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[hdEmbree] add lighting support for IES files
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pmolodo committed Oct 21, 2024
1 parent 7eb43eb commit efe71ff
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Showing 3 changed files with 70 additions and 0 deletions.
36 changes: 36 additions & 0 deletions pxr/imaging/plugin/hdEmbree/light.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -233,6 +233,42 @@ HdEmbree_Light::Sync(HdSceneDelegate *sceneDelegate,
_lightData.shaping.coneSoftness = value.UncheckedGet<float>();
}

if (const auto value = sceneDelegate->GetLightParamValue(
id, HdLightTokens->shapingIesFile);
value.IsHolding<SdfAssetPath>()) {
SdfAssetPath iesAssetPath = value.UncheckedGet<SdfAssetPath>();
std::string iesPath = iesAssetPath.GetResolvedPath();
if (iesPath.empty()) {
iesPath = iesAssetPath.GetAssetPath();
}

if (!iesPath.empty()) {
std::ifstream in(iesPath);
if (!in.is_open()) {
TF_WARN("could not open ies file %s", iesPath.c_str());
} else {
std::stringstream buffer;
buffer << in.rdbuf();

if (!_lightData.shaping.ies.iesFile.load(buffer.str())) {
TF_WARN("could not load ies file %s", iesPath.c_str());
}
}
}
}

if (const auto value = sceneDelegate->GetLightParamValue(
id, HdLightTokens->shapingIesNormalize);
value.IsHolding<bool>()) {
_lightData.shaping.ies.normalize = value.UncheckedGet<bool>();
}

if (const auto value = sceneDelegate->GetLightParamValue(
id, HdLightTokens->shapingIesAngleScale);
value.IsHolding<float>()) {
_lightData.shaping.ies.angleScale = value.UncheckedGet<float>();
}

_PopulateRtcLight(device, scene);

HdEmbreeRenderer *renderer = embreeRenderParam->GetRenderer();
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10 changes: 10 additions & 0 deletions pxr/imaging/plugin/hdEmbree/light.h
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@
#ifndef PXR_IMAGING_PLUGIN_HD_EMBREE_LIGHT_H
#define PXR_IMAGING_PLUGIN_HD_EMBREE_LIGHT_H

#include "pxr/imaging/plugin/hdEmbree/pxrIES/pxrIES.h"

#include "pxr/base/gf/vec3f.h"
#include "pxr/base/gf/matrix3f.h"
#include "pxr/base/gf/matrix4f.h"
Expand Down Expand Up @@ -71,12 +73,20 @@ struct HdEmbree_LightTexture
int height = 0;
};

struct HdEmbree_IES
{
PxrIESFile iesFile;
bool normalize = false;
float angleScale = 0.0f;
};

struct HdEmbree_Shaping
{
GfVec3f focusTint;
float focus = 0.0f;
float coneAngle = 180.0f;
float coneSoftness = 0.0f;
HdEmbree_IES ies;
};

struct HdEmbree_LightData
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24 changes: 24 additions & 0 deletions pxr/imaging/plugin/hdEmbree/renderer.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -389,6 +389,27 @@ _IntersectAreaLight(HdEmbree_LightData const& light, RTCRayHit const& rayHit)
};
}

float
_EvalIES(HdEmbree_LightData const& light, GfVec3f const& wI)
{
HdEmbree_IES const& ies = light.shaping.ies;

if (!ies.iesFile.valid()) {
// Either none specified or there was an error loading. In either case,
// just ignore
return 1.0f;
}

// emission direction in light space
GfVec3f wE = light.xformWorldToLight.TransformDir(wI).GetNormalized();

float theta = _Theta(wE);
float phi = _Phi(wE);
float norm = ies.normalize ? ies.iesFile.power() : 1.0f;

return ies.iesFile.eval(theta, phi, ies.angleScale) / norm;
}

GfVec3f
_EvalLightBasic(HdEmbree_LightData const& light)
{
Expand Down Expand Up @@ -495,6 +516,9 @@ _EvalAreaLight(HdEmbree_LightData const& light, _ShapeSample const& ss,
const float thetaOffZ = acosf(cosThetaOffZ);
Le *= 1.0f - _Smoothstep(thetaOffZ, GfRange1f(thetaSoft, thetaCone));

// Apply IES
Le *= _EvalIES(light, wI);

return _LightSample {
Le,
wI,
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