From 98be298d724f141b75444e714eca82bf546a30f0 Mon Sep 17 00:00:00 2001
From: Enno Rehling <enno.rehling@gmail.com>
Date: Tue, 7 Nov 2017 19:35:21 +0100
Subject: [PATCH] reduce monster spawning with configuration settings.

---
 conf/e2/config.json |  1 +
 src/monsters.c      | 14 +++++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/conf/e2/config.json b/conf/e2/config.json
index 5cbe4e378..5d29cd1f5 100644
--- a/conf/e2/config.json
+++ b/conf/e2/config.json
@@ -18,6 +18,7 @@
         "modules.wormhole": true,
         "modules.iceberg": true,
         "modules.volcano": true,
+        "monsters.spawn.chance": 50,
         "entertain.base": 0,
         "entertain.perlevel": 20,
         "taxing.perlevel": 20,
diff --git a/src/monsters.c b/src/monsters.c
index 115759d29..9079b29d6 100644
--- a/src/monsters.c
+++ b/src/monsters.c
@@ -874,19 +874,27 @@ void spawn_dragons(void)
 {
     region *r;
     faction *monsters = get_or_create_monsters();
+    int minage = config_get_int("monsters.spawn.min_age", 100);
+    int spawn_chance = 100 * config_get_int("monsters.spawn.chance", 100);
 
+    if (spawn_chance <= 0) {
+        /* monster spawning disabled */
+        return;
+    }
     for (r = regions; r; r = r->next) {
         unit *u;
-
+        if (r->age < minage) {
+            continue;
+        }
         if (fval(r->terrain, SEA_REGION)) {
-            if (rng_int() % 10000 < 1) {
+            if (rng_int() % spawn_chance < 1) {
                 u = spawn_seaserpent(r, monsters);
             }
         }
         else if ((r->terrain == newterrain(T_GLACIER)
             || r->terrain == newterrain(T_SWAMP)
             || r->terrain == newterrain(T_DESERT))
-            && rng_int() % 10000 < (5 + 100 * chaosfactor(r))) {
+            && rng_int() % spawn_chance < (5 + 100 * chaosfactor(r))) {
             if (chance(0.80)) {
                 u = create_unit(r, monsters, nrand(60, 20) + 1, get_race(RC_FIREDRAGON), 0, NULL, NULL);
             }