Walls and Textures

08 - Walls and Textures

A sector script can reach every wall of its sector:

for i = 1, sector.wallCount do
    local wall = sector:GetWall(i)   -- a Wall
    if wall.isValid then             -- always check, some slots can be empty
        Debug.Print("wall", wall.id, "is", wall.length, "units long")
    end
end

Useful Wall members:

Member	Type	Notes
wall.color	Vector4	Tint, 0..1 per channel (r, g, b, a)
wall.textureOffset	Vector2	Scrolls the texture. Change it over time for moving surfaces
wall.textureFileName	string	Swap the texture. wall:clearTextureFileName() removes it
wall.start, wall["end"], wall.length	read-only	Endpoints (Vector2) and length. end is a Lua keyword, so use wall["end"]
wall.frontSector, wall.backSector	integer IDs	backSector identifies the neighbour on a portal wall
wall:HasTag("Name")	boolean	Tags are assigned in the editor

Tags are the easiest way to say which walls a script should touch. Create a tag in the project settings, put it on the walls, and filter with wall:HasTag(...).

---

Scrolling texture

Attach to: the sector whose walls should scroll: a waterfall, a conveyor belt, lava.

-- Scripts/Walls/ScrollingWall.lua (sector script)
public number scrollX = 0.0
public number scrollY = 0.25
public string onlyTag = ""

local walls = {}

function Start()
    for i = 1, sector.wallCount do
        local wall = sector:GetWall(i)

        if wall.isValid and (onlyTag == "" or wall:HasTag(onlyTag)) then
            walls[#walls + 1] = wall
        end
    end
end

function Update()
    local dt = GameTime.deltaTime

    for _, wall in ipairs(walls) do
        local offset = wall.textureOffset
        wall.textureOffset = Vector2(offset.x + scrollX * dt, offset.y + scrollY * dt)
    end
end

Notes

• Walls are looked up once in Start and kept in a table, so Update doesn't have to search the sector every frame.
• Set onlyTag to something like Scroll to animate only some walls of the sector.

---

Texture switch (press to change a wall's texture)

Attach to: the sector containing a wall tagged Switch.

Looks at the wall and presses a key to flip it between an "off" and an "on" texture. It uses Game.Raycast from the camera to see which wall is being looked at.

-- Scripts/Walls/TextureSwitch.lua (sector script)
public Entity player = nil
public string switchTag = "Switch"
public Texture offTexture = nil
public Texture onTexture = nil
public Key useKey = Key.E
public number useDistance = 40

local switches = {}   -- wall -> on/off

function Start()
    if player == nil then
        Debug.LogWarning("TextureSwitch in sector " .. sector.id .. " has no player assigned")
        return
    end

    for i = 1, sector.wallCount do
        local wall = sector:GetWall(i)

        if wall.isValid and wall:HasTag(switchTag) then
            switches[#switches + 1] = { wall = wall, on = false }
        end
    end
end

function Update()
    if player == nil or not player.isValid or #switches == 0 then return end
    if not Input.GetKeyDown(useKey) then return end

    local camera = player.camera
    local pc = player.playerController
    if camera == nil or pc == nil then return end

    -- Cast a ray from the player's eyes (feet position + eye height) along the camera's forward direction.
    local p = player.transform.position
    local eyes = Vector3(p.x, p.y + pc.eyeHeight, p.z)
    local hit = Game.Raycast(eyes, camera.forward, useDistance, player.id, false)
    if hit == nil or hit.type ~= "Wall" then return end

    for _, s in ipairs(switches) do
        if s.wall.id == hit.wallID then
            s.on = not s.on

            local texture = s.on and onTexture or offTexture
            if texture ~= nil then s.wall.textureFileName = texture end

            Debug.Print("Switch is now " .. (s.on and "ON" or "OFF"))
            return
        end
    end
end

Notes

• hit.wallID is the ID of the wall the ray struck, which is compared to each switch wall's id.
• The fifth argument to Raycast (false) means entities don't need a collider to be hit. Walls are always hit.
• Texture fields (Texture) hold the asset's path, which can be assigned directly to wall.textureFileName.
• To make the switch do something, set a channel from 05_doors.md right where s.on changes: Global.channels = Global.channels or {} then Global.channels["door1"] = s.on.

---

Color cycling

Attach to: a sector with walls that should shimmer, like a disco room.

Cycles the tint of walls through the rainbow with three phase-shifted sine waves.

-- Scripts/Walls/ColorCycle.lua (sector script)
public number cyclesPerSecond = 0.25
public string onlyTag = ""

local walls = {}
local clock = 0.0

function Start()
    for i = 1, sector.wallCount do
        local wall = sector:GetWall(i)

        if wall.isValid and (onlyTag == "" or wall:HasTag(onlyTag)) then
            walls[#walls + 1] = wall
        end
    end
end

function Update()
    clock = clock + GameTime.deltaTime * cyclesPerSecond * 2 * math.pi

    -- Three sine waves 120 degrees apart, remapped from -1..1 to 0..1.
    local r = 0.5 + 0.5 * math.sin(clock)
    local g = 0.5 + 0.5 * math.sin(clock + 2.094)
    local b = 0.5 + 0.5 * math.sin(clock + 4.188)

    for _, wall in ipairs(walls) do
        local current = wall.color
        wall.color = Vector4(r, g, b, current.w)   -- keep each wall's own alpha
    end
end