Fix #8739: savegame from original game crashes when cruising through map (#8746)

distribution/changelog.txt

@@ -71,6 +71,7 @@
 - Fix: [#8647] Marketing campaigns check for entry fees below £1 (original bug). 
 - Fix: [#8653] Crash when peeps attempt to enter a ride with no vehicles.
 - Fix: [#8720] Desync due to boats colliding with ghost pieces.
+- Fix: [#8739] Savegame from original game crashes when cruising through map.
 - Fix: [#8742] Access violation in vehicle_update_sound_params.
 - Improved: [#2940] Allow mouse-dragging to set patrol area (Singleplayer only).
 - Improved: [#7730] Draw extreme vertical and lateral Gs red in the ride window's graph tab.

src/openrct2/ride/VehiclePaint.cpp

@@ -3075,8 +3075,6 @@ void vehicle_visual_splash_effect(
 {
     switch (vehicleEntry->effect_visual)
     {
-        case 1: /* nullsub */
-            break;
         case VEHICLE_VISUAL_SPLASH1_EFFECT:
             vehicle_visual_splash1_effect(session, z, vehicle);
             break;
@@ -3092,9 +3090,6 @@ void vehicle_visual_splash_effect(
         case VEHICLE_VISUAL_SPLASH5_EFFECT:
             vehicle_visual_splash5_effect(session, z, vehicle);
             break;
-        default:
-            assert(false);
-            break;
     }
 }
 
@@ -3143,13 +3138,19 @@ void vehicle_paint(paint_session* session, const rct_vehicle* vehicle, int32_t i
         {
             return;
         }
-        vehicleEntry = &rideEntry->vehicles[vehicle->vehicle_type];
 
+        auto vehicleEntryIndex = vehicle->vehicle_type;
         if (vehicle->update_flags & VEHICLE_UPDATE_FLAG_USE_INVERTED_SPRITES)
         {
-            vehicleEntry++;
+            vehicleEntryIndex++;
             z += 16;
         }
+
+        if (vehicleEntryIndex >= std::size(rideEntry->vehicles))
+        {
+            return;
+        }
+        vehicleEntry = &rideEntry->vehicles[vehicleEntryIndex];
     }
 
     switch (vehicleEntry->car_visual)