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Berke edited this page Oct 6, 2026 · 1 revision

Wall

A wall is one straight edge of a sector's outline, from a start point to an end point on the map. Walls aren't drawn separately: they appear automatically when you draw sectors, one for every edge.

What a wall looks like in the game depends on the sectors on its two sides:

Sides Result
Sector on one side only A solid wall from that sector's floor to its ceiling.
Sectors on both sides An opening (a portal) between the two rooms. Solid pieces are drawn only where the two rooms don't overlap in height: a step up, a lintel over a doorway, the face of a raised platform.

So you never make a "doorway wall". You make two sectors with different floor or ceiling heights next to each other, and the wall between them fills in the difference.

Front and back

Every wall has a direction, from start to end. Looking down on the map:

  • the front sector is on the left side of that direction;
  • the back sector is on the right side;
  • normal points toward the front (left) side.

A one-sided wall has only one of them set; the other is invalid (4294967295).

Collision

Physics tests entity colliders against the solid parts of each wall. An opening is passable as long as the entity fits through the gap. If the solid part in the way is a low step at the entity's feet, and it is no taller than its collider's Step Size, the entity steps up onto it instead of being blocked. See Collider.

In the editor

Field Lua Notes
Name Editor only. Scripts can't read it.
Front Sector / Back Sector frontSector / backSector Set by the map topology. Read-only.
Texture Index textureFileName Texture drawn on the solid parts. Empty means colour only.
Wall Color color Tint, Vector4, 0..1 per channel.
UV Offset textureOffset Shifts the texture, in texture repeats: 1.0 moves it by one whole image.
UV Scale How many times the texture repeats. 2.0 means twice as many repeats. Editor only.
Flip U / Flip V Mirror the texture horizontally or vertically. Editor only.
Tags HasTag, GetTag, tagCount Read-only from scripts.

The sector's light also darkens the wall (see Sector).

Scripting

Getting a wall

Where from How
A public field public Wall switchWall
A sector sector:GetWall(i), i from 1 to sector.wallCount
A raycast hit hit.wall, when hit.type == "Wall"

A Wall value is a safe handle. If the wall stops existing (the map was edited), isValid becomes false and any other use raises an error. sector:GetWall(i) can also return an invalid wall, so check isValid.

Properties

Property Type Description
id integer read-only Stable wall ID.
isValid boolean read-only false if the wall no longer exists.
start Vector2 read-only Start point (x, z).
end Vector2 read-only End point (x, z). end is a Lua keyword, so write wall["end"].
dir Vector2 read-only Unit vector from start to end.
normal Vector2 read-only Unit vector perpendicular to the wall, pointing to the front side.
length number read-only Length in map units.
frontSector integer read-only ID of the front sector.
backSector integer read-only ID of the back sector.
color Vector4 read/write Tint, 0..1.
textureOffset Vector2 read/write Texture shift in repeats. Change it over time to scroll.
textureFileName string read/write Texture path relative to Assets, e.g. "Textures/brick.png".
tagCount integer read-only

Methods

Method Returns Description
ClearTextureFileName() Removes the texture.
HasTag(tag) boolean true if the wall has tag.
GetTag(index) string The index-th tag, 1-based.

Any image in Assets can be switched to. When the level loads, the engine packs every .png, .jpg and .jpeg file under Assets into the texture atlas, so a script can switch to an image the level doesn't use yet. An image added to Assets while the game is running is only picked up the next time the level loads.

Getting the sector on each side

frontSector and backSector are IDs, not Sector values. To get the sector itself, look up a point just off the wall's middle:

local function SideSector(wall, side)  -- side = 1 for front, -1 for back
    local s, e = wall.start, wall["end"]
    local mid = Vector2((s.x + e.x) * 0.5, (s.y + e.y) * 0.5)
    return Game.GetSectorAt(mid + wall.normal * (0.5 * side))
end

In a sector script, the neighbour behind a wall is also in sector:GetNeighbor(i).

Walls have no callbacks

Walls can't hold scripts. To react to a wall, use a sector script on one of its sectors, or a raycast from an entity script.

Examples

Scrolling texture

-- Scripts/Walls/Scroll.lua (sector script)
-- Scrolls every wall of this sector that has the "conveyor" tag.
public Vector2 speed = Vector2(0.5, 0)

local walls = {}

function Start()
    for i = 1, sector.wallCount do
        local wall = sector:GetWall(i)
        if wall.isValid and wall:HasTag("conveyor") then walls[#walls + 1] = wall end
    end
end

function Update()
    local step = speed * GameTime.deltaTime
    for _, wall in ipairs(walls) do
        wall.textureOffset = wall.textureOffset + step
    end
end

Switch that changes texture when used

-- Scripts/Walls/WallSwitch.lua (on the player)
-- Look at a wall tagged "switch" and press E to flip it.
public number reach = 48
public Texture onTexture = nil
public Sector door = nil

function Update()
    if not Input.GetKeyDown(Key.E) then return end

    local camera = entity.camera
    if camera == nil then return end

    local hit = camera:Raycast(reach, false)

    if hit == nil or hit.wall == nil or not hit.wall:HasTag("switch") then return end

    -- An unassigned Texture field is an empty string, not nil.
    if onTexture ~= nil and onTexture ~= "" then hit.wall.textureFileName = onTexture end
    if door ~= nil then door:MoveCeilingTo(1, door.floorHeight + 40, 60) end
end

Flash every wall in a room

-- Scripts/Walls/Alarm.lua (sector script)
public Vector4 flashColor = Vector4(1, 0.2, 0.2, 1)

local walls = {}
local original = {}
local t = 0

function Start()
    for i = 1, sector.wallCount do
        local wall = sector:GetWall(i)
        if wall.isValid then
            walls[#walls + 1] = wall
            original[#original + 1] = wall.color
        end
    end
end

function Update()
    t = t + GameTime.deltaTime
    local k = (mathT.Sin(t * 6) + 1) * 0.5

    for i, wall in ipairs(walls) do
        wall.color = mathT.Vector4Lerp(original[i], flashColor, k)
    end
end

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