From f3321cef5fd504ab487410ed76bd3de8a91c6552 Mon Sep 17 00:00:00 2001
From: Garux <garux@mail.ru>
Date: Wed, 8 Sep 2021 19:22:18 +0300
Subject: [PATCH] * auto fog direction: try all sides, not just axial; default
 to none, if no visible sides 	* q3map_fogDir: pick best matching side, not
 strict match only; ignore invisible 'bevel' sides

---
 tools/quake3/q3map2/fog.cpp      | 16 +++++++--------
 tools/quake3/q3map2/writebsp.cpp | 34 ++++++++++++++++++++++----------
 2 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/tools/quake3/q3map2/fog.cpp b/tools/quake3/q3map2/fog.cpp
index add59ae9..f763f358 100644
--- a/tools/quake3/q3map2/fog.cpp
+++ b/tools/quake3/q3map2/fog.cpp
@@ -670,17 +670,17 @@ void CreateMapFogs( void ){
 			fog.visibleSide = -1;
 
 			/* if shader specifies an explicit direction, then find a matching brush side with an opposed normal */
-			if ( vector3_length( fog.si->fogDir ) ) {
-				/* flip it */
-				const Vector3 invFogDir = -fog.si->fogDir;
-
+			if ( fog.si->fogDir != g_vector3_identity ) {
+				double bestDot = 0;
 				/* find the brush side */
 				for ( size_t j = 0; j < brush.sides.size(); ++j )
 				{
-					if ( VectorCompare( invFogDir, mapplanes[ brush.sides[ j ].planenum ].normal() ) ) {
-						fog.visibleSide = j;
-						//%	Sys_Printf( "Brush num: %d Side num: %d\n", fog->brushNum, fog->visibleSide );
-						break;
+					if( !brush.sides[ j ].bevel ){
+						const double dot = vector3_dot( fog.si->fogDir, mapplanes[ brush.sides[ j ].planenum ].normal() );
+						if( dot < bestDot ){
+							bestDot = dot;
+							fog.visibleSide = j;
+						}
 					}
 				}
 			}
diff --git a/tools/quake3/q3map2/writebsp.cpp b/tools/quake3/q3map2/writebsp.cpp
index 813effe6..16a0da19 100644
--- a/tools/quake3/q3map2/writebsp.cpp
+++ b/tools/quake3/q3map2/writebsp.cpp
@@ -476,35 +476,49 @@ void EmitFogs( void ){
 	/* walk list */
 	for ( int i = 0; i < numMapFogs; i++ )
 	{
+		const fog_t& fog = mapFogs[i];
+		bspFog_t& bspFog = bspFogs[i];
 		/* set shader */
 		// copy and clear the rest of memory
-		strncpy( bspFogs[ i ].shader, mapFogs[ i ].si->shader, sizeof( bspFogs[ i ].shader ) );
+		strncpy( bspFog.shader, fog.si->shader, sizeof( bspFog.shader ) );
 
 		/* global fog doesn't have an associated brush */
-		if ( mapFogs[ i ].brush == NULL ) {
-			bspFogs[ i ].brushNum = -1;
-			bspFogs[ i ].visibleSide = -1;
+		if ( fog.brush == NULL ) {
+			bspFog.brushNum = -1;
+			bspFog.visibleSide = -1;
 		}
 		else
 		{
 			/* set brush */
-			bspFogs[ i ].brushNum = mapFogs[ i ].brush->outputNum;
+			bspFog.brushNum = fog.brush->outputNum;
+			bspFog.visibleSide = -1; // default to something sensible, not just zero index
 
 			/* try to use forced visible side */
-			if ( mapFogs[ i ].visibleSide >= 0 ) {
-				bspFogs[ i ].visibleSide = mapFogs[ i ].visibleSide;
+			if ( fog.visibleSide >= 0 ) {
+				bspFog.visibleSide = fog.visibleSide;
 				continue;
 			}
 
-			/* find visible side */
+			/* find visible axial side */
 			for ( int j = 6; j-- > 0; ) // prioritize +Z (index 5) then -Z (index 4) in ambiguous case; fogged pit is assumed as most likely case
 			{
-				if ( !mapFogs[ i ].brush->sides[ j ].visibleHull.empty() ) {
+				if ( !fog.brush->sides[ j ].visibleHull.empty() ) {
 					Sys_Printf( "Fog %d has visible side %d\n", i, j );
-					bspFogs[ i ].visibleSide = j;
+					bspFog.visibleSide = j;
 					break;
 				}
 			}
+			/* try other sides */
+			if( bspFog.visibleSide < 0 ){
+				for ( size_t j = 6; j < fog.brush->sides.size(); ++j )
+				{
+					if ( !fog.brush->sides[ j ].visibleHull.empty() ) {
+						Sys_Printf( "Fog %d has visible side %d\n", i, j );
+						bspFog.visibleSide = j;
+						break;
+					}
+				}
+			}
 		}
 	}