Introduction

This document outlines the controller components that are used to abstract input in Pie Noon.

Overview

Pie Noon uses the concept of controllers (controller.h) to abstract input from multiple controller types into one consistent interface. Each controller serves as an adapter between a specific type of input (keyboard, touchscreen, gamepad, etc) and the game.

This way, the game can ignore the details of how the input is being created, and simply operate on a consistent set of input fields.

Logical Inputs

Input is broken down into a number of "Logical Inputs", enumerated in character_state_machine.fbs. These correspond to basic actions that a player can trigger. Things like "navigate left", "Throw a pie", "select a menu option" are all logical inputs. The controller classes then serve primarily to serve as a translation layer, and map things like "Keyevent_Gamepad_Left" onto their corresponding logical input. (LogicalInputs_Left in this case.)

Note that there are also several logical inputs that are not triggered by the player's input, but rather by the game state. (NoHealth, AnimationEnd, JoinedGame, etc.)

Controller Handling

There are several different types of controllers, each responsible for handling a different sort of input. The main game (pie_noon_game.h/.cpp) maintains maintains a list of all controllers it is listening to, as well as a separate list of all controllers that are currently in the game. Whenever a player indicates that they want to join the game, the corresponding controller for that player is moved into the list of controllers in the game. When a game starts, the remaining slots are populated by ai controllers.

Each controller is responsible for implementing an AdvanceFrame() method, which the game guarantees it will call once per update. It typically uses this function to query whatever input it is listening for, and translate it into logical input bits.

Controller

The base class for all controllers. In addition to defining a virtual method for AdvanceFrame(), it also contains some common code for bookkeeping and accessors for the logical input bits.

PlayerController

Represents a controller that listens to keyboard input. It contains several different keyboard configurations, and each instance can be set to listen to a different one.

Controller

A controller that listens to gamepad input. Note that because these use the android event system to track gamepad inputs, they are ommitted from non-android builds.

AI controllers

These controllers are somewhat unique - they don't translate inputs from a player into game inputs - instead they represent computer-controlled players, and as such take the gamestate itself as input, and choose moves based on what would make sense for them to do.

There are several constants in config.json that control the behavior of the computer-controlled players.