From 96c7658b80b85612239fec53ab5464f863e31822 Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Tue, 7 Feb 2023 00:56:27 -0700
Subject: [PATCH] light: nudge lightgrid points if stuck in solid

---
 include/light/entities.hh |  1 +
 light/entities.cc         | 19 +++++++++++--------
 light/light.cc            |  9 +++++++++
 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/include/light/entities.hh b/include/light/entities.hh
index 4142cdde..e98ff5f2 100644
--- a/include/light/entities.hh
+++ b/include/light/entities.hh
@@ -149,3 +149,4 @@ aabb3d EstimateVisibleBoundsAtPoint(const qvec3d &point);
 bool EntDict_CheckNoEmptyValues(const mbsp_t *bsp, const entdict_t &entdict);
 
 entdict_t &WorldEnt();
+std::tuple<qvec3d, bool> FixLightOnFace(const mbsp_t *bsp, const qvec3d &point, bool warn = true, float max_dist = 2.f);
diff --git a/light/entities.cc b/light/entities.cc
index 5326614e..a8e50f02 100644
--- a/light/entities.cc
+++ b/light/entities.cc
@@ -1018,11 +1018,11 @@ void LoadEntities(const settings::worldspawn_keys &cfg, const mbsp_t *bsp)
     logging::print("{} entities read, {} are lights.\n", entdicts.size(), all_lights.size());
 }
 
-static qvec3d FixLightOnFace(const mbsp_t *bsp, const qvec3d &point)
+std::tuple<qvec3d, bool> FixLightOnFace(const mbsp_t *bsp, const qvec3d &point, bool warn, float max_dist)
 {
     // FIXME: Check all shadow casters
     if (!Light_PointInWorld(bsp, point)) {
-        return point;
+        return {point, true};
     }
 
     for (int i = 0; i < 6; i++) {
@@ -1030,24 +1030,27 @@ static qvec3d FixLightOnFace(const mbsp_t *bsp, const qvec3d &point)
 
         int axis = i / 2;
         bool add = i % 2;
-        testpoint[axis] += (add ? 2 : -2); // sample points are 1 unit off faces. so nudge by 2 units, so the lights are
-                                           // above the sample points
+        // sample points are 1 unit off faces. so nudge by 2 units, so the lights are
+        // above the sample points
+        testpoint[axis] += (add ? max_dist : -max_dist);
 
         // FIXME: Check all shadow casters
         if (!Light_PointInWorld(bsp, testpoint)) {
-            return testpoint;
+            return {testpoint, true};
         }
     }
 
-    logging::print("WARNING: couldn't nudge light out of solid at {}\n", point);
-    return point;
+    if (warn)
+        logging::print("WARNING: couldn't nudge light out of solid at {}\n", point);
+    return {point, false};
 }
 
 void FixLightsOnFaces(const mbsp_t *bsp)
 {
     for (auto &entity : all_lights) {
         if (entity->light.value() != 0 && !entity->nonudge.value()) {
-            entity->origin.setValue(FixLightOnFace(bsp, entity->origin.value()), settings::source::MAP);
+            auto [fixed_pos, success] = FixLightOnFace(bsp, entity->origin.value());
+            entity->origin.setValue(fixed_pos, settings::source::MAP);
         }
     }
 }
diff --git a/light/light.cc b/light/light.cc
index ade81cd0..959a9def 100644
--- a/light/light.cc
+++ b/light/light.cc
@@ -1079,6 +1079,15 @@ static void LightGrid(bspdata_t *bspdata)
         qvec3d world_point = grid_mins + (qvec3d{x,y,z} * light_options.lightgrid_dist.value());
 
         bool occluded = Light_PointInWorld(&bsp, world_point);
+        if (occluded) {
+            // search for a nearby point
+            auto [fixed_pos, success] = FixLightOnFace(&bsp, world_point, false, 2.0f);
+            if (success) {
+                occluded = false;
+                world_point = fixed_pos;
+            }
+        }
+
         lightgrid_samples_t samples;
 
         if (!occluded)