EMP pulse

Immobilizes objects inside a warhead-sized radius for a weapon-defined number of frames.

Changed in 0.2.0

Firing a pulse

A projectile whose warhead sets EMEffect=yes creates a pulse where it detonates, instead of dealing blast damage. The warhead’s Spread sets the pulse’s radius in cells. The firing weapon’s Damage sets how long its stun lasts, in game frames.

In ordinary combat, the firer’s firepower modifiers scale Damage before it becomes the duration. The EM pulse cannon and the mobile EMP vehicle below use Damage unscaled.

The explosion animation is picked at random from the warhead’s AnimList, not by the size of Damage.

[EMPuls]           ; the warhead that makes the pulse
Spread=11          ; the pulse's radius, in cells
EMEffect=yes       ; detonation creates a pulse instead of blast damage

[EMPulseWeapon]    ; the weapon the pulse comes from
Damage=1200        ; the pulse's duration, in frames
Range=40           ; how far from the cannon the cursor allows a launch
Warhead=EMPuls

[NAPULS]           ; a structure that can serve as a launch site
EMPulseCannon=yes
SuperWeapon=EMPulseSpecial
Primary=EMPulseWeapon

[EMPulseSpecial]   ; the superweapon that launch site serves
Type=EMPulse
Action=EMPulse     ; the targeting cursor

EM Pulse Cannon superweapon

A superweapon declared Type=EMPulse fires from a launch site. On launch it picks the structure nearest the target that meets all of:

it belongs to the firing house;
it is on the map, not in limbo;
its type sets EMPulseCannon=yes;
it is operational: not stunned, not switched off, and not idled by low power.

If no structure qualifies, nothing is fired, but the superweapon’s charge is still spent. Superweapons covers why a one-time EM pulse never launches.

Each house holds one pulse target. A second launch before a cannon has fired therefore sends that cannon’s shot to the new target.

Give the superweapon Action=EMPulse so the player can aim it. A click on the in-range cursor fires the first superweapon that declares Action=EMPulse, so two EM pulse superweapons cannot be aimed separately.

While the player aims an EM pulse superweapon, the cursor shows the in-range form only if the player owns an operational cannon and the target lies within the Range of the nearest such cannon’s primary weapon. Elsewhere it shows the out-of-range form. The superweapon’s Action does not change which form appears.

A click on the out-of-range cursor fires the first superweapon that declares Action=EMPulseRange, and launches nothing if none does. The launch has no range limit of its own, so an EM pulse superweapon declared Action=EMPulseRange fires at any distance.

The chosen cannon turns toward the target and creates the hard-coded animation PULSBALL at its muzzle. Thirty-two frames later it fires its primary weapon at the target, and the pulse comes from that weapon’s warhead. EMPulseWarhead and EMPulseProjectile in [SpecialWeapons] have no effect.

Mobile EMP vehicle

A UnitType with IsMobileEMP=yes starts with StartCharge and gains one point of charge per frame up to MaxCharge. It gains nothing while stunned. Deploying does nothing until the charge is full, and the deploy cursor is refused until then.

With a full charge, deploying fires the weapon MobileEMPulseWeapon at the vehicle’s position, resets the charge to 0, and returns the vehicle to guard. The weapon name is hard-coded. The pulse does not stun the vehicle that fired it.

Scripted explosion

The Do Explosion At trigger action deals its weapon’s ordinary blast damage at the waypoint. If the weapon’s ID is empulseweapon, in any letter case, it then also creates a pulse there from that weapon’s Damage and its warhead’s Spread.

Because the same warhead deals the blast, Spread sets both the pulse’s radius and the blast’s falloff. The two cannot be tuned separately on this path.

A scripted pulse has no firer. Kills it causes are credited to no one.

What a pulse reaches

A pulse takes effect once, on the frame it is created. It never grows, and an object that enters the radius afterward is unaffected. The pulse checks aircraft first, then burrowing objects, then every cell in its radius. That cell sweep covers every cell within Spread cells of the pulse’s cell, measured in whole cells, boundary included.

An immune type is one that sets ImmuneToEMP=yes. A structure or vehicle type that omits the key is immune when it sets IsCoreDefender=yes.

Aircraft

The pulse catches an aircraft when all of:

it is on the map, not in limbo;
its strength is above zero;
it is less than one height level above the ground;
its center is less than Spread cells from the center of the pulse’s cell.

The distance also counts the aircraft’s height above the map’s lowest ground level. Each terrain height level adds about four tenths of a cell, so over raised terrain the reach shrinks. On high ground a small pulse can miss an aircraft in its own cell.

A caught aircraft springs the Paralyzed event on its trigger. If it is off the ground, it crashes unless its type is immune. Its strength drops to zero, the firer is credited with the kill, and its passengers die. An aircraft taking off or landing is caught this way.

An aircraft standing on the ground does not crash. The cell sweep below then treats it like a vehicle, so it springs Paralyzed a second time and, unless immune, is stunned. The sweep skips it if it stands in a structure’s cell.

An aircraft one height level or more above the ground is out of the pulse’s reach entirely, so a pulse under a flight of aircraft leaves them flying.

Burrowing objects

An object traveling underground with a tunnel locomotor is stunned when its cell is less than Spread cells from the pulse’s cell. An immune type is not stunned, but it still springs Paralyzed.

At either end of its trip the object stands on the surface, and the cell sweep handles it instead. The sweep also takes cells exactly Spread cells away, so at that distance an underground object escapes where a surface object would not.

Structures

A structure is tested only on the cell that holds its center:

An InvisibleInGame=yes structure is skipped entirely.
An immune structure springs Paralyzed and nothing else.
An IsLimpetMine=yes structure is destroyed, with the firer credited.
Any other structure is powered off and stunned, and springs Paralyzed. A structure that is one of the deployed-vehicle kinds also gets an EMPulseSparkles animation.

Vehicles and infantry

The sweep reaches only objects on the ground. A vehicle in the air, such as a jumpjet in flight, is out of reach.

The sweep skips every object in a cell that holds any part of a structure, even when that structure is outside the radius. Objects on a bridge are not reached either.

In other cells, the result depends on the object:

Object	Result
Vehicle or aircraft	Stunned and springs Paralyzed
Infantry whose type sets `Cyborg=yes`	Stunned and springs Paralyzed
Either of the above with an immune type	Springs Paralyzed only
The vehicle or aircraft that fired the pulse	Nothing, or Paralyzed only if its type is immune
A large or small visceroid	Nothing, unless its type is immune, which springs Paralyzed only
Other infantry	Nothing

When several objects share a cell, as cyborgs can, the sweep may miss some of them.

While stunned

A stun lasts the pulse’s full duration. A second pulse sets the stun to its own duration, which can shorten a stun already running.

A stunned vehicle, cyborg or aircraft stops where it is and cannot move. It is given an EMPulseSparkles animation. The player cannot deploy it, and a mobile EMP vehicle neither charges nor discharges.

A stunned object cannot fire. Unless it has the CLOAK ability or stands in its house’s cloaking field, it uncloaks and cannot recloak until the stun ends.

A stunned structure is powered off: its lights, laser fence and cloaking field stop. Its powered animations stop too, but restart the next time its house’s power balance changes while the house has enough power. The player cannot switch it back on or undeploy it. It cannot serve as a launch site for the EM pulse cannon. A stunned Radar=yes structure can take away the player’s radar map, as radar describes.

A stun does not change a structure’s power output or drain. A stunned power plant keeps feeding the grid, as what each structure contributes describes.

Recovery

Each object recovers when its own stun runs out:

A structure powers back on, and a Radar=yes structure can supply the radar map again. One the player had switched off stays off.
A vehicle, cyborg or aircraft can move again.
A harvester listed in HarvesterUnit is sent back to harvesting, unless it was unloading.

A sparkle animation still playing stops at the end of its current loop.

Filter keys

9 of 9

Key	Description	Value	When omitted
`Damage`AnimType, ParticleType, VoxelAnimType, WeaponType	A weapon's damage per shot, or the damage an animation, particle or voxel animation deals.	floating point	Varies by type
`EMEffect`WarheadType	A projectile carrying the warhead creates an EM pulse where it detonates instead of dealing blast damage.	boolean	`no`
`EMPulseCannon`BuildingType	Lets a BuildingType serve as the launch site of an EMPulse superweapon.	boolean	`no`
`EMPulseSparkles`global rules	The animation attached to an object an EM pulse stuns.	class	`none`
`ImmuneToEMP`AircraftType, BuildingType, InfantryType, UnitType	Stops an EM pulse from stunning, powering off, downing or destroying objects of this type.	boolean	Context-dependent
`IsMobileEMP`UnitType	Makes a vehicle build up an EM pulse charge and discharge it where it stands when it is deployed.	boolean	`no`
`MaxCharge`UnitType	The charge a mobile EMP vehicle must reach before it may discharge.	integer	`0`
`Spread`WarheadType, Tiberium	How slowly a warhead's damage thins with distance, or the frames a Tiberium type waits between spread passes.	integer	Varies by type
`StartCharge`UnitType	The charge a vehicle is created with, which only a mobile EMP vehicle spends.	integer	`0`

History

Changed0.2.0In development
Let a type say it is immune to an EM pulse