diff --git a/common/bspinfo.cc b/common/bspinfo.cc
index 6fc71100..991aa2e8 100644
--- a/common/bspinfo.cc
+++ b/common/bspinfo.cc
@@ -235,7 +235,7 @@ static faceextents_t get_face_extents(const mbsp_t &bsp, const bspxentries_t &bs
         (float)nth_bit(reinterpret_cast<const char *>(bspx.at("LMSHIFT").data())[&face - bsp.dfaces.data()])};
 }
 
-full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx, bool use_bspx, bool use_decoupled)
+full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx, const std::vector<uint8_t> &litdata, bool use_bspx, bool use_decoupled)
 {
     struct face_rect
     {
@@ -248,7 +248,19 @@ full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx,
     };
 
     constexpr size_t atlas_size = 512;
-    const bool is_rgb = bsp.loadversion->game->has_rgb_lightmap;
+    const uint8_t *lightdata_source;
+    bool is_rgb;
+    bool is_lit;
+
+    if (!litdata.empty()) {
+        is_lit = true;
+        is_rgb = true;
+        lightdata_source = litdata.data();
+    } else {
+        is_lit = false;
+        is_rgb = bsp.loadversion->game->has_rgb_lightmap;
+        lightdata_source = bsp.dlightdata.data();
+    }
 
     struct atlas
     {
@@ -408,7 +420,7 @@ full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx,
             }
 
             auto in_pixel =
-                bsp.dlightdata.begin() + rect.lightofs + (rect.extents.numsamples() * (is_rgb ? 3 : 1) * style_index);
+                lightdata_source + ((is_lit ? 3 : 1) * rect.lightofs) + (rect.extents.numsamples() * (is_rgb ? 3 : 1) * style_index);
 
             for (size_t y = 0; y < rect.extents.height(); y++) {
                 for (size_t x = 0; x < rect.extents.width(); x++) {
@@ -475,7 +487,8 @@ full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx,
 static void export_obj_and_lightmaps(const mbsp_t &bsp, const bspxentries_t &bspx, bool use_bspx, bool use_decoupled,
     fs::path obj_path, fs::path lightmaps_path)
 {
-    const auto atlas = build_lightmap_atlas(bsp, bspx, use_bspx, use_decoupled);
+    // FIXME: pass in .lit
+    const auto atlas = build_lightmap_atlas(bsp, bspx, {}, use_bspx, use_decoupled);
 
     if (atlas.facenum_to_lightmap_uvs.empty()) {
         return;
diff --git a/include/common/bspinfo.hh b/include/common/bspinfo.hh
index f34412bf..1fc1267c 100644
--- a/include/common/bspinfo.hh
+++ b/include/common/bspinfo.hh
@@ -41,6 +41,6 @@ struct full_atlas_t
     std::map<int, img::texture> style_to_lightmap_atlas;
 };
 
-full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx, bool use_bspx, bool use_decoupled);
+full_atlas_t build_lightmap_atlas(const mbsp_t &bsp, const bspxentries_t &bspx, const std::vector<uint8_t> &litdata, bool use_bspx, bool use_decoupled);
 
 void serialize_bsp(const bspdata_t &bspdata, const mbsp_t &bsp, const fs::path &name);
diff --git a/lightpreview/mainwindow.cpp b/lightpreview/mainwindow.cpp
index c75afc2a..f46e2aa2 100644
--- a/lightpreview/mainwindow.cpp
+++ b/lightpreview/mainwindow.cpp
@@ -725,6 +725,17 @@ int MainWindow::compileMap(const QString &file, bool is_reload)
         return 1;
     }
 
+    // try to load .lit
+    auto lit_path = fs_path;
+    lit_path.replace_extension(".lit");
+
+    try {
+        m_litdata = LoadLitFile(lit_path);
+    } catch (const std::runtime_error &error) {
+        logging::print("error loading lit: {}", error.what());
+        m_litdata = {};
+    }
+
     return 0;
 }
 
@@ -746,7 +757,7 @@ void MainWindow::compileThreadExited()
     auto ents = EntData_Parse(bsp);
 
     // build lightmap atlas
-    auto atlas = build_lightmap_atlas(bsp, m_bspdata.bspx.entries, false, bspx_decoupled_lm->isChecked());
+    auto atlas = build_lightmap_atlas(bsp, m_bspdata.bspx.entries, m_litdata, false, bspx_decoupled_lm->isChecked());
 
     glView->renderBSP(m_mapFile, bsp, m_bspdata.bspx.entries, ents, atlas, render_settings, bspx_normals->isChecked());
 
diff --git a/lightpreview/mainwindow.h b/lightpreview/mainwindow.h
index 9de058c7..b8e71bcb 100644
--- a/lightpreview/mainwindow.h
+++ b/lightpreview/mainwindow.h
@@ -71,6 +71,7 @@ private:
     bool m_fileWasReload = false;
     QString m_mapFile;
     bspdata_t m_bspdata;
+    std::vector<uint8_t> m_litdata;
     settings::common_settings render_settings;
     qint64 m_fileSize = -1;
     ETLogTab m_activeLogTab = ETLogTab::TAB_LIGHTPREVIEW;