=======
Console
=======

The Console displays information, warnings, errors, and debug output from the
Level Editor, the running game, and other engine components. It also lets you
interact with runtime instances by sending commands and Lua expressions.

.. figure:: images/console.png
   :align: center

   The Console displaying messages from the editor and runtimes.

Runtime connections
===================

Each engine runtime spawned by the Level Editor is connected via TCP/IP, and
the Console is the main UI for communicating with those instances. By default
the Console is set to communicate with the editor runtime itself. When you
start the game from the Level Editor, Crown switches the Console to
communicate with the game runtime. You can also select manually which runtime
the Console talks to using the runtime selector:

.. figure:: images/console_runtime_selector.svg
   :align: center

   The runtime selector in the Console.

Commands
========

You can type both commands and Lua expressions in the Command Bar. Use
commands for low-level testing, profiling, or engine configuration. Commands
must be prefixed with a colon (``:``) so they are distinguished from Lua
expressions. Type ``:help`` in the Command Bar to see the available commands.

See :ref:`console commands` for full documentation.

Lua expressions
===============

You can send arbitrary Lua expressions to the connected runtime. Enter a Lua
expression in the Command Bar and press ``Enter``. The runtime evaluates the
expression and prints the result back to the Console. This is useful for
inspecting state, calling engine APIs, or invoking game code while the game
is running.

.. figure:: images/console_lua_expression.svg
   :align: center

   Evaluating a Lua expression in the Console.

History navigation
==================

The Console keeps a history of executed commands and expressions. Use the ``Up
Arrow`` and ``Down Arrow`` keys to navigate backward and forward through
recent entries. The maximum history size is configurable from Preferences
dialog.

Resource ID lookup
==================

For efficiency, Crown runtimes in most cases use hashed numeric identifiers
instead of plain-text strings. When the Console detects such numeric IDs, it
attempts to resolve them back to readable names so logs are easier to
understand:

.. figure:: images/console_id_lookup.svg
   :align: center

   Automatic resource ID lookup in the Console.