Chapter 4: Input and Player Movement

Technical requirements

Overview of the input system

rawinput.go, physical input abstraction

Imports and InputButtonType

RawInputButton struct

Constructors for RawInputButton

IsPressed, IsJustPressed, IsJustReleased, the temporal difference

IsPressed, current held state

IsJustPressed, first frame only

IsJustReleased, release frame only

PressDuration, frames held

action.go, Action with trigger mode

ActionMode, when the action fires

ActionMode.Has, flag check

ActionType, input device

Action struct

Action constructors

Action getters

actionmap.go, ActionID to Action mapping

ActionID and ActionMap struct

NewActionMap and AddAction

RemoveAction, GetAction, ClearActions

SetKeyBinding and ErrActionNotFound

statebuffer.go, tracking state across frames

InputState and StateBuffer struct

NewStateBuffer

Update, keyboard loop

Update, mouse loop

IsActionActive and checkState

inputmanager.go, two input APIs

Frame flow through InputManager

ActionBinding and InputManager struct

NewInputManager

Update

AddAction

RemoveAction

IsActionPressed, IsActionJustPressed, IsActionJustReleased, IsActionReleased, comparing the four methods

IsActionPressed

IsActionJustPressed, IsActionJustReleased, IsActionReleased

RegisterAction and IsActionActive (ActionID API)

ActionMap accessor

engine.go, adding InputManager and Update

Engine struct

NewEngine

Input accessor

Update with input.Update()

Draw and Layout

Game setup and movement

Game struct

NewGame, building the scene

game_init.go, loading textures

game_init.go, binding arrow keys

game_init.go, floor setup

player.go, player constants and type

player.go, creating the player

player.go, reading movement input

player.go, normalize and move

game.go, Update, Draw, and Layout

run.go and cmd/main.go, entry point

Running the chapter

Summary