Competitive Recoil | Technical Documentation

Thank you for taking the time to check out Competitive Recoil. On this page you’ll find a breakdown of each of the Blueprints contained within the project, how they’re intended to be used, and how you can integrate them into your own game.

BP_RecoilComponent

The Recoil Component contains the logic for equipping, shooting, and reloading weapons, as well as for calculating shot trajectory and animating the camera to simulate the recoil. As you can imagine, this one does most of the heavy lifting.

Intended to be added to a Pawn with a Camera Component, this Blueprint won’t activate unless Initialized with valid Weapon, Recoil, and Crosshair settings. Each of these is contained with their own Data Asset, making it very easy to create a wide range of weapons with different recoil parameters.

The project includes a number of sample weapons/recoil configurations to get you started.

This Blueprint adds several additional Components to your Pawn and places them in a specific hierarchy to assist with the recoil animation:

• DummyComponent (a dummy Scene Component, it always helps to have an extra transform!)
  • KickbackComponent (handles the kickback part of the recoil animation)
    • PatternComponent (handles the pattern part of the recoil animation)
• FullAutoSound (an Audio Component that plays a looping sound when firing your weapon on full auto)

Sample Curves

Name	Description
Curve_AR_Vector	Sample recoil pattern (Assault Rifle)
Curve_LMG_Vector	Sample recoil pattern (Light Machine Gun)
Curve_SG_Vector	Sample recoil pattern (Shotgun)
Curve_HeavyKickback_Float	An animation curve for heavy kickback with some oscillation
Curve_LightKickback_Float	An animation curve for light kickback, best used with rapid-fire guns

Settings

All of Competitive Recoil’s functions and variables have been given internal descriptions, but if something doesn’t make sense you’re probably not the only one, so please let me know!

Weapon

Name	Description
NiceName	The name of the weapon that’s presented in the interface
MaximumRange	The maximum distance for impact calculation
bIsAutomatic	Will this gun keep firing if you hold the trigger down?
FireRate	How many times this gun shoots per second
MagazineSize	The maximum number of times this gun can shoot before needing to be reloaded
NumberOfProjectilesPerShot	How many projectiles are fired with each shot
bUseSeedForPerProjectileDeviation	Should the random seed be used when calculating shot spread? If false the outcome will not be reproducible between shots.
MaximumPerProjectileDeviation	The maximum random deviation for each fired projectile. Only useful for guns that shoot multiple projectiles per shot.
ReloadTime	How long in seconds this weapon takes to reload
CrosshairOffset	A per-gun crosshair offset to help differentiate between more and less accurate weapons
EquipCue	The sound that plays when this gun is equipped
SingleShotCue	The sound that plays when this gun is fired once
FullAutoCue	The looping sound that plays when this gun is being fired on full auto
TailCue	The sound that plays when the gun stops firing on full auto
DryfireCue	The sound that plays when the gun is fired and the magazine is empty
ReloadCue	The sound that plays when the gun has finished reloading

Recoil

Name	Description
KickbackCurve	The name of the weapon that’s presented in the interface
KickbackStrength	The strength of this gun’s kickback animation. This is reflected in the intensity of the camera movement.
KickbackDuration	The duration of this gun’s kickback animation
bUseSeedForPatternSpread	Should the random seed be used when calculating pattern spread? If false, the random pattern spread will be different each time.
PatternCurve	The maximum random deviation while firing in a pattern. This gets more pronounced the longer you fire.
PatternDeviation	How many projectiles are fired with each shot
PatternResetDuration	How long before the recoil pattern resets after we stop shooting
bUseSeedForMovementSpread	Should the random seed be used when calculating movement spread?
MovementDeviationWalking	The maximum random deviation while moving
MovementDeviationJumping	The maximum random deviation while jumping/in midair
CameraTrackingMultiplier	How much the camera should follow the recoil pattern. Too little and the gun doesn’t feel powerful, but too much and your camera goes all over the place!

WBP_Crosshair

This Widget Blueprint contains the elements that make up the Crosshair. It draws its values from a Crosshair Settings Data Asset, making it highly customizable.

Settings

Crosshair

Name	Description
bUseCenterDot	Enable the Center Dot?
bFadeCenterDotWhenFiring	Should the Center Dot fade out while firing?
bCenterDotMovesWithFireError	Should the Center Dot animate with vertical fire error?
CenterDotColor	The color of the Center Dot
CenterDotThickness	The size of the Center Dot in pixels
bUseInnerLines	Enable the Inner Lines?
InnerLineColor	The color of the Inner Lines
InnerLineLength	The length of the Inner Lines in pixels
InnerLineThickness	The width of the Inner Lines in pixels
InnerLineOffset	The distance from the center in pixels at which the Inner Lines start
bInnerLinesUseMovementError	Should the Inner Lines animate with player movement?
bInnerLinesUseFiringError	Should the Inner Lines animate with gun recoil?
bUseOuterLines	Enable the Outer Lines?
OuterLineColor	The color of the Outer Lines
OuterLineLength	The length of the Outer Lines in pixels
OuterLineThickness	The width of the Outer Lines in pixels
OuterLineOffset	The distance from the center in pixels at which the Outer Lines start
bOuterLinesUseMovementError	Should the Outer Lines animate with player movement?
bOuterLinesUseFiringError	Should the Outer Lines animate with gun recoil?
bUseOutlines	Enable Outlines?
OutlineColor	The color of the Outlines
OutlineThickness	The thickness of the Outlines in pixels
MovementErrorMultiplier	The amount of movement when the player moves
MovementErrorSpeed	The speed of the movement when the player moves
KickbackMultiplier	The strength of the kickback movement
FireErrorMultiplier	The intensity of the recoil pattern movement
FireErrorSpeed	The speed of the recoil pattern movement
FireErrorStartFade	The distance from the center at which the topmost line starts to fade out
FireErrorEndFade	The distance from the center at which the topmost line has fully faded out
FireErrorMaxiumumHorizontal	How far the fire error will move the Crosshair horizontally. Reduce this value if crosshair movement is a little too wild when the recoil makes it move back and forth.

Frequently Asked Questions

Does it support multiplayer?

Absolutely. At the moment the client handles most of the recoil calculation, informing the server as to where to trace the trajectory of each projectile. If you’d like to add additional anti-cheat protection or gameplay effects look for where the decals are placed as a good starting place.

Does it work in VR?

I don’t see why not, but I’ve not tested it. If you’d like me to confirm before you purchase, let me know!

Why does my Crosshair get weird when I change my project’s DPI Scaling settings?

By default Unreal will try to scale your interface elements using a DPI Curve to ensure that their relative scale is consistent across a broad range of resolutions and aspect ratios. The weirdness you are seeing may be because your Crosshair is really thin (between 1-2 pixels) and as the engine tries to scale the Widget it ends up being spread across ‘half’ a pixel, making things look a little lopsided.

In the demo project I’ve solved this issue by turning DPI Scaling off entirely. This is great for me, but its a global setting so it may not be desirable if you have other interface elements that rely on it.

This is a tricky situation, and the solution may be to tweak the DPI Curve until your Crosshair looks as you expect. If that isn’t working out you may need to have multiple crosshairs for each of your target resolutions, or add some additional logic so WBP_Crosshair automatically adapts to different resolutions.