Pighaus Games Docs

Infrared

Illuminators, aiming lasers and strobes that only night vision sees. Light the dark for the tubes alone, put a laser on a rifle, mark a helmet with a strobe, and watch a laser pointed at you bloom in the tube.

A tube sees further into the red than an eye does. Near-infrared light, invisible to the bare eye, lights the photocathode just as well as visible light, so anything that shines in the near infrared is a lamp to the goggle and nothing at all to everyone else. That's what infrared kit is built on: illuminators that light the dark for the tubes alone, aiming lasers that draw a line to the target, and strobes that mark a friend.

Blendable FX draws all three into every goggle, and into the scopes and binoculars that see at night. None of it shows to the bare eye, round a monocular or with the goggle off.

A fireteam's aiming lasers on a wrecked car outside the wire, and the strobes on their helmets.

Illuminators#

An illuminator is a torch for the tubes. In real deep dark, with no moon and cloud overhead, there's too little light for even a new tube to see by, and an illuminator gives it some. It lights what it points at, falling off with distance, and in haze or dust its beam shows in the air as a cone.

A goggle has one of its own. Turn on Illuminator in the goggle's settings, or call Set Night Vision Illuminator while the game runs, and a cone of infrared lights what's ahead of the player's eyes. Illuminator Strength, Beam, Range and In Air tune it.

The goggle's own illuminator switched on in the dark outside the wire, then the tower's IR flood across the ground.

For anything else, add a Blendable IR Emitter component to it, or place the Blendable IR Emitter actor, and point it along its arrow. Set its Kind to Illuminator for a weapon light, a vehicle's IR headlights or a tower's IR flood, and its Brightness, Beam Angle and Range to suit. Beam In Air is how hazy the air is: seen from the side, a tower's flood shows as a cone, and seen from right behind, as a player sees the light on their own rifle, the haze glows across the whole beam. A light the player carries looks best dim and in clear air: the rifle's light in these clips has a Brightness of 0.25 and a Beam In Air of 0.006, and the tower's flood 2 and 0.6.

Aiming lasers#

An aiming laser draws a line from the weapon to the target, through the air, and puts a dot where it lands. Through a tube the beam is a thin bright line, brightest near the emitter, and the dot is a small glowing ball that blooms. It's a ball rather than a spot painted on the surface because a painted spot stretches into a long smear when you see the surface edge on, which reads as a hole at the end of the beam; the tube blooms a real dot round anyway. The dot sits on whatever is drawn where it lands, even when the collision the laser stopped at is a few centimetres behind it, as under a wall's painted skin, a floor's finish or a decal. On a real rifle the laser comes from an aiming unit on the rail, a box that usually carries an IR aiming laser and an IR illuminator side by side, zeroed to the sights. So attach the emitters to that unit, at a socket on its mesh where each aperture is: set one IR Emitter's Kind to Laser and another's to Illuminator. A laser stops at the first thing in its way, so the dot lands on walls, ground and people as the weapon moves. Whatever carries it never gets in its way: the actor it's attached to, and whoever owns that.

A real beam isn't a clean line. It shows because dust and moisture in the air catch it, so it flickers as the air moves and it's brighter in some places than others. Beam Flicker and Beam Flicker Rate set how much it dips and how quickly; Beam Noise sets how patchy it is along its length, Beam Noise Size how long the patches are and Beam Noise Drift how fast they float along it. Beam Glow is the soft glow round the line, from a bare thin line at 0. For the dot, Dot Size and Dot Brightness set the ball, Dot Glow its bloom (turn it down if the end of the beam gets lost in it) and Dot Spill adds a flat spot of light on the surface round it, which looks right head on and stretches at a shallow angle. Every laser flickers and drifts to its own pattern, so a team's lasers never pulse together.

The aiming unit on the player's rifle, its laser and illuminator swept across the dark.

A laser is a line pointing straight back at whoever holds it, and that works both ways. Every illuminator and laser glows when it faces the tube and nothing stands in the way, faint from the side and brightest straight on: Glow sets how much. Look straight down a laser's beam, or stand in an illuminator's, and it floods the tube the way a real one does, blooming into a star while the gain drops round it.

A guard turns their laser on the camera.

Strobes#

An IR strobe is a small flashing marker, invisible to the bare eye: on a helmet to pick a friend out of a crowd, on a vehicle, or on a post to mark a landing zone. Set an IR Emitter's Kind to Strobe, with Flashes Per Second, Flash Length and Strobe Brightness. Strobes side by side don't flash together, each keeping its own beat.

Only through the tubes#

Infrared is drawn into the tubes' own light, before the gain, so the goggle treats it as it treats any other light. A strong illuminator close up lights the scene enough that the auto gain gates down for it, and a dot or a strobe blooms into a halo as wide as the tube's halos are. Round a monocular, the bare eye sees none of it.

A monocular: the lasers in the tube, nothing beside it, and nothing when the goggle comes off.

Set On and Toggle on the component switch an emitter while the game runs, so a player can switch their laser and illuminator with a key.

Go deeperWhy it isn't a real light

The game renders its world once, and every eye sees that one picture: the bare eye round a monocular, the world round and under any goggle, and everyone when it flips up. A real Unreal light lights that picture, so the bare eye would see it too, and Unreal can't light the world for one eye and not the other. So infrared isn't in the scene the game renders: the tube adds it to its own light, and only the tube sees it.

Each frame the plugin gathers the IR emitters that are on, the nearest four illuminators, four lasers and eight strobes to the camera, traces each laser to where it lands, and checks whether each emitter is in sight. The tube's pass then lights the picture with them as a lamp would, from its own depth, normals, colours and glossiness: each surface by how it faces the light, wet and polished ones glinting, in the shadow of anything in the picture between it and the light, with each illuminator's beam brightest in the middle and fading softly to its edge. The beams in the air are gathered along the view, and each laser by its closest approach to every pixel. It costs nothing when no emitter is on. Shadows come only from what's in the picture: something off screen between a flood and what it lights doesn't block it, and a light at the eye, as a goggle's own or a rifle's is, hides its shadows behind what casts them anyway.

Where next#