diff --git a/3rdparty/fmt b/3rdparty/fmt
index 7bdf0628..a3370119 160000
--- a/3rdparty/fmt
+++ b/3rdparty/fmt
@@ -1 +1 @@
-Subproject commit 7bdf0628b1276379886c7f6dda2cef2b3b374f0b
+Subproject commit a33701196adfad74917046096bf5a2aa0ab0bb50
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 50aa0f57..d92c6cd2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,7 +37,7 @@ if (UNIX)
 endif (UNIX)
 
 # set our C/C++ dialects
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_C_STANDARD 99)
 
diff --git a/appveyor.yml b/appveyor.yml
index d514f219..b181162b 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,5 +1,5 @@
 image:
-  - Visual Studio 2019
+  - Visual Studio 2022
 platform:
 - x64
 
diff --git a/build-appveyor.ps1 b/build-appveyor.ps1
index 5c91680a..b76e1b7d 100644
--- a/build-appveyor.ps1
+++ b/build-appveyor.ps1
@@ -18,7 +18,7 @@ mkdir cmakebuild
 
 cd cmakebuild
 
-cmake .. -T v142 -Dembree_DIR="C:\embree-3.12.1.x64.vc14.windows" -DTBB_DIR="C:\tbb\cmake" -DCMAKE_GENERATOR_PLATFORM=x64 -DENABLE_LIGHTPREVIEW=NO -DQt5Widgets_DIR="C:\Qt\5.8\msvc2013_64\lib\cmake\Qt5Widgets"
+cmake .. -T v143 -Dembree_DIR="C:\embree-3.12.1.x64.vc14.windows" -DTBB_DIR="C:\tbb\cmake" -DCMAKE_GENERATOR_PLATFORM=x64 -DENABLE_LIGHTPREVIEW=NO -DQt5Widgets_DIR="C:\Qt\5.8\msvc2013_64\lib\cmake\Qt5Widgets"
 
 $cmakePlatform = "x64"
 
diff --git a/common/bspfile.cc b/common/bspfile.cc
index 9662ec5b..b9fa51c0 100644
--- a/common/bspfile.cc
+++ b/common/bspfile.cc
@@ -1693,14 +1693,14 @@ const bspversion_t bspver_qbism{Q2_QBISMIDENT, Q2_BSPVERSION, "qbism", "Quake II
 
 bool surfflags_t::needs_write() const
 {
-    return no_dirt || no_shadow || no_bounce || no_minlight || no_expand || light_ignore || phong_angle ||
+    return no_dirt || no_shadow || no_bounce || no_minlight || no_expand || light_ignore || !surflight_rescale || phong_angle ||
            phong_angle_concave || minlight || !qv::emptyExact(minlight_color) || light_alpha || maxlight || lightcolorscale != 1.0;
 }
 
 static auto as_tuple(const surfflags_t &flags)
 {
     return std::tie(flags.native, flags.is_nodraw, flags.is_hintskip, flags.is_hint, flags.no_dirt, flags.no_shadow, flags.no_bounce, flags.no_minlight, flags.no_expand,
-        flags.light_ignore, flags.phong_angle, flags.phong_angle_concave, flags.minlight, flags.minlight_color, flags.light_alpha, flags.maxlight, flags.lightcolorscale);
+        flags.light_ignore, flags.surflight_rescale, flags.phong_angle, flags.phong_angle_concave, flags.minlight, flags.minlight_color, flags.light_alpha, flags.maxlight, flags.lightcolorscale);
 }
 
 bool surfflags_t::operator<(const surfflags_t &other) const
diff --git a/common/bspinfo.cc b/common/bspinfo.cc
index a1088a10..a0888e6b 100644
--- a/common/bspinfo.cc
+++ b/common/bspinfo.cc
@@ -228,7 +228,7 @@ static faceextents_t get_face_extents(const mbsp_t &bsp, const bspxentries_t &bs
         return {face, bsp, bspx.lmwidth, bspx.lmheight, bspx.world_to_lm_space};
     }
     if (!use_bspx) {
-        return {face, bsp, 16.0};
+        return {face, bsp, LMSCALE_DEFAULT};
     }
 
     return {face, bsp,
diff --git a/common/bsputils.cc b/common/bsputils.cc
index 3182bf50..f3416c5e 100644
--- a/common/bsputils.cc
+++ b/common/bsputils.cc
@@ -622,6 +622,20 @@ void DecompressRow(const uint8_t *in, const int numbytes, uint8_t *decompressed)
     } while (out - decompressed < row);
 }
 
+bspx_decoupled_lm_perface BSPX_DecoupledLM(const bspxentries_t &entries, int face_num)
+{
+    auto &lump_bytes = entries.at("DECOUPLED_LM");
+
+    auto stream = imemstream(lump_bytes.data(), lump_bytes.size());
+
+    stream.seekg(face_num * sizeof(bspx_decoupled_lm_perface));
+    stream >> endianness<std::endian::little>;
+
+    bspx_decoupled_lm_perface result;
+    stream >= result;
+    return result;
+}
+
 qvec2d WorldToTexCoord(const qvec3d &world, const mtexinfo_t *tex)
 {
     /*
@@ -901,3 +915,27 @@ qvec3f faceextents_t::LMCoordToWorld(qvec2f lm) const
     const qvec4f res = lmToWorldMatrix * lmPadded;
     return res;
 }
+
+/**
+ * Samples the lightmap at an integer coordinate
+ */
+qvec3b LM_Sample(const mbsp_t *bsp, const faceextents_t &faceextents, int byte_offset_of_face, qvec2i coord)
+{
+    int pixel = coord[0] + (coord[1] * faceextents.width());
+
+    const uint8_t* data = bsp->dlightdata.data();
+
+    if (bsp->loadversion->game->has_rgb_lightmap) {
+        return qvec3f{
+            data[byte_offset_of_face + (pixel * 3) + 0],
+            data[byte_offset_of_face + (pixel * 3) + 1],
+            data[byte_offset_of_face + (pixel * 3) + 2]
+        };
+    } else {
+        return qvec3f{
+            data[byte_offset_of_face + pixel],
+            data[byte_offset_of_face + pixel],
+            data[byte_offset_of_face + pixel]
+        };
+    }
+}
\ No newline at end of file
diff --git a/common/log.cc b/common/log.cc
index 9073d6f5..00369fb8 100644
--- a/common/log.cc
+++ b/common/log.cc
@@ -304,16 +304,14 @@ void stat_tracker_t::print_stats()
 
     stats_printed = true;
 
-    auto old = std::locale::global(std::locale("en_US.UTF-8"));
     // add 8 char padding just to keep it away from the left side
     size_t number_padding = number_of_digit_padding() + 4;
 
     for (auto &stat : stats) {
         if (stat.show_even_if_zero || stat.count) {
-            print(flag::STAT, "{}{:{}L} {}\n", stat.is_warning ? "WARNING: " : "", stat.count, stat.is_warning ? 0 : number_padding, stat.name);
+            print(flag::STAT, "{}{:{}} {}\n", stat.is_warning ? "WARNING: " : "", fmt::group_digits(stat.count.load()), stat.is_warning ? 0 : number_padding, stat.name);
         }
     }
-    std::locale::global(old);
 }
 
 stat_tracker_t::~stat_tracker_t()
diff --git a/include/common/aabb.hh b/include/common/aabb.hh
index 3aa29883..c9938036 100644
--- a/include/common/aabb.hh
+++ b/include/common/aabb.hh
@@ -224,11 +224,11 @@ struct fmt::formatter<aabb<T, Dim>> : formatter<qvec<T, Dim>>
     template<typename FormatContext>
     auto format(const aabb<T, Dim> &b, FormatContext &ctx) -> decltype(ctx.out())
     {
-        format_to(ctx.out(), "{{mins: ");
-        formatter<qvec<T, Dim>>::format(b.mins(), ctx);
-        format_to(ctx.out(), ", maxs: ");
-        formatter<qvec<T, Dim>>::format(b.maxs(), ctx);
-        format_to(ctx.out(), "}}");
+        fmt::format_to(ctx.out(), "{{mins: ");
+        fmt::formatter<qvec<T, Dim>>::format(b.mins(), ctx);
+        fmt::format_to(ctx.out(), ", maxs: ");
+        fmt::formatter<qvec<T, Dim>>::format(b.maxs(), ctx);
+        fmt::format_to(ctx.out(), "}}");
         return ctx.out();
     }
 };
diff --git a/include/common/bspfile.hh b/include/common/bspfile.hh
index b395fa73..12107bcb 100644
--- a/include/common/bspfile.hh
+++ b/include/common/bspfile.hh
@@ -185,6 +185,10 @@ struct surfflags_t
     // this face doesn't receive light
     bool light_ignore;
 
+    // if true, rescales any surface light emitted by these brushes to emit 50% light at 90 degrees from the surface normal
+    // if false, use a more natural angle falloff of 0% at 90 degrees
+    bool surflight_rescale = true;
+
     // if non zero, enables phong shading and gives the angle threshold to use
     vec_t phong_angle;
 
@@ -351,18 +355,18 @@ struct fmt::formatter<bspversion_t>
     auto format(const bspversion_t &v, FormatContext &ctx) -> decltype(ctx.out())
     {
         if (v.name) {
-            format_to(ctx.out(), "{} ", v.name);
+            fmt::format_to(ctx.out(), "{} ", v.name);
         }
 
         // Q2-esque BSPs are printed as, ex, IBSP:38
         if (v.version.has_value()) {
             char ident[5] = {(char)(v.ident & 0xFF), (char)((v.ident >> 8) & 0xFF), (char)((v.ident >> 16) & 0xFF),
                 (char)((v.ident >> 24) & 0xFF), '\0'};
-            return format_to(ctx.out(), "{}:{}", ident, v.version.value());
+            return fmt::format_to(ctx.out(), "{}:{}", ident, v.version.value());
         }
 
         // Q1-esque BSPs are printed as, ex, bsp29
-        return format_to(ctx.out(), "{}", v.short_name);
+        return fmt::format_to(ctx.out(), "{}", v.short_name);
     }
 };
 
@@ -406,7 +410,7 @@ struct texvec : qmat<T, 2, 4>
 
 // Fmt support
 template<class T>
-struct fmt::formatter<texvec<T>> : formatter<qmat<T, 2, 4>>
+struct fmt::formatter<texvec<T>> : fmt::formatter<qmat<T, 2, 4>>
 {
 };
 
diff --git a/include/common/bsputils.hh b/include/common/bsputils.hh
index f28cd115..2a6f37b5 100644
--- a/include/common/bsputils.hh
+++ b/include/common/bsputils.hh
@@ -20,6 +20,7 @@
 #pragma once
 
 #include <common/bspfile.hh>
+#include <common/bspxfile.hh>
 #include <common/mathlib.hh>
 #include <common/qvec.hh>
 #include <common/aabb.hh>
@@ -107,6 +108,8 @@ void Face_DebugPrint(const mbsp_t *bsp, const mface_t *face);
 void CompressRow(const uint8_t *vis, const size_t numbytes, std::back_insert_iterator<std::vector<uint8_t>> it);
 void DecompressRow(const uint8_t *in, const int numbytes, uint8_t *decompressed);
 
+bspx_decoupled_lm_perface BSPX_DecoupledLM(const bspxentries_t &entries, int face_num);
+
 /* ======================================================================== */
 
 qvec2d WorldToTexCoord(const qvec3d &world, const mtexinfo_t *tex);
@@ -122,6 +125,8 @@ constexpr size_t MAXDIMENSION = 255 + 1;
 
 struct world_units_per_luxel_t {};
 
+constexpr float LMSCALE_DEFAULT = 16.0f;
+
 class faceextents_t
 {
 public:
@@ -150,3 +155,5 @@ public:
     qvec2f worldToLMCoord(qvec3f world) const;
     qvec3f LMCoordToWorld(qvec2f lm) const;
 };
+
+qvec3b LM_Sample(const mbsp_t *bsp, const faceextents_t &faceextents, int byte_offset_of_face, qvec2i coord);
diff --git a/include/common/cmdlib.hh b/include/common/cmdlib.hh
index 65e53e80..b4a93ae0 100644
--- a/include/common/cmdlib.hh
+++ b/include/common/cmdlib.hh
@@ -108,25 +108,8 @@ time_point I_FloatTime();
  *                            BYTE ORDER FUNCTIONS
  * ============================================================================
  */
-// C++20 polyfill
-#if defined(__cpp_lib_endian) && __cpp_lib_endian >= 201907L
-#include <bit>
-#else
-namespace std
-{
-enum class endian
-{
-    little = 0,
-    big = 1,
 
-#ifdef __BIG_ENDIAN__
-    native = big
-#else
-    native = little
-#endif
-};
-} // namespace std
-#endif
+#include <bit>
 
 // Binary streams; by default, streams use the native endianness
 // (unchanged bytes) but can be changed to a specific endianness
diff --git a/include/common/fs.hh b/include/common/fs.hh
index 8fb78f51..f0bbf34a 100644
--- a/include/common/fs.hh
+++ b/include/common/fs.hh
@@ -113,6 +113,6 @@ struct fmt::formatter<fs::path>
     template<typename FormatContext>
     auto format(const fs::path &p, FormatContext &ctx)
     {
-        return format_to(ctx.out(), "{}", p.string());
+        return fmt::format_to(ctx.out(), "{}", p.string());
     }
 };
diff --git a/include/common/log.hh b/include/common/log.hh
index 491242a2..295e221b 100644
--- a/include/common/log.hh
+++ b/include/common/log.hh
@@ -74,15 +74,15 @@ template<typename... Args>
 inline void print(flag type, const char *fmt, const Args &...args)
 {
     if (mask & type) {
-        print(type, fmt::format(fmt, std::forward<const Args &>(args)...).c_str());
+        print(type, fmt::format(fmt::runtime(fmt), std::forward<const Args &>(args)...).c_str());
     }
 }
 
 // format print to default targets
 template<typename... Args>
-inline void print(const char *fmt, const Args &...args)
+inline void print(const char *formt, const Args &...args)
 {
-    print(flag::DEFAULT, fmt::format(fmt, std::forward<const Args &>(args)...).c_str());
+    print(flag::DEFAULT, fmt::format(fmt::runtime(formt), std::forward<const Args &>(args)...).c_str());
 }
 
 void header(const char *name);
@@ -182,7 +182,7 @@ struct stat_tracker_t
 template<typename... Args>
 [[noreturn]] inline void Error(const char *fmt, const Args &...args)
 {
-    auto formatted = fmt::format(fmt, std::forward<const Args &>(args)...);
+    auto formatted = fmt::format(fmt::runtime(fmt), std::forward<const Args &>(args)...);
     Error(formatted.c_str());
 }
 
diff --git a/include/common/parser.hh b/include/common/parser.hh
index 13b332e3..02ab5f4a 100644
--- a/include/common/parser.hh
+++ b/include/common/parser.hh
@@ -93,13 +93,13 @@ struct fmt::formatter<parser_source_location>
     auto format(const parser_source_location &v, FormatContext &ctx) -> decltype(ctx.out())
     {
         if (v.source_name) {
-            format_to(ctx.out(), "{}", *v.source_name.get());
+            fmt::format_to(ctx.out(), "{}", *v.source_name.get());
         } else {
-            format_to(ctx.out(), "unknown/unset location");
+            fmt::format_to(ctx.out(), "unknown/unset location");
         }
 
         if (v.line_number.has_value()) {
-            format_to(ctx.out(), "[line {}]", v.line_number.value());
+            fmt::format_to(ctx.out(), "[line {}]", v.line_number.value());
         }
 
         return ctx.out();
diff --git a/include/common/qvec.hh b/include/common/qvec.hh
index 55c5c7a1..f522fd1f 100644
--- a/include/common/qvec.hh
+++ b/include/common/qvec.hh
@@ -341,11 +341,11 @@ struct fmt::formatter<qvec<T, N>>
     auto format(const qvec<T, N> &p, FormatContext &ctx) -> decltype(ctx.out())
     {
         for (size_t i = 0; i < N - 1; i++) {
-            format_to(ctx.out(), "{}", p[i]);
-            format_to(ctx.out(), " ");
+            fmt::format_to(ctx.out(), "{}", p[i]);
+            fmt::format_to(ctx.out(), " ");
         }
 
-        return format_to(ctx.out(), "{}", p[N - 1]);
+        return fmt::format_to(ctx.out(), "{}", p[N - 1]);
     }
 };
 
@@ -838,9 +838,9 @@ struct fmt::formatter<qplane3<T>> : formatter<qvec<T, 3>>
     template<typename FormatContext>
     auto format(const qplane3<T> &p, FormatContext &ctx) -> decltype(ctx.out())
     {
-        format_to(ctx.out(), "{{normal: ");
-        formatter<qvec<T, 3>>::format(p.normal, ctx);
-        format_to(ctx.out(), ", dist: {}}}", p.dist);
+        fmt::format_to(ctx.out(), "{{normal: ");
+        fmt::formatter<qvec<T, 3>>::format(p.normal, ctx);
+        fmt::format_to(ctx.out(), ", dist: {}}}", p.dist);
         return ctx.out();
     }
 };
@@ -1026,12 +1026,12 @@ struct fmt::formatter<qmat<T, NRow, NCol>> : formatter<qvec<T, NCol>>
     auto format(const qmat<T, NRow, NCol> &p, FormatContext &ctx) -> decltype(ctx.out())
     {
         for (size_t i = 0; i < NRow; i++) {
-            format_to(ctx.out(), "[ ");
-            formatter<qvec<T, NCol>>::format(p.row(i), ctx);
-            format_to(ctx.out(), " ]");
+            fmt::format_to(ctx.out(), "[ ");
+            fmt::formatter<qvec<T, NCol>>::format(p.row(i), ctx);
+            fmt::format_to(ctx.out(), " ]");
 
             if (i != NRow - 1) {
-                format_to(ctx.out(), "\n");
+                fmt::format_to(ctx.out(), "\n");
             }
         }
 
diff --git a/include/common/settings.hh b/include/common/settings.hh
index a92125fb..89deb097 100644
--- a/include/common/settings.hh
+++ b/include/common/settings.hh
@@ -34,6 +34,7 @@
 #include <limits>
 #include <optional>
 #include <unordered_set>
+#include <functional>
 
 namespace settings
 {
diff --git a/include/light/bounce.hh b/include/light/bounce.hh
index 8c306812..448fd877 100644
--- a/include/light/bounce.hh
+++ b/include/light/bounce.hh
@@ -32,5 +32,6 @@
 
 // public functions
 
+void ResetBounce();
 const std::vector<surfacelight_t> &BounceLights();
 void MakeBounceLights(const settings::worldspawn_keys &cfg, const mbsp_t *bsp);
diff --git a/include/light/entities.hh b/include/light/entities.hh
index f038cf5e..c5de03f8 100644
--- a/include/light/entities.hh
+++ b/include/light/entities.hh
@@ -122,6 +122,7 @@ public:
  *    Stores the RGB values to determine the light color
  */
 
+void ResetLightEntities();
 std::string TargetnameForLightStyle(int style);
 std::vector<std::unique_ptr<light_t>> &GetLights();
 std::vector<sun_t> &GetSuns();
diff --git a/include/light/light.hh b/include/light/light.hh
index ad6abc50..d2f04e54 100644
--- a/include/light/light.hh
+++ b/include/light/light.hh
@@ -161,7 +161,8 @@ enum class debugmodes
     debugoccluded,
     debugneighbours,
     phong_tangents,
-    phong_bitangents
+    phong_bitangents,
+    mottle
 };
 
 enum class lightfile
@@ -385,6 +386,7 @@ public:
     setting_func phongdebug_obj;
     setting_func debugoccluded;
     setting_func debugneighbours;
+    setting_func debugmottle;
 
     light_settings();
 
@@ -425,5 +427,6 @@ const modelinfo_t *ModelInfoForFace(const mbsp_t *bsp, int facenum);
 const img::texture *Face_Texture(const mbsp_t *bsp, const mface_t *face);
 const qvec3b &Face_LookupTextureColor(const mbsp_t *bsp, const mface_t *face);
 const qvec3d &Face_LookupTextureBounceColor(const mbsp_t *bsp, const mface_t *face);
+void light_reset();
 int light_main(int argc, const char **argv);
 int light_main(const std::vector<std::string> &args);
diff --git a/include/light/ltface.hh b/include/light/ltface.hh
index 70d8adf3..0f090963 100644
--- a/include/light/ltface.hh
+++ b/include/light/ltface.hh
@@ -61,3 +61,4 @@ void FinishLightmapSurface(const mbsp_t *bsp, lightsurf_t *lightsurf);
 void SaveLightmapSurface(const mbsp_t *bsp, mface_t *face, facesup_t *facesup,
     bspx_decoupled_lm_perface *facesup_decoupled, lightsurf_t *lightsurf, const faceextents_t &extents,
     const faceextents_t &output_extents);
+void ResetLtFace();
diff --git a/include/light/phong.hh b/include/light/phong.hh
index 341eb889..d2fbb674 100644
--- a/include/light/phong.hh
+++ b/include/light/phong.hh
@@ -79,3 +79,4 @@ public:
 };
 
 const face_cache_t &FaceCacheForFNum(int fnum);
+void ResetPhong();
diff --git a/include/light/surflight.hh b/include/light/surflight.hh
index 532eeeaf..c04104e6 100644
--- a/include/light/surflight.hh
+++ b/include/light/surflight.hh
@@ -49,6 +49,7 @@ struct surfacelight_t
     bool rescale;
 };
 
+void ResetSurflight();
 std::vector<surfacelight_t> &GetSurfaceLights();
 std::optional<std::tuple<int32_t, int32_t>> IsSurfaceLitFace(const mbsp_t *bsp, const mface_t *face);
 const std::vector<int> &SurfaceLightsForFaceNum(int facenum);
diff --git a/include/light/trace_embree.hh b/include/light/trace_embree.hh
index 219a3eac..05f73115 100644
--- a/include/light/trace_embree.hh
+++ b/include/light/trace_embree.hh
@@ -27,6 +27,7 @@
 #include <common/polylib.hh>
 #include <vector>
 
+void ResetEmbree();
 void Embree_TraceInit(const mbsp_t *bsp);
 hitresult_t Embree_TestSky(const qvec3d &start, const qvec3d &dirn, const modelinfo_t *self, const mface_t **face_out);
 hitresult_t Embree_TestLight(const qvec3d &start, const qvec3d &stop, const modelinfo_t *self);
diff --git a/include/qbsp/qbsp.hh b/include/qbsp/qbsp.hh
index c6dfb87b..a8146475 100644
--- a/include/qbsp/qbsp.hh
+++ b/include/qbsp/qbsp.hh
@@ -368,9 +368,9 @@ struct fmt::formatter<qbsp_plane_t> : formatter<qplane3d>
     template<typename FormatContext>
     auto format(const qbsp_plane_t &p, FormatContext &ctx) -> decltype(ctx.out())
     {
-        format_to(ctx.out(), "<");
-        formatter<qplane3d>::format(p.get_plane(), ctx);
-        format_to(ctx.out(), ", type: {}>", p.get_type());
+        fmt::format_to(ctx.out(), "<");
+        fmt::formatter<qplane3d>::format(p.get_plane(), ctx);
+        fmt::format_to(ctx.out(), ", type: {}>", p.get_type());
         return ctx.out();
     }
 };
diff --git a/light/bounce.cc b/light/bounce.cc
index c74ecce1..974f6723 100644
--- a/light/bounce.cc
+++ b/light/bounce.cc
@@ -44,6 +44,12 @@ mutex bouncelights_lock;
 static std::vector<surfacelight_t> bouncelights;
 static std::atomic_size_t bouncelightpoints;
 
+void ResetBounce()
+{
+    bouncelights.clear();
+    bouncelightpoints = 0;
+}
+
 static bool Face_ShouldBounce(const mbsp_t *bsp, const mface_t *face)
 {
     // make bounce light, only if this face is shadow casting
diff --git a/light/entities.cc b/light/entities.cc
index d413fb0a..637680dd 100644
--- a/light/entities.cc
+++ b/light/entities.cc
@@ -33,6 +33,27 @@ std::vector<std::unique_ptr<light_t>> all_lights;
 std::vector<sun_t> all_suns;
 std::vector<entdict_t> entdicts;
 std::vector<entdict_t> radlights;
+static std::vector<std::pair<std::string, int>> lightstyleForTargetname;
+static std::vector<std::unique_ptr<light_t>> surfacelight_templates;
+static std::ofstream surflights_dump_file;
+static fs::path surflights_dump_filename;
+
+/**
+ * Resets global data in this file
+ */
+void ResetLightEntities()
+{
+    all_lights.clear();
+    all_suns.clear();
+    entdicts.clear();
+    radlights.clear();
+
+    lightstyleForTargetname.clear();
+
+    surfacelight_templates.clear();
+    surflights_dump_file = {};
+    surflights_dump_filename.clear();
+}
 
 std::vector<std::unique_ptr<light_t>> &GetLights()
 {
@@ -104,8 +125,6 @@ void light_t::expandAABB(const qvec3d &pt) { bounds += pt; }
  * ============================================================================
  */
 
-static std::vector<std::pair<std::string, int>> lightstyleForTargetname;
-
 entdict_t &WorldEnt()
 {
     if (entdicts.size() == 0 || entdicts.at(0).get("classname") != "worldspawn") {
@@ -1152,16 +1171,11 @@ void WriteEntitiesToString(const settings::worldspawn_keys &cfg, mbsp_t *bsp)
  * =======================================================================
  */
 
-static std::vector<std::unique_ptr<light_t>> surfacelight_templates;
-
 const std::vector<std::unique_ptr<light_t>> &GetSurfaceLightTemplates()
 {
     return surfacelight_templates;
 }
 
-static std::ofstream surflights_dump_file;
-static fs::path surflights_dump_filename;
-
 static void SurfLights_WriteEntityToFile(light_t *entity, const qvec3d &pos)
 {
     Q_assert(entity->epairs != nullptr);
diff --git a/light/light.cc b/light/light.cc
index 45704665..098c54f6 100644
--- a/light/light.cc
+++ b/light/light.cc
@@ -351,7 +351,14 @@ light_settings::light_settings()
               CheckNoDebugModeSet();
               debugmode = debugmodes::debugneighbours;
           },
-          &debug_group, "save neighboring faces data to lightmap (requires -debugface)"}
+          &debug_group, "save neighboring faces data to lightmap (requires -debugface)"},
+
+      debugmottle{this, "debugmottle",
+          [&](source) {
+              CheckNoDebugModeSet();
+              debugmode = debugmodes::mottle;
+          },
+          &debug_group, "save mottle pattern to lightmap"}
 {
 }
 
@@ -707,10 +714,10 @@ static void FindModelInfo(const mbsp_t *bsp)
 
     float lightmapscale = WorldEnt().get_int("_lightmap_scale");
     if (!lightmapscale)
-        lightmapscale = 16; /* the default */
+        lightmapscale = LMSCALE_DEFAULT; /* the default */
     if (lightmapscale <= 0)
         FError("lightmap scale is 0 or negative\n");
-    if (light_options.lightmap_scale.isChanged() || lightmapscale != 16)
+    if (light_options.lightmap_scale.isChanged() || lightmapscale != LMSCALE_DEFAULT)
         logging::print("Forcing lightmap scale of {}qu\n", lightmapscale);
     /*I'm going to do this check in the hopes that there's a benefit to cheaper scaling in engines (especially software
      * ones that might be able to just do some mip hacks). This tool doesn't really care.*/
@@ -1065,6 +1072,9 @@ static void LoadExtendedTexinfoFlags(const fs::path &sourcefilename, const mbsp_
         if (val.contains("light_ignore")) {
             flags.light_ignore = val.at("light_ignore").get<bool>();
         }
+        if (val.contains("surflight_rescale")) {
+            flags.surflight_rescale = val.at("surflight_rescale").get<bool>();
+        }
         if (val.contains("phong_angle")) {
             flags.phong_angle = val.at("phong_angle").get<vec_t>();
         }
@@ -1458,6 +1468,51 @@ void load_textures(const mbsp_t *bsp)
     }
 }
 
+/**
+ * Resets globals in this file
+ */
+static void ResetLight()
+{
+    dirt_in_use = false;
+    light_surfaces.clear();
+    faces_sup.clear();
+    facesup_decoupled_global.clear();
+
+    filebase.clear();
+    file_p = 0;
+    file_end = 0;
+
+    lit_filebase.clear();
+    lit_file_p = 0;
+    lit_file_end = 0;
+
+    lux_filebase.clear();
+    lux_file_p = 0;
+    lux_file_end = 0;
+
+    modelinfo.clear();
+    tracelist.clear();
+    selfshadowlist.clear();
+    shadowworldonlylist.clear();
+    switchableshadowlist.clear();
+
+    extended_texinfo_flags.clear();
+
+    dump_facenum = -1;
+    dump_vertnum = -1;
+}
+
+void light_reset()
+{
+    ResetBounce();
+    ResetLightEntities();
+    ResetLight();
+    ResetLtFace();
+    ResetPhong();
+    ResetSurflight();
+    ResetEmbree();
+}
+
 /*
  * ==================
  * main
@@ -1466,6 +1521,8 @@ void load_textures(const mbsp_t *bsp)
  */
 int light_main(int argc, const char **argv)
 {
+    light_reset();
+
     bspdata_t bspdata;
 
     light_options.preinitialize(argc, argv);
diff --git a/light/ltface.cc b/light/ltface.cc
index e26d0ad2..1295e48f 100644
--- a/light/ltface.cc
+++ b/light/ltface.cc
@@ -703,7 +703,7 @@ static std::unique_ptr<lightsurf_t> Lightsurf_Init(const modelinfo_t *modelinfo,
     } else {
         lightsurf->extents = faceextents_t(*face, *bsp, lightsurf->lightmapscale);
     }
-    lightsurf->vanilla_extents = faceextents_t(*face, *bsp, 16.0);
+    lightsurf->vanilla_extents = faceextents_t(*face, *bsp, LMSCALE_DEFAULT);
 
     CalcPoints(modelinfo, modelinfo->offset, lightsurf.get(), bsp, face);
 
@@ -1395,6 +1395,110 @@ static void LightFace_Sky(const sun_t *sun, lightsurf_t *lightsurf, lightmapdict
     }
 }
 
+// Mottle
+
+static int mod_round_to_neg_inf(int x, int y) {
+    assert(y > 0);
+    if (x >= 0) {
+        return x % y;
+    }
+    // e.g. with mod_round_to_neg_inf(-7, 3) we want +2
+    const int temp = (-x) % y;
+    return y - temp;
+}
+
+constexpr int mottle_texsize = 256;
+
+/**
+ * integers 0 through 255 shuffled with Python:
+ *
+ * import random
+ * a = list(range(0, 256))
+ * random.shuffle(a)
+ */
+static constexpr uint8_t MottlePermutation256[] = {11, 255, 250, 82, 217, 9, 144, 93, 136, 153, 55, 71, 73, 204, 96,
+    180, 126, 8, 50, 46, 113, 91, 238, 143, 30, 215, 191, 243, 65, 58, 208, 33, 86, 1, 182, 118, 83, 115, 207, 52, 94,
+    112, 205, 48, 99, 254, 117, 101, 157, 140, 72, 242, 244, 154, 10, 135, 155, 168, 125, 183, 148, 116, 187, 166, 25,
+    156, 177, 231, 165, 57, 221, 105, 28, 211, 127, 41, 142, 253, 146, 87, 122, 229, 162, 137, 194, 174, 167, 15, 220,
+    26, 235, 3, 39, 80, 88, 42, 202, 12, 97, 53, 70, 123, 170, 110, 214, 192, 173, 84, 169, 188, 64, 102, 147, 158, 100,
+    69, 213, 193, 43, 20, 13, 237, 171, 103, 32, 190, 223, 150, 131, 206, 85, 124, 163, 18, 139, 132, 79, 29, 216, 232,
+    178, 74, 24, 141, 201, 181, 152, 4, 7, 159, 134, 212, 226, 245, 164, 239, 47, 66, 27, 40, 197, 81, 78, 219, 228,
+    241, 121, 23, 120, 230, 76, 252, 199, 184, 45, 203, 161, 89, 16, 21, 119, 5, 209, 196, 68, 130, 195, 176, 225, 233,
+    128, 22, 248, 179, 249, 61, 108, 138, 145, 31, 49, 107, 56, 172, 224, 210, 6, 160, 189, 104, 200, 44, 175, 133, 77,
+    62, 106, 92, 186, 227, 14, 38, 247, 37, 17, 222, 36, 75, 129, 185, 251, 240, 54, 151, 2, 98, 149, 0, 63, 218, 60,
+    198, 19, 59, 90, 246, 234, 67, 51, 109, 95, 236, 35, 34, 114, 111};
+
+/**
+ * Return a noise texture value from 0-47.
+ *
+ * Vanilla Q2 tools just called (rand() % 48) per-luxel, which generates seams
+ * and scales in size with lightmap scale.
+ *
+ * Replacement code uses "value noise", generating a tiling 3D texture
+ * in world space.
+ */
+static float Mottle(const qvec3d &position)
+{
+#if 0
+    return rand() % 48;
+#else
+    const float world_to_tex = 1/16.0f;
+
+    qvec3d texspace_pos = position * world_to_tex;
+
+    int coord_floor_x = static_cast<int>(floor(texspace_pos[0]));
+    int coord_floor_y = static_cast<int>(floor(texspace_pos[1]));
+    int coord_floor_z = static_cast<int>(floor(texspace_pos[2]));
+
+    float coord_frac_x = static_cast<float>(texspace_pos[0] - coord_floor_x);
+    float coord_frac_y = static_cast<float>(texspace_pos[1] - coord_floor_y);
+    float coord_frac_z = static_cast<float>(texspace_pos[2] - coord_floor_z);
+
+    assert(coord_frac_x >= 0 && coord_frac_x <= 1);
+    assert(coord_frac_y >= 0 && coord_frac_y <= 1);
+    assert(coord_frac_z >= 0 && coord_frac_z <= 1);
+
+    coord_floor_x = mod_round_to_neg_inf(coord_floor_x, mottle_texsize);
+    coord_floor_y = mod_round_to_neg_inf(coord_floor_y, mottle_texsize);
+    coord_floor_z = mod_round_to_neg_inf(coord_floor_z, mottle_texsize);
+
+    assert(coord_floor_x >= 0 && coord_floor_x < mottle_texsize);
+    assert(coord_floor_y >= 0 && coord_floor_y < mottle_texsize);
+    assert(coord_floor_z >= 0 && coord_floor_z < mottle_texsize);
+
+    // look up sample in the 3d texture at an integer coordinate
+    auto tex = [](int x, int y, int z) -> uint8_t {
+        int v;
+        v = MottlePermutation256[x % 256];
+        v = MottlePermutation256[(v + y) % 256];
+        v = MottlePermutation256[(v + z) % 256];
+        return v;
+    };
+
+    // 3D bilinear interpolation
+    float res = mix(
+        mix(
+            mix(tex(coord_floor_x, coord_floor_y, coord_floor_z),
+                tex(coord_floor_x + 1, coord_floor_y, coord_floor_z),
+                coord_frac_x),
+            mix(tex(coord_floor_x, coord_floor_y + 1, coord_floor_z),
+                tex(coord_floor_x + 1, coord_floor_y + 1, coord_floor_z),
+                coord_frac_x),
+            coord_frac_y),
+        mix(
+            mix(tex(coord_floor_x, coord_floor_y, coord_floor_z + 1),
+                tex(coord_floor_x + 1, coord_floor_y, coord_floor_z + 1),
+                coord_frac_x),
+            mix(tex(coord_floor_x, coord_floor_y + 1, coord_floor_z + 1),
+                tex(coord_floor_x + 1, coord_floor_y + 1, coord_floor_z + 1),
+                coord_frac_x),
+            coord_frac_y),
+        coord_frac_z);
+
+    return (res / 255.0f) * 48.0f;
+#endif
+}
+
 /*
  * ============
  * LightFace_Min
@@ -1425,7 +1529,7 @@ static void LightFace_Min(const mbsp_t *bsp, const mface_t *face, const qvec3d &
             sample.color += color * (value / 255.0);
         } else {
             if (lightsurf->minlightMottle) {
-                value += rand() % 48;
+                value += Mottle(lightsurf->points[i]);
             }
             Light_ClampMin(sample, value, color);
         }
@@ -1563,6 +1667,23 @@ static void LightFace_PhongDebug(const lightsurf_t *lightsurf, lightmapdict_t *l
     Lightmap_Save(lightmaps, lightsurf, lightmap, 0);
 }
 
+static void LightFace_DebugMottle(const lightsurf_t *lightsurf, lightmapdict_t *lightmaps)
+{
+    /* use a style 0 light map */
+    lightmap_t *lightmap = Lightmap_ForStyle(lightmaps, 0, lightsurf);
+
+    /* Overwrite each point with the mottle noise for that sample... */
+    for (int i = 0; i < lightsurf->points.size(); i++) {
+        lightsample_t &sample = lightmap->samples[i];
+        // mottle is meant to be applied on top of minlight, so add some here
+        // for preview purposes.
+        const float minlight = 20.0f;
+        sample.color = qvec3f(minlight + Mottle(lightsurf->points[i]));
+    }
+
+    Lightmap_Save(lightmaps, lightsurf, lightmap, 0);
+}
+
 // mxd. Surface light falloff. Returns color in [0,255]
 inline qvec3f SurfaceLight_ColorAtDist(
     const settings::worldspawn_keys &cfg, const float &surf_scale, const float &intensity, const qvec3d &color, const float &dist, const float &hotspot_clamp)
@@ -1832,6 +1953,7 @@ void SetupDirt(settings::worldspawn_keys &cfg)
 
     /* iterate angle */
     float angle = 0.0f;
+    numDirtVectors = 0;
     for (int i = 0; i < DIRT_NUM_ANGLE_STEPS; i++, angle += angleStep) {
         /* iterate elevation */
         float elevation = elevationStep * 0.5f;
@@ -2534,6 +2656,80 @@ static void WriteSingleLightmap(const mbsp_t *bsp, const mface_t *face, const li
     }
 }
 
+/**
+ * - Writes (output_width * output_height) bytes to `out`
+ * - Writes (output_width * output_height * 3) bytes to `lit`
+ * - Writes (output_width * output_height * 3) bytes to `lux`
+ */
+static void WriteSingleLightmap_FromDecoupled(const mbsp_t *bsp, const mface_t *face, const lightsurf_t *lightsurf,
+    const lightmap_t *lm, const int output_width, const int output_height, uint8_t *out, uint8_t *lit, uint8_t *lux)
+{
+    // this is the lightmap data in the "decoupled" coordinate system
+    std::vector<qvec4f> fullres = LightmapColorsToGLMVector(lightsurf, lm);
+
+    // maps a luxel in the vanilla lightmap to the corresponding position in the decoupled lightmap
+    const qmat4x4f vanillaLMToDecoupled = lightsurf->extents.worldToLMMatrix * lightsurf->vanilla_extents.lmToWorldMatrix;
+
+    // samples the "decoupled" lightmap at an integer coordinate, with clamping
+    auto tex = [&lightsurf, &fullres](int x, int y) -> qvec4f {
+        const int x_clamped = clamp(x, 0, lightsurf->width - 1);
+        const int y_clamped = clamp(y, 0, lightsurf->height - 1);
+
+        const int sampleindex = (y_clamped * lightsurf->width) + x_clamped;
+        assert(sampleindex >= 0);
+        assert(sampleindex < fullres.size());
+
+        return fullres[sampleindex];
+    };
+
+    for (int t = 0; t < output_height; t++) {
+        for (int s = 0; s < output_width; s++) {
+            // convert from vanilla lm coord to decoupled lm coord
+            qvec2f decoupled_lm_coord = vanillaLMToDecoupled * qvec4f(s, t, 0, 1);
+
+            decoupled_lm_coord = decoupled_lm_coord * light_options.extra.value();
+
+            // split into integer/fractional part for bilinear interpolation
+            const int coord_floor_x = (int)decoupled_lm_coord[0];
+            const int coord_floor_y = (int)decoupled_lm_coord[1];
+
+            const float coord_frac_x = decoupled_lm_coord[0] - coord_floor_x;
+            const float coord_frac_y = decoupled_lm_coord[1] - coord_floor_y;
+
+            // 2D bilinear interpolation
+            const qvec4f color =
+                mix(
+                    mix(tex(coord_floor_x, coord_floor_y),
+                        tex(coord_floor_x + 1, coord_floor_y),
+                        coord_frac_x),
+                    mix(tex(coord_floor_x, coord_floor_y + 1),
+                        tex(coord_floor_x + 1, coord_floor_y + 1),
+                        coord_frac_x),
+                    coord_frac_y);
+
+            if (lit || out) {
+                if (lit) {
+                    *lit++ = color[0];
+                    *lit++ = color[1];
+                    *lit++ = color[2];
+                }
+
+                if (out) {
+                    // FIXME: implement
+                    *out++ = 0;
+                }
+            }
+
+            if (lux) {
+                // FIXME: implement
+                *lux++ = 0;
+                *lux++ = 0;
+                *lux++ = 0;
+            }
+        }
+    }
+}
+
 void SaveLightmapSurface(const mbsp_t *bsp, mface_t *face, facesup_t *facesup,
     bspx_decoupled_lm_perface *facesup_decoupled, lightsurf_t *lightsurf, const faceextents_t &extents,
     const faceextents_t &output_extents)
@@ -2726,13 +2922,13 @@ void SaveLightmapSurface(const mbsp_t *bsp, mface_t *face, facesup_t *facesup,
         lightofs = out - filebase.data();
     }
 
-    if (facesup) {
+    if (facesup_decoupled) {
+        facesup_decoupled->offset = lightofs;
+        face->lightofs = -1;
+    } else if (facesup) {
         facesup->lightofs = lightofs;
     } else {
         face->lightofs = lightofs;
-        if (facesup_decoupled) {
-            facesup_decoupled->offset = lightofs;
-        }
     }
 
     // sanity check that we don't save a lightmap for a non-lightmapped face
@@ -2758,6 +2954,37 @@ void SaveLightmapSurface(const mbsp_t *bsp, mface_t *face, facesup_t *facesup,
             lux += (size * 3);
         }
     }
+
+    // write vanilla lightmap if -world_units_per_luxel is in use but not -novanilla
+    if (facesup_decoupled && !light_options.novanilla.value()) {
+        // FIXME: duplicates some code from above
+        GetFileSpace(&out, &lit, &lux, lightsurf->vanilla_extents.numsamples() * numstyles);
+
+        // Q2/HL native colored lightmaps
+        if (bsp->loadversion->game->has_rgb_lightmap) {
+            lightofs = lit - lit_filebase.data();
+        } else {
+            lightofs = out - filebase.data();
+        }
+        face->lightofs = lightofs;
+
+        for (int mapnum = 0; mapnum < numstyles; mapnum++) {
+            const lightmap_t *lm = sorted.at(mapnum);
+
+            WriteSingleLightmap_FromDecoupled(bsp, face, lightsurf, lm, lightsurf->vanilla_extents.width(),
+                lightsurf->vanilla_extents.height(), out, lit, lux);
+
+            if (out) {
+                out += lightsurf->vanilla_extents.numsamples();
+            }
+            if (lit) {
+                lit += (lightsurf->vanilla_extents.numsamples() * 3);
+            }
+            if (lux) {
+                lux += (lightsurf->vanilla_extents.numsamples() * 3);
+            }
+        }
+    }
 }
 
 std::unique_ptr<lightsurf_t> CreateLightmapSurface(const mbsp_t *bsp, const mface_t *face, const facesup_t *facesup,
@@ -2888,6 +3115,9 @@ void DirectLightFace(const mbsp_t *bsp, lightsurf_t &lightsurf, const settings::
 
     if (light_options.debugmode == debugmodes::debugneighbours)
         LightFace_DebugNeighbours(&lightsurf, lightmaps);
+
+    if (light_options.debugmode == debugmodes::mottle)
+        LightFace_DebugMottle(&lightsurf, lightmaps);
 }
 
 /*
@@ -2913,3 +3143,20 @@ void IndirectLightFace(const mbsp_t *bsp, lightsurf_t &lightsurf, const settings
         }
     }
 }
+
+void ResetLtFace()
+{
+    total_light_rays = 0;
+    total_light_ray_hits = 0;
+    total_samplepoints = 0;
+
+    total_bounce_rays = 0;
+    total_bounce_ray_hits = 0;
+    total_surflight_rays = 0;
+    total_surflight_ray_hits = 0;
+
+    fully_transparent_lightmaps = 0;
+
+    warned_about_light_map_overflow = false;
+    warned_about_light_style_overflow = false;
+}
diff --git a/light/phong.cc b/light/phong.cc
index 24e57edb..e9d793ef 100644
--- a/light/phong.cc
+++ b/light/phong.cc
@@ -182,6 +182,17 @@ static map<int, vector<const mface_t *>> planesToFaces;
 static edgeToFaceMap_t EdgeToFaceMap;
 static vector<face_cache_t> FaceCache;
 
+void ResetPhong()
+{
+    s_builtPhongCaches = false;
+    vertex_normals = {};
+    smoothFaces = {};
+    vertsToFaces = {};
+    planesToFaces = {};
+    EdgeToFaceMap = {};
+    FaceCache = {};
+}
+
 vector<const mface_t *> FacesUsingVert(int vertnum)
 {
     const auto &vertsToFaces_const = vertsToFaces;
diff --git a/light/surflight.cc b/light/surflight.cc
index 904a62ed..0436022f 100644
--- a/light/surflight.cc
+++ b/light/surflight.cc
@@ -42,6 +42,13 @@ static std::vector<surfacelight_t> surfacelights;
 static std::map<int, std::vector<int>> surfacelightsByFacenum;
 static size_t total_surflight_points = 0;
 
+void ResetSurflight()
+{
+    surfacelights = {};
+    surfacelightsByFacenum = {};
+    total_surflight_points = {};
+}
+
 std::vector<surfacelight_t> &GetSurfaceLights()
 {
     return surfacelights;
@@ -54,6 +61,8 @@ static void MakeSurfaceLight(const mbsp_t *bsp, const settings::worldspawn_keys
     auto poly = GLM_FacePoints(bsp, face);
     const float facearea = qv::PolyArea(poly.begin(), poly.end());
 
+    const surfflags_t &extended_flags = extended_texinfo_flags[face->texinfo];
+
     // Avoid small, or zero-area faces
     if (facearea < 1)
         return;
@@ -108,7 +117,7 @@ static void MakeSurfaceLight(const mbsp_t *bsp, const settings::worldspawn_keys
     l.omnidirectional = !is_directional;
     l.points = std::move(points);
     l.style = style;
-    l.rescale = true;
+    l.rescale = extended_flags.surflight_rescale;
 
     // Init bbox...
     if (light_options.visapprox.value() == visapprox_t::RAYS) {
diff --git a/light/trace_embree.cc b/light/trace_embree.cc
index 9290171c..65766ead 100644
--- a/light/trace_embree.cc
+++ b/light/trace_embree.cc
@@ -32,6 +32,30 @@ sceneinfo skygeom; // sky. always occludes.
 sceneinfo solidgeom; // solids. always occludes.
 sceneinfo filtergeom; // conditional occluders.. needs to run ray intersection filter
 
+static RTCDevice device;
+RTCScene scene;
+
+static const mbsp_t *bsp_static;
+
+void ResetEmbree()
+{
+    skygeom = {};
+    solidgeom = {};
+    filtergeom = {};
+
+    if (scene) {
+        rtcReleaseScene(scene);
+        scene = nullptr;
+    }
+
+    if (device) {
+        rtcReleaseDevice(device);
+        device = nullptr;
+    }
+
+    bsp_static = nullptr;
+}
+
 /**
  * Returns 1.0 unless a custom alpha value is set.
  * The priority is: "_light_alpha" (read from extended_texinfo_flags), then "alpha", then Q2 surface flags
@@ -229,11 +253,6 @@ static void CreateGeometryFromWindings(RTCDevice g_device, RTCScene scene, const
     rtcCommitGeometry(geom_1);
 }
 
-RTCDevice device;
-RTCScene scene;
-
-static const mbsp_t *bsp_static;
-
 void ErrorCallback(void *userptr, const RTCError code, const char *str)
 {
     fmt::print("RTC Error {}: {}\n", code, str);
diff --git a/qbsp/brush.cc b/qbsp/brush.cc
index 9e8f0217..f5f383db 100644
--- a/qbsp/brush.cc
+++ b/qbsp/brush.cc
@@ -779,31 +779,24 @@ static void Brush_LoadEntity(mapentity_t &dst, mapentity_t &src, hull_index_t hu
 
         /* entities in some games never use water merging */
         if (!map.is_world_entity(dst) && !qbsp_options.target_game->allow_contented_bmodels) {
-            contents = qbsp_options.target_game->create_solid_contents();
+            // bmodels become solid in Q1
 
-            /* Hack to turn bmodels with "_mirrorinside" into func_detail_fence in hull 0.
-                this is to allow "_mirrorinside" to work on func_illusionary, func_wall, etc.
-                Otherwise they would be CONTENTS_SOLID and the inside faces would be deleted.
-
-                It's CONTENTS_DETAIL_FENCE because this gets mapped to CONTENTS_SOLID just
-                before writing the bsp, and bmodels normally have CONTENTS_SOLID as their
-                contents type.
-                */
-            if (!hullnum.value_or(0) && contents.is_mirrored(qbsp_options.target_game)) {
-                contents = qbsp_options.target_game->create_detail_fence_contents(contents);
-            }
+            // to allow use of _mirrorinside, we'll set it to detail fence, which will get remapped back
+            // to CONTENTS_SOLID at export. (we wouldn't generate inside faces if the content was CONTENTS_SOLID
+            // from the start.)
+            contents = qbsp_options.target_game->create_detail_fence_contents(qbsp_options.target_game->create_solid_contents());
         }
 
         if (hullnum.value_or(0)) {
             /* nonsolid brushes don't show up in clipping hulls */
-            if (!contents.is_any_solid(qbsp_options.target_game) && !contents.is_sky(qbsp_options.target_game)) {
+            if (!contents.is_any_solid(qbsp_options.target_game)
+                && !contents.is_sky(qbsp_options.target_game)
+                && !contents.is_fence(qbsp_options.target_game)) {
                 continue;
             }
 
-            /* sky brushes are solid in the collision hulls */
-            if (contents.is_sky(qbsp_options.target_game)) {
-                contents = qbsp_options.target_game->create_solid_contents();
-            }
+            /* all used brushes are solid in the collision hulls */
+            contents = qbsp_options.target_game->create_solid_contents();
         }
 
         // fixme-brushbsp: function calls above can override the values below
diff --git a/qbsp/map.cc b/qbsp/map.cc
index 8c428b9b..769c3e91 100644
--- a/qbsp/map.cc
+++ b/qbsp/map.cc
@@ -576,6 +576,8 @@ static surfflags_t SurfFlagsForEntity(const maptexinfo_t &texinfo, const mapenti
         flags.no_minlight = true;
     if (entity.epairs.get_int("_lightignore") == 1)
         flags.light_ignore = true;
+    if (entity.epairs.has("_surflight_rescale") && entity.epairs.get_int("_surflight_rescale") == 0)
+        flags.surflight_rescale = false;
 
     // "_minlight_exclude", "_minlight_exclude2", "_minlight_exclude3"...
     for (int i = 0; i <= 9; i++) {
diff --git a/qbsp/portals.cc b/qbsp/portals.cc
index 98727fd5..9c44ada1 100644
--- a/qbsp/portals.cc
+++ b/qbsp/portals.cc
@@ -770,7 +770,7 @@ void EmitAreaPortals(node_t *headnode)
 
 struct visible_faces_stats_t : logging::stat_tracker_t
 {
-    stat &sides_not_found = register_stat("sides not found", false, true);
+    stat &sides_not_found = register_stat("sides not found (use -verbose to display)", false, true);
     stat &sides_visible = register_stat("sides visible");
 };
 
@@ -870,6 +870,7 @@ static void FindPortalSide(portal_t *p, visible_faces_stats_t &stats)
 
     if (!bestside[0] && !bestside[1]) {
         stats.sides_not_found++;
+        logging::print(logging::flag::VERBOSE, "couldn't find portal side at {}\n", p->winding.center());
     }
 
     p->sidefound = true;
diff --git a/qbsp/writebsp.cc b/qbsp/writebsp.cc
index 8574b339..297e4323 100644
--- a/qbsp/writebsp.cc
+++ b/qbsp/writebsp.cc
@@ -368,6 +368,9 @@ static void WriteExtendedTexinfoFlags(void)
         if (tx.flags.light_ignore) {
             t["light_ignore"] = tx.flags.light_ignore;
         }
+        if (tx.flags.surflight_rescale == false) {
+            t["surflight_rescale"] = tx.flags.surflight_rescale;
+        }
         if (tx.flags.phong_angle) {
             t["phong_angle"] = tx.flags.phong_angle;
         }
diff --git a/testmaps/light_q2_emissive_cube.map b/testmaps/light_q2_emissive_cube.map
new file mode 100644
index 00000000..49891712
--- /dev/null
+++ b/testmaps/light_q2_emissive_cube.map
@@ -0,0 +1,82 @@
+// Game: Quake 2
+// Format: Quake2 (Valve)
+// entity 0
+{
+"classname" "worldspawn"
+"_tb_textures" "textures/e1u1"
+"_bounce" "0"
+// brush 0
+{
+( 928 -1072 880 ) ( 928 -1504 880 ) ( 928 -1504 864 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 928 -1504 880 ) ( 1120 -1504 880 ) ( 1120 -1504 864 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1504 864 ) ( 1120 -1072 864 ) ( 928 -1072 864 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 928 -1072 880 ) ( 1120 -1072 880 ) ( 1120 -1504 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 1120 -1072 864 ) ( 1120 -1072 880 ) ( 928 -1072 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1504 880 ) ( 1120 -1072 880 ) ( 1120 -1072 864 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+}
+// brush 1
+{
+( 928 -1072 1040 ) ( 928 -1504 1040 ) ( 928 -1504 1024 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 928 -1504 1040 ) ( 1120 -1504 1040 ) ( 1120 -1504 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1504 1024 ) ( 1120 -1072 1024 ) ( 928 -1072 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 928 -1072 1040 ) ( 1120 -1072 1040 ) ( 1120 -1504 1040 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 1120 -1072 1024 ) ( 1120 -1072 1040 ) ( 928 -1072 1040 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1504 1040 ) ( 1120 -1072 1040 ) ( 1120 -1072 1024 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+}
+// brush 2
+{
+( 1120 -1072 1024 ) ( 1120 -1504 1024 ) ( 1120 -1504 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1504 1024 ) ( 1136 -1504 1024 ) ( 1136 -1504 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1136 -1504 880 ) ( 1136 -1072 880 ) ( 1120 -1072 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 1120 -1072 1024 ) ( 1136 -1072 1024 ) ( 1136 -1504 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 1136 -1072 880 ) ( 1136 -1072 1024 ) ( 1120 -1072 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1136 -1504 1024 ) ( 1136 -1072 1024 ) ( 1136 -1072 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+}
+// brush 3
+{
+( 928 -1072 1024 ) ( 928 -1504 1024 ) ( 928 -1504 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 928 -1504 1024 ) ( 944 -1504 1024 ) ( 944 -1504 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 944 -1504 880 ) ( 944 -1072 880 ) ( 928 -1072 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 928 -1072 1024 ) ( 944 -1072 1024 ) ( 944 -1504 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 944 -1072 880 ) ( 944 -1072 1024 ) ( 928 -1072 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 944 -1504 1024 ) ( 944 -1072 1024 ) ( 944 -1072 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+}
+// brush 4
+{
+( 944 -1072 1024 ) ( 944 -1088 1024 ) ( 944 -1088 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 944 -1088 1024 ) ( 1120 -1088 1024 ) ( 1120 -1088 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1088 880 ) ( 1120 -1072 880 ) ( 944 -1072 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 944 -1072 1024 ) ( 1120 -1072 1024 ) ( 1120 -1088 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 1120 -1072 880 ) ( 1120 -1072 1024 ) ( 944 -1072 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1120 -1088 1024 ) ( 1120 -1072 1024 ) ( 1120 -1072 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+}
+// brush 5
+{
+( 936 -1504 1024 ) ( 936 -1520 1024 ) ( 936 -1520 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 936 -1520 1024 ) ( 1112 -1520 1024 ) ( 1112 -1520 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1112 -1520 880 ) ( 1112 -1504 880 ) ( 936 -1504 880 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 936 -1504 1024 ) ( 1112 -1504 1024 ) ( 1112 -1520 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 0 0
+( 1112 -1504 880 ) ( 1112 -1504 1024 ) ( 936 -1504 1024 ) e1u1/box3_7 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+( 1112 -1520 1024 ) ( 1112 -1504 1024 ) ( 1112 -1504 880 ) e1u1/box3_7 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 0 0
+}
+}
+// entity 1
+{
+"classname" "info_player_start"
+"origin" "1040 -1184 904"
+"angle" "270"
+}
+// entity 2
+{
+"classname" "func_group"
+"_surflight_rescale" "0"
+// brush 0
+{
+( 968 -1264 992 ) ( 968 -1464 992 ) ( 968 -1464 904 ) e1u1/box3_6 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 1 100
+( 968 -1464 992 ) ( 1104 -1464 992 ) ( 1104 -1464 904 ) e1u1/box3_6 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 1 100
+( 1104 -1464 904 ) ( 1104 -1264 904 ) ( 968 -1264 904 ) e1u1/box3_6 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 1 100
+( 968 -1264 992 ) ( 1104 -1264 992 ) ( 1104 -1464 992 ) e1u1/box3_6 [ 1 0 0 0 ] [ 0 -1 0 0 ] 0 1 1 0 1 100
+( 1104 -1264 904 ) ( 1104 -1264 992 ) ( 968 -1264 992 ) e1u1/box3_6 [ 1 0 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 1 100
+( 1104 -1464 992 ) ( 1104 -1264 992 ) ( 1104 -1264 904 ) e1u1/box3_6 [ 0 1 0 0 ] [ 0 0 -1 0 ] 0 1 1 0 1 100
+}
+}
diff --git a/testmaps/q2_lightmap_custom_scale.map b/testmaps/q2_lightmap_custom_scale.map
index 6ce8e512..91d70052 100644
--- a/testmaps/q2_lightmap_custom_scale.map
+++ b/testmaps/q2_lightmap_custom_scale.map
@@ -977,3 +977,10 @@
 "origin" "-398 -160 94"
 "light" "1200"
 }
+// entity 7
+{
+"classname" "light"
+"origin" "232 -248 104"
+"style" "1"
+"_color" "183 255 227"
+}
diff --git a/testmaps/qbsp_bmodel_mirrorinside_with_liquid.map b/testmaps/qbsp_bmodel_mirrorinside_with_liquid.map
new file mode 100644
index 00000000..d35519ba
--- /dev/null
+++ b/testmaps/qbsp_bmodel_mirrorinside_with_liquid.map
@@ -0,0 +1,97 @@
+// Game: Quake
+// Format: Valve
+// entity 0
+{
+"mapversion" "220"
+"classname" "worldspawn"
+"wad" "deprecated/free_wad.wad;deprecated/fence.wad;deprecated/origin.wad;deprecated/hintskip.wad"
+"_wateralpha" "0.5"
+"_tb_def" "builtin:Quake.fgd"
+// brush 0
+{
+( -112 -112 96 ) ( -112 -111 96 ) ( -112 -112 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -272 80 ) ( -81 -272 80 ) ( -80 -272 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -432 80 ) ( -80 -431 80 ) ( -81 -432 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -112 96 ) ( -161 -112 96 ) ( -160 -111 96 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 0 96 ) ( -160 0 97 ) ( -161 0 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -432 80 ) ( 64 -432 81 ) ( 64 -431 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 1
+{
+( -112 -96 96 ) ( -112 -95 96 ) ( -112 -96 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 0 80 ) ( -81 0 80 ) ( -80 0 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -416 80 ) ( -80 -415 80 ) ( -81 -416 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -96 224 ) ( -161 -96 224 ) ( -160 -95 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 16 96 ) ( -160 16 97 ) ( -161 16 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -416 80 ) ( 64 -416 81 ) ( 64 -415 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 2
+{
+( -112 -384 96 ) ( -112 -383 96 ) ( -112 -384 97 ) orangestuff8 [ 0 1 0 8 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -288 80 ) ( -81 -288 80 ) ( -80 -288 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -704 80 ) ( -80 -703 80 ) ( -81 -704 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 -8 ] 180 2 2
+( -160 -384 224 ) ( -161 -384 224 ) ( -160 -383 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 -8 ] 180 2 2
+( -160 -272 96 ) ( -160 -272 97 ) ( -161 -272 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -704 80 ) ( 64 -704 81 ) ( 64 -703 80 ) orangestuff8 [ 0 -1 0 -8 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 3
+{
+( -128 -112 96 ) ( -128 -111 96 ) ( -128 -112 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -256 -272 80 ) ( -257 -272 80 ) ( -256 -272 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -256 -432 80 ) ( -256 -431 80 ) ( -257 -432 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -336 -112 224 ) ( -337 -112 224 ) ( -336 -111 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -336 0 96 ) ( -336 0 97 ) ( -337 0 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( -112 -432 80 ) ( -112 -432 81 ) ( -112 -431 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 4
+{
+( 64 -112 96 ) ( 64 -111 96 ) ( 64 -112 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -64 -272 80 ) ( -65 -272 80 ) ( -64 -272 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -64 -432 80 ) ( -64 -431 80 ) ( -65 -432 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -144 -112 224 ) ( -145 -112 224 ) ( -144 -111 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -144 0 96 ) ( -144 0 97 ) ( -145 0 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 80 -432 80 ) ( 80 -432 81 ) ( 80 -431 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 5
+{
+( -112 -112 240 ) ( -112 -111 240 ) ( -112 -112 241 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -272 224 ) ( -81 -272 224 ) ( -80 -272 225 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -432 224 ) ( -80 -431 224 ) ( -81 -432 224 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -112 240 ) ( -161 -112 240 ) ( -160 -111 240 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 0 240 ) ( -160 0 241 ) ( -161 0 240 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -432 224 ) ( 64 -432 225 ) ( 64 -431 224 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+}
+// entity 1
+{
+"classname" "info_player_start"
+"origin" "-88 -64 120"
+}
+// entity 2
+{
+"classname" "func_wall"
+"_mirrorinside" "1"
+// brush 0
+{
+( -16 -76 112 ) ( -16 -75 112 ) ( -16 -76 113 ) {trigger [ 0 -1 0 -16 ] [ 0 0 -1 16 ] 0 1 1
+( -8 -80 112 ) ( -8 -80 113 ) ( -7 -80 112 ) {trigger [ 1 0 0 16 ] [ 0 0 -1 16 ] 0 1 1
+( -8 -76 112 ) ( -7 -76 112 ) ( -8 -75 112 ) {trigger [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 0 1 1
+( 56 -28 208 ) ( 56 -27 208 ) ( 57 -28 208 ) {trigger [ 1 0 0 16 ] [ 0 -1 0 -16 ] 0 1 1
+( 56 -32 128 ) ( 57 -32 128 ) ( 56 -32 129 ) {trigger [ -1 0 0 -16 ] [ 0 0 -1 16 ] 0 1 1
+( 32 -28 128 ) ( 32 -28 129 ) ( 32 -27 128 ) {trigger [ 0 1 0 16 ] [ 0 0 -1 16 ] 0 1 1
+}
+}
+// entity 3
+{
+"classname" "func_wall"
+"_mirrorinside" "1"
+// brush 0
+{
+( -16 -140 112 ) ( -16 -139 112 ) ( -16 -140 113 ) *swater4 [ 0 -1 0 -16 ] [ 0 0 -1 16 ] 0 1 1
+( -8 -144 112 ) ( -8 -144 113 ) ( -7 -144 112 ) *swater4 [ 1 0 0 16 ] [ 0 0 -1 16 ] 0 1 1
+( -8 -140 112 ) ( -7 -140 112 ) ( -8 -139 112 ) *swater4 [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 0 1 1
+( 56 -92 208 ) ( 56 -91 208 ) ( 57 -92 208 ) *swater4 [ 1 0 0 16 ] [ 0 -1 0 -16 ] 0 1 1
+( 56 -96 128 ) ( 57 -96 128 ) ( 56 -96 129 ) *swater4 [ -1 0 0 -16 ] [ 0 0 -1 16 ] 0 1 1
+( 32 -92 128 ) ( 32 -92 129 ) ( 32 -91 128 ) *swater4 [ 0 1 0 16 ] [ 0 0 -1 16 ] 0 1 1
+}
+}
diff --git a/tests/test_light.cc b/tests/test_light.cc
index 710b79d8..f9c9c9d9 100644
--- a/tests/test_light.cc
+++ b/tests/test_light.cc
@@ -188,7 +188,7 @@ TEST_CASE("PolygonCentroid")
     const std::initializer_list<qvec3d> poly{{0, 0, 0}, {0, 32, 0}, // colinear
         {0, 64, 0}, {64, 64, 0}, {64, 0, 0}};
 
-    CHECK(qvec3f(32, 32, 0) == qv::PolyCentroid(poly.begin(), poly.end()));
+    CHECK(qvec3d(32, 32, 0) == qv::PolyCentroid(poly.begin(), poly.end()));
 }
 
 TEST_CASE("PolygonArea")
diff --git a/tests/test_ltface.cc b/tests/test_ltface.cc
index b81f0ce9..2ef5aba9 100644
--- a/tests/test_ltface.cc
+++ b/tests/test_ltface.cc
@@ -5,7 +5,12 @@
 #include <qbsp/qbsp.hh>
 #include <testmaps.hh>
 
-static void LoadTestmap(const std::filesystem::path &name, std::vector<std::string> extra_args)
+struct testresults_t {
+    mbsp_t bsp;
+    bspxentries_t bspx;
+};
+
+static testresults_t LoadTestmap(const std::filesystem::path &name, std::vector<std::string> extra_args)
 {
     auto map_path = std::filesystem::path(testmaps_dir) / name;
 
@@ -52,9 +57,93 @@ static void LoadTestmap(const std::filesystem::path &name, std::vector<std::stri
         // write to .json for inspection
         serialize_bsp(bspdata, std::get<mbsp_t>(bspdata.bsp),
             fs::path(qbsp_options.bsp_path).replace_extension(".bsp.json"));
+
+        return {std::move(std::get<mbsp_t>(bspdata.bsp)),
+                std::move(bspdata.bspx.entries)};
     }
 }
 
-TEST_CASE("TestLight") {
-    LoadTestmap("q2_lightmap_custom_scale.map", {"-threads", "1", "-extra", "-world_units_per_luxel", "8"});
+TEST_CASE("-world_units_per_luxel") {
+    LoadTestmap("q2_lightmap_custom_scale.map", {"-world_units_per_luxel", "8"});
+}
+
+TEST_CASE("emissive cube artifacts") {
+    // A cube with surface flags "light", value "100", placed in a hallway.
+    //
+    // Generates harsh lines on the walls/ceiling due to a hack in `light` allowing
+    // surface lights to emit 50% at 90 degrees off their surface normal (when physically it should be 0%).
+    //
+    // It's wanted in some cases (base1.map sewer lights flush with the wall, desired for them to
+    // emit some lights on to their adjacent wall faces.)
+    //
+    // To disable the behaviour in this case with the cube lighting a hallway we have a entity key:
+    //
+    //     "_surflight_rescale" "0"
+    //
+    auto [bsp, bspx] = LoadTestmap("light_q2_emissive_cube.map", {"-threads", "1", "-world_units_per_luxel", "4", "-novanilla"});
+
+    const auto start = qvec3d{1044, -1244, 880};
+    const auto end = qvec3d{1044, -1272, 880};
+
+    auto *floor = BSP_FindFaceAtPoint(&bsp, &bsp.dmodels[0], start, {0, 0, 1});
+    auto lm_info = BSPX_DecoupledLM(bspx, Face_GetNum(&bsp, floor));
+
+    const faceextents_t extents(*floor, bsp, lm_info.lmwidth, lm_info.lmheight, lm_info.world_to_lm_space);
+
+    // sample the lightmap along the floor, approaching the glowing cube
+    // should get brighter
+    qvec3b previous_sample{};
+    for (int y = start[1]; y >= end[1]; y -= 4) {
+        qvec3d pos = start;
+        pos[1] = y;
+
+        auto lm_coord = extents.worldToLMCoord(pos);
+
+        auto sample = LM_Sample(&bsp, extents, lm_info.offset, lm_coord);
+        CHECK(sample[0] >= previous_sample[0]);
+
+        //logging::print("world: {} lm_coord: {} sample: {} lm size: {}x{}\n", pos, lm_coord, sample, lm_info.lmwidth, lm_info.lmheight);
+
+        previous_sample = sample;
+    }
+}
+
+TEST_CASE("-novanilla + -world_units_per_luxel")
+{
+    auto [bsp, bspx] = LoadTestmap("q2_lightmap_custom_scale.map", {"-novanilla", "-world_units_per_luxel", "8"});
+
+    for (auto &face : bsp.dfaces) {
+        CHECK(face.lightofs == -1);
+    }
+
+    // make sure no other bspx lumps are written
+    CHECK(bspx.size() == 1);
+    CHECK(bspx.find("DECOUPLED_LM") != bspx.end());
+
+    // make sure all dlightdata bytes are accounted for by the DECOUPLED_LM lump
+    // and no extra was written.
+    size_t expected_dlightdata_bytes = 0;
+    for (auto &face : bsp.dfaces) {
+        // count used styles
+        size_t face_used_styles = 0;
+        for (auto style : face.styles) {
+            if (style != 255) {
+                ++face_used_styles;
+            }
+        }
+
+        // count used pixels per style
+        auto lm_info = BSPX_DecoupledLM(bspx, Face_GetNum(&bsp, &face));
+        const faceextents_t extents(face, bsp, lm_info.lmwidth, lm_info.lmheight, lm_info.world_to_lm_space);
+        int samples_per_face = extents.numsamples() * face_used_styles;
+
+        // round up to multiple of 4
+        if (samples_per_face % 4) {
+            samples_per_face += (4 - (samples_per_face % 4));
+        }
+
+        int bytes_per_face = 3 * samples_per_face;
+        expected_dlightdata_bytes += bytes_per_face;
+    }
+    CHECK(bsp.dlightdata.size() == expected_dlightdata_bytes);
 }
diff --git a/tests/test_qbsp.cc b/tests/test_qbsp.cc
index f020cc54..d9d565f5 100644
--- a/tests/test_qbsp.cc
+++ b/tests/test_qbsp.cc
@@ -822,6 +822,29 @@ TEST_CASE("water_detail_illusionary" * doctest::test_suite("testmaps_q1"))
     }
 }
 
+TEST_CASE("qbsp_bmodel_mirrorinside_with_liquid" * doctest::test_suite("testmaps_q1"))
+{
+    const auto [bsp, bspx, prt] = LoadTestmapQ1("qbsp_bmodel_mirrorinside_with_liquid.map");
+
+    REQUIRE(prt.has_value());
+
+    const qvec3d model1_fenceface{-16, -56, 168};
+    const qvec3d model2_waterface{-16, -120, 168};
+
+    CHECK(2 == BSP_FindFacesAtPoint(&bsp, &bsp.dmodels[1], model1_fenceface).size());
+    CHECK(2 == BSP_FindFacesAtPoint(&bsp, &bsp.dmodels[2], model2_waterface).size());
+
+    // both bmodels should be CONTENTS_SOLID in all hulls
+    for (int model_idx = 1; model_idx <= 2; ++model_idx) {
+        for (int hull = 0; hull <= 2; ++hull) {
+            auto &model = bsp.dmodels[model_idx];
+
+            INFO("model: ", model_idx, " hull: ", hull);
+            CHECK(CONTENTS_SOLID == BSP_FindContentsAtPoint(&bsp, {hull}, &model, (model.mins + model.maxs) / 2));
+        }
+    }
+}
+
 TEST_CASE("noclipfaces" * doctest::test_suite("testmaps_q1"))
 {
     const auto [bsp, bspx, prt] = LoadTestmapQ1("qbsp_noclipfaces.map");
@@ -1123,7 +1146,7 @@ TEST_CASE("q1_cube")
 
     REQUIRE_FALSE(prt.has_value());
 
-    const aabb3d cube_bounds {
+    const aabb3f cube_bounds {
         {32, -240, 80},
         {80, -144, 112}
     };
@@ -1134,8 +1157,8 @@ TEST_CASE("q1_cube")
 
     // check the solid leaf
     auto& solid_leaf = bsp.dleafs[0];
-    CHECK(solid_leaf.mins == qvec3d(0,0,0));
-    CHECK(solid_leaf.maxs == qvec3d(0,0,0));
+    CHECK(solid_leaf.mins == qvec3f(0,0,0));
+    CHECK(solid_leaf.maxs == qvec3f(0,0,0));
 
     // check the empty leafs
     for (int i = 1; i < 7; ++i) {
@@ -1185,7 +1208,7 @@ TEST_CASE("q1_clip_func_wall" * doctest::test_suite("testmaps_q1"))
 
     REQUIRE(prt.has_value());
 
-    const aabb3d cube_bounds {
+    const aabb3f cube_bounds {
         {64, 64, 48},
         {128, 128, 80}
     };
diff --git a/tests/test_qbsp_q2.cc b/tests/test_qbsp_q2.cc
index 1eef1618..4949f2a3 100644
--- a/tests/test_qbsp_q2.cc
+++ b/tests/test_qbsp_q2.cc
@@ -492,8 +492,8 @@ TEST_CASE("q2_door" * doctest::test_suite("testmaps_q2")) {
 
     CHECK(GAME_QUAKE_II == bsp.loadversion->game->id);
 
-    const aabb3d world_tight_bounds {{-64, -64, -16}, {64, 80, 128}};
-    const aabb3d bmodel_tight_bounds {{-48, 48, 16}, {48, 64, 112}};
+    const aabb3f world_tight_bounds {{-64, -64, -16}, {64, 80, 128}};
+    const aabb3f bmodel_tight_bounds {{-48, 48, 16}, {48, 64, 112}};
 
     CHECK(world_tight_bounds.mins() == bsp.dmodels[0].mins);
     CHECK(world_tight_bounds.maxs() == bsp.dmodels[0].maxs);