From 0baa788d7e3805e39510d8e6211f0cf1f693b766 Mon Sep 17 00:00:00 2001
From: Jonathan <jonno.5000@gmail.com>
Date: Sat, 2 Jul 2022 16:59:04 -0400
Subject: [PATCH] fix bounced lighting

---
 light/bounce.cc    | 11 +++++++++--
 light/ltface.cc    | 13 ++++---------
 light/surflight.cc |  2 +-
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/light/bounce.cc b/light/bounce.cc
index a1e68823..281aeeb4 100644
--- a/light/bounce.cc
+++ b/light/bounce.cc
@@ -71,6 +71,14 @@ static bool Face_ShouldBounce(const mbsp_t *bsp, const mface_t *face)
         return false;
     }
 
+    // don't bounce *from* emission surfaces
+    // FIXME: better way that works for Q1 too
+    if (bsp->loadversion->game->id == GAME_QUAKE_II) {
+        if (bsp->texinfo[face->texinfo].flags.native & Q2_SURF_LIGHT) {
+            return false;
+        }
+    }
+
     return true;
 }
 
@@ -163,7 +171,7 @@ static void MakeBounceLightsThread(const settings::worldspawn_keys &cfg, const m
         return;
     }
 
-    const vec_t sample_scalar = 1.f / area;
+    const vec_t sample_scalar = 1.f / sqrt(area);
 
     qplane3d faceplane = winding.plane();
 
@@ -183,7 +191,6 @@ static void MakeBounceLightsThread(const settings::worldspawn_keys &cfg, const m
 
     for (auto &styleColor : sum) {
         styleColor.second *= sample_scalar;
-        styleColor.second /= 255.0f;
         styleColor.second *= cfg.bouncescale.value();
         total += styleColor.second;
     }
diff --git a/light/ltface.cc b/light/ltface.cc
index 445cb179..a2a6e594 100644
--- a/light/ltface.cc
+++ b/light/ltface.cc
@@ -1841,18 +1841,13 @@ static void LightFace_BounceLightsDebug(const lightsurf_t *lightsurf, lightmapdi
 
 // returns color in [0,255]
 inline qvec3f BounceLight_ColorAtDist(
-    const settings::worldspawn_keys &cfg, float area, const qvec3f &bounceLightColor, float dist)
+    const settings::worldspawn_keys &cfg, float area, const qvec3f &color, float dist)
 {
-    // clamp away hotspots
-    if (dist < 128.0f) {
-        dist = 128.0f;
-    }
-
-    const float dist2 = (dist * dist);
-    const float scale = (1.0f / dist2);
+    const float d = max(dist, 128.f); // Clamp away hotspots, also avoid division by 0..
+    const float scale = (1.0f / (d * d));
 
     // get light contribution
-    return bounceLightColor * area * (255.0f * scale);
+    return color * area * scale;
 }
 
 // mxd. Surface light falloff. Returns color in [0,255]
diff --git a/light/surflight.cc b/light/surflight.cc
index 41ee42d2..ae932df1 100644
--- a/light/surflight.cc
+++ b/light/surflight.cc
@@ -159,7 +159,7 @@ static void MakeSurfaceLightsThread(const mbsp_t *bsp, const settings::worldspaw
             return;
         }
 
-        MakeSurfaceLight(bsp, cfg, face, std::nullopt, false, (info->flags.native & Q2_SURF_SKY), 0, info->value);
+        MakeSurfaceLight(bsp, cfg, face, std::nullopt, false/*!(info->flags.native & Q2_SURF_SKY)*/, (info->flags.native & Q2_SURF_SKY), 0, info->value);
     }
 
     // check matching templates