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Fix Cycles random walk SSS differences between CPU and GPU 

The Embree logic did not match the GPU.
This commit is contained in:
Brecht Van Lommel 2021-10-07 21:23:02 +02:00
parent 4ee97f129a
commit 23791db145
1 changed files with 25 additions and 17 deletions
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42
intern/cycles/bvh/bvh_embree.cpp
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@ -155,41 +155,49 @@ static void rtc_filter_occluded_func(const RTCFilterFunctionNArguments *args)
break;
}
/* See triangle_intersect_subsurface() for the native equivalent. */
for (int i = min(ctx->max_hits, ctx->local_isect->num_hits) - 1; i >= 0; --i) {
if (ctx->local_isect->hits[i].t == ray->tfar) {
/* This tells Embree to continue tracing. */
*args->valid = 0;
break;
}
}
LocalIntersection *local_isect = ctx->local_isect;
int hit_idx = 0;
if (ctx->lcg_state) {
/* See triangle_intersect_subsurface() for the native equivalent. */
for (int i = min(ctx->max_hits, local_isect->num_hits) - 1; i >= 0; --i) {
if (local_isect->hits[i].t == ray->tfar) {
/* This tells Embree to continue tracing. */
*args->valid = 0;
return;
}
}
++ctx->local_isect->num_hits;
if (ctx->local_isect->num_hits <= ctx->max_hits) {
hit_idx = ctx->local_isect->num_hits - 1;
local_isect->num_hits++;
if (local_isect->num_hits <= ctx->max_hits) {
hit_idx = local_isect->num_hits - 1;
}
else {
/* reservoir sampling: if we are at the maximum number of
* hits, randomly replace element or skip it */
hit_idx = lcg_step_uint(ctx->lcg_state) % ctx->local_isect->num_hits;
hit_idx = lcg_step_uint(ctx->lcg_state) % local_isect->num_hits;
if (hit_idx >= ctx->max_hits) {
/* This tells Embree to continue tracing. */
*args->valid = 0;
break;
return;
}
}
}
else {
ctx->local_isect->num_hits = 1;
/* Record closest intersection only. */
if (local_isect->num_hits && current_isect.t > local_isect->hits[0].t) {
*args->valid = 0;
return;
}
local_isect->num_hits = 1;
}
/* record intersection */
ctx->local_isect->hits[hit_idx] = current_isect;
ctx->local_isect->Ng[hit_idx] = normalize(make_float3(hit->Ng_x, hit->Ng_y, hit->Ng_z));
local_isect->hits[hit_idx] = current_isect;
local_isect->Ng[hit_idx] = normalize(make_float3(hit->Ng_x, hit->Ng_y, hit->Ng_z));
/* This tells Embree to continue tracing. */
*args->valid = 0;
break;