make the sky darkening better and customizable

pk7/language.txt

@@ -1650,6 +1650,7 @@
 "LITH_sv_revenge" = "Explode on death";
 "LITH_sv_scoremul" = "Score multiplier";
 "LITH_sv_sky" = "Replace skies";
+"LITH_sv_skydarkening" = "Sky darkening (for sky replacements)";
 "LITH_sv_wepdrop" = "Drop weapons from zombies";
 "LITH_weapons_alpha" = "Weapon opacity";
 "LITH_weapons_casingfadeout" = "Casings fade out";

pk7/lzscript/Playsim/Events.zsc

@@ -148,8 +148,8 @@ override void WorldLoaded(WorldEvent ev)
       for(int i = 0, j = level.sectors.size(); i < j; i++) {
          Sector sec = level.sectors[i];
          if(sec.getTexture(Sector.Ceiling) == skyflatnum) {
-            if(in_hell) sec.setColor("#440000");
-            else        sec.lightlevel = clamp(sec.lightlevel - 86, 0, 255);
+            if(in_hell) sec.setColor("#ff7777");
+            sec.lightlevel = clamp(sec.lightlevel * lith_sv_skydarkening, 64, 255);
          }
       }
    }

source/p_settings.c

@@ -357,6 +357,7 @@ struct setting const st_wld[] = {
    {S_boole, "sv_nobosses",       S_svBoole},
    {S_boole, "sv_rain",           S_svBoole},
    {S_boole, "sv_sky",            S_svBoole},
+   {S_fixed, "sv_skydarkening",   S_svFixed, S_bndk(0.0, 1.0),  "mult"},
    {S_fixed, "sv_scoremul",       S_svFixed, S_bndk(0.0, 10.0), "mult"},
    {S_integ, "sv_autosave",       S_svInteg, S_bndi(0,   30),   "minu"},
    {S_integ, "sv_difficulty",     S_svInteg, S_bndi(1,   100),  "perc"},

text/en/Misc/Settings.txt

@@ -206,6 +206,7 @@
 == \#sv_revenge             | Explode on death
 == \#sv_scoremul            | Score multiplier
 == \#sv_sky                 | Replace skies
+== \#sv_skydarkening        | Sky darkening (for sky replacements)
 == \#sv_wepdrop             | Drop weapons from zombies
 == \#weapons_alpha          | Weapon opacity
 == \#weapons_casingfadeout  | Casings fade out