light: add _lightgrid_hint point entity key for customizing lightgrid bounds

use it as a info_null key: "_lightgrid_hint" "1"

include/common/aabb.hh

@@ -194,6 +194,17 @@ public:
 
     constexpr value_type size() const { return maxs() - mins(); }
 
+    constexpr bool valid() const {
+        value_type our_size = size();
+
+        if (our_size[0] < static_cast<V>(0)
+            || our_size[1] < static_cast<V>(0)
+            || our_size[2] < static_cast<V>(0)) {
+            return false;
+        }
+        return true;
+    }
+
     constexpr aabb grow(const value_type &size) const { return {mins() - size, maxs() + size}; }
 
     constexpr value_type &operator[](const size_t &index) { return m_corners[index]; }

include/light/entities.hh

@@ -131,6 +131,7 @@ public:
 void ResetLightEntities();
 std::string TargetnameForLightStyle(int style);
 std::vector<std::unique_ptr<light_t>> &GetLights();
+const std::vector<entdict_t> &GetEntdicts();
 std::vector<sun_t> &GetSuns();
 std::vector<entdict_t> &GetRadLights();
 

light/entities.cc

@@ -29,10 +29,10 @@
 #include <common/bsputils.hh>
 #include <common/parallel.hh>
 
-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::unique_ptr<light_t>> all_lights;
+static std::vector<sun_t> all_suns;
+static std::vector<entdict_t> entdicts;
+static 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;
@@ -60,6 +60,11 @@ std::vector<std::unique_ptr<light_t>> &GetLights()
     return all_lights;
 }
 
+const std::vector<entdict_t> &GetEntdicts()
+{
+    return entdicts;
+}
+
 std::vector<sun_t> &GetSuns()
 {
     return all_suns;

light/lightgrid.cc

@@ -51,6 +51,30 @@ static std::vector<uint8_t> StringToVector(const std::string &str)
     return result;
 }
 
+static aabb3f LightGridBounds(const mbsp_t &bsp)
+{
+    aabb3f result;
+
+    // see if `_lightgrid_hint` entities are in use
+    for (auto &entity : GetEntdicts()) {
+        if (entity.get_int("_lightgrid_hint")) {
+            qvec3d point{};
+            entity.get_vector("origin", point);
+            result += point;
+        }
+    }
+
+    if (result.valid()) {
+        auto size = result.size();
+        if (size[0] > 0 && size[1] > 0 && size[2] > 0) {
+            return result;
+        }
+    }
+
+    result = Model_BoundsOfFaces(bsp, bsp.dmodels[0]);
+    return result;
+}
+
 void LightGrid(bspdata_t *bspdata)
 {
     if (!light_options.lightgrid.value())
@@ -60,9 +84,9 @@ void LightGrid(bspdata_t *bspdata)
 
     auto &bsp = std::get<mbsp_t>(bspdata->bsp);
 
-    auto faces_size = Model_BoundsOfFaces(bsp, bsp.dmodels[0]);
-    const qvec3f grid_maxs = faces_size.maxs();
-    const qvec3f grid_mins = faces_size.mins();
+    const auto grid_bounds = LightGridBounds(bsp);
+    const qvec3f grid_maxs = grid_bounds.maxs();
+    const qvec3f grid_mins = grid_bounds.mins();
     const qvec3f world_size = grid_maxs - grid_mins;
 
     // number of grid points on each axis

qbsp/outside.cc

@@ -306,6 +306,18 @@ static void WriteLeafVolumes(const std::vector<portal_t *> &leakline, std::strin
     WriteBspBrushMap(filename_suffix, volumes_to_write);
 }
 
+/**
+ * Is this entity allowed to be in the void without causing a leak?
+ */
+static bool IsNofillEntity(const entdict_t &edict)
+{
+    if (edict.get_int("_nofill"))
+        return true;
+    if (edict.get_int("_lightgrid_hint"))
+        return true;
+    return false;
+}
+
 /*
 ==================
 FindOccupiedLeafs
@@ -323,7 +335,7 @@ static void MarkOccupiedClusters(node_t *headnode)
             continue;
 
         // skip nofill entities
-        if (entity.epairs.has("_nofill") && entity.epairs.get_int("_nofill")) {
+        if (IsNofillEntity(entity.epairs)) {
             continue;
         }