From f4d5dcbd5aefcb45f532ccbe8468ee2d7562438b Mon Sep 17 00:00:00 2001
From: Jarrod Doyle <thejarroddoyle@gmail.com>
Date: Sun, 16 Feb 2025 11:44:02 +0000
Subject: [PATCH] Apply LmParams attenuation

---
 KeepersCompound.Lightmapper/Light.cs       | 20 ++++++++++++--------
 KeepersCompound.Lightmapper/LightMapper.cs | 13 ++++++++++++-
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/KeepersCompound.Lightmapper/Light.cs b/KeepersCompound.Lightmapper/Light.cs
index 7c77426..d6c1b07 100644
--- a/KeepersCompound.Lightmapper/Light.cs
+++ b/KeepersCompound.Lightmapper/Light.cs
@@ -56,23 +56,26 @@ public class Light
         SpotlightDir = Vector3.Normalize(Vector3.Transform(vhotLightDir, scale * rotate));
     }
 
-    public float StrengthAtPoint(Vector3 point, Plane plane, uint lightCutoff)
+    public float StrengthAtPoint(Vector3 point, Plane plane, uint lightCutoff, float attenuation)
     {
         // Calculate light strength at a given point. As far as I can tell
-        // this is exact to Dark (I'm a genius??). It's just an inverse distance
-        // falloff with diffuse angle, except we have to scale the length.
+        // this is exact to Dark (I'm a genius??).
         var dir = Position - point;
-        var angle = Vector3.Dot(Vector3.Normalize(dir), plane.Normal);
         var len = dir.Length();
-        var slen = len / 4.0f;
-        var strength = (angle + 1.0f) / slen;
+        dir = Vector3.Normalize(dir);
+
+        // Base strength is a scaled inverse falloff
+        var strength = 4.0f / MathF.Pow(len, attenuation);
+        
+        // Diffuse light angle
+        strength *= 1.0f + MathF.Pow(Vector3.Dot(dir, plane.Normal), attenuation);
 
         // Inner radius starts a linear falloff to 0 at the radius
         if (InnerRadius != 0 && len > InnerRadius)
         {
-            strength *= (Radius - len) / (Radius - InnerRadius);
+            strength *= MathF.Pow((Radius - len) / (Radius - InnerRadius), attenuation);
         }
-
+        
         // Anim lights have a (configurable) minimum light cutoff. This is checked before
         // spotlight multipliers are applied so we don't cutoff the spot radius falloff.
         if (Anim && strength * Brightness < lightCutoff)
@@ -102,6 +105,7 @@ public class Light
             }
             else
             {
+                // Interestingly DromEd doesn't apply attenuation here
                 spotlightMultiplier = (spotAngle - outer) / (inner - outer);
             }
 
diff --git a/KeepersCompound.Lightmapper/LightMapper.cs b/KeepersCompound.Lightmapper/LightMapper.cs
index aed3f78..cdb0763 100644
--- a/KeepersCompound.Lightmapper/LightMapper.cs
+++ b/KeepersCompound.Lightmapper/LightMapper.cs
@@ -22,12 +22,19 @@ public class LightMapper
     {
         public Vector3[] AmbientLight;
         public bool Hdr;
+        public float Attenuation;
+        public float Saturation;
         public SoftnessMode MultiSampling;
         public float MultiSamplingCenterWeight;
         public bool LightmappedWater;
         public SunSettings Sunlight;
         public uint AnimLightCutoff;
         public bool UsePvs;
+
+        public override string ToString()
+        {
+            return $"Ambient Levels: {AmbientLight}, Hdr: {Hdr}, Attenuation: {Attenuation}, Saturation: {Saturation}";
+        }
     }
 
     private ResourcePathManager.CampaignResources _campaign;
@@ -106,6 +113,8 @@ public class LightMapper
         {
             Hdr = worldRep.DataHeader.LightmapFormat == 2,
             AmbientLight = [..ambientLight],
+            Attenuation =  lmParams.Attenuation,
+            Saturation =  lmParams.Saturation,
             MultiSampling = lmParams.ShadowSoftness,
             MultiSamplingCenterWeight = lmParams.CenterWeight,
             LightmappedWater = lmParams.LightmappedWater,
@@ -114,6 +123,8 @@ public class LightMapper
             UsePvs = pvs,
         };
         
+        Log.Information("Lighting Settings: {Settings}", settings);
+        
         Timing.TimeStage("Gather Lights", BuildLightList);
         Timing.TimeStage("Set Light Indices", () => SetCellLightIndices(settings));
         Timing.TimeStage("Trace Scene", () => TraceScene(settings));
@@ -791,7 +802,7 @@ public class LightMapper
                                 
                                 if (!TraceOcclusion(_scene, light.Position, point))
                                 {
-                                    strength += targetWeights[idx] * light.StrengthAtPoint(point, plane, settings.AnimLightCutoff);
+                                    strength += targetWeights[idx] * light.StrengthAtPoint(point, plane, settings.AnimLightCutoff, settings.Attenuation);
                                 }
                             }