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2102b4f6b2
OpenSubdiv/opensubdiv/osd/glslPatchCommon.glsl
Takahito Tejima 2102b4f6b2 Fix screen-space tessellation on single crease patch. 
- Rename OsdPerPatchVertexBSpline to OsdPerPatchVertexBezier
- Split OsdGetTessLevels into 3 functions,
  OsdGetTessLevelUniform, OsdGetTessLevelAdaptiveRefinedPoints,
  OsdGetTessLevelAdaptiveLimitPoints.
- Add a regression test shape : catmark_single_crease
2015-05-30 22:41:24 -07:00

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//
// 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.
//
//
// typical shader composition ordering (see glDrawRegistry:_CompileShader)
//
//
// - glsl version string (#version 430)
//
// - common defines (#define OSD_ENABLE_PATCH_CULL, ...)
// - source defines (#define VERTEX_SHADER, ...)
//
// - osd headers (glslPatchCommon: varying structs,
// glslPtexCommon: ptex functions)
// - client header (Osd*Matrix(), displacement callback, ...)
//
// - osd shader source (glslPatchBSpline, glslPatchGregory, ...)
// or
// client shader source (vertex/geometry/fragment shader)
//
//----------------------------------------------------------
// 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
// XXXdyu-patch-drawing support for fractional spacing
#undef OSD_FRACTIONAL_ODD_SPACING
#undef OSD_FRACTIONAL_EVEN_SPACING
#if defined OSD_FRACTIONAL_ODD_SPACING
#define OSD_SPACING fractional_odd_spacing
#elif defined OSD_FRACTIONAL_EVEN_SPACING
#define OSD_SPACING fractional_even_spacing
#else
#define OSD_SPACING equal_spacing
#endif
#define M_PI 3.14159265359f
#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;
centroid vec4 patchCoord; // u, v, faceLevel, faceId
centroid vec2 tessCoord; // tesscoord.st
#if defined OSD_COMPUTE_NORMAL_DERIVATIVES
vec3 Nu;
vec3 Nv;
#endif
};
// osd shaders need following functions defined
mat4 OsdModelViewMatrix();
mat4 OsdProjectionMatrix();
mat4 OsdModelViewProjectionMatrix();
float OsdTessLevel();
int OsdGregoryQuadOffsetBase();
int OsdPrimitiveIdBase();
int OsdBaseVertex();
#ifndef OSD_DISPLACEMENT_CALLBACK
#define OSD_DISPLACEMENT_CALLBACK
#endif
// ----------------------------------------------------------------------------
// Patch Parameters
// ----------------------------------------------------------------------------
//
// Each patch has a corresponding patchParam. This is a set of three values
// specifying additional information about the patch:
//
// faceId -- topological face identifier (e.g. Ptex FaceId)
// bitfield -- refinement-level, non-quad, boundary, transition, uv-offset
// sharpness -- crease sharpness for single-crease patches
//
// 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;
}
int OsdGetPatchFaceId(ivec3 patchParam)
{
return patchParam.x;
}
int OsdGetPatchFaceLevel(ivec3 patchParam)
{
return (1 << ((patchParam.y & 0x7) - ((patchParam.y >> 3) & 1)));
}
int OsdGetPatchRefinementLevel(ivec3 patchParam)
{
return (patchParam.y & 0x7);
}
int OsdGetPatchBoundaryMask(ivec3 patchParam)
{
return ((patchParam.y >> 4) & 0xf);
}
int OsdGetPatchTransitionMask(ivec3 patchParam)
{
return ((patchParam.y >> 8) & 0xf);
}
ivec2 OsdGetPatchFaceUV(ivec3 patchParam)
{
int u = (patchParam.y >> 22) & 0x3ff;
int v = (patchParam.y >> 12) & 0x3ff;
return ivec2(u,v);
}
float OsdGetPatchSharpness(ivec3 patchParam)
{
return intBitsToFloat(patchParam.z);
}
ivec4 OsdGetPatchCoord(ivec3 patchParam)
{
int faceId = OsdGetPatchFaceId(patchParam);
int faceLevel = OsdGetPatchFaceLevel(patchParam);
ivec2 faceUV = OsdGetPatchFaceUV(patchParam);
return ivec4(faceUV.x, faceUV.y, faceLevel, faceId);
}
vec4 OsdInterpolatePatchCoord(vec2 localUV, ivec3 patchParam)
{
ivec4 perPrimPatchCoord = OsdGetPatchCoord(patchParam);
int faceId = perPrimPatchCoord.w;
int faceLevel = perPrimPatchCoord.z;
vec2 faceUV = vec2(perPrimPatchCoord.x, perPrimPatchCoord.y);
vec2 uv = localUV/faceLevel + faceUV/faceLevel;
// add 0.5 to integer values for more robust interpolation
return vec4(uv.x, uv.y, faceLevel+0.5f, faceId+0.5f);
}
// ----------------------------------------------------------------------------
// face varyings
// ----------------------------------------------------------------------------
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 (loop) ---------
// XXX: no interpolation supproted
#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); \
}
// ----------------------------------------------------------------------------
// 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
// ----------------------------------------------------------------------------
void
OsdUnivar4x4(in float u, out float B[4], out float D[4])
{
float t = u;
float s = 1.0f - u;
float A0 = s * s;
float A1 = 2 * s * t;
float A2 = t * t;
B[0] = s * A0;
B[1] = t * A0 + s * A1;
B[2] = t * A1 + s * A2;
B[3] = t * A2;
D[0] = - A0;
D[1] = A0 - A1;
D[2] = A1 - A2;
D[3] = A2;
}
void
OsdUnivar4x4(in float u, out float B[4], out float D[4], out float C[4])
{
float t = u;
float s = 1.0f - u;
float A0 = s * s;
float A1 = 2 * s * t;
float A2 = t * t;
B[0] = s * A0;
B[1] = t * A0 + s * A1;
B[2] = t * A1 + s * A2;
B[3] = t * A2;
D[0] = - A0;
D[1] = A0 - A1;
D[2] = A1 - A2;
D[3] = A2;
A0 = - s;
A1 = s - t;
A2 = t;
C[0] = - A0;
C[1] = A0 - A1;
C[2] = A1 - A2;
C[3] = A2;
}
// ----------------------------------------------------------------------------
struct OsdPerPatchVertexBezier {
ivec3 patchParam;
vec3 P;
#if defined OSD_PATCH_ENABLE_SINGLE_CREASE
vec3 P1;
vec3 P2;
vec2 vSegments;
#endif
};
vec3
OsdEvalBezier(vec3 cp[16], vec2 uv)
{
vec3 BUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0));
float B[4], D[4];
OsdUnivar4x4(uv.x, B, D);
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = cp[4*i + j];
BUCP[i] += A * B[j];
}
}
vec3 P = vec3(0);
OsdUnivar4x4(uv.y, B, D);
for (int k=0; k<4; ++k) {
P += B[k] * BUCP[k];
}
return P;
}
// When OSD_PATCH_ENABLE_SINGLE_CREASE is defined,
// this function evaluates single-crease patch, which is segmented into
// 3 parts in the v-direction.
//
// v=0 vSegment.x vSegment.y v=1
// +------------------+-------------------+------------------+
// | cp 0 | cp 1 | cp 2 |
// | (infinite sharp) | (floor sharpness) | (ceil sharpness) |
// +------------------+-------------------+------------------+
//
vec3
OsdEvalBezier(OsdPerPatchVertexBezier cp[16], vec2 uv)
{
vec3 BUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0));
float B[4], D[4];
OsdUnivar4x4(uv.x, B, D);
#if defined OSD_PATCH_ENABLE_SINGLE_CREASE
vec2 vSegments = cp[0].vSegments;
if (uv.y < vSegments.x) {
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = cp[4*i + j].P.xyz;
BUCP[i] += A * B[j];
}
}
} else if (uv.y < vSegments.y) {
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = cp[4*i + j].P1.xyz;
BUCP[i] += A * B[j];
}
}
} else {
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = cp[4*i + j].P2.xyz;
BUCP[i] += A * B[j];
}
}
}
#else
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = cp[4*i + j].P;
BUCP[i] += A * B[j];
}
}
#endif
vec3 P = vec3(0);
OsdUnivar4x4(uv.y, B, D);
for (int k=0; k<4; ++k) {
P += B[k] * BUCP[k];
}
return P;
}
// ----------------------------------------------------------------------------
// Boundary Interpolation
// ----------------------------------------------------------------------------
void
OsdComputeBSplineBoundaryPoints(inout vec3 cpt[16], ivec3 patchParam)
{
int boundaryMask = OsdGetPatchBoundaryMask(patchParam);
if ((boundaryMask & 1) != 0) {
cpt[0] = 2*cpt[4] - cpt[8];
cpt[1] = 2*cpt[5] - cpt[9];
cpt[2] = 2*cpt[6] - cpt[10];
cpt[3] = 2*cpt[7] - cpt[11];
}
if ((boundaryMask & 2) != 0) {
cpt[3] = 2*cpt[2] - cpt[1];
cpt[7] = 2*cpt[6] - cpt[5];
cpt[11] = 2*cpt[10] - cpt[9];
cpt[15] = 2*cpt[14] - cpt[13];
}
if ((boundaryMask & 4) != 0) {
cpt[12] = 2*cpt[8] - cpt[4];
cpt[13] = 2*cpt[9] - cpt[5];
cpt[14] = 2*cpt[10] - cpt[6];
cpt[15] = 2*cpt[11] - cpt[7];
}
if ((boundaryMask & 8) != 0) {
cpt[0] = 2*cpt[1] - cpt[2];
cpt[4] = 2*cpt[5] - cpt[6];
cpt[8] = 2*cpt[9] - cpt[10];
cpt[12] = 2*cpt[13] - cpt[14];
}
}
// ----------------------------------------------------------------------------
// Tessellation
// ----------------------------------------------------------------------------
//
// Organization of B-spline and Bezier control points.
//
// Each patch is defined by 16 control points (labeled 0-15).
//
// The patch will be evaluated across the domain from (0,0) at
// the lower-left to (1,1) at the upper-right. When computing
// adaptive tessellation metrics, we consider refined vertex-vertex
// and edge-vertex points along the transition edges of the patch
// (labeled vv* and ev* respectively).
//
// The two segments of each transition edge are labeled Lo and Hi,
// with the Lo segment occuring before the Hi segment along the
// transition edge's domain parameterization. These Lo and Hi segment
// tessellation levels determine how domain evaluation coordinates
// are remapped along transition edges. The Hi segment value will
// be zero for a non-transition edge.
//
// (0,1) (1,1)
//
// vv3 ev23 vv2
// | Lo3 | Hi3 |
// --O-----------O-----+-----O-----------O--
// | 12 | 13 14 | 15 |
// | | | |
// | | | |
// Hi0 | | | | Hi2
// | | | |
// O-----------O-----------O-----------O
// | 8 | 9 10 | 11 |
// | | | |
// ev03 --+ | | +-- ev12
// | | | |
// | 4 | 5 6 | 7 |
// O-----------O-----------O-----------O
// | | | |
// Lo0 | | | | Lo2
// | | | |
// | | | |
// | 0 | 1 2 | 3 |
// --O-----------O-----+-----O-----------O--
// | Lo1 | Hi1 |
// vv0 ev01 vv1
//
// (0,0) (1,0)
//
float OsdComputePostProjectionSphereExtent(vec3 center, float diameter)
{
vec4 p = OsdProjectionMatrix() * vec4(center, 1.0);
return abs(diameter * OsdProjectionMatrix()[1][1] / p.w);
}
float OsdComputeTessLevel(vec3 p0, vec3 p1)
{
// Adaptive factor can be any computation that depends only on arg values.
// Project the diameter of the edge's bounding sphere instead of using the
// length of the projected edge itself to avoid problems near silhouettes.
p0 = (OsdModelViewMatrix() * vec4(p0, 1.0)).xyz;
p1 = (OsdModelViewMatrix() * vec4(p1, 1.0)).xyz;
vec3 center = (p0 + p1) / 2.0;
float diameter = distance(p0, p1);
float projLength = OsdComputePostProjectionSphereExtent(center, diameter);
return round(max(1.0, OsdTessLevel() * projLength));
}
void
OsdGetTessLevelsUniform(ivec3 patchParam,
out vec4 tessOuterLo, out vec4 tessOuterHi)
{
int refinementLevel = OsdGetPatchRefinementLevel(patchParam);
float tessLevel = OsdTessLevel() / pow(2, refinementLevel-1);
tessOuterLo = vec4(tessLevel);
tessOuterHi = vec4(0);
}
void
OsdGetTessLevelsRefinedPoints(vec3 cp[16], ivec3 patchParam,
out vec4 tessOuterLo, out vec4 tessOuterHi)
{
// Each edge of a transition patch is adjacent to one or two patches
// at the next refined level of subdivision. We compute the corresponding
// vertex-vertex and edge-vertex refined points along the edges of the
// patch using Catmull-Clark subdivision stencil weights.
// For simplicity, we let the optimizer discard unused computation.
vec3 vv0 = (cp[0] + cp[2] + cp[8] + cp[10]) * 0.015625 +
(cp[1] + cp[4] + cp[6] + cp[9]) * 0.09375 + cp[5] * 0.5625;
vec3 ev01 = (cp[1] + cp[2] + cp[9] + cp[10]) * 0.0625 +
(cp[5] + cp[6]) * 0.375;
vec3 vv1 = (cp[1] + cp[3] + cp[9] + cp[11]) * 0.015625 +
(cp[2] + cp[5] + cp[7] + cp[10]) * 0.09375 + cp[6] * 0.5625;
vec3 ev12 = (cp[5] + cp[7] + cp[9] + cp[11]) * 0.0625 +
(cp[6] + cp[10]) * 0.375;
vec3 vv2 = (cp[5] + cp[7] + cp[13] + cp[15]) * 0.015625 +
(cp[6] + cp[9] + cp[11] + cp[14]) * 0.09375 + cp[10] * 0.5625;
vec3 ev23 = (cp[5] + cp[6] + cp[13] + cp[14]) * 0.0625 +
(cp[9] + cp[10]) * 0.375;
vec3 vv3 = (cp[4] + cp[6] + cp[12] + cp[14]) * 0.015625 +
(cp[5] + cp[8] + cp[10] + cp[13]) * 0.09375 + cp[9] * 0.5625;
vec3 ev03 = (cp[4] + cp[6] + cp[8] + cp[10]) * 0.0625 +
(cp[5] + cp[9]) * 0.375;
tessOuterLo = vec4(0);
tessOuterHi = vec4(0);
int transitionMask = OsdGetPatchTransitionMask(patchParam);
if ((transitionMask & 8) != 0) {
tessOuterLo[0] = OsdComputeTessLevel(vv0, ev03);
tessOuterHi[0] = OsdComputeTessLevel(vv3, ev03);
} else {
tessOuterLo[0] = OsdComputeTessLevel(cp[5], cp[9]);
}
if ((transitionMask & 1) != 0) {
tessOuterLo[1] = OsdComputeTessLevel(vv0, ev01);
tessOuterHi[1] = OsdComputeTessLevel(vv1, ev01);
} else {
tessOuterLo[1] = OsdComputeTessLevel(cp[5], cp[6]);
}
if ((transitionMask & 2) != 0) {
tessOuterLo[2] = OsdComputeTessLevel(vv1, ev12);
tessOuterHi[2] = OsdComputeTessLevel(vv2, ev12);
} else {
tessOuterLo[2] = OsdComputeTessLevel(cp[6], cp[10]);
}
if ((transitionMask & 4) != 0) {
tessOuterLo[3] = OsdComputeTessLevel(vv3, ev23);
tessOuterHi[3] = OsdComputeTessLevel(vv2, ev23);
} else {
tessOuterLo[3] = OsdComputeTessLevel(cp[9], cp[10]);
}
}
void
OsdGetTessLevelsLimitPoints(OsdPerPatchVertexBezier cpBezier[16],
ivec3 patchParam, out vec4 tessOuterLo, out vec4 tessOuterHi)
{
// Each edge of a transition patch is adjacent to one or two patches
// at the next refined level of subdivision. When the patch control
// points have been converted to the Bezier basis, the control points
// at the four corners are on the limit surface (since a Bezier patch
// interpolates its corner control points). We can compute an adaptive
// tessellation level for transition edges on the limit surface by
// evaluating a limit position at the mid point of each transition edge.
tessOuterLo = vec4(0);
tessOuterHi = vec4(0);
int transitionMask = OsdGetPatchTransitionMask(patchParam);
#if defined OSD_PATCH_ENABLE_SINGLE_CREASE
if ((transitionMask & 8) != 0) {
vec3 ev03 = OsdEvalBezier(cpBezier, vec2(0.0, 0.5));
tessOuterLo[0] = OsdComputeTessLevel(cpBezier[0].P, ev03);
tessOuterHi[0] = OsdComputeTessLevel(cpBezier[12].P2, ev03);
} else {
tessOuterLo[0] = OsdComputeTessLevel(cpBezier[0].P, cpBezier[12].P2);
}
if ((transitionMask & 1) != 0) {
vec3 ev01 = OsdEvalBezier(cpBezier, vec2(0.5, 0.0));
tessOuterLo[1] = OsdComputeTessLevel(cpBezier[0].P, ev01);
tessOuterHi[1] = OsdComputeTessLevel(cpBezier[3].P, ev01);
} else {
tessOuterLo[1] = OsdComputeTessLevel(cpBezier[0].P, cpBezier[3].P);
}
if ((transitionMask & 2) != 0) {
vec3 ev12 = OsdEvalBezier(cpBezier, vec2(1.0, 0.5));
tessOuterLo[2] = OsdComputeTessLevel(cpBezier[3].P, ev12);
tessOuterHi[2] = OsdComputeTessLevel(cpBezier[15].P2, ev12);
} else {
tessOuterLo[2] = OsdComputeTessLevel(cpBezier[3].P, cpBezier[15].P2);
}
if ((transitionMask & 4) != 0) {
vec3 ev23 = OsdEvalBezier(cpBezier, vec2(0.5, 1.0));
tessOuterLo[3] = OsdComputeTessLevel(cpBezier[12].P2, ev23);
tessOuterHi[3] = OsdComputeTessLevel(cpBezier[15].P2, ev23);
} else {
tessOuterLo[3] = OsdComputeTessLevel(cpBezier[12].P2, cpBezier[15].P2);
}
#else
if ((transitionMask & 8) != 0) {
vec3 ev03 = OsdEvalBezier(cpBezier, vec2(0.0, 0.5));
tessOuterLo[0] = OsdComputeTessLevel(cpBezier[0].P, ev03);
tessOuterHi[0] = OsdComputeTessLevel(cpBezier[12].P, ev03);
} else {
tessOuterLo[0] = OsdComputeTessLevel(cpBezier[0].P, cpBezier[12].P);
}
if ((transitionMask & 1) != 0) {
vec3 ev01 = OsdEvalBezier(cpBezier, vec2(0.5, 0.0));
tessOuterLo[1] = OsdComputeTessLevel(cpBezier[0].P, ev01);
tessOuterHi[1] = OsdComputeTessLevel(cpBezier[3].P, ev01);
} else {
tessOuterLo[1] = OsdComputeTessLevel(cpBezier[0].P, cpBezier[3].P);
}
if ((transitionMask & 2) != 0) {
vec3 ev12 = OsdEvalBezier(cpBezier, vec2(1.0, 0.5));
tessOuterLo[2] = OsdComputeTessLevel(cpBezier[3].P, ev12);
tessOuterHi[2] = OsdComputeTessLevel(cpBezier[15].P, ev12);
} else {
tessOuterLo[2] = OsdComputeTessLevel(cpBezier[3].P, cpBezier[15].P);
}
if ((transitionMask & 4) != 0) {
vec3 ev23 = OsdEvalBezier(cpBezier, vec2(0.5, 1.0));
tessOuterLo[3] = OsdComputeTessLevel(cpBezier[12].P, ev23);
tessOuterHi[3] = OsdComputeTessLevel(cpBezier[15].P, ev23);
} else {
tessOuterLo[3] = OsdComputeTessLevel(cpBezier[12].P, cpBezier[15].P);
}
#endif
}
void
OsdGetTessLevelsUniform(ivec3 patchParam,
out vec4 tessLevelOuter, out vec2 tessLevelInner,
out vec4 tessOuterLo, out vec4 tessOuterHi)
{
// uniform tessellation
OsdGetTessLevelsUniform(patchParam, tessOuterLo, tessOuterHi);
// Outer levels are the sum of the Lo and Hi segments where the Hi
// segments will have a length of zero for non-transition edges.
tessLevelOuter = tessOuterLo + tessOuterHi;
// Inner levels are the average the corresponding outer levels.
tessLevelInner[0] = (tessLevelOuter[1] + tessLevelOuter[3]) * 0.5;
tessLevelInner[1] = (tessLevelOuter[0] + tessLevelOuter[2]) * 0.5;
}
void
OsdGetTessLevelsAdaptiveRefinedPoints(vec3 cpRefined[16], ivec3 patchParam,
out vec4 tessLevelOuter, out vec2 tessLevelInner,
out vec4 tessOuterLo, out vec4 tessOuterHi)
{
OsdGetTessLevelsRefinedPoints(cpRefined, patchParam, tessOuterLo, tessOuterHi);
// Outer levels are the sum of the Lo and Hi segments where the Hi
// segments will have a length of zero for non-transition edges.
tessLevelOuter = tessOuterLo + tessOuterHi;
// Inner levels are the average the corresponding outer levels.
tessLevelInner[0] = (tessLevelOuter[1] + tessLevelOuter[3]) * 0.5;
tessLevelInner[1] = (tessLevelOuter[0] + tessLevelOuter[2]) * 0.5;
}
void
OsdGetTessLevelsAdaptiveLimitPoints(OsdPerPatchVertexBezier cpBezier[16],
ivec3 patchParam,
out vec4 tessLevelOuter, out vec2 tessLevelInner,
out vec4 tessOuterLo, out vec4 tessOuterHi)
{
OsdGetTessLevelsLimitPoints(cpBezier, patchParam, tessOuterLo, tessOuterHi);
// Outer levels are the sum of the Lo and Hi segments where the Hi
// segments will have a length of zero for non-transition edges.
tessLevelOuter = tessOuterLo + tessOuterHi;
// Inner levels are the average the corresponding outer levels.
tessLevelInner[0] = (tessLevelOuter[1] + tessLevelOuter[3]) * 0.5;
tessLevelInner[1] = (tessLevelOuter[0] + tessLevelOuter[2]) * 0.5;
}
void
OsdGetTessLevels(vec3 cp0, vec3 cp1, vec3 cp2, vec3 cp3,
ivec3 patchParam,
out vec4 tessLevelOuter, out vec2 tessLevelInner)
{
vec4 tessOuterLo = vec4(0);
vec4 tessOuterHi = vec4(0);
#if defined OSD_ENABLE_SCREENSPACE_TESSELLATION
tessOuterLo[0] = OsdComputeTessLevel(cp0, cp1);
tessOuterLo[1] = OsdComputeTessLevel(cp0, cp3);
tessOuterLo[2] = OsdComputeTessLevel(cp2, cp3);
tessOuterLo[3] = OsdComputeTessLevel(cp1, cp2);
tessOuterHi = vec4(0);
#else
OsdGetTessLevelsUniform(patchParam, tessOuterLo, tessOuterHi);
#endif
// Outer levels are the sum of the Lo and Hi segments where the Hi
// segments will have a length of zero for non-transition edges.
tessLevelOuter = tessOuterLo + tessOuterHi;
// Inner levels are the average the corresponding outer levels.
tessLevelInner[0] = (tessLevelOuter[1] + tessLevelOuter[3]) * 0.5;
tessLevelInner[1] = (tessLevelOuter[0] + tessLevelOuter[2]) * 0.5;
}
float
OsdGetTessTransitionSplit(float t, float n0, float n1)
{
float ti = round(t * (n0 + n1));
if (ti <= n0) {
return 0.5 * (ti / n0);
} else {
return 0.5 * ((ti - n0) / n1) + 0.5;
}
}
vec2
OsdGetTessParameterization(vec2 uv, vec4 tessOuterLo, vec4 tessOuterHi)
{
vec2 UV = uv;
if (UV.x == 0 && tessOuterHi[0] > 0) {
UV.y = OsdGetTessTransitionSplit(UV.y, tessOuterLo[0], tessOuterHi[0]);
} else
if (UV.y == 0 && tessOuterHi[1] > 0) {
UV.x = OsdGetTessTransitionSplit(UV.x, tessOuterLo[1], tessOuterHi[1]);
} else
if (UV.x == 1 && tessOuterHi[2] > 0) {
UV.y = OsdGetTessTransitionSplit(UV.y, tessOuterLo[2], tessOuterHi[2]);
} else
if (UV.y == 1 && tessOuterHi[3] > 0) {
UV.x = OsdGetTessTransitionSplit(UV.x, tessOuterLo[3], tessOuterHi[3]);
}
return UV;
}
// ----------------------------------------------------------------------------
// BSpline
// ----------------------------------------------------------------------------
// compute single-crease patch matrix
mat4
OsdComputeMs(float sharpness)
{
float s = pow(2.0f, sharpness);
float s2 = s*s;
float s3 = s2*s;
mat4 m = mat4(
0, s + 1 + 3*s2 - s3, 7*s - 2 - 6*s2 + 2*s3, (1-s)*(s-1)*(s-1),
0, (1+s)*(1+s), 6*s - 2 - 2*s2, (s-1)*(s-1),
0, 1+s, 6*s - 2, 1-s,
0, 1, 6*s - 2, 1);
m /= (s*6.0);
m[0][0] = 1.0/6.0;
return m;
}
// convert BSpline cv to Bezier cv
void
OsdComputePerPatchVertexBSpline(ivec3 patchParam, int ID, vec3 cv[16],
out OsdPerPatchVertexBezier result)
{
// Regular BSpline to Bezier
mat4 Q = mat4(
1.f/6.f, 4.f/6.f, 1.f/6.f, 0.f,
0.f, 4.f/6.f, 2.f/6.f, 0.f,
0.f, 2.f/6.f, 4.f/6.f, 0.f,
0.f, 1.f/6.f, 4.f/6.f, 1.f/6.f
);
result.patchParam = patchParam;
OsdComputeBSplineBoundaryPoints(cv, patchParam);
int i = ID%4;
int j = ID/4;
vec3 H[4];
for (int l=0; l<4; ++l) {
H[l] = vec3(0);
for (int k=0; k<4; ++k) {
H[l] += Q[i][k] * cv[l*4 + k];
}
}
#if defined OSD_PATCH_ENABLE_SINGLE_CREASE
// Infinitly Sharp (boundary)
mat4 Mi = mat4(
1.f/6.f, 4.f/6.f, 1.f/6.f, 0.f,
0.f, 4.f/6.f, 2.f/6.f, 0.f,
0.f, 2.f/6.f, 4.f/6.f, 0.f,
0.f, 0.f, 1.f, 0.f
);
float sharpness = OsdGetPatchSharpness(patchParam);
if (sharpness > 0) {
float Sf = floor(sharpness);
float Sc = ceil(sharpness);
float Sr = fract(sharpness);
mat4 Mf = OsdComputeMs(Sf);
mat4 Mc = OsdComputeMs(Sc);
mat4 Mj = (1-Sr) * Mf + Sr * Mi;
mat4 Ms = (1-Sr) * Mf + Sr * Mc;
float s0 = 1 - pow(2, -floor(sharpness));
float s1 = 1 - pow(2, -ceil(sharpness));
result.P = vec3(0);
result.P1 = vec3(0);
result.P2 = vec3(0);
result.vSegments = vec2(s0, s1);
for (int k=0; k<4; ++k) {
result.P += Mi[j][k]*H[k]; // 0 to 1-2^(-Sf)
result.P1 += Mj[j][k]*H[k]; // 1-2^(-Sf) to 1-2^(-Sc)
result.P2 += Ms[j][k]*H[k]; // 1-2^(-Sc) to 1
}
} else {
result.P = vec3(0);
for (int k=0; k<4; ++k) {
result.P += Q[j][k]*H[k];
}
result.P1 = result.P;
result.P2 = result.P;
result.vSegments = vec2(0);
}
#else
{
result.P = vec3(0);
for (int k=0; k<4; ++k) {
result.P += Q[j][k]*H[k];
}
}
#endif
}
void
OsdEvalPatchBezier(ivec3 patchParam, vec2 UV,
OsdPerPatchVertexBezier cv[16],
out vec3 P, out vec3 dPu, out vec3 dPv,
out vec3 N, out vec3 dNu, out vec3 dNv)
{
#ifdef OSD_COMPUTE_NORMAL_DERIVATIVES
float B[4], D[4], C[4];
vec3 BUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0)),
DUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0)),
CUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0));
OsdUnivar4x4(UV.x, B, D, C);
#else
float B[4], D[4];
vec3 BUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0)),
DUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0));
OsdUnivar4x4(UV.x, B, D);
#endif
// ----------------------------------------------------------------
#if defined OSD_PATCH_ENABLE_SINGLE_CREASE
vec2 vSegments = cv[0].vSegments;
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
int k = 4*i + j;
float s = UV.y;
vec3 A = (s <= vSegments.x) ? cv[k].P.xyz
: ((s <= vSegments.y) ? cv[k].P1.xyz
: cv[k].P2.xyz);
BUCP[i] += A * B[j];
DUCP[i] += A * D[j];
#ifdef OSD_COMPUTE_NORMAL_DERIVATIVES
CUCP[i] += A * C[j];
#endif
}
}
#else
// ----------------------------------------------------------------
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = cv[4*i + j].P;
BUCP[i] += A * B[j];
DUCP[i] += A * D[j];
#ifdef OSD_COMPUTE_NORMAL_DERIVATIVES
CUCP[i] += A * C[j];
#endif
}
}
#endif
// ----------------------------------------------------------------
P = vec3(0);
dPu = vec3(0);
dPv = vec3(0);
#ifdef OSD_COMPUTE_NORMAL_DERIVATIVES
// used for weingarten term
OsdUnivar4x4(UV.y, B, D, C);
vec3 dUU = vec3(0);
vec3 dVV = vec3(0);
vec3 dUV = vec3(0);
for (int k=0; k<4; ++k) {
P += B[k] * BUCP[k];
dPu += B[k] * DUCP[k];
dPv += D[k] * BUCP[k];
dUU += B[k] * CUCP[k];
dVV += C[k] * BUCP[k];
dUV += D[k] * DUCP[k];
}
int level = OsdGetPatchFaceLevel(patchParam);
dPu *= 3 * level;
dPv *= 3 * level;
dUU *= 6 * level;
dVV *= 6 * level;
dUV *= 9 * level;
vec3 n = cross(dPu, dPv);
N = normalize(n);
float E = dot(dPu, dPu);
float F = dot(dPu, dPv);
float G = dot(dPv, dPv);
float e = dot(N, dUU);
float f = dot(N, dUV);
float g = dot(N, dVV);
dNu = (f*F-e*G)/(E*G-F*F) * dPu + (e*F-f*E)/(E*G-F*F) * dPv;
dNv = (g*F-f*G)/(E*G-F*F) * dPu + (f*F-g*E)/(E*G-F*F) * dPv;
dNu = dNu/length(n) - n * (dot(dNu,n)/pow(dot(n,n), 1.5));
dNv = dNv/length(n) - n * (dot(dNv,n)/pow(dot(n,n), 1.5));
#else
OsdUnivar4x4(UV.y, B, D);
for (int k=0; k<4; ++k) {
P += B[k] * BUCP[k];
dPu += B[k] * DUCP[k];
dPv += D[k] * BUCP[k];
}
int level = OsdGetPatchFaceLevel(patchParam);
dPu *= 3 * level;
dPv *= 3 * level;
N = normalize(cross(dPu, dPv));
dNu = vec3(0);
dNv = vec3(0);
#endif
}
// ----------------------------------------------------------------------------
// Gregory Basis
// ----------------------------------------------------------------------------
struct OsdPerPatchVertexGregoryBasis {
ivec3 patchParam;
vec3 P;
};
void
OsdComputePerPatchVertexGregoryBasis(ivec3 patchParam, int ID, vec3 cv,
out OsdPerPatchVertexGregoryBasis result)
{
result.patchParam = patchParam;
result.P = cv;
}
void
OsdEvalPatchGregory(ivec3 patchParam, vec2 UV, vec3 cv[20],
out vec3 P, out vec3 dPu, out vec3 dPv,
out vec3 N, out vec3 dNu, out vec3 dNv)
{
float u = UV.x, v = UV.y;
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;
vec3 q[16];
q[ 5] = (u*cv[3] + v*cv[4])/d11;
q[ 6] = (U*cv[9] + v*cv[8])/d12;
q[ 9] = (u*cv[19] + V*cv[18])/d21;
q[10] = (U*cv[13] + V*cv[14])/d22;
q[ 0] = cv[0];
q[ 1] = cv[1];
q[ 2] = cv[7];
q[ 3] = cv[5];
q[ 4] = cv[2];
q[ 7] = cv[6];
q[ 8] = cv[16];
q[11] = cv[12];
q[12] = cv[15];
q[13] = cv[17];
q[14] = cv[11];
q[15] = cv[10];
P = vec3(0);
dPu = vec3(0);
dPv = vec3(0);
#ifdef OSD_COMPUTE_NORMAL_DERIVATIVES
float B[4], D[4], C[4];
vec3 BUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0)),
DUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0)),
CUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0));
vec3 dUU = vec3(0);
vec3 dVV = vec3(0);
vec3 dUV = vec3(0);
OsdUnivar4x4(UV.x, B, D, C);
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = q[4*i + j];
BUCP[i] += A * B[j];
DUCP[i] += A * D[j];
CUCP[i] += A * C[j];
}
}
OsdUnivar4x4(UV.y, B, D, C);
for (int i=0; i<4; ++i) {
P += B[i] * BUCP[i];
dPu += B[i] * DUCP[i];
dPv += D[i] * BUCP[i];
dUU += B[i] * CUCP[i];
dVV += C[i] * BUCP[i];
dUV += D[i] * DUCP[i];
}
int level = OsdGetPatchFaceLevel(patchParam);
dPu *= 3 * level;
dPv *= 3 * level;
dUU *= 6 * level;
dVV *= 6 * level;
dUV *= 9 * level;
vec3 n = cross(dPu, dPv);
N = normalize(n);
float E = dot(dPu, dPu);
float F = dot(dPu, dPv);
float G = dot(dPv, dPv);
float e = dot(N, dUU);
float f = dot(N, dUV);
float g = dot(N, dVV);
dNu = (f*F-e*G)/(E*G-F*F) * dPu + (e*F-f*E)/(E*G-F*F) * dPv;
dNv = (g*F-f*G)/(E*G-F*F) * dPu + (f*F-g*E)/(E*G-F*F) * dPv;
dNu = dNu/length(n) - n * (dot(dNu,n)/pow(dot(n,n), 1.5));
dNv = dNv/length(n) - n * (dot(dNv,n)/pow(dot(n,n), 1.5));
#else
float B[4], D[4];
vec3 BUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0)),
DUCP[4] = vec3[4](vec3(0), vec3(0), vec3(0), vec3(0));
OsdUnivar4x4(UV.x, B, D);
for (int i=0; i<4; ++i) {
for (int j=0; j<4; ++j) {
vec3 A = q[4*i + j];
BUCP[i] += A * B[j];
DUCP[i] += A * D[j];
}
}
OsdUnivar4x4(UV.y, B, D);
for (int i=0; i<4; ++i) {
P += B[i] * BUCP[i];
dPu += B[i] * DUCP[i];
dPv += D[i] * BUCP[i];
}
int level = OsdGetPatchFaceLevel(patchParam);
dPu *= 3 * level;
dPv *= 3 * level;
N = normalize(cross(dPu, dPv));
dNu = vec3(0);
dNv = vec3(0);
#endif
}
// ----------------------------------------------------------------------------
// Legacy Gregory
// ----------------------------------------------------------------------------
#if defined(OSD_PATCH_GREGORY) || defined(OSD_PATCH_GREGORY_BOUNDARY)
#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 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;
}
v.e0 *= ef[valence - 3];
v.e1 *= ef[valence - 3];
#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+ 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 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
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