diff options
| -rw-r--r-- | src/ground_vehicle.cpp | 15 | ||||
| -rw-r--r-- | src/table/engines.h | 2 |
2 files changed, 16 insertions, 1 deletions
diff --git a/src/ground_vehicle.cpp b/src/ground_vehicle.cpp index 6ccba6aa7..0ea7cef8b 100644 --- a/src/ground_vehicle.cpp +++ b/src/ground_vehicle.cpp @@ -46,7 +46,20 @@ void GroundVehicle<T, Type>::PowerChanged() } this->acc_cache.cached_axle_resistance = 60 * number_of_parts; - this->acc_cache.cached_air_drag = 20 + 3 * number_of_parts; + + byte air_drag; + byte air_drag_value = v->GetAirDrag(); + + /* If air drag is set to zero (default), the resulting air drag coefficient is dependent on max speed. */ + if (air_drag_value == 0) { + /* Simplification of the method used in TTDPatch. It uses <= 10 to change more steadily from 128 to 196. */ + air_drag = (max_track_speed <= 10) ? 192 : max(2048 / max_track_speed, 1); + } else { + /* According to the specs, a value of 0x01 in the air drag property means "no air drag". */ + air_drag = (air_drag_value == 1) ? 0 : air_drag_value; + } + + this->acc_cache.cached_air_drag = air_drag + 3 * air_drag * number_of_parts / 20; max_te *= 10000; // Tractive effort in (tonnes * 1000 * 10 =) N. max_te /= 256; // Tractive effort is a [0-255] coefficient. diff --git a/src/table/engines.h b/src/table/engines.h index 63c830ddf..6ff3ecfb7 100644 --- a/src/table/engines.h +++ b/src/table/engines.h @@ -362,6 +362,7 @@ static const EngineInfo _orig_engine_info[] = { * @param j railtype * @param k engclass * Tractive effort coefficient by default is the same as TTDPatch, 0.30*256=76 + * Air drag value depends on the top speed of the vehicle. */ #define RVI(a, b, c, d, e, f, g, h, i, j, k) { a, b, c, {j}, d, e, f, g, h, k, i, 0, 0, 0, 0, 0, 76, 0, 0 } #define M RAILVEH_MULTIHEAD @@ -642,6 +643,7 @@ static const AircraftVehicleInfo _orig_aircraft_vehicle_info[] = { * @param g weight (1/4 ton) * @param h power (10 hp) * Tractive effort coefficient by default is the same as TTDPatch, 0.30*256=76 + * Air drag value depends on the top speed of the vehicle. */ #define ROV(a, b, c, d, e, f, g, h) { a, b, c, PR_RUNNING_ROADVEH, d, e, f, g, h, 76, 0 } static const RoadVehicleInfo _orig_road_vehicle_info[] = { |