7f4479da42
This commit contains all the work related on the AMD megakernel split work which was mainly done by Varun Sundar, George Kyriazis and Lenny Wang, plus some help from Sergey Sharybin, Martijn Berger, Thomas Dinges and likely someone else which we're forgetting to mention. Currently only AMD cards are enabled for the new split kernel, but it is possible to force split opencl kernel to be used by setting the following environment variable: CYCLES_OPENCL_SPLIT_KERNEL_TEST=1. Not all the features are supported yet, and that being said no motion blur, camera blur, SSS and volumetrics for now. Also transparent shadows are disabled on AMD device because of some compiler bug. This kernel is also only implements regular path tracing and supporting branched one will take a bit. Branched path tracing is exposed to the interface still, which is a bit misleading and will be hidden there soon. More feature will be enabled once they're ported to the split kernel and tested. Neither regular CPU nor CUDA has any difference, they're generating the same exact code, which means no regressions/improvements there. Based on the research paper: https://research.nvidia.com/sites/default/files/publications/laine2013hpg_paper.pdf Here's the documentation: https://docs.google.com/document/d/1LuXW-CV-sVJkQaEGZlMJ86jZ8FmoPfecaMdR-oiWbUY/edit Design discussion of the patch: https://developer.blender.org/T44197 Differential Revision: https://developer.blender.org/D1200
107 lines
2.9 KiB
C
107 lines
2.9 KiB
C
/*
|
|
* Copyright 2011-2013 Blender Foundation
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
CCL_NAMESPACE_BEGIN
|
|
|
|
/* See "Tracing Ray Differentials", Homan Igehy, 1999. */
|
|
|
|
ccl_device void differential_transfer(ccl_addr_space differential3 *dP_, const differential3 dP, float3 D, const differential3 dD, float3 Ng, float t)
|
|
{
|
|
/* ray differential transfer through homogeneous medium, to
|
|
* compute dPdx/dy at a shading point from the incoming ray */
|
|
|
|
float3 tmp = D/dot(D, Ng);
|
|
float3 tmpx = dP.dx + t*dD.dx;
|
|
float3 tmpy = dP.dy + t*dD.dy;
|
|
|
|
dP_->dx = tmpx - dot(tmpx, Ng)*tmp;
|
|
dP_->dy = tmpy - dot(tmpy, Ng)*tmp;
|
|
}
|
|
|
|
ccl_device void differential_incoming(ccl_addr_space differential3 *dI, const differential3 dD)
|
|
{
|
|
/* compute dIdx/dy at a shading point, we just need to negate the
|
|
* differential of the ray direction */
|
|
|
|
dI->dx = -dD.dx;
|
|
dI->dy = -dD.dy;
|
|
}
|
|
|
|
ccl_device void differential_dudv(ccl_addr_space differential *du, ccl_addr_space differential *dv, float3 dPdu, float3 dPdv, differential3 dP, float3 Ng)
|
|
{
|
|
/* now we have dPdx/dy from the ray differential transfer, and dPdu/dv
|
|
* from the primitive, we can compute dudx/dy and dvdx/dy. these are
|
|
* mainly used for differentials of arbitrary mesh attributes. */
|
|
|
|
/* find most stable axis to project to 2D */
|
|
float xn = fabsf(Ng.x);
|
|
float yn = fabsf(Ng.y);
|
|
float zn = fabsf(Ng.z);
|
|
|
|
if(zn < xn || zn < yn) {
|
|
if(yn < xn || yn < zn) {
|
|
dPdu.x = dPdu.y;
|
|
dPdv.x = dPdv.y;
|
|
dP.dx.x = dP.dx.y;
|
|
dP.dy.x = dP.dy.y;
|
|
}
|
|
|
|
dPdu.y = dPdu.z;
|
|
dPdv.y = dPdv.z;
|
|
dP.dx.y = dP.dx.z;
|
|
dP.dy.y = dP.dy.z;
|
|
}
|
|
|
|
/* using Cramer's rule, we solve for dudx and dvdx in a 2x2 linear system,
|
|
* and the same for dudy and dvdy. the denominator is the same for both
|
|
* solutions, so we compute it only once.
|
|
*
|
|
* dP.dx = dPdu * dudx + dPdv * dvdx;
|
|
* dP.dy = dPdu * dudy + dPdv * dvdy; */
|
|
|
|
float det = (dPdu.x*dPdv.y - dPdv.x*dPdu.y);
|
|
|
|
if(det != 0.0f)
|
|
det = 1.0f/det;
|
|
|
|
du->dx = (dP.dx.x*dPdv.y - dP.dx.y*dPdv.x)*det;
|
|
dv->dx = (dP.dx.y*dPdu.x - dP.dx.x*dPdu.y)*det;
|
|
|
|
du->dy = (dP.dy.x*dPdv.y - dP.dy.y*dPdv.x)*det;
|
|
dv->dy = (dP.dy.y*dPdu.x - dP.dy.x*dPdu.y)*det;
|
|
}
|
|
|
|
ccl_device differential differential_zero()
|
|
{
|
|
differential d;
|
|
d.dx = 0.0f;
|
|
d.dy = 0.0f;
|
|
|
|
return d;
|
|
}
|
|
|
|
ccl_device differential3 differential3_zero()
|
|
{
|
|
differential3 d;
|
|
d.dx = make_float3(0.0f, 0.0f, 0.0f);
|
|
d.dy = make_float3(0.0f, 0.0f, 0.0f);
|
|
|
|
return d;
|
|
}
|
|
|
|
CCL_NAMESPACE_END
|
|
|