Fix #13409: Peeps sometimes stray too far from the path centre (#13415)

* Fix #13409: Clamp peep distances from path centers

The debunch-peeps improvement did not account for the fact that peeps may change direction when they are only at the very edge of a tile - it's not entirely clear to me why this happens, but it does. The previous code would push these peeps back towards the center line over time, but the new behaviour allows them to keep walking along these very edge-y lines, which means they sometimes appear to be walking on the wrong sides of benches, railings, etc.

To fix the problem, do not simply keep the target coordinate constant for the direction the peep is moving in, but clamp it, so that peeps in these outlier positions will get pulled back to a more acceptable position within one tile. Peeps who are already debunched within the reasonable center area of the path are unaffected.

* Update replays for change

* Add changelog entry

* Fix broken hashes

Co-authored-by: duncanspumpkin <duncans_pumpkin@hotmail.co.uk>

CMakeLists.txt

@@ -44,8 +44,8 @@ set(TITLE_SEQUENCE_SHA1 "304d13a126c15bf2c86ff13b81a2f2cc1856ac8d")
 set(OBJECTS_URL  "https://github.com/OpenRCT2/objects/releases/download/v1.0.18/objects.zip")
 set(OBJECTS_SHA1 "4a3c32a0251c3babe014844f2c683fc32138b3f2")
 
-set(REPLAYS_URL  "https://github.com/OpenRCT2/replays/releases/download/v0.0.21/replays.zip")
-set(REPLAYS_SHA1 "23BF9B52D2D0BDBAF7E2DE4F35ED53F6A416539D")
+set(REPLAYS_URL  "https://github.com/OpenRCT2/replays/releases/download/v0.0.22/replays.zip")
+set(REPLAYS_SHA1 "7591db0a3842a7ac44fcbfbff9a573c9cb3ddc56")
 
 option(FORCE32 "Force 32-bit build. It will add `-m32` to compiler flags.")
 option(WITH_TESTS "Build tests")

distribution/changelog.txt

@@ -6,6 +6,7 @@
 - Fix: [#12895] Mechanics are called to repair rides that have already been fixed.
 - Fix: [#13334] Uninitialised variables in CustomTabDesc.
 - Fix: [#13342] Rename tabChange to onTabChange in WindowDesc interface.
+- Fix: [#13409] Clamp peep distances from path centers.
 - Improved: [#12917] Changed peep movement so that they stay more spread out over the full width of single tile paths.
 - Removed: [#13423] Built-in explode guests cheat (replaced by plug-in).
 

openrct2.proj

@@ -48,8 +48,8 @@
     <TitleSequencesSha1>304d13a126c15bf2c86ff13b81a2f2cc1856ac8d</TitleSequencesSha1>
     <ObjectsUrl>https://github.com/OpenRCT2/objects/releases/download/v1.0.18/objects.zip</ObjectsUrl>
     <ObjectsSha1>4a3c32a0251c3babe014844f2c683fc32138b3f2</ObjectsSha1>
-    <ReplaysUrl>https://github.com/OpenRCT2/replays/releases/download/v0.0.21/replays.zip</ReplaysUrl>
-    <ReplaysSha1>23BF9B52D2D0BDBAF7E2DE4F35ED53F6A416539D</ReplaysSha1>
+    <ReplaysUrl>https://github.com/OpenRCT2/replays/releases/download/v0.0.22/replays.zip</ReplaysUrl>
+    <ReplaysSha1>7591db0a3842a7ac44fcbfbff9a573c9cb3ddc56</ReplaysSha1>
   </PropertyGroup>
 
   <ItemGroup>

src/openrct2/peep/GuestPathfinding.cpp

@@ -148,18 +148,27 @@ static int32_t peep_move_one_tile(Direction direction, Peep* peep)
         //
         // What we want instead is to apply that randomness in the direction they are walking ONLY, and keep their
         // other coordinate constant.
+        //
+        // However, we have also seen some situations where guests end up too far from the center of paths. We've
+        // not identified exactly what causes this yet, but to limit the impact of it, we don't just keep the other
+        // coordinate constant, but instead clamp it to an acceptable range. This brings in 'outlier' guests from
+        // the edges of the path, while allowing guests who are already in an acceptable position to stay there.
 
         int8_t offset = (scenario_rand() & 7) - 3;
         if (direction == 0 || direction == 2)
         {
-            // Peep is moving along X, so apply the offset to the X position of the destination and keep their current Y
+            // Peep is moving along X, so apply the offset to the X position of the destination and clamp their current Y
             peep->DestinationX += offset;
-            peep->DestinationY = peep->y;
+            const uint16_t centerLine = (peep->y & 0xFFE0) + COORDS_XY_HALF_TILE;
+            peep->DestinationY = std::clamp(
+                peep->y, static_cast<int16_t>(centerLine - 3), static_cast<int16_t>(centerLine + 3));
         }
         else
         {
-            // Peep is moving along Y, so apply the offset to the Y position of the destination and keep their current X
-            peep->DestinationX = peep->x;
+            // Peep is moving along Y, so apply the offset to the Y position of the destination and clamp their current X
+            const uint16_t centerLine = (peep->x & 0xFFE0) + COORDS_XY_HALF_TILE;
+            peep->DestinationX = std::clamp(
+                peep->x, static_cast<int16_t>(centerLine - 3), static_cast<int16_t>(centerLine + 3));
             peep->DestinationY += offset;
         }
     }