Holograms ​

A hologram block declares a named stack of floating text: a base location, a billboard mode, an optional scale and refresh cadence, and a restricted lines { } DSL that reads like the scoreboard sidebar. Each line is a text display entity, auto-stacked 0.28 blocks apart; the runtime tracks them by name, so you show, edit, move, and remove holograms by name — never by entity handle.

hologram "rules" {
    location: location(4, 70, 4)
    billboard: fixed
    lines {
        line "<aqua><bold>Server Rules"
        line "<gray>1. Be nice"
        line "<gray>2. No griefing"
    }
}

command "showrules" {
    execute {
        show hologram "rules" to all
    }
}

A hologram is declared once at the top level and shown from any handler. Declaring it does not place it in the world — nothing renders until a show statement targets a player or all.

Declaration keys ​

The billboard mode is an enum, checked at compile time — center, vertical, horizontal, and fixed are the four Minecraft display billboard constraints. Anything else is rejected:

bad_hologram_billboard.sw:3:5: error: unknown billboard mode 'diagonal'

The lines block ​

lines { } is a restricted DSL — only four statement forms are allowed, the same shape as a scoreboard's lines:

hologram "board" {
    location: location(0, 66, 0)
    lines {
        line "<gold><bold>Leaderboard"
        blank
        loop 3 times {
            line "<yellow>* * *"
        }
    }
}

Anything else inside lines { } is a compile error that names the four legal forms:

hologram_bad_line_dsl.sw:4:9: error: Unexpected identifier 'entry': only 'line', 'blank', 'if', and 'loop' are allowed inside 'lines { }'

Per-viewer holograms ​

When a line interpolates a player-scoped path — ${player.name}, player.health, anything reached through the viewing player — the whole stack renders per viewer. The compiler detects this automatically: the same player-binding machinery as per-viewer scoreboards runs the lines block once per player who is shown the hologram, so each sees their own text.

hologram "spawn_info" {
    location: location(0, 65, 0)
    billboard: center
    scale: 1.5
    update: every 1 seconds
    lines {
        line "<gold><bold>Welcome!"
        blank
        line "<gray>Hi ${player.name}"
        if player.health > 10 {
            line "<green>Healthy"
        } else {
            line "<red>Careful"
        }
    }
}

command "welcome" {
    execute {
        show hologram "spawn_info" to sender
    }
}

A hologram with no player-scoped line is global: one shared stack rendered for everyone it is shown to. update: every <dur> re-runs the lines block on that cadence, so interpolated counters and per-viewer conditions stay current without a manual refresh loop.

Per-tick handler ​

An on_tick() handler runs every tick with this bound to the hologram's text-display stack, a lower-level companion to update: every <dur> when you need per-frame control over the line displays rather than a fixed re-render cadence:

hologram "clock" {
    location: location(0, 66, 0)
    lines {
        line "<aqua>Clock"
    }
    on_tick() {
        set this.text to "<aqua>Clock"
    }
}

Statements ​

Every hologram statement addresses a declared hologram by name:

hologram "shop" {
    location: location(0, 82, 0)
    lines {
        line "<gold><bold>Item Shop"
        line "<gray>open"
    }
}

command "closeshop" {
    execute {
        set hologram "shop" line 1 to "<red>closed for maintenance"
        move hologram "shop" to location(2, 82, 0)
        show hologram "shop" to all
    }
}

Holograms are cleared on engine reload and shutdown, and re-torn-down when a viewer disconnects — no dangling display entities to sweep up.

Coming from a hologram plugin ​

# FancyHolograms — holograms.yml, then an in-game /hologram create,
# then commands or a separate Skript to change lines at runtime
rules:
  location: world, 4, 70, 4
  billboard: FIXED
  lines:
    - "<aqua><bold>Server Rules"
    - "<gray>1. Be nice"

hologram "rules" {
    location: location(4, 70, 4)
    billboard: fixed
    lines {
        line "<aqua><bold>Server Rules"
        line "<gray>1. Be nice"
    }
}

command "showrules" {
    execute {
        show hologram "rules" to all
    }
}

Diagnostics ​

A hologram statement that names a hologram no script declares is caught at compile time, with the declaration you're missing spelled out:

unknown_hologram_ref.sw:3:9: error: unknown hologram 'ghost'; declare it with 'hologram "ghost" { }'