Try not to respawn monsters in player visual rangemobspawn

1 files changed, 59 insertions, 10 deletions

diff --git a/src/map/mob.cpp b/src/map/mob.cpp
index 4fd9d6d..4097230 100644
--- a/src/map/mob.cpp
+++ b/src/map/mob.cpp
@@ -2,7 +2,7 @@
 //    mob.cpp - Really scary code.
 //
 //    Copyright © ????-2004 Athena Dev Teams
-//    Copyright © 2004-2011 The Mana World Development Team
+//    Copyright © 2004-2024 The Mana World Development Team
 //    Copyright © 2011-2014 Ben Longbons <b.r.longbons@gmail.com>
 //    Copyright © 2013 Freeyorp
 //
@@ -1132,7 +1132,6 @@ int mob_setdelayspawn(BlockId id)
  */
 int mob_spawn(BlockId id)
 {
-    int x = 0, y = 0;
     tick_t tick = gettick();
     dumb_ptr<mob_data> md;
     dumb_ptr<block_list> bl;
@@ -1155,11 +1154,19 @@ int mob_spawn(BlockId id)
         map_delblock(md);
     }
 
+    // good coordinates, passability test only.
+    int good_x = 0, good_y = 0;
+    // best coordinates
+    int best_x = 0, best_y = 0, best_distance = -1;
+
     md->bl_m = md->spawn.m;
     {
-        int i = 0;
-        do
+        int coord_test_count = 0;
+        int proximity_test_count = 0;
+
+        for (; coord_test_count < 50; ++coord_test_count)
         {
+            int x = 0, y = 0;
             if (md->spawn.x0 == 0 && md->spawn.y0 == 0)
             {
                 x = random_::in(1, md->bl_m->xs - 2);
@@ -1172,12 +1179,54 @@ int mob_spawn(BlockId id)
                 x = md->spawn.x0 - md->spawn.xs / 2 + random_::in(0, md->spawn.xs);
                 y = md->spawn.y0 - md->spawn.ys / 2 + random_::in(0, md->spawn.ys);
             }
-            i++;
+
+            if (bool(map_getcell(md->bl_m, x, y) & MapCell::UNWALKABLE))
+                continue;
+
+            // Record good coordinates
+            good_x = x;
+            good_y = y;
+
+            // Set to 5 attempts, because
+            //  (1) That's what ML is set to;
+            //  (2) TODO foreachinarea fills up a std::vector... expensive.
+            if (proximity_test_count < 5)
+            {
+                proximity_test_count++;
+
+                int min_distance = std::numeric_limits<int>::max();
+                auto proximity_check = [&x, &y, &min_distance](dumb_ptr<block_list> bl)
+                {
+                    // Set min_distance to closest player's distance
+                    int dx = abs(bl->bl_x - x);
+                    int dy = abs(bl->bl_y - y);
+                    int dist = std::max(dx, dy);
+                    if (dist < min_distance)
+                        min_distance = dist;
+                };
+                //map_foreachinarea(std::bind(clif_movemob_sub, ph::_1, md),
+                map_foreachinarea(proximity_check,
+                    md->bl_m,
+                    x - AREA_SIZE, y - AREA_SIZE,
+                    x + AREA_SIZE, y + AREA_SIZE,
+                    BL::PC);
+
+                // update best coordinates, if needed
+                if (min_distance > best_distance)
+                {
+                    best_x = x;
+                    best_y = y;
+                    best_distance = min_distance;
+                }
+
+                if (min_distance < AREA_SIZE)
+                    continue; // try harder
+            }
+
+            break; // above two tests passed.
         }
-        while (bool(map_getcell(md->bl_m, x, y) & MapCell::UNWALKABLE)
-            && i < 50);
 
-        if (i >= 50)
+        if (coord_test_count >= 50)
         {
             Timer(tick + 5_s,
                     std::bind(mob_delayspawn, ph::_1, ph::_2,
@@ -1187,8 +1236,8 @@ int mob_spawn(BlockId id)
         }
     }
 
-    md->to_x = md->bl_x = x;
-    md->to_y = md->bl_y = y;
+    md->to_x = md->bl_x = good_x;
+    md->to_y = md->bl_y = good_y;
     md->dir = DIR::S;
 
     map_addblock(md);