Basic Input System

This snippet was created and submitted by h4x0r1337.

Description

A basic way to interact with the game-engine's input system.

Code

local ffi = require "ffi"
local ffi_string, vtable_bind, getmetatable, setmetatable = ffi.string, vtable_bind, getmetatable, setmetatable

-- Module
local ButtonCode_t = {}
local ButtonCode_mt = { __index = ButtonCode_t, __metatable = "ButtonCode_t" }

--[[ Sorted by the vtable | https://github.com/perilouswithadollarsign/cstrike15_src/blob/master/public/inputsystem/iinputsystem.h#L89]]
local native_IsButtonDown = vtable_bind("inputsystem.dll", "InputSystemVersion001", 15, "bool(__thiscall*)(void*, int)")
local native_GetButtonPressedTick = vtable_bind("inputsystem.dll", "InputSystemVersion001", 16, "int(__thiscall*)(void*, int)")
local native_GetButtonReleasedTick = vtable_bind("inputsystem.dll", "InputSystemVersion001", 17, "int(__thiscall*)(void*, int)")
local native_ButtonCodeToString = vtable_bind("inputsystem.dll", "InputSystemVersion001", 40, "const char*(__thiscall*)(void*, int)")
local native_ButtonCodeToVirtualKey = vtable_bind("inputsystem.dll", "InputSystemVersion001", 46, "int(__thiscall*)(void*, int)")

function is_valid_key(value)
    return getmetatable(value) == "ButtonCode_t"
end

function ButtonCode_mt.__call(button, buttoncode_new)
    buttoncode_new = buttoncode_new or button.button
    button.button = buttoncode_new
end

function ButtonCode_mt.__eq(button_a, button_b)
    local a, b = button_a, button_b

    if is_valid_key(button_a) then a = button_a.button end
    if is_valid_key(button_b) then b = button_b.button end

    return a == b
end

function ButtonCode_t.new(button)
    return setmetatable({ button = button or 0 }, ButtonCode_mt)
end

function ButtonCode_t:is_down()
    return native_IsButtonDown(self.button)
end

function ButtonCode_t:get_pressed_tick()
    return native_GetButtonPressedTick(self.button)
end

function ButtonCode_t:get_released_tick()
    return native_GetButtonReleasedTick(self.button)
end

function ButtonCode_t:to_string()
    local string = native_ButtonCodeToString(self.button)
    if string[0] ~= nil then return ffi_string(string) end

    return nil
end

function ButtonCode_t:to_vkey()
    return native_ButtonCodeToVirtualKey(self.button)
end

return ButtonCode_t