From 450a2b8a258f09ec7e0824861e2306340ccbb3f4 Mon Sep 17 00:00:00 2001
From: Adrien Gruson <adrien.gruson@gmail.com>
Date: Fri, 10 Aug 2018 17:54:21 +0900
Subject: [PATCH] evaluate the orientation value when calling
 'HeterogeneousMedium::eval' if needed. (#84)

---
 src/medium/heterogeneous.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/medium/heterogeneous.cpp b/src/medium/heterogeneous.cpp
index 4c9833ca..1f59614f 100644
--- a/src/medium/heterogeneous.cpp
+++ b/src/medium/heterogeneous.cpp
@@ -668,11 +668,15 @@ public:
             Float mintDensity = lookupDensity(ray(ray.mint), ray.d) * m_scale;
             Float maxtDensity = 0.0f;
             Spectrum maxtAlbedo(0.0f);
+            Vector orientation(0.0f);
             if (ray.maxt < std::numeric_limits<Float>::infinity()) {
                 Point p = ray(ray.maxt);
                 maxtDensity = lookupDensity(p, ray.d) * m_scale;
                 maxtAlbedo = m_albedo->lookupSpectrum(p);
+                orientation = m_orientation != NULL
+                             ? m_orientation->lookupVector(p) : Vector(0.0f);
             }
+            mRec.orientation = orientation;
             mRec.transmittance = Spectrum(expVal);
             mRec.pdfFailure = expVal;
             mRec.pdfSuccess = expVal * maxtDensity;