Deflection shooting is a technique of

shooting Shooting is the act or process of discharging a projectile from a ranged weapon (such as a gun, bow, crossbow, slingshot, or blowpipe). Even the acts of launching flame, artillery, darts, harpoons, grenades, rockets, and guided missile ...

ahead of a moving target, also known as leading the target, so that the

projectile A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found ...

will "intercept" and collide with the target at a predicted point. This technique is necessary when the target will have significantly displaced its position during the time the projectile would take to reach the target, which can become the case over very long distances (e.g. a long sniper shot), due to fast moving targets (e.g. aerial

dogfight A dogfight, or dog fight, is an air combat manoeuvring, aerial battle between fighter aircraft that is conducted at close range. Modern terminology for air-to-air combat is air combat manoeuvring (ACM), which refers to tactical situations requir ...

against an opposing aircraft, or

anti-aircraft Anti-aircraft warfare (AAW) is the counter to aerial warfare and includes "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It encompasses surface-based, subsurface ( submarine-launched), and air-ba ...

fire against passing aircraft), hunting a running animal, or while using relatively slow projectiles (e.g. a bolt shot from a

crossbow A crossbow is a ranged weapon using an Elasticity (physics), elastic launching device consisting of a Bow and arrow, bow-like assembly called a ''prod'', mounted horizontally on a main frame called a ''tiller'', which is hand-held in a similar f ...

, or a

basketball Basketball is a team sport in which two teams, most commonly of five players each, opposing one another on a rectangular Basketball court, court, compete with the primary objective of #Shooting, shooting a basketball (ball), basketball (appro ...

thrown to a running teammate). Gyro gunsights developed for aircraft of the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

displayed a

reticle A reticle or reticule, also known as a graticule or crosshair, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the electronic v ...

that compensated for target lead. Modern

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

have automated deflection sights, where a computer calculates lead and projects the solution onto a

head-up display A head-up display, or heads-up display, also known as a HUD () or head-up guidance system (HGS), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a ...

(HUD). The visual assistance with targeting the gun is offset by the speed and agility of modern aircraft, compared to the days when targeting was less advanced. In

artillery Artillery consists of ranged weapons that launch Ammunition, munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and l ...

, deflection is also used against fixed targets to compensate for

windage In aerodynamics, firearms ballistics, and automobiles, windage is the effects of some fluid, usually air (e.g., wind) and sometimes liquids, such as oil. Aerodynamics Windage is a force created on an object by friction when there is relative m ...

and range. Due to the

Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in progra ...

, surface points have different velocities and curved motion, leading to apparent Coriolis drift of a long-range target.

Computer games

Modern computer games of the

first-person shooter A first-person shooter (FPS) is a video game genre, video game centered on gun fighting and other weapon-based combat seen from a First person (video games), first-person perspective, with the player experiencing the action directly through t ...

genre typically feature a number of relatively low-velocity projectile weapons such as unguided shoulder-fired missiles, or fictional projectile weapons such as "plasma guns", which necessitates an attacker to lead his aim ahead of moving targets. Computer games that accurately model the ballistic trajectories (including velocity) of firearms also require leading of fire, much as in real life. This applies equally to combat aircraft (or even combat spacecraft) simulators, where the velocities of the craft involved are great enough to require leading with projectile weapons. Additionally, in older

multiplayer video game A multiplayer video game is a video game in which more than one person can play in the same game environment at the same time, either locally on the same computing system (couch co-op), on different computing systems via a local area network, or ...

s that calculate behavior on a remote server, even for high-velocity or hitscan weapons, there are issues of latency that may require leading. Essentially, even if the shooter has the target exactly in their sights, by the time the information relating weapon fire from the shooter's computer has reached the server, the target may have moved enough to avoid the shot. However, modern game-engines use a

lag compensation In computers, lag is delay (Latency (engineering), latency) between the action of the User (computing), user (input) and the reaction of the Server (computing), server supporting the Task (computing), task, which has to be sent back to the Client ...

system which moves all players back to a point in time based on the shooter's

client interpolation Client(s) or The Client may refer to: * Client (business) * Client (computing), hardware or software that accesses a remote service on another computer * Customer or client, a recipient of goods or services in return for monetary or other valuable ...

time and ping (or, alternatively, by trusting the result calculated entirely on the client side) to evaluate if there was a hit or not. Such systems eliminate the need to lead hitscan weapons, but introduce the risk of players being hit by enemy fire shortly after taking cover behind objects, due to the latency causing a delay before the victim's computer receives the message that he has been shot.

References

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Computer games

References

See also