OpenSubdiv/opensubdiv/osd/glslPatchGregory.glsl
manuelk f1518a5f59 Fix Gregory Boundary patch buffer overrun
Prevent boundaryEdgeNeighbors[2] from being overrun when an interior
vertex has more than 2 boundary neighbor vertices. The fix is applied
to the GLSL / HLSL and CPU implementations.

Note: this appears to fix long-standing problems with Gregory patches,
but i am not entirely convinced that this fixes the general case.

fixes #259
2014-02-13 11:30:33 -08:00

671 lines
23 KiB
GLSL

//
// Copyright 2013 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
// names, trademarks, service marks, or product names of the Licensor
// and its affiliates, except as required to comply with Section 4(c) of
// the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
//----------------------------------------------------------
// Patches.Coefficients
//----------------------------------------------------------
#if OSD_MAX_VALENCE<=10
uniform float ef[7] = float[](
0.813008, 0.500000, 0.363636, 0.287505,
0.238692, 0.204549, 0.179211
);
#else
uniform float ef[27] = float[](
0.812816, 0.500000, 0.363644, 0.287514,
0.238688, 0.204544, 0.179229, 0.159657,
0.144042, 0.131276, 0.120632, 0.111614,
0.103872, 0.09715, 0.0912559, 0.0860444,
0.0814022, 0.0772401, 0.0734867, 0.0700842,
0.0669851, 0.0641504, 0.0615475, 0.0591488,
0.0569311, 0.0548745, 0.0529621
);
#endif
float csf(uint n, uint j)
{
if (j%2 == 0) {
return cos((2.0f * M_PI * float(float(j-0)/2.0f))/(float(n)+3.0f));
} else {
return sin((2.0f * M_PI * float(float(j-1)/2.0f))/(float(n)+3.0f));
}
}
//----------------------------------------------------------
// Patches.TessVertexGregory
//----------------------------------------------------------
#ifdef OSD_PATCH_VERTEX_GREGORY_SHADER
uniform samplerBuffer OsdVertexBuffer;
uniform isamplerBuffer OsdValenceBuffer;
layout (location=0) in vec4 position;
OSD_USER_VARYING_ATTRIBUTE_DECLARE
out block {
GregControlVertex v;
OSD_USER_VARYING_DECLARE
} outpt;
void main()
{
int vID = gl_VertexID;
outpt.v.hullPosition = (OsdModelViewMatrix() * position).xyz;
OSD_PATCH_CULL_COMPUTE_CLIPFLAGS(position);
OSD_USER_VARYING_PER_VERTEX();
int ivalence = texelFetch(OsdValenceBuffer,int(vID * (2 * OSD_MAX_VALENCE + 1))).x;
outpt.v.valence = ivalence;
uint valence = uint(abs(ivalence));
vec3 f[OSD_MAX_VALENCE];
vec3 pos = position.xyz;
vec3 opos = vec3(0,0,0);
#ifdef OSD_PATCH_GREGORY_BOUNDARY
outpt.v.org = position.xyz;
int boundaryEdgeNeighbors[2];
uint currNeighbor = 0;
uint ibefore = 0;
uint zerothNeighbor = 0;
#endif
for (uint i=0; i<valence; ++i) {
uint im=(i+valence-1)%valence;
uint ip=(i+1)%valence;
uint idx_neighbor = uint(texelFetch(OsdValenceBuffer, int(vID * (2*OSD_MAX_VALENCE+1) + 2*i + 0 + 1)).x);
#ifdef OSD_PATCH_GREGORY_BOUNDARY
bool isBoundaryNeighbor = false;
int valenceNeighbor = texelFetch(OsdValenceBuffer,int(idx_neighbor * (2*OSD_MAX_VALENCE+1))).x;
if (valenceNeighbor < 0) {
isBoundaryNeighbor = true;
if (currNeighbor<2) {
boundaryEdgeNeighbors[currNeighbor] = int(idx_neighbor);
}
currNeighbor++;
if (currNeighbor == 1) {
ibefore = i;
zerothNeighbor = i;
} else {
if (i-ibefore == 1) {
int tmp = boundaryEdgeNeighbors[0];
boundaryEdgeNeighbors[0] = boundaryEdgeNeighbors[1];
boundaryEdgeNeighbors[1] = tmp;
zerothNeighbor = i;
}
}
}
#endif
vec3 neighbor =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor+2)).x);
uint idx_diagonal = uint(texelFetch(OsdValenceBuffer, int(vID * (2*OSD_MAX_VALENCE+1) + 2*i + 1 + 1)).x);
vec3 diagonal =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal+2)).x);
uint idx_neighbor_p = uint(texelFetch(OsdValenceBuffer, int(vID * (2*OSD_MAX_VALENCE+1) + 2*ip + 0 + 1)).x);
vec3 neighbor_p =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor_p)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor_p+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor_p+2)).x);
uint idx_neighbor_m = uint(texelFetch(OsdValenceBuffer, int(vID * (2*OSD_MAX_VALENCE+1) + 2*im + 0 + 1)).x);
vec3 neighbor_m =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor_m)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor_m+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor_m+2)).x);
uint idx_diagonal_m = uint(texelFetch(OsdValenceBuffer, int(vID * (2*OSD_MAX_VALENCE+1) + 2*im + 1 + 1)).x);
vec3 diagonal_m =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal_m)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal_m+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal_m+2)).x);
f[i] = (pos * float(valence) + (neighbor_p + neighbor)*2.0f + diagonal) / (float(valence)+5.0f);
opos += f[i];
outpt.v.r[i] = (neighbor_p-neighbor_m)/3.0f + (diagonal - diagonal_m)/6.0f;
}
opos /= valence;
outpt.v.position = vec4(opos, 1.0f).xyz;
vec3 e;
outpt.v.e0 = vec3(0,0,0);
outpt.v.e1 = vec3(0,0,0);
for(uint i=0; i<valence; ++i) {
uint im = (i + valence -1) % valence;
e = 0.5f * (f[i] + f[im]);
outpt.v.e0 += csf(valence-3, 2*i) *e;
outpt.v.e1 += csf(valence-3, 2*i + 1)*e;
}
outpt.v.e0 *= ef[valence - 3];
outpt.v.e1 *= ef[valence - 3];
#ifdef OSD_PATCH_GREGORY_BOUNDARY
outpt.v.zerothNeighbor = zerothNeighbor;
if (currNeighbor == 1) {
boundaryEdgeNeighbors[1] = boundaryEdgeNeighbors[0];
}
if (ivalence < 0) {
if (valence > 2) {
outpt.v.position = (
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0])).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0]+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0]+2)).x) +
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1])).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1]+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1]+2)).x) +
4.0f * pos)/6.0f;
} else {
outpt.v.position = pos;
}
outpt.v.e0 = (
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0])).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0]+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0]+2)).x) -
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1])).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1]+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1]+2)).x)
)/6.0;
float k = float(float(valence) - 1.0f); //k is the number of faces
float c = cos(M_PI/k);
float s = sin(M_PI/k);
float gamma = -(4.0f*s)/(3.0f*k+c);
float alpha_0k = -((1.0f+2.0f*c)*sqrt(1.0f+c))/((3.0f*k+c)*sqrt(1.0f-c));
float beta_0 = s/(3.0f*k + c);
int idx_diagonal = texelFetch(OsdValenceBuffer,int((vID) * (2*OSD_MAX_VALENCE+1) + 2*zerothNeighbor + 1 + 1)).x;
idx_diagonal = abs(idx_diagonal);
vec3 diagonal =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal+2)).x);
outpt.v.e1 = gamma * pos +
alpha_0k * vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0])).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0]+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[0]+2)).x) +
alpha_0k * vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1])).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1]+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*boundaryEdgeNeighbors[1]+2)).x) +
beta_0 * diagonal;
for (uint x=1; x<valence - 1; ++x) {
uint curri = ((x + zerothNeighbor)%valence);
float alpha = (4.0f*sin((M_PI * float(x))/k))/(3.0f*k+c);
float beta = (sin((M_PI * float(x))/k) + sin((M_PI * float(x+1))/k))/(3.0f*k+c);
int idx_neighbor = texelFetch(OsdValenceBuffer, int((vID) * (2*OSD_MAX_VALENCE+1) + 2*curri + 0 + 1)).x;
idx_neighbor = abs(idx_neighbor);
vec3 neighbor =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_neighbor+2)).x);
idx_diagonal = texelFetch(OsdValenceBuffer, int((vID) * (2*OSD_MAX_VALENCE+1) + 2*curri + 1 + 1)).x;
diagonal =
vec3(texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal+1)).x,
texelFetch(OsdVertexBuffer, int(OSD_NUM_ELEMENTS*idx_diagonal+2)).x);
outpt.v.e1 += alpha * neighbor + beta * diagonal;
}
outpt.v.e1 /= 3.0f;
}
#endif
}
#endif
//----------------------------------------------------------
// Patches.TessControlGregory
//----------------------------------------------------------
#ifdef OSD_PATCH_TESS_CONTROL_GREGORY_SHADER
layout(vertices = 4) out;
uniform isamplerBuffer OsdQuadOffsetBuffer;
in block {
GregControlVertex v;
OSD_USER_VARYING_DECLARE
} inpt[];
out block {
GregEvalVertex v;
OSD_USER_VARYING_DECLARE
} outpt[];
#define ID gl_InvocationID
void main()
{
uint i = gl_InvocationID;
uint ip = (i+1)%4;
uint im = (i+3)%4;
uint valence = abs(inpt[i].v.valence);
uint n = valence;
int base = OsdGregoryQuadOffsetBase();
outpt[ID].v.position = inpt[ID].v.position;
uint start = uint(texelFetch(OsdQuadOffsetBuffer, int(4*gl_PrimitiveID+base + i)).x) & 0x00ffu;
uint prev = uint(texelFetch(OsdQuadOffsetBuffer, int(4*gl_PrimitiveID+base + i)).x) & 0xff00u;
prev = uint(prev/256);
uint start_m = uint(texelFetch(OsdQuadOffsetBuffer, int(4*gl_PrimitiveID+base + im)).x) & 0x00ffu;
uint prev_p = uint(texelFetch(OsdQuadOffsetBuffer, int(4*gl_PrimitiveID+base + ip)).x) & 0xff00u;
prev_p = uint(prev_p/256);
uint np = abs(inpt[ip].v.valence);
uint nm = abs(inpt[im].v.valence);
// Control Vertices based on :
// "Approximating Subdivision Surfaces with Gregory Patches for Hardware Tessellation"
// Loop, Schaefer, Ni, Castafio (ACM ToG Siggraph Asia 2009)
//
// P3 e3- e2+ E2
// O--------O--------O--------O
// | | | |
// | | | |
// | | f3- | f2+ |
// | O O |
// e3+ O------O O------O e2-
// | f3+ f2- |
// | |
// | |
// | f0- f1+ |
// e0- O------O O------O e1+
// | O O |
// | | f0+ | f1- |
// | | | |
// | | | |
// O--------O--------O--------O
// P0 e0+ e1- E1
//
#ifdef OSD_PATCH_GREGORY_BOUNDARY
vec3 Ep = vec3(0.0f,0.0f,0.0f);
vec3 Em = vec3(0.0f,0.0f,0.0f);
vec3 Fp = vec3(0.0f,0.0f,0.0f);
vec3 Fm = vec3(0.0f,0.0f,0.0f);
vec3 Em_ip;
if (inpt[ip].v.valence < -2) {
uint j = (np + prev_p - inpt[ip].v.zerothNeighbor) % np;
Em_ip = inpt[ip].v.position + cos((M_PI*j)/float(np-1))*inpt[ip].v.e0 + sin((M_PI*j)/float(np-1))*inpt[ip].v.e1;
} else {
Em_ip = inpt[ip].v.position + inpt[ip].v.e0*csf(np-3, 2*prev_p ) + inpt[ip].v.e1*csf(np-3, 2*prev_p + 1);
}
vec3 Ep_im;
if (inpt[im].v.valence < -2) {
uint j = (nm + start_m - inpt[im].v.zerothNeighbor) % nm;
Ep_im = inpt[im].v.position + cos((M_PI*j)/float(nm-1))*inpt[im].v.e0 + sin((M_PI*j)/float(nm-1))*inpt[im].v.e1;
} else {
Ep_im = inpt[im].v.position + inpt[im].v.e0*csf(nm-3, 2*start_m) + inpt[im].v.e1*csf(nm-3, 2*start_m + 1);
}
if (inpt[i].v.valence < 0) {
n = (n-1)*2;
}
if (inpt[im].v.valence < 0) {
nm = (nm-1)*2;
}
if (inpt[ip].v.valence < 0) {
np = (np-1)*2;
}
if (inpt[i].v.valence > 2) {
Ep = inpt[i].v.position + inpt[i].v.e0*csf(n-3, 2*start) + inpt[i].v.e1*csf(n-3, 2*start + 1);
Em = inpt[i].v.position + inpt[i].v.e0*csf(n-3, 2*prev ) + inpt[i].v.e1*csf(n-3, 2*prev + 1);
float s1=3-2*csf(n-3,2)-csf(np-3,2);
float s2=2*csf(n-3,2);
Fp = (csf(np-3,2)*inpt[i].v.position + s1*Ep + s2*Em_ip + inpt[i].v.r[start])/3.0f;
s1 = 3.0f-2.0f*cos(2.0f*M_PI/float(n))-cos(2.0f*M_PI/float(nm));
Fm = (csf(nm-3,2)*inpt[i].v.position + s1*Em + s2*Ep_im - inpt[i].v.r[prev])/3.0f;
} else if (inpt[i].v.valence < -2) {
uint j = (valence + start - inpt[i].v.zerothNeighbor) % valence;
Ep = inpt[i].v.position + cos((M_PI*j)/float(valence-1))*inpt[i].v.e0 + sin((M_PI*j)/float(valence-1))*inpt[i].v.e1;
j = (valence + prev - inpt[i].v.zerothNeighbor) % valence;
Em = inpt[i].v.position + cos((M_PI*j)/float(valence-1))*inpt[i].v.e0 + sin((M_PI*j)/float(valence-1))*inpt[i].v.e1;
vec3 Rp = ((-2.0f * inpt[i].v.org - 1.0f * inpt[im].v.org) + (2.0f * inpt[ip].v.org + 1.0f * inpt[(i+2)%4].v.org))/3.0f;
vec3 Rm = ((-2.0f * inpt[i].v.org - 1.0f * inpt[ip].v.org) + (2.0f * inpt[im].v.org + 1.0f * inpt[(i+2)%4].v.org))/3.0f;
float s1 = 3-2*csf(n-3,2)-csf(np-3,2);
float s2 = 2*csf(n-3,2);
Fp = (csf(np-3,2)*inpt[i].v.position + s1*Ep + s2*Em_ip + inpt[i].v.r[start])/3.0f;
s1 = 3.0f-2.0f*cos(2.0f*M_PI/float(n))-cos(2.0f*M_PI/float(nm));
Fm = (csf(nm-3,2)*inpt[i].v.position + s1*Em + s2*Ep_im - inpt[i].v.r[prev])/3.0f;
if (inpt[im].v.valence < 0) {
s1 = 3-2*csf(n-3,2)-csf(np-3,2);
Fp = Fm = (csf(np-3,2)*inpt[i].v.position + s1*Ep + s2*Em_ip + inpt[i].v.r[start])/3.0f;
} else if (inpt[ip].v.valence < 0) {
s1 = 3.0f-2.0f*cos(2.0f*M_PI/n)-cos(2.0f*M_PI/nm);
Fm = Fp = (csf(nm-3,2)*inpt[i].v.position + s1*Em + s2*Ep_im - inpt[i].v.r[prev])/3.0f;
}
} else if (inpt[i].v.valence == -2) {
Ep = (2.0f * inpt[i].v.org + inpt[ip].v.org)/3.0f;
Em = (2.0f * inpt[i].v.org + inpt[im].v.org)/3.0f;
Fp = Fm = (4.0f * inpt[i].v.org + inpt[(i+2)%n].v.org + 2.0f * inpt[ip].v.org + 2.0f * inpt[im].v.org)/9.0f;
}
#else // not OSD_PATCH_GREGORY_BOUNDARY
vec3 Ep = inpt[i].v.position + inpt[i].v.e0 * csf(n-3, 2*start) + inpt[i].v.e1*csf(n-3, 2*start + 1);
vec3 Em = inpt[i].v.position + inpt[i].v.e0 * csf(n-3, 2*prev ) + inpt[i].v.e1*csf(n-3, 2*prev + 1);
vec3 Em_ip = inpt[ip].v.position + inpt[ip].v.e0 * csf(np-3, 2*prev_p ) + inpt[ip].v.e1*csf(np-3, 2*prev_p + 1);
vec3 Ep_im = inpt[im].v.position + inpt[im].v.e0 * csf(nm-3, 2*start_m) + inpt[im].v.e1*csf(nm-3, 2*start_m + 1);
float s1 = 3-2*csf(n-3,2)-csf(np-3,2);
float s2 = 2*csf(n-3,2);
vec3 Fp = (csf(np-3,2)*inpt[i].v.position + s1*Ep + s2*Em_ip + inpt[i].v.r[start])/3.0f;
s1 = 3.0f-2.0f*cos(2.0f*M_PI/float(n))-cos(2.0f*M_PI/float(nm));
vec3 Fm = (csf(nm-3,2)*inpt[i].v.position + s1*Em + s2*Ep_im - inpt[i].v.r[prev])/3.0f;
#endif
outpt[ID].v.Ep = Ep;
outpt[ID].v.Em = Em;
outpt[ID].v.Fp = Fp;
outpt[ID].v.Fm = Fm;
OSD_USER_VARYING_PER_CONTROL_POINT(ID, ID);
int patchLevel = GetPatchLevel();
outpt[ID].v.patchCoord = vec4(0, 0,
patchLevel+0.5f,
GetPrimitiveID()+0.5f);
OSD_COMPUTE_PTEX_COORD_TESSCONTROL_SHADER;
if (ID == 0) {
OSD_PATCH_CULL(4);
#ifdef OSD_ENABLE_SCREENSPACE_TESSELLATION
gl_TessLevelOuter[0] =
TessAdaptive(inpt[0].v.hullPosition.xyz, inpt[1].v.hullPosition.xyz);
gl_TessLevelOuter[1] =
TessAdaptive(inpt[0].v.hullPosition.xyz, inpt[3].v.hullPosition.xyz);
gl_TessLevelOuter[2] =
TessAdaptive(inpt[2].v.hullPosition.xyz, inpt[3].v.hullPosition.xyz);
gl_TessLevelOuter[3] =
TessAdaptive(inpt[1].v.hullPosition.xyz, inpt[2].v.hullPosition.xyz);
gl_TessLevelInner[0] =
max(gl_TessLevelOuter[1], gl_TessLevelOuter[3]);
gl_TessLevelInner[1] =
max(gl_TessLevelOuter[0], gl_TessLevelOuter[2]);
#else
gl_TessLevelInner[0] = GetTessLevel(patchLevel);
gl_TessLevelInner[1] = GetTessLevel(patchLevel);
gl_TessLevelOuter[0] = GetTessLevel(patchLevel);
gl_TessLevelOuter[1] = GetTessLevel(patchLevel);
gl_TessLevelOuter[2] = GetTessLevel(patchLevel);
gl_TessLevelOuter[3] = GetTessLevel(patchLevel);
#endif
}
}
#endif
//----------------------------------------------------------
// Patches.TessEvalGregory
//----------------------------------------------------------
#ifdef OSD_PATCH_TESS_EVAL_GREGORY_SHADER
layout(quads) in;
layout(cw) in;
#if defined OSD_FRACTIONAL_ODD_SPACING
layout(fractional_odd_spacing) in;
#elif defined OSD_FRACTIONAL_EVEN_SPACING
layout(fractional_even_spacing) in;
#endif
in block {
GregEvalVertex v;
OSD_USER_VARYING_DECLARE
} inpt[];
out block {
OutputVertex v;
OSD_USER_VARYING_DECLARE
} outpt;
void main()
{
float u = gl_TessCoord.x,
v = gl_TessCoord.y;
vec3 p[20];
p[0] = inpt[0].v.position;
p[1] = inpt[0].v.Ep;
p[2] = inpt[0].v.Em;
p[3] = inpt[0].v.Fp;
p[4] = inpt[0].v.Fm;
p[5] = inpt[1].v.position;
p[6] = inpt[1].v.Ep;
p[7] = inpt[1].v.Em;
p[8] = inpt[1].v.Fp;
p[9] = inpt[1].v.Fm;
p[10] = inpt[2].v.position;
p[11] = inpt[2].v.Ep;
p[12] = inpt[2].v.Em;
p[13] = inpt[2].v.Fp;
p[14] = inpt[2].v.Fm;
p[15] = inpt[3].v.position;
p[16] = inpt[3].v.Ep;
p[17] = inpt[3].v.Em;
p[18] = inpt[3].v.Fp;
p[19] = inpt[3].v.Fm;
vec3 q[16];
float U = 1-u, V=1-v;
float d11 = u+v; if(u+v==0.0f) d11 = 1.0f;
float d12 = U+v; if(U+v==0.0f) d12 = 1.0f;
float d21 = u+V; if(u+V==0.0f) d21 = 1.0f;
float d22 = U+V; if(U+V==0.0f) d22 = 1.0f;
q[ 5] = (u*p[3] + v*p[4])/d11;
q[ 6] = (U*p[9] + v*p[8])/d12;
q[ 9] = (u*p[19] + V*p[18])/d21;
q[10] = (U*p[13] + V*p[14])/d22;
q[ 0] = p[0];
q[ 1] = p[1];
q[ 2] = p[7];
q[ 3] = p[5];
q[ 4] = p[2];
q[ 7] = p[6];
q[ 8] = p[16];
q[11] = p[12];
q[12] = p[15];
q[13] = p[17];
q[14] = p[11];
q[15] = p[10];
vec3 WorldPos = vec3(0, 0, 0);
vec3 Tangent = vec3(0, 0, 0);
vec3 BiTangent = vec3(0, 0, 0);
#ifdef OSD_COMPUTE_NORMAL_DERIVATIVES
float B[4], D[4], C[4];
vec3 BUCP[4], DUCP[4], CUCP[4];
vec3 dUU = vec3(0);
vec3 dVV = vec3(0);
vec3 dUV = vec3(0);
Univar4x4(u, B, D, C);
for (int i=0; i<4; ++i) {
BUCP[i] = vec3(0);
DUCP[i] = vec3(0);
CUCP[i] = vec3(0);
for (uint j=0; j<4; ++j) {
// reverse face front
vec3 A = q[i + 4*j];
BUCP[i] += A * B[j];
DUCP[i] += A * D[j];
CUCP[i] += A * C[j];
}
}
Univar4x4(v, B, D, C);
for (int i=0; i<4; ++i) {
WorldPos += B[i] * BUCP[i];
Tangent += B[i] * DUCP[i];
BiTangent += D[i] * BUCP[i];
dUU += B[i] * CUCP[i];
dVV += C[i] * BUCP[i];
dUV += D[i] * DUCP[i];
}
int level = int(inpt[0].v.ptexInfo.z);
BiTangent *= 3 * level;
Tangent *= 3 * level;
dUU *= 6 * level;
dVV *= 6 * level;
dUV *= 9 * level;
vec3 n = cross(Tangent, BiTangent);
vec3 normal = normalize(n);
float E = dot(Tangent, Tangent);
float F = dot(Tangent, BiTangent);
float G = dot(BiTangent, BiTangent);
float e = dot(normal, dUU);
float f = dot(normal, dUV);
float g = dot(normal, dVV);
vec3 Nu = (f*F-e*G)/(E*G-F*F) * Tangent + (e*F-f*E)/(E*G-F*F) * BiTangent;
vec3 Nv = (g*F-f*G)/(E*G-F*F) * Tangent + (f*F-g*E)/(E*G-F*F) * BiTangent;
Nu = Nu/length(n) - n * (dot(Nu,n)/pow(dot(n,n), 1.5));
Nv = Nv/length(n) - n * (dot(Nv,n)/pow(dot(n,n), 1.5));
BiTangent = (OsdModelViewMatrix() * vec4(BiTangent, 0)).xyz;
Tangent = (OsdModelViewMatrix() * vec4(Tangent, 0)).xyz;
normal = normalize(cross(BiTangent, Tangent));
outpt.v.Nu = Nu;
outpt.v.Nv = Nv;
#else
float B[4], D[4];
vec3 BUCP[4], DUCP[4];
Univar4x4(u, B, D);
for (int i=0; i<4; ++i) {
BUCP[i] = vec3(0);
DUCP[i] = vec3(0);
for (uint j=0; j<4; ++j) {
// reverse face front
vec3 A = q[i + 4*j];
BUCP[i] += A * B[j];
DUCP[i] += A * D[j];
}
}
Univar4x4(v, B, D);
for (int i=0; i<4; ++i) {
WorldPos += B[i] * BUCP[i];
Tangent += B[i] * DUCP[i];
BiTangent += D[i] * BUCP[i];
}
int level = int(inpt[0].v.ptexInfo.z);
BiTangent *= 3 * level;
Tangent *= 3 * level;
BiTangent = (OsdModelViewMatrix() * vec4(BiTangent, 0)).xyz;
Tangent = (OsdModelViewMatrix() * vec4(Tangent, 0)).xyz;
vec3 normal = normalize(cross(BiTangent, Tangent));
#endif
outpt.v.position = OsdModelViewMatrix() * vec4(WorldPos, 1.0f);
outpt.v.normal = normal;
outpt.v.tangent = BiTangent;
outpt.v.bitangent = Tangent;
OSD_USER_VARYING_PER_EVAL_POINT(vec2(u,v), 0, 3, 1, 2);
outpt.v.patchCoord = inpt[0].v.patchCoord;
outpt.v.patchCoord.xy = vec2(v, u);
OSD_COMPUTE_PTEX_COORD_TESSEVAL_SHADER;
OSD_DISPLACEMENT_CALLBACK;
gl_Position = OsdModelViewProjectionMatrix() * vec4(WorldPos, 1.0f);
}
#endif