From 55df37941c7769d7b918733dfcbdb6038975969f Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Fri, 20 May 2016 12:00:57 -0600
Subject: [PATCH] light: add -bouncecolorscale flag

---
 include/light/light.h | 3 ++-
 light/entities.c      | 4 ++++
 light/light.cc        | 5 +++++
 light/ltface.c        | 9 ++++++++-
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/light/light.h b/include/light/light.h
index 48baa3b1..ea46d569 100644
--- a/include/light/light.h
+++ b/include/light/light.h
@@ -232,7 +232,8 @@ extern qboolean dirtAngleSetOnCmdline;
 extern qboolean bounce;
 extern qboolean bouncedebug;
 extern vec_t bouncescale;
-
+extern vec_t bouncecolorscale;
+    
 /*
  * Return space for the lightmap and colourmap at the same time so it can
  * be done in a thread-safe manner.
diff --git a/light/entities.c b/light/entities.c
index 96284287..3b3cf147 100644
--- a/light/entities.c
+++ b/light/entities.c
@@ -1062,6 +1062,10 @@ LoadEntities(const bsp2_t *bsp)
                 bouncescale = atof(com_token);
                 logprint("_bouncescale set to %f\n", bouncescale);
             }
+            else if (!strcmp(key, "_bouncecolorscale")) {
+                bouncecolorscale = atof(com_token);
+                logprint("_bouncecolorscale set to %f\n", bouncecolorscale);
+            }
         }
 
         /*
diff --git a/light/light.cc b/light/light.cc
index 543c60a2..041d49b5 100644
--- a/light/light.cc
+++ b/light/light.cc
@@ -74,6 +74,7 @@ qboolean dirtAngleSetOnCmdline = false;
 qboolean bounce = false;
 qboolean bouncedebug = false;
 vec_t bouncescale = 1.0f;
+vec_t bouncecolorscale = 0.0f;
 
 qboolean testFenceTextures = false;
 qboolean surflight_dump = false;
@@ -1318,6 +1319,10 @@ main(int argc, const char **argv)
             bounce = true;
             bouncescale = atof( argv[ ++i ] );
             logprint( "Bounce scale factor set to %f on command line\n", bouncescale );
+        } else if ( !strcmp( argv[ i ], "-bouncecolorscale" ) ) {
+            bounce = true;
+            bouncecolorscale = atof( argv[ ++i ] );
+            logprint( "Bounce color scale factor set to %f on command line\n", bouncecolorscale );
         } else if ( !strcmp( argv[ i ], "-fence" ) ) {
             testFenceTextures = true;
             logprint( "Fence texture tracing enabled on command line\n" );
diff --git a/light/ltface.c b/light/ltface.c
index 7010a789..9caae2bb 100644
--- a/light/ltface.c
+++ b/light/ltface.c
@@ -2164,9 +2164,16 @@ LightFace(bsp2_dface_t *face, facesup_t *facesup, const modelinfo_t *modelinfo,
     
     // make bounce light
     if (bounce) {
+        vec3_t gray = {127, 127, 127};
+        
+        // lerp between gray and the texture color according to `bouncecolorscale`
+        vec3_t blendedcolor = {0, 0, 0};
+        VectorMA(blendedcolor, bouncecolorscale, lightsurf->texturecolor, blendedcolor);
+        VectorMA(blendedcolor, 1-bouncecolorscale, gray, blendedcolor);
+        
         vec3_t emitcolor;
         for (int k=0; k<3; k++) {
-            emitcolor[k] = (lightsurf->radiosity[k] / 255.0f) * (lightsurf->texturecolor[k] / 255.0f);
+            emitcolor[k] = (lightsurf->radiosity[k] / 255.0f) * (blendedcolor[k] / 255.0f);
         }
         winding_t *w = WindingFromFace(bsp, face);
         AddBounceLight(lightsurf->midpoint, emitcolor, lightsurf->plane.normal, WindingArea(w), bsp);