OpenSubdiv/opensubdiv/osd/glslPatchLegacy.glsl
David G Yu c2ed7d5cf0 Reorganized legacy patch drawing shader source
Relocated from PatchCommon to PatchLegacy several aspects of the
shader source which can cause problems with typical use cases.
Specifically, things like resource bindings, input assembler and
interstage declarations are best left to client code.

These are not removed, just relocated and remain available for
backward compatibility. Updated the GLSL, HLSL, and MSL source.
2023-09-12 19:21:51 -07:00

634 lines
23 KiB
GLSL

//
// Copyright 2013-2018 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.Common
//----------------------------------------------------------
// XXXdyu all handling of varying data can be managed by client code
#ifndef OSD_USER_VARYING_DECLARE
#define OSD_USER_VARYING_DECLARE
// type var;
#endif
#ifndef OSD_USER_VARYING_ATTRIBUTE_DECLARE
#define OSD_USER_VARYING_ATTRIBUTE_DECLARE
// layout(location = loc) in type var;
#endif
#ifndef OSD_USER_VARYING_PER_VERTEX
#define OSD_USER_VARYING_PER_VERTEX()
// output.var = var;
#endif
#ifndef OSD_USER_VARYING_PER_CONTROL_POINT
#define OSD_USER_VARYING_PER_CONTROL_POINT(ID_OUT, ID_IN)
// output[ID_OUT].var = input[ID_IN].var
#endif
#ifndef OSD_USER_VARYING_PER_EVAL_POINT
#define OSD_USER_VARYING_PER_EVAL_POINT(UV, a, b, c, d)
// output.var =
// mix(mix(input[a].var, input[b].var, UV.x),
// mix(input[c].var, input[d].var, UV.x), UV.y)
#endif
#ifndef OSD_USER_VARYING_PER_EVAL_POINT_TRIANGLE
#define OSD_USER_VARYING_PER_EVAL_POINT_TRIANGLE(UV, a, b, c)
// output.var =
// input[a].var * (1.0f-UV.x-UV.y) +
// input[b].var * UV.x +
// input[c].var * UV.y;
#endif
#if __VERSION__ < 420
#define centroid
#endif
struct ControlVertex {
vec4 position;
#ifdef OSD_ENABLE_PATCH_CULL
ivec3 clipFlag;
#endif
};
// XXXdyu all downstream data can be handled by client code
struct OutputVertex {
vec4 position;
vec3 normal;
vec3 tangent;
vec3 bitangent;
vec4 patchCoord; // u, v, faceLevel, faceId
vec2 tessCoord; // tesscoord.st
#if defined OSD_COMPUTE_NORMAL_DERIVATIVES
vec3 Nu;
vec3 Nv;
#endif
};
mat4 OsdModelViewProjectionMatrix();
int OsdGregoryQuadOffsetBase();
int OsdPrimitiveIdBase();
int OsdBaseVertex();
#ifndef OSD_DISPLACEMENT_CALLBACK
#define OSD_DISPLACEMENT_CALLBACK
#endif
// These are stored in OsdPatchParamBuffer indexed by the value returned
// from OsdGetPatchIndex() which is a function of the current PrimitiveID
// along with an optional client provided offset.
uniform isamplerBuffer OsdPatchParamBuffer;
int OsdGetPatchIndex(int primitiveId)
{
return (primitiveId + OsdPrimitiveIdBase());
}
ivec3 OsdGetPatchParam(int patchIndex)
{
return texelFetch(OsdPatchParamBuffer, patchIndex).xyz;
}
// ----------------------------------------------------------------------------
// patch culling
// ----------------------------------------------------------------------------
#ifdef OSD_ENABLE_PATCH_CULL
#define OSD_PATCH_CULL_COMPUTE_CLIPFLAGS(P) \
vec4 clipPos = OsdModelViewProjectionMatrix() * P; \
bvec3 clip0 = lessThan(clipPos.xyz, vec3(clipPos.w)); \
bvec3 clip1 = greaterThan(clipPos.xyz, -vec3(clipPos.w)); \
outpt.v.clipFlag = ivec3(clip0) + 2*ivec3(clip1); \
#define OSD_PATCH_CULL(N) \
ivec3 clipFlag = ivec3(0); \
for(int i = 0; i < N; ++i) { \
clipFlag |= inpt[i].v.clipFlag; \
} \
if (clipFlag != ivec3(3) ) { \
gl_TessLevelInner[0] = 0; \
gl_TessLevelInner[1] = 0; \
gl_TessLevelOuter[0] = 0; \
gl_TessLevelOuter[1] = 0; \
gl_TessLevelOuter[2] = 0; \
gl_TessLevelOuter[3] = 0; \
return; \
}
#else
#define OSD_PATCH_CULL_COMPUTE_CLIPFLAGS(P)
#define OSD_PATCH_CULL(N)
#endif
// ----------------------------------------------------------------------------
// Legacy Gregory
// ----------------------------------------------------------------------------
#if defined(OSD_PATCH_GREGORY) || defined(OSD_PATCH_GREGORY_BOUNDARY)
#define M_PI 3.14159265359f
// precomputed catmark coefficient table up to valence 29
uniform float OsdCatmarkCoefficient[30] = float[](
0, 0, 0, 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
);
float
OsdComputeCatmarkCoefficient(int valence)
{
#if OSD_MAX_VALENCE < 30
return OsdCatmarkCoefficient[valence];
#else
if (valence < 30) {
return OsdCatmarkCoefficient[valence];
} else {
float t = 2.0f * float(M_PI) / float(valence);
return 1.0f / (valence * (cos(t) + 5.0f +
sqrt((cos(t) + 9) * (cos(t) + 1)))/16.0f);
}
#endif
}
float cosfn(int n, int j) {
return cos((2.0f * M_PI * j)/float(n));
}
float sinfn(int n, int j) {
return sin((2.0f * M_PI * j)/float(n));
}
#if !defined OSD_MAX_VALENCE || OSD_MAX_VALENCE < 1
#undef OSD_MAX_VALENCE
#define OSD_MAX_VALENCE 4
#endif
struct OsdPerVertexGregory {
vec3 P;
ivec3 clipFlag;
int valence;
vec3 e0;
vec3 e1;
#ifdef OSD_PATCH_GREGORY_BOUNDARY
int zerothNeighbor;
vec3 org;
#endif
vec3 r[OSD_MAX_VALENCE];
};
struct OsdPerPatchVertexGregory {
ivec3 patchParam;
vec3 P;
vec3 Ep;
vec3 Em;
vec3 Fp;
vec3 Fm;
};
#ifndef OSD_NUM_ELEMENTS
#define OSD_NUM_ELEMENTS 3
#endif
uniform samplerBuffer OsdVertexBuffer;
uniform isamplerBuffer OsdValenceBuffer;
vec3 OsdReadVertex(int vertexIndex)
{
int index = int(OSD_NUM_ELEMENTS * (vertexIndex + OsdBaseVertex()));
return vec3(texelFetch(OsdVertexBuffer, index).x,
texelFetch(OsdVertexBuffer, index+1).x,
texelFetch(OsdVertexBuffer, index+2).x);
}
int OsdReadVertexValence(int vertexID)
{
int index = int(vertexID * (2 * OSD_MAX_VALENCE + 1));
return texelFetch(OsdValenceBuffer, index).x;
}
int OsdReadVertexIndex(int vertexID, int valenceVertex)
{
int index = int(vertexID * (2 * OSD_MAX_VALENCE + 1) + 1 + valenceVertex);
return texelFetch(OsdValenceBuffer, index).x;
}
uniform isamplerBuffer OsdQuadOffsetBuffer;
int OsdReadQuadOffset(int primitiveID, int offsetVertex)
{
int index = int(4*primitiveID+OsdGregoryQuadOffsetBase() + offsetVertex);
return texelFetch(OsdQuadOffsetBuffer, index).x;
}
void
OsdComputePerVertexGregory(int vID, vec3 P, out OsdPerVertexGregory v)
{
v.clipFlag = ivec3(0);
int ivalence = OsdReadVertexValence(vID);
v.valence = ivalence;
int valence = abs(ivalence);
vec3 f[OSD_MAX_VALENCE];
vec3 pos = P;
vec3 opos = vec3(0);
#ifdef OSD_PATCH_GREGORY_BOUNDARY
v.org = pos;
int boundaryEdgeNeighbors[2];
int currNeighbor = 0;
int ibefore = 0;
int zerothNeighbor = 0;
#endif
for (int i=0; i<valence; ++i) {
int im = (i+valence-1)%valence;
int ip = (i+1)%valence;
int idx_neighbor = OsdReadVertexIndex(vID, 2*i);
#ifdef OSD_PATCH_GREGORY_BOUNDARY
bool isBoundaryNeighbor = false;
int valenceNeighbor = OsdReadVertexValence(idx_neighbor);
if (valenceNeighbor < 0) {
isBoundaryNeighbor = true;
if (currNeighbor<2) {
boundaryEdgeNeighbors[currNeighbor] = 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 = OsdReadVertex(idx_neighbor);
int idx_diagonal = OsdReadVertexIndex(vID, 2*i + 1);
vec3 diagonal = OsdReadVertex(idx_diagonal);
int idx_neighbor_p = OsdReadVertexIndex(vID, 2*ip);
vec3 neighbor_p = OsdReadVertex(idx_neighbor_p);
int idx_neighbor_m = OsdReadVertexIndex(vID, 2*im);
vec3 neighbor_m = OsdReadVertex(idx_neighbor_m);
int idx_diagonal_m = OsdReadVertexIndex(vID, 2*im + 1);
vec3 diagonal_m = OsdReadVertex(idx_diagonal_m);
f[i] = (pos * float(valence) + (neighbor_p + neighbor)*2.0f + diagonal) / (float(valence)+5.0f);
opos += f[i];
v.r[i] = (neighbor_p-neighbor_m)/3.0f + (diagonal - diagonal_m)/6.0f;
}
opos /= valence;
v.P = vec4(opos, 1.0f).xyz;
vec3 e;
v.e0 = vec3(0);
v.e1 = vec3(0);
for(int i=0; i<valence; ++i) {
int im = (i + valence -1) % valence;
e = 0.5f * (f[i] + f[im]);
v.e0 += cosfn(valence, i)*e;
v.e1 += sinfn(valence, i)*e;
}
float ef = OsdComputeCatmarkCoefficient(valence);
v.e0 *= ef;
v.e1 *= ef;
#ifdef OSD_PATCH_GREGORY_BOUNDARY
v.zerothNeighbor = zerothNeighbor;
if (currNeighbor == 1) {
boundaryEdgeNeighbors[1] = boundaryEdgeNeighbors[0];
}
if (ivalence < 0) {
if (valence > 2) {
v.P = (OsdReadVertex(boundaryEdgeNeighbors[0]) +
OsdReadVertex(boundaryEdgeNeighbors[1]) +
4.0f * pos)/6.0f;
} else {
v.P = pos;
}
v.e0 = (OsdReadVertex(boundaryEdgeNeighbors[0]) -
OsdReadVertex(boundaryEdgeNeighbors[1]))/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 = OsdReadVertexIndex(vID, 2*zerothNeighbor + 1);
vec3 diagonal = OsdReadVertex(idx_diagonal);
v.e1 = gamma * pos +
alpha_0k * OsdReadVertex(boundaryEdgeNeighbors[0]) +
alpha_0k * OsdReadVertex(boundaryEdgeNeighbors[1]) +
beta_0 * diagonal;
for (int x=1; x<valence - 1; ++x) {
int 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 = OsdReadVertexIndex(vID, 2*curri);
vec3 neighbor = OsdReadVertex(idx_neighbor);
idx_diagonal = OsdReadVertexIndex(vID, 2*curri + 1);
diagonal = OsdReadVertex(idx_diagonal);
v.e1 += alpha * neighbor + beta * diagonal;
}
v.e1 /= 3.0f;
}
#endif
}
void
OsdComputePerPatchVertexGregory(ivec3 patchParam, int ID, int primitiveID,
in OsdPerVertexGregory v[4],
out OsdPerPatchVertexGregory result)
{
result.patchParam = patchParam;
result.P = v[ID].P;
int i = ID;
int ip = (i+1)%4;
int im = (i+3)%4;
int valence = abs(v[i].valence);
int n = valence;
int start = OsdReadQuadOffset(primitiveID, i) & 0xff;
int prev = (OsdReadQuadOffset(primitiveID, i) >> 8) & 0xff;
int start_m = OsdReadQuadOffset(primitiveID, im) & 0xff;
int prev_p = (OsdReadQuadOffset(primitiveID, ip) >> 8) & 0xff;
int np = abs(v[ip].valence);
int nm = abs(v[im].valence);
// Control Vertices based on :
// "Approximating Subdivision Surfaces with Gregory Patches
// for Hardware Tessellation"
// Loop, Schaefer, Ni, Castano (ACM ToG Siggraph Asia 2009)
//
// P3 e3- e2+ P2
// 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- P1
//
#ifdef OSD_PATCH_GREGORY_BOUNDARY
vec3 Em_ip;
if (v[ip].valence < -2) {
int j = (np + prev_p - v[ip].zerothNeighbor) % np;
Em_ip = v[ip].P + cos((M_PI*j)/float(np-1))*v[ip].e0 + sin((M_PI*j)/float(np-1))*v[ip].e1;
} else {
Em_ip = v[ip].P + v[ip].e0*cosfn(np, prev_p ) + v[ip].e1*sinfn(np, prev_p);
}
vec3 Ep_im;
if (v[im].valence < -2) {
int j = (nm + start_m - v[im].zerothNeighbor) % nm;
Ep_im = v[im].P + cos((M_PI*j)/float(nm-1))*v[im].e0 + sin((M_PI*j)/float(nm-1))*v[im].e1;
} else {
Ep_im = v[im].P + v[im].e0*cosfn(nm, start_m) + v[im].e1*sinfn(nm, start_m);
}
if (v[i].valence < 0) {
n = (n-1)*2;
}
if (v[im].valence < 0) {
nm = (nm-1)*2;
}
if (v[ip].valence < 0) {
np = (np-1)*2;
}
if (v[i].valence > 2) {
result.Ep = v[i].P + v[i].e0*cosfn(n, start) + v[i].e1*sinfn(n, start);
result.Em = v[i].P + v[i].e0*cosfn(n, prev ) + v[i].e1*sinfn(n, prev);
float s1=3-2*cosfn(n,1)-cosfn(np,1);
float s2=2*cosfn(n,1);
result.Fp = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
s1 = 3.0f-2.0f*cos(2.0f*M_PI/float(n))-cos(2.0f*M_PI/float(nm));
result.Fm = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
} else if (v[i].valence < -2) {
int j = (valence + start - v[i].zerothNeighbor) % valence;
result.Ep = v[i].P + cos((M_PI*j)/float(valence-1))*v[i].e0 + sin((M_PI*j)/float(valence-1))*v[i].e1;
j = (valence + prev - v[i].zerothNeighbor) % valence;
result.Em = v[i].P + cos((M_PI*j)/float(valence-1))*v[i].e0 + sin((M_PI*j)/float(valence-1))*v[i].e1;
vec3 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;
vec3 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;
float s1 = 3-2*cosfn(n,1)-cosfn(np,1);
float s2 = 2*cosfn(n,1);
result.Fp = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
s1 = 3.0f-2.0f*cos(2.0f*M_PI/float(n))-cos(2.0f*M_PI/float(nm));
result.Fm = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
if (v[im].valence < 0) {
s1 = 3-2*cosfn(n,1)-cosfn(np,1);
result.Fp = result.Fm = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
} else if (v[ip].valence < 0) {
s1 = 3.0f-2.0f*cos(2.0f*M_PI/n)-cos(2.0f*M_PI/nm);
result.Fm = result.Fp = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
}
} else if (v[i].valence == -2) {
result.Ep = (2.0f * v[i].org + v[ip].org)/3.0f;
result.Em = (2.0f * v[i].org + v[im].org)/3.0f;
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;
}
#else // not OSD_PATCH_GREGORY_BOUNDARY
result.Ep = v[i].P + v[i].e0 * cosfn(n, start) + v[i].e1*sinfn(n, start);
result.Em = v[i].P + v[i].e0 * cosfn(n, prev ) + v[i].e1*sinfn(n, prev);
vec3 Em_ip = v[ip].P + v[ip].e0 * cosfn(np, prev_p ) + v[ip].e1*sinfn(np, prev_p);
vec3 Ep_im = v[im].P + v[im].e0 * cosfn(nm, start_m) + v[im].e1*sinfn(nm, start_m);
float s1 = 3-2*cosfn(n,1)-cosfn(np,1);
float s2 = 2*cosfn(n,1);
result.Fp = (cosfn(np,1)*v[i].P + s1*result.Ep + s2*Em_ip + v[i].r[start])/3.0f;
s1 = 3.0f-2.0f*cos(2.0f*M_PI/float(n))-cos(2.0f*M_PI/float(nm));
result.Fm = (cosfn(nm,1)*v[i].P + s1*result.Em + s2*Ep_im - v[i].r[prev])/3.0f;
#endif
}
#endif // OSD_PATCH_GREGORY || OSD_PATCH_GREGORY_BOUNDARY
// ----------------------------------------------------------------------------
// Legacy Face-varying
// ----------------------------------------------------------------------------
uniform samplerBuffer OsdFVarDataBuffer;
#ifndef OSD_FVAR_WIDTH
#define OSD_FVAR_WIDTH 0
#endif
// ------ extract from quads (catmark, bilinear) ---------
// XXX: only linear interpolation is supported
#define OSD_COMPUTE_FACE_VARYING_1(result, fvarOffset, tessCoord) \
{ \
float v[4]; \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 4; \
for (int i = 0; i < 4; ++i) { \
int index = (primOffset+i)*OSD_FVAR_WIDTH + fvarOffset; \
v[i] = texelFetch(OsdFVarDataBuffer, index).s \
} \
result = mix(mix(v[0], v[1], tessCoord.s), \
mix(v[3], v[2], tessCoord.s), \
tessCoord.t); \
}
#define OSD_COMPUTE_FACE_VARYING_2(result, fvarOffset, tessCoord) \
{ \
vec2 v[4]; \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 4; \
for (int i = 0; i < 4; ++i) { \
int index = (primOffset+i)*OSD_FVAR_WIDTH + fvarOffset; \
v[i] = vec2(texelFetch(OsdFVarDataBuffer, index).s, \
texelFetch(OsdFVarDataBuffer, index + 1).s); \
} \
result = mix(mix(v[0], v[1], tessCoord.s), \
mix(v[3], v[2], tessCoord.s), \
tessCoord.t); \
}
#define OSD_COMPUTE_FACE_VARYING_3(result, fvarOffset, tessCoord) \
{ \
vec3 v[4]; \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 4; \
for (int i = 0; i < 4; ++i) { \
int index = (primOffset+i)*OSD_FVAR_WIDTH + fvarOffset; \
v[i] = vec3(texelFetch(OsdFVarDataBuffer, index).s, \
texelFetch(OsdFVarDataBuffer, index + 1).s, \
texelFetch(OsdFVarDataBuffer, index + 2).s); \
} \
result = mix(mix(v[0], v[1], tessCoord.s), \
mix(v[3], v[2], tessCoord.s), \
tessCoord.t); \
}
#define OSD_COMPUTE_FACE_VARYING_4(result, fvarOffset, tessCoord) \
{ \
vec4 v[4]; \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 4; \
for (int i = 0; i < 4; ++i) { \
int index = (primOffset+i)*OSD_FVAR_WIDTH + fvarOffset; \
v[i] = vec4(texelFetch(OsdFVarDataBuffer, index).s, \
texelFetch(OsdFVarDataBuffer, index + 1).s, \
texelFetch(OsdFVarDataBuffer, index + 2).s, \
texelFetch(OsdFVarDataBuffer, index + 3).s); \
} \
result = mix(mix(v[0], v[1], tessCoord.s), \
mix(v[3], v[2], tessCoord.s), \
tessCoord.t); \
}
// ------ extract from triangles barycentric (loop) ---------
// XXX: no interpolation supported
#define OSD_COMPUTE_FACE_VARYING_TRI_1(result, fvarOffset, triVert) \
{ \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 3; \
int index = (primOffset+triVert)*OSD_FVAR_WIDTH + fvarOffset; \
result = texelFetch(OsdFVarDataBuffer, index).s; \
}
#define OSD_COMPUTE_FACE_VARYING_TRI_2(result, fvarOffset, triVert) \
{ \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 3; \
int index = (primOffset+triVert)*OSD_FVAR_WIDTH + fvarOffset; \
result = vec2(texelFetch(OsdFVarDataBuffer, index).s, \
texelFetch(OsdFVarDataBuffer, index + 1).s); \
}
#define OSD_COMPUTE_FACE_VARYING_TRI_3(result, fvarOffset, triVert) \
{ \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 3; \
int index = (primOffset+triVert)*OSD_FVAR_WIDTH + fvarOffset; \
result = vec3(texelFetch(OsdFVarDataBuffer, index).s, \
texelFetch(OsdFVarDataBuffer, index + 1).s, \
texelFetch(OsdFVarDataBuffer, index + 2).s); \
}
#define OSD_COMPUTE_FACE_VARYING_TRI_4(result, fvarOffset, triVert) \
{ \
int primOffset = OsdGetPatchIndex(gl_PrimitiveID) * 3; \
int index = (primOffset+triVert)*OSD_FVAR_WIDTH + fvarOffset; \
result = vec4(texelFetch(OsdFVarDataBuffer, index).s, \
texelFetch(OsdFVarDataBuffer, index + 1).s, \
texelFetch(OsdFVarDataBuffer, index + 2).s, \
texelFetch(OsdFVarDataBuffer, index + 3).s); \
}