OpenSubdiv/opensubdiv/osd/glslXFBKernel.glsl
David G. Yu f0128a5f5e Fixed Far::PatchParam encoding of refinement level
This change restores the use of 4-bits in Far::PatchParam to
encode the refinement level of a patch. This restores one bit
that was stolen to allow for more general encoding of boundary
edge and transition edge masks. In order to accommodate all
of the bits that are required, the transition edge mask bits
are now stored along with the faceId bits.

Also, accessors are now exposed directly as members of Far::PatchParam
and the internal bitfield class is no longer directly exposed.
2015-06-11 15:10:30 -07:00

288 lines
7.9 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.
//
//------------------------------------------------------------------------------
uniform samplerBuffer vertexBuffer;
uniform int srcOffset = 0;
out float outVertexBuffer[LENGTH];
//------------------------------------------------------------------------------
struct Vertex {
float vertexData[LENGTH];
};
void clear(out Vertex v) {
for (int i = 0; i < LENGTH; i++) {
v.vertexData[i] = 0;
}
}
void addWithWeight(inout Vertex v, Vertex src, float weight) {
for(int j = 0; j < LENGTH; j++) {
v.vertexData[j] += weight * src.vertexData[j];
}
}
Vertex readVertex(int index) {
Vertex v;
int vertexIndex = srcOffset + index * SRC_STRIDE;
for(int j = 0; j < LENGTH; j++) {
v.vertexData[j] = texelFetch(vertexBuffer, vertexIndex+j).x;
}
return v;
}
void writeVertex(Vertex v) {
for(int i = 0; i < LENGTH; i++) {
outVertexBuffer[i] = v.vertexData[i];
}
}
//------------------------------------------------------------------------------
#if defined(OPENSUBDIV_GLSL_XFB_USE_DERIVATIVES)
out float outDuBuffer[LENGTH];
out float outDvBuffer[LENGTH];
void writeDu(Vertex v) {
for(int i = 0; i < LENGTH; i++) {
outDuBuffer[i] = v.vertexData[i];
}
}
void writeDv(Vertex v) {
for(int i = 0; i < LENGTH; i++) {
outDvBuffer[i] = v.vertexData[i];
}
}
#endif
//------------------------------------------------------------------------------
#if defined(OPENSUBDIV_GLSL_XFB_KERNEL_EVAL_STENCILS)
uniform usamplerBuffer sizes;
uniform isamplerBuffer offsets;
uniform isamplerBuffer indices;
uniform samplerBuffer weights;
#if defined(OPENSUBDIV_GLSL_XFB_USE_DERIVATIVES)
uniform samplerBuffer duWeights;
uniform samplerBuffer dvWeights;
#endif
uniform int batchStart = 0;
uniform int batchEnd = 0;
void main() {
int current = gl_VertexID + batchStart;
if (current>=batchEnd) {
return;
}
Vertex dst, du, dv;
clear(dst);
clear(du);
clear(dv);
int offset = texelFetch(offsets, current).x;
uint size = texelFetch(sizes, current).x;
for (int stencil=0; stencil<size; ++stencil) {
int index = texelFetch(indices, offset+stencil).x;
float weight = texelFetch(weights, offset+stencil).x;
addWithWeight(dst, readVertex( index ), weight);
#if defined(OPENSUBDIV_GLSL_XFB_USE_DERIVATIVES)
float duWeight = texelFetch(duWeights, offset+stencil).x;
float dvWeight = texelFetch(dvWeights, offset+stencil).x;
addWithWeight(du, readVertex(index), duWeight);
addWithWeight(dv, readVertex(index), dvWeight);
#endif
}
writeVertex(dst);
#if defined(OPENSUBDIV_GLSL_XFB_USE_DERIVATIVES)
writeDu(du);
writeDv(dv);
#endif
}
#endif
//------------------------------------------------------------------------------
#if defined(OPENSUBDIV_GLSL_XFB_KERNEL_EVAL_PATCHES)
layout (location = 0) in ivec3 patchHandles;
layout (location = 1) in vec2 patchCoords;
//struct PatchArray {
// int patchType;
// int numPatches;
// int indexBase; // an offset within the index buffer
// int primitiveIdBase; // an offset within the patch param buffer
//};
// # of patcharrays is 1 or 2.
uniform ivec4 patchArray[2];
uniform isamplerBuffer patchParamBuffer;
uniform isamplerBuffer patchIndexBuffer;
void getBSplineWeights(float t, inout vec4 point, inout vec4 deriv) {
// The four uniform cubic B-Spline basis functions evaluated at t:
float one6th = 1.0f / 6.0f;
float t2 = t * t;
float t3 = t * t2;
point.x = one6th * (1.0f - 3.0f*(t - t2) - t3);
point.y = one6th * (4.0f - 6.0f*t2 + 3.0f*t3);
point.z = one6th * (1.0f + 3.0f*(t + t2 - t3));
point.w = one6th * ( t3);
// Derivatives of the above four basis functions at t:
deriv.x = -0.5f*t2 + t - 0.5f;
deriv.y = 1.5f*t2 - 2.0f*t;
deriv.z = -1.5f*t2 + t + 0.5f;
deriv.w = 0.5f*t2;
}
uint getDepth(uint patchBits) {
return (patchBits & 0xfU);
}
float getParamFraction(uint patchBits) {
uint nonQuadRoot = (patchBits >> 4) & 0x1U;
uint depth = getDepth(patchBits);
if (nonQuadRoot == 1) {
return 1.0f / float( 1 << (depth-1) );
} else {
return 1.0f / float( 1 << depth );
}
}
vec2 normalizePatchCoord(uint patchBits, vec2 uv) {
float frac = getParamFraction(patchBits);
uint iu = (patchBits >> 22) & 0x3ffU;
uint iv = (patchBits >> 12) & 0x3ffU;
// top left corner
float pu = float(iu*frac);
float pv = float(iv*frac);
// normalize u,v coordinates
return vec2((uv.x - pu) / frac, (uv.y - pv) / frac);
}
void adjustBoundaryWeights(uint bits, inout vec4 sWeights, inout vec4 tWeights) {
uint boundary = ((bits >> 8) & 0xfU);
if ((boundary & 1U) != 0) {
tWeights[2] -= tWeights[0];
tWeights[1] += 2*tWeights[0];
tWeights[0] = 0;
}
if ((boundary & 2U) != 0) {
sWeights[1] -= sWeights[3];
sWeights[2] += 2*sWeights[3];
sWeights[3] = 0;
}
if ((boundary & 4U) != 0) {
tWeights[1] -= tWeights[3];
tWeights[2] += 2*tWeights[3];
tWeights[3] = 0;
}
if ((boundary & 8U) != 0) {
sWeights[2] -= sWeights[0];
sWeights[1] += 2*sWeights[0];
sWeights[0] = 0;
}
}
void main() {
int current = gl_VertexID;
ivec3 handle = patchHandles;
int patchIndex = handle.y;
vec2 coord = patchCoords;
ivec4 array = patchArray[handle.x];
int patchType = array.x;
int numControlVertices = 16;
uint patchBits = texelFetch(patchParamBuffer, patchIndex).y;
// normalize
coord = normalizePatchCoord(patchBits, coord);
float dScale = float(1 << getDepth(patchBits));
// if regular
float wP[20], wDs[20], wDt[20];
{
vec4 sWeights, tWeights, dsWeights, dtWeights;
getBSplineWeights(coord.s, sWeights, dsWeights);
getBSplineWeights(coord.t, tWeights, dtWeights);
adjustBoundaryWeights(patchBits, sWeights, tWeights);
adjustBoundaryWeights(patchBits, dsWeights, dtWeights);
for (int k = 0; k < 4; ++k) {
for (int l = 0; l < 4; ++l) {
wP[4*k+l] = sWeights[l] * tWeights[k];
wDs[4*k+l] = dsWeights[l] * tWeights[k] * dScale;
wDt[4*k+l] = sWeights[l] * dtWeights[k] * dScale;
}
}
}
Vertex dst, du, dv;
clear(dst);
clear(du);
clear(dv);
int indexBase = array.z + handle.z;
for (int cv = 0; cv < numControlVertices; ++cv) {
int index = texelFetch(patchIndexBuffer, indexBase + cv).x;
addWithWeight(dst, readVertex(index), wP[cv]);
addWithWeight(du, readVertex(index), wDs[cv]);
addWithWeight(dv, readVertex(index), wDt[cv]);
}
writeVertex(dst);
#if defined(OPENSUBDIV_GLSL_XFB_USE_DERIVATIVES)
writeDu(du);
writeDv(dv);
#endif
}
#endif