Vehicles (programming)

Category:Vehicle Programming
This article is meant to give an in-depth analysis of the vehicles in Source and to provide the necessary information to create and modify source vehicles.
== In General ==
All vehicles, including the airboat, inherit from the same base classes:
At the end of the day, the typical source vehicle is made up of 3 parts:
*The main vehicle, inheriting from CPropVehicleDriveable.
*The "Server" Vehicle, inheriting from CBaseServerVehicle.
*The vehicle physics, CFourWheelVehiclePhysics.
=== prop_vehicle_driveable Entity ===
This is the main part of the vehicle, it's the entity that has the actual name of the vehicle and inherits from CPropVehicleDriveable. Like CPropAirboat. 
This entity doesn't handle passengers or passengers entry, since the code the player used to ride vehicles needs a IServerVehicle. That's why there is a member pointer on a CFourWheelsServerVehicle stored in the instance.
=== Server Vehicle ===
This class's primary purpose is to handle passenger entry, and sound state, along with acting as a proxy between the Driveable Vehicle, and the physic vehicle. It uses data structures named operating, control, and vehicle params, to share information between the driveable and physics classes. 
Its other purpose is to trigger the loading of the vehicle script data on its creation, along with the creation of the physics vehicle object.
=== Vehicle Physics ===
This class isn't an entity, it's mostly a wrapper between the driveable and server vehicle entities and the vehicle physics controller (IPhysicsVehicleController). It transmits data from the IPhysicsVehicleController object (that's in the physics DLL) through the GetVehicleOperatingParams() method. It also transmits to the IPhysicsVehicleController the data in the control params (m_controls) structure.
This object is responsible for loading and parsing the physics vehicle data, through the bool ParseVehicleScript( const char *pScriptName, solid_t &solid, vehicleparams_t &vehicle ) method.
=== Vehicle Data Structures ===
== Vehicles Specifics ==
=== Vehicles types values ===
From "..\src\public\vphysics\vehicles.h"
#define VEHICLE_TYPE_CAR_WHEELS			(1<<0)
#define VEHICLE_TYPE_CAR_RAYCAST		(1<<1)
#define VEHICLE_TYPE_JETSKI_RAYCAST		(1<<2)
#define VEHICLE_TYPE_AIRBOAT_RAYCAST	(1<<3)
=== The Buggy and Jalopy ===
The buggy
=== The Airboat ===
The airboat uses the same physical entity as the buggy CFourWheelVehiclePhysics. But it changes the vehicle type value to VEHICLE_TYPE_AIRBOAT_RAYCAST.
== Player Interaction ==
== Vehicles Components ==
=== Interfaces ===
* IClientVehicle - Client Side
* IVehicle - Vehicle Generalizations
* IServerVehicle 
* IDrivableVehicle
* INPCPassengerCarrier
* IPhysicsVehicleController
=== Classes ===
*Server:
**CFourWheelVehiclePhysics
**CBaseServerVehicle
**CFourWheelServerVehicle
**CPropVehicle
**CPropVehicleDriveable
*Client:
**C_PropVehicleDriveable
== Additional Help ==
===Source code:===
==== Multi-passenger vehicles ====
* The Jurassic Rage coding team has released their multi-passenger vehicle code:
** Here is the forum thread (archived)
** Here are the files (archived) [mirror #1]
* Multipassenger Vehicle Abstract
==== Pilotable code ====
* TheQuartz, creator of the Pilotable Strider Mod, has released the "Strider, Helicopter, and APC" source code:
** Here is the blog post (archived)
** Here are the files (archived)
=== Fixes: ===
==== Half-Life 2 SDK vehicles ====
* Some information on fixing source vehicle code for use in Multiplayer can be found here.
==== HL2DM vehicle fix ====
* A partial fix to make vehicles predicted and work in HL2DM can be found here.
== External links ==
* Design3 Vehicle Programming Video Tutorials