The Minecraft Overviewer

a high-resolution Minecraft world renderer with a LeafletJS interface

EmceeOverviewer Help

Our #overviewer IRC channel has a customized bot named EmceeOverviewer, which is able to do a lot of interesting and helpful things. This is an incomplete list of the things it can do.

EmceeOverviewer is free software, and may be found on GitHub. Some of the more specialized commands (like build and render) are not in the public source, because the code is ugly and/or contains location-specific hacks.

Issuing Commands

There are 3 primary ways to issue commands to EmceeOverviewer. The classic way is much like addressing him directly:

EmceeOverviewer, <command>

EmceeOverviewer will also respond to the names "emcee" and "mco", and will accept a colon or space instead of a comma. So, all of the following are acceptable:

EmceeOverviewer: <command>
emcee, <command>
mco <command>

You may also issue commands by prefixing the command with a "!", for example:


If you want to issue a (usually short) command inside a more general message, you can surround any command with parenthesis "()" or brackets "[]" to issue an inline command. For example:

Hey, check out this (!<command>) cool link!
I'll render that for you. [emcee, <command>]

If you want to issue a command but don't want to spam up the channel, use private messages. If you use PMs, you don't need any special syntax for commands, just use the command name:

/msg EmceeOverviewer <command>

All of these forms work with all commands, so do whatever seems best to you.

Convenience Commands

GitHub Integration and Commands

EmceeOverviewer will announce GitHub events (like pushes, open issues, ...) to the channel as they happen, for all repositories he follows on GitHub. If you want to be added to this list, just ask agrif (Emcee's operator).

In addition to announcing events, Emcee also supports a few convenience commands.

Searching Issues

To do a search for a specific issue number, use issue <num>. Emcee also supports issue #<num>. If you want to search by phrase instead, use issue <phrase>, where <phrase> can be anything (even including spaces!).

If you want to search on something other than the main repo, put on <username> at the end to search through that user's repo issues instead. For example,

!issue blocks on agrif

will search for issue with the phrase "blocks" on agrif's repo. This works with issue numbers too, and will also accept "in", "for", or "of" instead of "on". The pull command is an alias for issue.

Linking to Specific Lines

You can have Emcee generate a link to a specific file and line by issuing a command of the form <filename>:<lineno>. For example, to link to line #50 of, you could issue:


Like the issue command, this supports the "in", "for", "of", "on" syntax to select a specific user's repo.

This is particularly useful as an inline command. For example:

Hey, what does this line do? (!src/overviewer.h:12)

Building Overviewer Packages

(Note: right now, for safety reasons, this command is restricted-access. If you want to be put on the access list, just ask agrif)

Emcee is able to build py2exe and debian packages (and possibly other binary packages) automatically, on command. To have Emcee build something for you, use build <target>. Run build (with no targets) to get a list of supported targets.

If you want to build something other than the default sources, you can add a repo user and commit to the build command. For example,

build <target> agrif

will build the "master" branch on agrif's repo, and

build <target> agrif/some-branch

will build the "some-branch" branch on agrif's repo.

Uploading Packages

Emcee now has the ability to build and upload a bunch of targets at once, to facilitate releasing new versions of Overviewer. The basic command is upload, which will build and upload every available target. Windows packages are uploaded to GitHub, and debian packages are uploaded to the APT repository.

Like build, upload also takes a repo/branch as an optional argument if you wish to release something other than overviewer/master. In this case, Windows builds are uploaded to the appropriate repository.

Finally, you can specify what targets you want to upload:

upload targets deb32 deb64
upload agrif targets win*

The target list supports shell-style globbing.

release is an alias for upload, and both commands require confirmation before doing anything, as a precaution.

Rendering the Exmaple

In addition to building packages, Emcee can also do render tests on command. To generate a test render, run render. Like the build command, render also supports specifying a user and commit.

Renders generated this way will always have all rendermodes enabled, but will otherwise be completely unmodified.

Recently I added support for providing options to each render. Just provide them after the command like you would on the command line. Because of this new flexibility, this command is now limited to people with build access.

For example,

!render overviewer --north-direction="upper-left"