Renders a scannable QR code to a player on a completely unmodified 3.3.5a client. No addon, no MPQ patch, no client-side files of any kind.
.qr https://www.azerothcore.org
- How it works
- Two-factor setup by QR
- Colouring QR Code
- Backends (chat and quest frame)
- Calibrating the geometry
- Known limitations
None beyond AzerothCore itself. The QR generator is vendored, so there is no new dependency, and the
only SQL shipped is one command table row, for .account 2fa qrcode.
cd modules
git clone https://github.com/azerothcore/mod-qr-code
cd ..
# reconfigure and rebuild the core as usualThen edit qrcode.conf in your config directory (the build copies conf/qrcode.conf.dist there).
| Command | Level | Description |
|---|---|---|
.qr <text> |
Game Master | Renders <text> as a QR code via the configured backend. |
.qr gossip <text> |
Game Master | Opens a gossip menu whose "Show the QR code" option presents the code, whatever the backend. |
.qr say <text> |
Game Master | Says the code aloud, so everyone in say range can scan it off their own screen. |
.qr color [name] [text] |
Game Master | Renders in one of the realm's configured colours. With no name, lists them. |
.qr swatch <texture> [texCoords] |
Game Master | Draws a candidate texture three ways so you can judge it as a module colour. |
.qr sweep <texture> [cells] |
Game Master | Samples a texture on a grid, drawing one flat bar per point with its texCoords beside it. |
.qr grid [rows] [cols] |
Game Master | Checkerboard at the active geometry, no QR encoding. Defaults to 10×10. |
.qr probe <n> |
Game Master | Draws one line of n alternating modules ending in a three-module black sentinel. |
.account 2fa qrcode [token] |
Player | Draws a new two-factor key as a code to scan; run again with a token to enable it. Turn off with QRCode.TwoFA.Enable. |
All of them need an in-game session; none work from the console. Both sides of grid are optional —
a single argument means a square of that size.
.qr say <text> sends the grid as the GM's own say chat instead of as a system message, one say per
line, so every client within ListenRange.Say (40 yards by default) draws the code in its own chat
frame. It is the way to put a scannable link in front of a crowd — an event sign-up, a Discord
invite — without every player having to run a command.
The rows always render at the chat geometry, whatever QRCode.Backend says, since chat is where they
land. Everything the chat backend needs still applies to every viewer individually: a chat frame tall
enough for the whole code, wide enough not to wrap a row, and timestamps off.
Each line arrives behind the client's <name> says: prefix. That prefix is the same width on every
row, so it shifts the grid sideways as a block rather than shearing it — which is exactly why
timestamps break the code and this does not. The say is sent as the universal language, because the
client garbles say text in a language the reading character does not know, and a garbled row is a
destroyed row.
Two things to be aware of before using it in a busy place. Viewers with chat bubbles enabled get one
bubble per line, each carrying a couple of kilobytes of escape sequences — the bubbles are not a
surface this module has calibrated, and they are the first thing to blame if a client behaves oddly.
And a code is tens of kilobytes sent to every player in range, not just to the caller, so leave the
command at Game Master and leave QRCode.CooldownSeconds alone.
.qr color <name> <text> draws a code in a named colour, and .qr color on its own lists what is
available. They ship compiled in, so they work with no configuration at all.
| red | green | blue |
|---|---|---|
 |
 |
 |
.qr color red <text> |
.qr color green <text> |
.qr color blue <text> |
| yellow | purple |
|---|---|
 |
 |
.qr color yellow <text> |
.qr color purple <text> |
Yellow is black modules on a gold ground rather than gold modules: gold is too light to threshold against white.
A coloured code is about three times taller than the same payload in black and white, because no client texture can pack several module rows into one chat line in colour.
Adding your own colour, picking a texture, and the luminance rule behind all of it: docs/colouring.md.
The world DB's command table overrides the compile-time level at load, so no rebuild is needed:
DELETE FROM `command` WHERE `name` = 'qr';
INSERT INTO `command` (`name`, `security`, `help`) VALUES
('qr', 0, 'Syntax: .qr $text\r\nRenders $text as a scannable QR code.');Reload with .reload command. Leave grid, probe, swatch and sweep at Game Master — they are
calibration tools, and probe exists specifically to send lines large enough to find the client's
limits. Leave say there too: it is the one command that ships its output to other people's clients.
The per-player cooldown and the payload echo's escape sanitisation are always compiled in, precisely so that opening the command up is a database change rather than a rebuild.
Every option lives in qrcode.conf and is documented inline there. The ones worth knowing about
before first use:
| Option | Default | Purpose |
|---|---|---|
QRCode.Backend |
1 | 1 = system chat, 2 = quest details frame |
QRCode.MaxVersion |
5 | Caps QR size. The quest frame cannot show past 3; chat past 5 is unwieldy |
QRCode.MaxPayloadBytes |
48000 | Hard cap on the generated string |
QRCode.CooldownSeconds |
5 | Per-player rate limit. Set to 0 while calibrating |
QRCode.QuietZone |
1 | Light border in modules, 1-4. Each one costs two chat lines; the spec asks for 4 |
QRCode.RowsPerLine |
3 | Module rows per chat line, 1-4. Cuts the height a code needs |
QRCode.TwoFA.Enable |
1 | Offers .account 2fa qrcode. Turn off if you set RowsPerLine to 1 |
QRCode.TwoFA.Issuer |
"" | Label shown by the authenticator app; empty means the realm name |
QRCode.DarkTexture / QRCode.LightTexture |
see conf | Texture per module colour — tinting is impossible |
QRCode.Palette.<name>.DarkTexture |
see conf | Overrides or adds a .qr color colour |
QRCode.DarkTexCoords / QRCode.LightTexCoords |
see conf | Sub-rect crop, texW:texH:left:right:top:bottom |
QRCode.Chat.ModuleWidth / .ModuleHeight |
4 / 5 | Module size. Paired with RowsPerLine; see calibrating |
QRCode.Chat.LineAdvance |
-4 | Row-offset dial; lower packs lines tighter |
QRCode.AnchorBottom |
1 | Sit the code at the bottom of its lines, not the top |
Every pixel value is a config option rather than a constant, so the whole module retunes with
.reload config — no restart, no rebuild.
Turning the code is not a way out of the height problem, tempting as it looks when the frame is
wider than it is tall. A QR symbol is square, so a quarter turn gives back a square of the same side:
the same 35 rows, the same 35 chat lines. Off-axis angles are worse than useless — a 45° turn needs a
bounding box √2 larger, taking 35 rows to about 50, and the |T escape places an axis-aligned quad
anyway, so the turned modules would have to be rasterised back onto square blocks, staircase edges
being exactly what a scanner fails on.
Compact modules keep the code small and unobtrusive. The trade-off is blank space above the code: a
chat line always reserves the full font line height (~12 px at the default chat font) however short
the drawn modules are, so every row leaves lineheight − ModuleHeight px of unfillable slack, which
piles up as empty chat above the code.
QRCode.Chat.ModuleWidth = 4
QRCode.Chat.ModuleHeight = 4
QRCode.Chat.LineAdvance = -8
Making each module as tall as the chat line itself eliminates the blank space entirely —
LineAdvance = ModuleHeight collapses the per-row offset to zero and every line is fully filled.
The code comes out ~300 px wide, so the chat frame must be wide enough: a wrapped row destroys the
grid. If thin seams appear between rows, the real line spacing is slightly larger than the module:
lower LineAdvance by 1; if rows overlap, raise it. ModuleWidth only affects width — the blank
space depends on ModuleHeight alone.
QRCode.Chat.ModuleWidth = 12
QRCode.Chat.ModuleHeight = 12
QRCode.Chat.LineAdvance = 12
The encoder wrapper, the renderer and the otpauth URI builder are pure functions with no server,
session or client dependency, and mod-qr-code.cmake registers their tests with the core's
unit_tests target:
cmake --build build --target unit_tests
./build/src/test/unit_tests --gtest_filter='Qr*'This requires the module to be built statically (the default), since unit_tests links the modules
static library.
QR symbol generation is Nayuki's QR Code generator,
C++ edition, vendored unmodified under src/vendor/ and used under the MIT licence.
AGPL-3.0, matching AzerothCore. See LICENSE.