valence);
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int nm = abs(v[im].valence);
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// Control Vertices based on :
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// "Approximating Subdivision Surfaces with Gregory Patches
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// for Hardware Tessellation"
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// Loop, Schaefer, Ni, Castano (ACM ToG Siggraph Asia 2009)
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//
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// P3 e3- e2+ P2
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// O--------O--------O--------O
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// | | | |
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// | | | |
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// | | f3- | f2+ |
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// | O O |
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// e3+ O------O O------O e2-
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// | f3+ f2- |
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// | |
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// | |
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// | f0- f1+ |
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// e0- O------O O------O e1+
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// | O O |
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// | | f0+ | f1- |
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// | | | |
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// | | | |
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// O--------O--------O--------O
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// P0 e0+ e1- P1
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//
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#ifdef OSD_PATCH_GREGORY_BOUNDARY
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float3 Em_ip;
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if (v[ip].valence < -2) {
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int j = (np + prev_p - v[ip].zerothNeighbor) % np;
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Em_ip = v[ip].P + cospi(j/float(np-1))*v[ip].e0 + sinpi(j/float(np-1))*v[ip].e1;
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} else {
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Em_ip = v[ip].P + v[ip].e0*cosfn(np, prev_p) + v[ip].e1*sinfn(np, prev_p);
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}
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float3 Ep_im;
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if (v[im].valence < -2) {
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int j = (nm + start_m - v[im].zerothNeighbor) % nm;
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Ep_im = v[im].P + cospi(j/float(nm-1))*v[im].e0 + sinpi(j/float(nm-1))*v[im].e1;
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} else {
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Ep_im = v[im].P + v[im].e0*cosfn(nm, start_m) + v[im].e1*sinfn(nm, start_m);
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}
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if (v[i].valence < 0) {
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n = (n-1)*2;
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}
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if (v[im].valence < 0) {
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nm = (nm-1)*2;
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}
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if (v[ip].valence < 0) {
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np = (np-1)*2;
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}
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if (v[i].valence > 2) {
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result.Ep = v[i].P + (v[i].e0*cosfn(n, start) + v[i].e1*sinfn(n, start));
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result.Em = v[i].P + (v[i].e0*cosfn(n, prev) + v[i].e1*sinfn(n, prev));
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float s1=3-2*cosfn(n,1)-cosfn(np,1);
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float s2=2*cosfn(n,1);
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result.Fp = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
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s1 = 3.0f-2.0f*cospi(2.0f/float(n))-cospi(2.0f/float(nm));
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result.Fm = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
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} else if (v[i].valence < -2) {
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int j = (valence + start - v[i].zerothNeighbor) % valence;
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result.Ep = v[i].P + cospi(j/float(valence-1))*v[i].e0 + sinpi(j/float(valence-1))*v[i].e1;
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j = (valence + prev - v[i].zerothNeighbor) % valence;
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result.Em = v[i].P + cospi(j/float(valence-1))*v[i].e0 + sinpi(j/float(valence-1))*v[i].e1;
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float3 Rp = ((-2.0f * v[i].org - 1.0f * v[im].org) + (2.0f * v[ip].org + 1.0f * v[(i+2)%4].org))/3.0f;
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float3 Rm = ((-2.0f * v[i].org - 1.0f * v[ip].org) + (2.0f * v[im].org + 1.0f * v[(i+2)%4].org))/3.0f;
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float s1 = 3-2*cosfn(n,1)-cosfn(np,1);
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float s2 = 2*cosfn(n,1);
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result.Fp = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
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s1 = 3.0f-2.0f*cospi(2.0f/float(n))-cospi(2.0f/float(nm));
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result.Fm = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
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if (v[im].valence < 0) {
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s1 = 3-2*cosfn(n,1)-cosfn(np,1);
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result.Fp = result.Fm = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
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} else if (v[ip].valence < 0) {
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s1 = 3.0f-2.0f*cospi(2.0f/n)-cospi(2.0f/nm);
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result.Fm = result.Fp = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
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}
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} else if (v[i].valence == -2) {
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result.Ep = (2.0f * v[i].org + v[ip].org)/3.0f;
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result.Em = (2.0f * v[i].org + v[im].org)/3.0f;
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result.Fp = result.Fm = (4.0f * v[i].org + v[(i+2)%n].org + 2.0f * v[ip].org + 2.0f * v[im].org)/9.0f;
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}
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#else // not OSD_PATCH_GREGORY_BOUNDARY
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result.Ep = v[i].P + v[i].e0 * cosfn(n, start) + v[i].e1*sinfn(n, start);
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result.Em = v[i].P + v[i].e0 * cosfn(n, prev ) + v[i].e1*sinfn(n, prev );
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float3 Em_ip = v[ip].P + v[ip].e0*cosfn(np, prev_p) + v[ip].e1*sinfn(np, prev_p);
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float3 Ep_im = v[im].P + v[im].e0*cosfn(nm, start_m) + v[im].e1*sinfn(nm, start_m);
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float s1 = 3-2*cosfn(n,1)-cosfn(np,1);
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float s2 = 2*cosfn(n,1);
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result.Fp = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
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s1 = 3.0f-2.0f*cospi(2.0f/float(n))-cospi(2.0f/float(nm));
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result.Fm = (cosfn(nm,1)*v[i].P + s1*result.Em +s2*Ep_im - v[i].r[prev])/3.0f;
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#endif
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}
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#endif // OSD_PATCH_GREGORY || OSD_PATCH_GREGORY_BOUNDARY
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