diff --git a/include/light/light.h b/include/light/light.h
index d6be2905..002f5f17 100644
--- a/include/light/light.h
+++ b/include/light/light.h
@@ -299,15 +299,20 @@ Face_TextureName(const bsp2_t *bsp, const bsp2_dface_t *face);
 
 void
 Face_MakeInwardFacingEdgePlanes(const bsp2_t *bsp, const bsp2_dface_t *face, plane_t *out);
+
+/* vis testing */
+const bsp2_dleaf_t *Light_PointInLeaf( const bsp2_t *bsp, const vec3_t point );
+int Light_PointContents( const bsp2_t *bsp, const vec3_t point );
+void Mod_LeafPvs(const bsp2_t *bsp, const bsp2_dleaf_t *leaf, byte *out);
+int DecompressedVisSize(const bsp2_t *bsp);
+bool Pvs_LeafVisible(const bsp2_t *bsp, const byte *pvs, const bsp2_dleaf_t *leaf);
+    
+/* PVS index (light.cc) */
+bool Leaf_HasSky(const bsp2_t *bsp, const bsp2_dleaf_t *leaf);
+const bsp2_dleaf_t **Face_CopyLeafList(const bsp2_t *bsp, const bsp2_dface_t *face);
     
 #ifdef __cplusplus
 }
 #endif
 
-/* vis testing */
-const bsp2_dleaf_t *Light_PointInLeaf( const bsp2_t *bsp, const vec3_t point );
-int PointInLeafnum (const bsp2_t *bsp, const vec3_t point);
-void PvsForOrigin (const bsp2_t *bsp, const vec3_t org, byte *pvs);
-int Light_PointContents( const bsp2_t *bsp, const vec3_t point );
-
 #endif /* __LIGHT_LIGHT_H__ */
diff --git a/light/light.cc b/light/light.cc
index ea256507..8ac59cd1 100644
--- a/light/light.cc
+++ b/light/light.cc
@@ -28,6 +28,8 @@
 #include <map>
 #include <set>
 
+using namespace std;
+
 float scaledist = 1.0;
 float rangescale = 0.5;
 float global_anglescale = 0.5;
@@ -754,6 +756,57 @@ ExportObj(const char *filename, const bsp2_t *bsp)
 
 //obj
 
+vector<vector<const bsp2_dleaf_t *>> faceleafs;
+vector<bool> leafhassky;
+
+// index some stuff from the bsp
+void BuildPvsIndex(const bsp2_t *bsp)
+{
+    // build leafsForFace
+    faceleafs.resize(bsp->numfaces);
+    for (int i = 0; i < bsp->numleafs; i++) {
+        const bsp2_dleaf_t *leaf = &bsp->dleafs[i];
+        for (int k = 0; k < leaf->nummarksurfaces; k++) {
+            const int facenum = bsp->dmarksurfaces[leaf->firstmarksurface + k];
+            faceleafs.at(facenum).push_back(leaf);
+        }
+    }
+    
+    // build leafhassky
+    leafhassky.resize(bsp->numleafs, false);
+    for (int i = 0; i < bsp->numleafs; i++) {
+        const bsp2_dleaf_t *leaf = &bsp->dleafs[i];
+        
+        // search for sky faces in it
+        for (int k = 0; k < leaf->nummarksurfaces; k++) {
+            const bsp2_dface_t *surf = &bsp->dfaces[bsp->dmarksurfaces[leaf->firstmarksurface + k]];
+            const char *texname = Face_TextureName(bsp, surf);
+            if (!strncmp("sky", texname, 3)) {
+                leafhassky.at(i) = true;
+                break;
+            }
+        }
+    }
+}
+
+bool Leaf_HasSky(const bsp2_t *bsp, const bsp2_dleaf_t *leaf)
+{
+    const int leafnum = leaf - bsp->dleafs;
+    return leafhassky.at(leafnum);
+}
+
+const bsp2_dleaf_t **Face_CopyLeafList(const bsp2_t *bsp, const bsp2_dface_t *face)
+{
+    const int facenum = face - bsp->dfaces;
+    auto &leafs = faceleafs.at(facenum);
+    
+    const bsp2_dleaf_t **result = (const bsp2_dleaf_t **) calloc(leafs.size() + 1, sizeof(const bsp2_dleaf_t *));
+    for (int i = 0; i<leafs.size(); i++) {
+        result[i] = leafs.at(i);
+    }
+    return result;
+}
+
 /*
  * ==================
  * main
@@ -980,6 +1033,7 @@ main(int argc, const char **argv)
     if (bspdata.version != BSP2VERSION)
         ConvertBSPFormat(BSP2VERSION, &bspdata);
 
+    BuildPvsIndex(bsp);
     LoadExtendedTexinfoFlags(source, bsp);
     LoadEntities(bsp);
 
diff --git a/light/ltface.c b/light/ltface.c
index c7bf851e..e07babe3 100644
--- a/light/ltface.c
+++ b/light/ltface.c
@@ -630,7 +630,7 @@ CalcPoints(const modelinfo_t *modelinfo, const vec3_t offset, lightsurf_t *surf,
     }
 }
 
-static int
+int
 DecompressedVisSize(const bsp2_t *bsp)
 {
     return (bsp->dmodels[0].visleafs + 7) / 8;
@@ -671,7 +671,7 @@ static void Mod_Q1BSP_DecompressVis(const unsigned char *in, const unsigned char
     }
 }
 
-static void
+void
 Mod_LeafPvs(const bsp2_t *bsp, const bsp2_dleaf_t *leaf, byte *out)
 {
     const int num_pvsclusterbytes = DecompressedVisSize(bsp);
@@ -701,7 +701,7 @@ Mod_LeafPvs(const bsp2_t *bsp, const bsp2_dleaf_t *leaf, byte *out)
 }
 
 // returns true if pvs can see leaf
-static bool
+bool
 Pvs_LeafVisible(const bsp2_t *bsp, const byte *pvs, const bsp2_dleaf_t *leaf)
 {
     const int leafnum = (leaf - bsp->dleafs);
@@ -712,7 +712,7 @@ Pvs_LeafVisible(const bsp2_t *bsp, const byte *pvs, const bsp2_dleaf_t *leaf)
     return !!(pvs[visleaf>>3] & (1<<(visleaf&7)));
 }
 
-void
+static void
 CalcPvs(const bsp2_t *bsp, lightsurf_t *lightsurf)
 {
     const int pvssize = DecompressedVisSize(bsp);
@@ -724,39 +724,22 @@ CalcPvs(const bsp2_t *bsp, lightsurf_t *lightsurf)
     if (!bsp->visdatasize) return;
     
     // gather the leafs this face is in
-    int numfaceleafs = 0;
-    const bsp2_dleaf_t *faceleafs[64];
-    
-    for (int i = 0; i < bsp->numleafs; i++) {
-        const bsp2_dleaf_t *leaf = &bsp->dleafs[i];
-        
-        for (int k = 0; k < leaf->nummarksurfaces; k++) {
-            const bsp2_dface_t *surf = &bsp->dfaces[bsp->dmarksurfaces[leaf->firstmarksurface + k]];
-            
-            if (surf == lightsurf->face) {
-                // store it
-                if (numfaceleafs < 64) {
-                    faceleafs[numfaceleafs++] = leaf;
-                } else {
-                    logprint("CalcPvs: warning: numfaceleafs == 64\n");
-                }
-            }
-        }
-    }
+    const bsp2_dleaf_t **faceleafs = Face_CopyLeafList(bsp, lightsurf->face);
     
     // set lightsurf->pvs
     byte *leafpvs = calloc(pvssize, 1);
     lightsurf->pvs = calloc(pvssize, 1);
     
-    for (int i = 0; i < numfaceleafs; i++) {
+    for (int i = 0; ; i++) {
         const bsp2_dleaf_t *leaf = faceleafs[i];
+        if (!leaf)
+            break;
 	
 	/* copy the pvs for this leaf into leafpvs */
         Mod_LeafPvs(bsp, leaf, leafpvs);
         
 	/* merge the pvs for this leaf into lightsurf->pvs */
-        for (int j=0; j<pvssize; j++)
-        {
+        for (int j=0; j<pvssize; j++) {
             lightsurf->pvs[j] |= leafpvs[j];
         }
     }
@@ -769,18 +752,11 @@ CalcPvs(const bsp2_t *bsp, lightsurf_t *lightsurf)
         const bsp2_dleaf_t *leaf = &bsp->dleafs[i];
         if (Pvs_LeafVisible(bsp, lightsurf->pvs, leaf)) {
             // we can see this leaf, search for sky faces in it
-            for (int k = 0; k < leaf->nummarksurfaces; k++) {
-                const bsp2_dface_t *surf = &bsp->dfaces[bsp->dmarksurfaces[leaf->firstmarksurface + k]];
-                const char *texname = Face_TextureName(bsp, surf);
-                if (!strncmp("sky", texname, 3)) {
-                    lightsurf->skyvisible = true;
-                    break;
-                }
+            if (Leaf_HasSky(bsp, leaf)) {
+                lightsurf->skyvisible = true;
+                break;
             }
         }
-        
-        if (lightsurf->skyvisible)
-            break; // we are done
     }
 }