diff --git a/map.cpp b/map.cpp
index 2f941ea..4795e21 100644
--- a/map.cpp
+++ b/map.cpp
@@ -52,11 +52,13 @@ Map::Map(size_t width, size_t height) :
   $input_map(height, MatrixRow(width, 1)),
   $walls(height, MatrixRow(width, INV_WALL)),
   $paths(height, MatrixRow(width, 1)),
-  $lightmap(height, MatrixRow(width, 0))
+  $lightmap(height, MatrixRow(width, 0)),
+  $light_paths(height, MatrixRow(width, 1)),
+  $light_input(height, MatrixRow(width, 1))
 {
 }
 
-// make explicit
+// Used on in tests to set an existing map
 Map::Map(Matrix input_map, Matrix walls_map, int limit) :
   $limit(limit),
   $input_map(input_map),
@@ -66,6 +68,8 @@ Map::Map(Matrix input_map, Matrix walls_map, int limit) :
   $height = $walls.size();
   $paths = Matrix($height, MatrixRow($width, 1));
   $lightmap = Matrix($height, MatrixRow($width, 0));
+  $light_paths = Matrix($height, MatrixRow($width, 1));
+  $light_input = Matrix($height, MatrixRow($width, 1));
 }
 
 inline void matrix_assign(Matrix &out, int new_value) {
@@ -77,12 +81,12 @@ inline void matrix_assign(Matrix &out, int new_value) {
 /*
  * Used https://github.com/HenrYxZ/dijkstra-map as a reference.
  */
-void Map::make_paths() {
+void Map::pathing_for(Matrix &input_map, Matrix &path_for) {
   INVARIANT();
   // Initialize the new array with every pixel at limit distance
   // NOTE: this is normally ones() * limit
   int limit = $limit == 0 ? $height * $width : $limit;
-  matrix_assign($paths, limit);
+  matrix_assign(path_for, limit);
 
   Matrix closed = $walls;
   PointList starting_pixels;
@@ -92,8 +96,8 @@ void Map::make_paths() {
  for(size_t counter = 0; counter < $height * $width; counter++) {
     size_t x = counter % $width; // BUG: is this right?
     size_t y = counter / $width;
-    if($input_map[y][x] == 0) {
-      $paths[y][x] = 0;
+    if(input_map[y][x] == 0) {
+      path_for[y][x] = 0;
       closed[y][x] = 1;
       starting_pixels.push_back({.x=x,.y=y});
     }
@@ -109,7 +113,7 @@ void Map::make_paths() {
   for(; counter < limit && !open_pixels.empty(); ++counter) {
     PointList next_open;
     for(auto sp : open_pixels) {
-      $paths[sp.y][sp.x] = counter;
+      path_for[sp.y][sp.x] = counter;
       add_neighbors(next_open, closed, sp.y, sp.x);
     }
     open_pixels = next_open;
@@ -117,10 +121,14 @@ void Map::make_paths() {
 
   // Last pass: flood last pixels
   for(auto sp : open_pixels) {
-    $paths[sp.y][sp.x] = counter;
+    path_for[sp.y][sp.x] = counter;
   }
 }
 
+void Map::make_paths() {
+  pathing_for($input_map, $paths);
+}
+
 void Map::make_room(size_t origin_x, size_t origin_y, size_t w, size_t h) {
   INVARIANT();
   dbc::pre("y out of bounds", origin_y + h < $height);
@@ -384,15 +392,15 @@ void Map::reset_light() {
 }
 
 void Map::clear_light_target(const Point &at) {
-  $input_map[at.y][at.x] = 1;
+  $light_input[at.y][at.x] = 1;
 }
 
 void Map::set_light_target(const Point &at, int value) {
-  set_target(at, value);
+  $light_input[at.y][at.x] = 0;
 }
 
 void Map::path_light() {
-    make_paths();
+  pathing_for($light_input, $light_paths);
 }
 
 void Map::light_box(LightSource source, Point from, Point &min_out, Point &max_out) {
@@ -404,7 +412,7 @@ void Map::light_box(LightSource source, Point from, Point &min_out, Point &max_o
 }
 
 int Map::light_level(int level, size_t x, size_t y) {
-  size_t at = level + $paths[y][x];
+  size_t at = level + $light_paths[y][x];
   int cur_level = $lightmap[y][x];
   int new_level = at < lighting::LEVELS.size() ? lighting::LEVELS[at] : lighting::MIN;
   return cur_level < new_level ? new_level : cur_level;
@@ -419,7 +427,7 @@ void Map::render_light(LightSource source, Point at) {
 
   for(size_t y = min.y; y <= max.y; ++y) {
     auto &light_row = $lightmap[y];
-    auto &path_row = $paths[y];
+    auto &path_row = $light_paths[y];
 
     for(size_t x = min.x; x <= max.x; ++x) {
       if(path_row[x] != UNPATH) {
@@ -432,7 +440,7 @@ void Map::render_light(LightSource source, Point at) {
   const int wall_light = source.strength + WALL_LIGHT_LEVEL;
   for(auto point : has_light) {
     for(int j = -1;point.y+j >= 0 && j <= 1 && point.y+j < $height; j++) {
-      auto &path_row = $paths[point.y+j];
+      auto &path_row = $light_paths[point.y+j];
       auto &light_row = $lightmap[point.y+j];
 
       for(int i = -1; point.x+i >= 0 && i <= 1 && point.x+i < $width; i++) {
@@ -447,6 +455,8 @@ void Map::render_light(LightSource source, Point at) {
 bool Map::INVARIANT() {
   using dbc::check;
 
+  check($light_paths.size() == height(), "paths wrong height");
+  check($light_paths[0].size() == width(), "paths wrong width");
   check($paths.size() == height(), "paths wrong height");
   check($paths[0].size() == width(), "paths wrong width");
   check($input_map.size() == height(), "input_map wrong height");
diff --git a/map.hpp b/map.hpp
index f3d4085..0ca250a 100644
--- a/map.hpp
+++ b/map.hpp
@@ -42,6 +42,8 @@ public:
   Matrix $walls;
   Matrix $paths;
   Matrix $lightmap;
+  Matrix $light_paths;
+  Matrix $light_input;
   std::vector<Room> $rooms;
 
   Map(Matrix input_map, Matrix walls_map, int limit);
@@ -76,6 +78,7 @@ public:
   bool neighbors(Point &out, bool up);
   bool inmap(size_t x, size_t y);
   bool iswall(size_t x, size_t y);
+  void pathing_for(Matrix &input_map, Matrix &path_for);
   void make_paths();
   void set_target(const Point &at, int value=0);
   void clear_target(const Point &at);