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// Copyright 2009 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#include "common/World.ih"
#include "render/pathtracer/PathStructs.ih"
#include "render/pathtracer/PathTracerUtil.ih"
#include "render/pathtracer/VirtualLight.ih"
#ifdef OSPRAY_ENABLE_VOLUMES
#include "render/pathtracer/volumes/VolumeSampler.ih"
#endif
// c++ shared
#include "lights/LightDispatch.ih"
#include "lights/LightShared.h"
OSPRAY_BEGIN_ISPC_NAMESPACE
inline box1f getMinMaxDistForVirtualLights(
const PathVertex &lastVertex, const PathVertex &pathVertex, const Ray &ray)
{
box1f interval;
// minimal distance is not always zero (when previously sampled a Dirac
// transmission)
interval.lower = distance(lastVertex.dg.P, ray.org);
// virtual lights are occluded by hit geometry
// because lastVertex.dg.P can be different from ray.org (when previously
// sampled a Dirac transmission) we cannot just use ray.t as maximum distance
interval.upper = distance(lastVertex.dg.P, ray.org + ray.t * ray.dir);
if (pathVertex.type == ENVIRONMENT)
interval.upper = inf;
return interval;
}
// add light from *virtual* lights by intersecting them
SYCL_EXTERNAL vec3f evaluateVirtualLights(const PathContext &pathContext,
PathState &pathState,
const PathVertex &lastVertex,
const PathVertex &pathVertex,
Ray &ray,
const uniform FeatureFlagsHandler &ffh)
{
vec3f L = make_vec3f(0.f);
if (pathContext.numLights <= pathContext.numGeoLights)
return L; // return if no virtual lights at all
box1f intervalLightDist =
getMinMaxDistForVirtualLights(lastVertex, pathVertex, ray);
// at the moment we only support uniform light selection
// therefore we can evaluate the selection PDF directly
const float selectionPDF =
lastVertex.numLightSamples / (float)pathContext.numLights;
for (uniform uint32 i = pathContext.numGeoLights; i < pathContext.numLights;
i++) {
const Light *uniform light = pathContext.lights[i];
if (!pathState.straightPath || light->isVisible) {
// to correctly handle MIS through transparencies the light pdf needs to
// be calculated wrt. lastVertex.dg
// however, we only have a valid intersection with the light in
// [minLightDist, maxLightDist], otherwise light could be added twice
Light_EvalRes le = Light_dispatch_eval(light,
lastVertex.dg,
ray.dir,
intervalLightDist.lower,
intervalLightDist.upper,
pathState.time,
ffh);
if (reduce_max(le.radiance) > 0.0f) {
float misWeight = 1.0f;
if (selectionPDF) {
float T = 1.f;
#ifdef OSPRAY_ENABLE_VOLUMES
Ray shadowRay;
setRay(shadowRay,
lastVertex.dg.P,
ray.dir,
intervalLightDist.lower,
intervalLightDist.upper,
ray.time);
// Trace ray in clipping geometries scene, fill array with ray
// intervals
RayIntervals rayIntervals;
traceClippingRay(pathContext.world, shadowRay, rayIntervals, ffh);
const uniform FeatureFlags ff = getFeatureFlags(ffh);
if (ff.other & FFO_VOLUME_IN_SCENE) {
T = volumeTransmittance(pathContext.world,
shadowRay,
rayIntervals,
&pathState.randomSampler,
ffh);
}
#endif
misWeight = misHeuristic(
pathContext, lastVertex.pdf_w * T, selectionPDF * le.pdf);
}
L = L + pathState.throughput * le.radiance * misWeight;
}
}
}
return L;
}
OSPRAY_END_ISPC_NAMESPACE
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