From b205127e81b97d5863587cea3628598996282903 Mon Sep 17 00:00:00 2001
From: Jonathan <jonno.5000@gmail.com>
Date: Mon, 27 Sep 2021 21:03:24 -0400
Subject: [PATCH] Fix exactEmpty Simplify output_dir

---
 include/common/qvec.hh |  2 +-
 light/ltface.cc        | 10 ++++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/include/common/qvec.hh b/include/common/qvec.hh
index 6083c2fb..55b1a8d3 100644
--- a/include/common/qvec.hh
+++ b/include/common/qvec.hh
@@ -343,7 +343,7 @@ template<size_t N, class T>
 bool emptyExact(const qvec<N, T> &v1)
 {
     for (size_t i = 0; i < N; i++) {
-        if (!v1[i])
+        if (v1[i])
             return false;
     }
     return true;
diff --git a/light/ltface.cc b/light/ltface.cc
index dd0c85af..236cf9e5 100644
--- a/light/ltface.cc
+++ b/light/ltface.cc
@@ -3153,9 +3153,11 @@ static void WriteSingleLightmap(const mbsp_t *bsp, const mface_t *face, const li
 
     const std::vector<qvec4f> output_color =
         IntegerDownsampleImage(fullres, oversampled_width, oversampled_height, oversample);
-    const std::vector<qvec4f> output_dir = (lux ? IntegerDownsampleImage(LightmapNormalsToGLMVector(lightsurf, lm),
-                                                      oversampled_width, oversampled_height, oversample)
-                                            : std::vector<qvec4f>()); // mxd. Skip when lux isn't needed
+    std::optional<std::vector<qvec4f>> output_dir;
+    
+    if (lux) {
+        output_dir = IntegerDownsampleImage(LightmapNormalsToGLMVector(lightsurf, lm), oversampled_width, oversampled_height, oversample);
+    }
 
     // copy from the float buffers to byte buffers in .bsp / .lit / .lux
 
@@ -3185,7 +3187,7 @@ static void WriteSingleLightmap(const mbsp_t *bsp, const mface_t *face, const li
             if (lux) {
                 vec3_t temp;
                 int v;
-                const qvec4f &direction = output_dir.at(sampleindex);
+                const qvec4f &direction = output_dir->at(sampleindex);
                 temp[0] = qv::dot(qvec3f(direction), qvec3f(lightsurf->snormal));
                 temp[1] = qv::dot(qvec3f(direction), qvec3f(lightsurf->tnormal));
                 temp[2] = qv::dot(qvec3f(direction), qvec3f(lightsurf->plane.normal));