The Powder Toy Lua API is a set of objects and functions that allow control over most aspects of the game, including graphics, element interactions, and interfaces.

If you are new to the Lua programming language, you should familiarize yourself with how to code in Lua. A great beginner's tutorial is available here

boxmein made a massive reference to most parts of the API, including some that are not added to this wiki yet. However, it is extremely outdated. You can find it here.

The API is split into several categories

Interface

Includes UI components such as buttons, labels, and checkboxes, access to the very primitive window manager, and input events

Renderer

Methods and constants for interacting with the display mode

Elements

Methods and constants for modifying and creating elements

Simulation

Methods for modifying the state of the simulation

Graphics

Methods for drawing simple shapes and text on the screen.

File System

Functions for creating, deleting, modifying, and enumerating files and folders.

Platform

Functions for doing OS-level things like opening URLs or interacting with the clipboard.

Event

Listen for events, such as mouse clicks or key presses.

Socket

Provides TCP sockets, effectively a severely feature-limited version of the LuaSocket library

HTTP

Provides access to basic HTTP functionality in the form of request objects.

Bzip2

Provides direct access to our bzip2 library, for compressing and decompressing data.

Bit

Doesn't actually provide any interaction with the game, but provides some functions for performing bitwise operations on integer numbers.

Legacy

Old Lua API with the tpt.* prefix