In some early videogames, the game engine did not have enough computational power to actually keep track of all moving projectiles (like the bullets fired from the player's gun), let alone incorporate realistic physical factors like atmospheric friction or gravity.

In some games, this was mediated by placing a limit of OneBulletAtATime. In others, developers chose a Hitscan weapon.

Hitscan weapons do not actually fire anything; instead, when the player pulls the trigger, the weapon traces a trajectory in front of the player and instantly hits whatever the line intersects with first. This differs from a ''projectile'' weapon, whose bullets are independent data objects with a known position and speed (be it fast or [[PainfullySlowProjectile slow]]) that the game actively tracks and checks against potential collisions. A hitscan can be useful in situations where the projectile is moving so fast that it would be difficult to track, such as with realistic lasers and bullets across short distances.

It should be noted that hitscans ''can'' overlap with projectile tracking: In some cases, the ''actual'' attack is hitscan, but the game will still animate a fake projectile moving from point A to B. This allows EveryBulletIsATracer to play together with hitscan weapons. This can become particularly obvious if the tracer is too slow or the game supports BulletTime, as you can see enemies react before the "bullet" strikes them.

In older shooters this was used for any bullet-based weapon, on the assumption that bullets moved too fast to evade or dodge anyway, and also to balance them against more powerful projectile-based weapons, which were trickier to aim. For example, in ''VideoGame/{{Doom}}'', the pistol, shotguns and chaingun were hitscan, while the plasma rifle and rocket launcher fired projectiles. The {{BFG}} fired both projectiles as well as a form of delayed hitscan tracers. Hitscan enemies are often GoddamnBats, since the player is more or less incapable of dodging their attacks.

Note that lacking or averting this trope does not ''necessarily'' mean that bullet projectiles behave realistically; for example, the game may still destroy projectiles once they reach an ArbitraryMaximumRange rather than having them follow a ballistic arc until they hit something. Gravity is also often [[NoArcInArchery not applied to projectiles]]; many (perhaps most) engines approximate the scanned trajectory as a straight line rather than a parabolic arc.

Paradoxically, while bullets are often implemented as a hitscan, energy weapons are usually portrayed as [[PainfullySlowProjectile Painfully Slow]] FrickinLaserBeams. See also HomingBoulders.

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!!Examples:

* ''VideoGame/Wolfenstein3D''. Any shot in the general direction of an enemy (or vice versa) was an immediate hit or miss, regardless of range.
* ''VideoGame/{{Doom}}'' featured hitscan detection for all bullet weapons and the secondary tracer rays of the BFG.
** To be specific, the pistol, shotgun(s), and chaingun all use hitscan. The fist, chainsaw, and monster melee attacks are also technically hitscan, though the range is so short it's hard to notice. The BFG is a special case; its visible plasma ball is a low-damage projectile. However, when the plasma ball hits something, the weapon then immediately releases invisible hitscan "tracer rays" in the '''originally-fired direction''' from the player's current physical position (if you fire facing north, then move and face west, the tracers will still head north from where you currently are when the plasma hits something). There are 20 of these tracers spread equally in an arc centered on the originally-fired direction, and these tracers are responsible for most of the weapon's actual damage output.
* ''VideoGame/{{Quake}}'' and ''VideoGame/QuakeII'' did likewise, though the nailgun, blaster, and hyperblaster fired modelled projectiles; the second game started a long-running trend for hitscan sniper rifles with the Railgun. The Gladiators are equipped with railguns, but have an 0.3 second delay between targeting and firing, allowing you a narrow window to dodge.
* ''MedalOfHonor'' did this with fake tracers, resulting in the infamous ScrappyLevel "Sniper's Last Stand" where the player had to face off against eerily prescient hidden snipers with hitscan rifles. Worse, it also means that enemies' shots can continue to hit you while they're [[KnockBack flinching]] or aiming the wrong way, and they can even hit you around corners or from behind objects that are supposedly too high for them to shoot over.
* ''[[VideoGame/GoldenEye1997 GoldenEye]]'' and ''PerfectDark'' both have fake tracers. In ''PerfectDark'' even ''crossbow bolts'' are hitscan.
* ''VideoGame/DeusEx'', where you can bind keys to slow time down and see bullets travel faster than the visible tracer does.
* ''FarCry'' makes the fakeness of tracers obvious due to very long ranges in the outdoor levels; firing a weapon at water from long range will cause a splash long before the tracer arrives.
* ''CallOfDuty'' does it for all bullets, except for the realistic sniping sequence in "One Shot, One Kill" from ''ModernWarfare''. Since the hitscan line is projected from the character's head rather than their gun, there is the frequent side-effect of enemy shots glitching around obstacles to hit the player.
* The ''VideoGame/{{Turok}}'' games do this up until ''3'' with bullet weapons and some enemy weapons; the fake tracers were particularly irritating in the latter case, since you couldn't dodge attacks which appeared to be relatively slow-moving.
* In ''{{Killer7}}'', all of the Smiths weapons do this, even Kevin and MASK's, who use throwing knives and grenade launchers respectively.
* ''VideoGame/{{Fallout 3}}'' weapons appear to be all hitscan when not using VATS. This is most obvious when, through mods, using a scope on a normally unscoped weapon. The enemy will drop almost a full half-second before the tracer projectile reaches them at long ranges.
** The Laser weapons you can use are in fact HitScan weapons, due to them being FrickinLaserBeams. This is their major advantage over the more damaging plasma weapons, whose {{Painfully Slow Projectile}}s have a very hard time hitting moving or distant targets, at least without VATS.
** ''3'' and ''[[VideoGame/FalloutNewVegas New Vegas]]'' do somewhat avert this for killing shots with the cinematic camera, however; for example, take aim and fire at an unaware Powder Ganger from far enough away with a scoped rifle, if it hits him the game will do a ''VideoGame/MaxPayne''-style bullet cam towards him before he drops dead from the [[ForMassiveDamage critical sneak attack bonus]]. Of course, you don't have to actually compensate for the Powder Ganger in question moving before you took the shot.
*** From lengthy testing and messing around, New Vegas is a weird sort of hitscan - you do have to compensate for movement and often have to lead your target, but if it registers a hit the game seems to know in advance, if not necessarily right away. It's a bit harder to be sure in Fallout 3 without mods because the sights are either horrible or nonexistent.
* In ''{{Halo}}'', most human weapons fire bullets and are hitscan. Covenant weapons, on the other hand, are almost all projectile weapons. Though it seems that the hitscan takes speed into account - this can be most easily seen with the shotgun. Firing it at the end of a wall causes the impact sparks on the near wall to appear noticeably before the far wall. In addition, the bullets (of, say, the pistol) are affected by the movements of the user. Bungie also made Marathon, which used projectile properties for all the weapons.
* In ''VideoGame/{{Unreal}}'', all of the gunpowder weapons are hitscan, but they have other drawbacks:
** The Automag is the only weapon in the game that needs reloading.
** The Sniper Rifle has the slowest firing rate.
** The Minigun has a slow ramp up and can still be dodged by your opponents in-game.
** The Combat Assault Rifle in ''[[ExpansionPack Return to Na Pali]]'' has no drawbacks whatsoever, making it the most powerful weapon in the game.
* ''VideoGame/UnrealTournament'''s version of the ASMD energy weapon is hitscan, but the tracer is particularly noticeable as not being so - because of the small shockwave that appears wherever the weapon hits, you see a small expanding circle of energy that is later joined by the tracer itself. This weapon is also used in the popular InstaGib mutator, whereupon it becomes very clear that the instant you shoot something, it dies. The gibs from the body you hit will likely be scattered everywhere before the tracer actually makes it to the location where the body once was.
* The pistol in ''[[VideoGame/LaMulana La-Mulana]]'' is hitscan, despite being a PlatformGame. It's also AwesomeButImpractical.
* The older ''VideoGame/RainbowSix'' games did this, allowing terrorists to get an [[BoomHeadshot insta-death shot]] from any range. And their accuracy wasn't affected by recoil or movement, [[TheComputerIsACheatingBastard unlike yours]].
* The Pistol, Shotgun, Plasma Rifle, and Firestorm Cannon in ''VideoGame/{{Turok}} 2''. Averted with the Bow, where the arrows are affected by gravity. (Just like real arrows!)
** The Firestorm suffers ''badly'' from tracers hitting the target long after the bullet itself.
* ''[=RoboWar=]'' originally had lasers do hitscan damage, but only 1/5 of power input, weaker even than rubber bullets. Lasers were later removed from the documentation (but left in the code for backward compatibility) and banned from tournament play.
* ''{{Warzone 2100}}'', in spite of animating and tracking individual projectiles, flagged every attack using a hitscan: If the attack was declared a hit, the target ''would'' receive damage when the projectile reached the target's location, regardless of whether the target was still there, or how long it actually took for the projectile to get there.
* ''VideoGame/TeamFortress2'': All bullet and melee weapons are hitscan, it is just the graphical tracer effect that looks slower. Stand at a distance and fire [[http://wiki.teamfortress.com/wiki/Hitscan one of these weapons]] at a wall. The bullet hole decal appears instantly, with the tracer hitting half a second later. One can also turn on damage feedback to see it in numbers. Realizing this quirk will greatly increases a player's efficiency, as attempting to LeadTheTarget (to compensate for the non-existent travel time) will actually ''cause'' HeroTrackingFailure.
** Also, while melee weapons initiate a short ranged hitscan attack, they do so only after a quarter-second delay to ensure that hits aren't made before the melee animation completes. The two exceptions to this rule are the Spy's backstab and when the Engineer uses his wrench on any of his buildings.
** The original Team Fortress had a few mods like [=MegaTF=] that, among others, changed nailguns to be HitScan, in an attempt to lower ping and latency rates.
* Lasers in ''VideoGame/MechWarrior 4'' are hitscan. This, along with good damage and range, made the Clan ER Large Laser the primary weapon of choice for online play for quite some time, well after the ExpansionPack (and later, ''[=MW4=]: Mercenaries'') were released. [[GameMod Later attempts by the fans to balance this]] only partially overcame this advantage, as lag issues (including the "No Damage Bug") tended to cause some players to miss with other, non-hitscan weaponry.
** Lasers are also hitscan in the other games of the franchise, [[AvertedTrope except for ''[=MechWarrior=] 2'' and its spinoffs]].
* In ''VideoGame/TheElderScrollsVSkyrim'', shock magic spells (e.g. Lightning Bolt) are hitscan.
* The blaster in ''VideoGame/EarthwormJim'' has a muzzle flash but fires no visible projectiles ... which is kind of bizarre in a 16-bit sprite-based platformer with minimal physics.
* Bullets in ''[[VideoGame/FirstEncounterAssaultRecon FEAR]]'' are obviously hitscan, as they hit instantly even when in BulletTime, and their impact points often don't match up with the visible tracers, sometimes hitting the player around corners.
* ''VideoGame/MapleStory'' had a (now fixed) bug in which a projectile was used and the hit would register before the projectile hit the target, also, arrows and throwing stars are known to "follow" an enemy like a heat seeking missle (Especially jumping ones).
* ''[[VideoGame/{{Tribes}} Tribes: Ascend]]'' originally had mostly hitscan weapons during the game's beta. Acting on player feedback, before the game's release Hi-Rez slowly phased out hitscan weaponry until only sniper rifles, shotguns, and two types of pistol remained hitscan weapons. Assault rifles, [=SMGs=], and other pistols were changed to projectile weapons.
* This is the main advantage of the ''VideoGame/Nitemare3D'''s pistol; the plasma gun and the magic wand both emit relatively slow-moving particles.
* In the ''Franchise/MassEffect'' series, weapon tech has reached the point to where bullets are actually small pieces from a block of metal ("ammunition block") that are first significantly reduced in mass by a new element ("element zero"), and then propelled electromagnetically to such ludicrous speeds that the hitscan is pretty well justified.
** Most of your powers have to be at least somewhat aimed because they follow a trajectory towards the nominated target, letting you do things like drop an Incinerate, Warp or Cryo Blast behind cover, and Shockwave takes a few seconds to reach the quarry, but the only delay in using Overload is the gesture you make while activating it; once it goes off, it hits the target instantly, so long as they're visible.
* ''ResidentEvil'' uses this trope for most guns, at least prior to ''ResidentEvil4''. Because you don't really aim in those games, the guns appear to use a rather generous cone of damage in which firing will damage zombies - as long as you're facing the right direction, you'll usually hit. Presumably your character handles the fine aim control him or herself. This is what makes modes like Invisible Enemy feasible (along with the fact that you rarely NEED to kill enemies, though it is helpful).

!!Aversions:
Note: For the sake of brevity, this is a list of games which do not contain hitscan weaponry ''at all''. Projectile modeling was common even in ''VideoGame/{{Doom}}''[='s=] time for certain weaponry (such as rocket launchers, which are never hitscan).

* ''VideoGame/{{Borderlands}}'' uses projectile modeling for every weapon in the game (with the Siren class having a special ability that jacks up bullet velocity, even!). So, they ALL avert this! Also, just because you don't see the projectile doesn't mean it is not there. There's a noticeable "delay" in a great majority of sniper guns, specially when you really need to snipe.
** Except for ''one''. The Eridian Lightning hits instantaneously at all ranges.
** In the second game, bullets from certain weapons (usually Torque's explosion shooting guns) take this to the point of being {{Painfully Slow Projectile}}s that you'll have to noticeably lead for human-sized targets less than ''ten feet away.''
* Give or take any Shump or Platformer game never has hit scan, and often times will depict lasers correctly.
* ''VideoGame/MaxPayne'' was one of the first games to make a big deal of not using hitscan weaponry at all; in BulletTime, every round fired can be seen as it travels towards the target.
** Particularly notable in that every round on every weapon is fully rendered even when ''not'' in BulletTime. The player can sometimes get a glimpse of bullets traveling past the player and towards the camera even in real time.
*** To show this off, on-target shots from the SniperRifle let you [[ArrowCam ride the bullet]] to the target. The FridgeLogic is that the game must know ahead of time whether or not the shot is on-target... the ArrowCam does ''occasionally'' trigger for a miss however, at least in the PC version, so presumably it's supposed to trigger when the game thinks there's a high probability of a hit.
*** This is easiest to see in ''Max Payne 2'' when you meet one of Vlad's named mooks firing his [=AK-47=]. One of Film/TheMatrix mods has a bug(?) that makes EveryBulletIsATracer at all times (as opposed to just in BulletTime), and every shot has one.
* ''[[VideoGame/{{Battlefield}} Battlefield 1942]]'' and all subsequent games in the series (excluding ''Battlefield Heroes'') also had realistic ballistics as a selling point; bizarrely, even the ''knife'' was a projectile weapon which "fired" a slow-moving instant death projectile fixed to the centre of the player's viewpoint.
* ''VideoGame/{{STALKER}}'' modeled projectile flight from all bullets, and weapon mods exist to make them fly straighter. It's also particularly helpful that EveryBulletIsATracer if you're sniping, as the bullets visibly drop over distance. It did, however, have an ''extremely'' strange quirk; the hit randomization rules for NPC targeting were also applied to the player. This meant that ''after'' you hit someone the game would basically roll a dice to check if you hit them, until ''Call of Pripyat'' removed this element.
** The Gauss Rifle is functionally a hitscan weapon, as it's firing bullets at a much greater speed than the other guns.
* ''AmericasArmy''.
* ''VideoGame/OperationFlashpoint'' and ''VideoGame/{{ArmA}}'': If it goes bang, then the projectile behaves according to the rule of physics.
* ''SniperElite'' is about keeping bullet and shooting mechanics as realistic as possible, at least without being overly aggravating. The player must account for flight time, bullet drop due to gravity, wind, and even the character's physical state. All of these can be toggled except flight time. The only jarring thing though is that certain effects like spalling from when the bullet hits a wall, tends to happen instantaneously.
* Most flight combat games (''AceCombat'', ''{{HAWX}}'', etc.) require you to lead your shots when using the airplane's main cannons.
* It's only apparent at longer ranges, but every bullet weapon in ''RedFaction'' has an actual projectile, and the rocket weapons have fuel, meaning that they will drop after a certain distance.
* ''StarWarsBattlefront'' averts this by necessity, as the nature of blaster bolts (glowing brightly and moving rather more slowly than most bullets) would make HitScan weapons very, very obvious.
** ''[[VideoGame/DarkForcesSaga Dark Forces]]'' even lowers the damage of blasters the farther the bolt has to travel.
** In ''[[VideoGame/DarkForcesSaga Jedi Knight]]'', using Force Speed and [[NotTheFallThatKillsYou running into a shot]] from a blaster weapon would result in more damage than if you'd been hit while standing still. It seems like a decent amount of the damage caused by rockets (especially noticeable with the ones that latch onto you and wait for a few seconds before detonating) was purely from the impact.
** However, one of the many technical books describing how the universe works describes that blaster bolts "hit instantly", and that the visible laser is really harmless. Of course, it's really just someone else's interpretation and not WordOfGod.
* ''VideoGame/{{Marathon}}''. All bullets, including those fired from rapid-fire weapons like the assault rifle, are tracked as regular projectiles, showing up on the player's [[EnemyDetectingRadar motion sensor]] in the process. They generally weren't affected by gravity, although grenades were. Also, the speeds Bungie set for most bullets were quite a bit slower than is realistic.
* In ''VideoGame/SilentScope'' your bullet's trajectories are affected by gravity, by movement while on a vehicle, the wind, etc., requiring you to LeadTheTarget. One of the few arcade lightgun games to do this.
* ''Police911'', where the bullets were [[PainfullySlowProjectile painfully slow]].
* Unlike its predecessor ''FarCry'', ''VideoGame/{{Crysis}}'' has no hit scan weaponry.
* ''ViewtifulJoe'' bullets and tank shells travel instantly unless you activate SlowMotion before they fire. In Slow Mo you can see the projectile and punch them back.
* The first two ''{{Descent}}'' games had an engine that did not support hitscan weapons at all, and used invisible projectiles instead for the Vulcan and Gauss cannons. However, they were so fast (around 10 times the speed of your ship) that it was just about impossible to dodge them.
* ''JaggedAlliance'' and its sequels all model the ballistics of each and every projectile fired. However, the "Chance to Hit" system determines whether the bullet will be fired at the "perfect" trajectory required to strike its target dead-center, before the bullet ever leaves the gun. It is still possible for such a bullet to end up striking the scenery nonetheless.
** The ''[=JA2 v1.13=]'' community patch adds a new system that works entirely with ballistics.
* Averted in the [[VideoGame/{{X}} X-Universe]] games. Beam weapons such as Kha'ak kyon emitters ''look'' HitScan, but modders have discovered that the game engine treats beam weapons as very fast projectile ones. This is normally transparent to the player because the projectiles are invisible, but occasionally -- typically while fighting very fast ships -- it can happen that the beam graphic crosses your target but the projectile isn't there yet, resulting in an irritatingly damage-free enemy.
* Averted by all weapons in ''VideoGame/BloodCrusher2'' except for laser-shooting guns.
* All kinetic weapons in ''{{Vanquish}}'' have visible projectiles that can be dodged in BulletTime.
* In a rare case for video games in the 90s, the PC sci-fi game Outwars averts using Hitscanning for all weaponry, even for what amounted to a man-portable railgun.
* All projectiles in ''VideoGame/{{Total Annihilation}}'' were modeled as moving projectiles, even (oddly) ones that would justifiably be hitscan such as lasers
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