Hitbox
A hitbox (also hit box;. Engl for "hit box " ) describes a predefined virtual, for the user is usually not visible to a 3D model in a 3D engine (or game engine ), which for the calculation of collisions and / or hit queries is used. Hit boxes are used here mainly to simplify calculations, as 3D models, especially those of people, consisting of a plurality of polygons. The more complex the engine, the more similar the hitbox is the corresponding 3D model.
History
Even if hitboxes in modern engines are much more complex than a simple box, the word derives originally from exactly this meaning. In the early days of gaming history every 3D object was a simple box circumscribed in fact. So-called bounding volumes are still fast Vorberechungen or test runs in 2D or 3D design programs used the basically simple geometric shapes (sphere, cylinder, cuboid / circle, rectangle ) are. Especially with FPS games, however, this leads to problems: of course, a simple geometric object performs in the hit query to a rather poor result, since even hit next to the actual 3D model of the opponent (ie the optically visible target ) hit the bounding volume and thus can the player / opponent violate virtually. In driving games nearly rectangular or square-shaped variants, however, are less problematic, the vehicles themselves are usually also designed very simple in its basic form.
In addition to the benefits for the calculation of the physical demarcation of an object to hit boxes are also suitable for the determination of different target areas. Again, this is primarily in FPS games important as a difficult headshots ( Headshot ) usually leads to a larger energy than a simple deduction to be affixed hit on the torso. The more accurately in this case the hit boxes ( these must as mentioned not necessarily be cubic or cuboid ) the corresponding model enclose the more realistic, it is also appropriate games make - Application areas exist sufficient about the limp in the case of a leg hit.
Even if a 3D model is circumscribed by several different boxes or other shapes, you still refer to a single hitbox per 3D model.
For example, Microsoft DirectX (the extension D3DX ) provides access to the D3DXComputeBoundingBox, D3DXComputeBoundingSphere, D3DXBoxBoundProbe for such purposes.
The hitbox system is the most widely used system for determining hits, a few games ( eg Doom 3 ) but use an absolutely exact system (per - polygon hit detection) - but these systems are unequal resource -heavy and allow in online games usually only a much smaller number of players.
Hitbox in two-dimensional game worlds
Hitboxes are also of vital importance in most shoot 'em up games. There are two different approaches: the complete detection of the character through the hitbox or marking the character by a very small hitbox ( often only a few pixels in size ), usually in an important region such as the cockpit. The second version is used mainly in Danmaku shooters use. Since the screen is partly almost completely covered with this type of the game of enemy ammunition, the game would thus unrealistic difficult.