HP Bar from GMCP

On a GMCP server, vitals arrive as data, with no prompt parsing. This renders them as a block graph docked above the input line:

local vitals = {}

rune.gmcp.subscribe("Char")
rune.gmcp.on("Char.Vitals", function(data)
    vitals = data
    rune.ui.refresh_bars()   -- render now, don't wait for the tick
end)

local function blocks(cur, max, width, color)
    local filled = max > 0 and math.floor(width * cur / max + 0.5) or 0
    return color(string.rep("█", filled)) ..
        rune.style.gray(string.rep("░", width - filled))
end

rune.ui.bar("vitals", function(width)
    local hp, mhp = tonumber(vitals.hp), tonumber(vitals.maxhp)
    if not (hp and mhp) then return "" end
    local sp, msp = tonumber(vitals.sp) or 0, tonumber(vitals.maxsp) or 1
    local hp_color = hp < mhp * 0.25 and rune.style.red or rune.style.green
    return string.format("HP %s %d/%d   SP %s %d/%d",
        blocks(hp, mhp, 14, hp_color), hp, mhp,
        blocks(sp, msp, 10, rune.style.cyan), sp, msp)
end)

rune.ui.layout({ bottom = { "vitals", "input", "status" } })

How it works

• The GMCP handler stores the data and calls refresh_bars(); the render function only formats. Keep that split, since renderers run four times a second.
• subscribe("Char") asks the server for the whole Char package.
• The layout line matters: a bar shows only if a layout dock names it.
• The bar turns red under 25% HP by swapping the style function.

Variations

• Without GMCP, feed vitals from a prompt trigger instead: rune.trigger.regex("^HP:(\\d+)/(\\d+)", ...). The bar code doesn’t change.
• Field names (sp/maxsp here) vary by game; /gmcp and the catch-all "gmcp" hook show what yours sends.

Related: Bars · GMCP · Layout & UI