From ff1698bcb9230c1bfd3ff87fa74ef0a057c35e17 Mon Sep 17 00:00:00 2001
From: aw20368 <aw20368@gmail.com>
Date: Sat, 28 Sep 2019 14:51:13 -0400
Subject: [PATCH] Improve #9987: Minimum load rounding (#9987)

Refactor code for vehicles waiting for a specific load level.
Original code rounded the target load down, changed to round up.
---
 distribution/changelog.txt       |  1 +
 src/openrct2/network/Network.cpp |  2 +-
 src/openrct2/ride/Vehicle.cpp    | 58 ++++++--------------------------
 3 files changed, 13 insertions(+), 48 deletions(-)

diff --git a/distribution/changelog.txt b/distribution/changelog.txt
index f3b0858bf1..9ea2f23ba9 100644
--- a/distribution/changelog.txt
+++ b/distribution/changelog.txt
@@ -24,6 +24,7 @@
 - Fix: [#9970] Wait for quarter load fails.
 - Fix: [#10017] Ghost elements influencing ride excitement.
 - Improved: [#9466] Add the rain weather effect to the OpenGL renderer.
+- Improved: [#9987] Minimum load rounding.
 
 0.2.3 (2019-07-10)
 ------------------------------------------------------------------------
diff --git a/src/openrct2/network/Network.cpp b/src/openrct2/network/Network.cpp
index 38539574e3..8176696298 100644
--- a/src/openrct2/network/Network.cpp
+++ b/src/openrct2/network/Network.cpp
@@ -34,7 +34,7 @@
 // This string specifies which version of network stream current build uses.
 // It is used for making sure only compatible builds get connected, even within
 // single OpenRCT2 version.
-#define NETWORK_STREAM_VERSION "15"
+#define NETWORK_STREAM_VERSION "16"
 #define NETWORK_STREAM_ID OPENRCT2_VERSION "-" NETWORK_STREAM_VERSION
 
 static Peep* _pickup_peep = nullptr;
diff --git a/src/openrct2/ride/Vehicle.cpp b/src/openrct2/ride/Vehicle.cpp
index 990c3c3430..14c87a4280 100644
--- a/src/openrct2/ride/Vehicle.cpp
+++ b/src/openrct2/ride/Vehicle.cpp
@@ -2363,60 +2363,24 @@ static void vehicle_update_waiting_for_passengers(rct_vehicle* vehicle)
                 return;
             }
 
+            // any load: load=4 , full: load=3 , 3/4s: load=2 , half: load=1 , quarter: load=0
             uint8_t load = ride->depart_flags & RIDE_DEPART_WAIT_FOR_LOAD_MASK;
-            if (load == 3)
-            {
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
 
-            uint8_t three_quater_seats = (3 * num_seats_on_train) / 4;
-            if (three_quater_seats != 0 && num_peeps_on_train >= three_quater_seats)
-            {
+            // We want to wait for ceiling((load+1)/4 * num_seats_on_train) peeps, the +3 below is used instead of
+            // ceil() to prevent issues on different cpus/platforms with floats. Note that vanilla RCT1/2 rounded
+            // down here; our change reflects the expected behaviour for waiting for a minimum load target (see #9987)
+            uint8_t peepTarget = ((load + 1) * num_seats_on_train + 3) / 4;
+
+            if (load == 4) // take care of "any load" special case
+                peepTarget = 1;
+
+            if (num_peeps_on_train >= peepTarget)
                 vehicle->update_flags |= VEHICLE_UPDATE_FLAG_TRAIN_READY_DEPART;
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
 
-            if (load == 2)
-            {
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
-
-            if (num_seats_on_train / 2 != 0 && num_peeps_on_train >= num_seats_on_train / 2)
-            {
-                vehicle->update_flags |= VEHICLE_UPDATE_FLAG_TRAIN_READY_DEPART;
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
-
-            if (load == 1)
-            {
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
-
-            if (num_seats_on_train / 4 != 0 && num_peeps_on_train >= num_seats_on_train / 4)
-            {
-                vehicle->update_flags |= VEHICLE_UPDATE_FLAG_TRAIN_READY_DEPART;
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
-
-            if (load == 0)
-            {
-                train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
-                return;
-            }
-
-            if (num_peeps_on_train != 0)
-            {
-                vehicle->update_flags |= VEHICLE_UPDATE_FLAG_TRAIN_READY_DEPART;
-            }
             train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
             return;
         }
+
         vehicle->update_flags |= VEHICLE_UPDATE_FLAG_TRAIN_READY_DEPART;
         train_ready_to_depart(vehicle, num_peeps_on_train, num_used_seats_on_train);
         return;