TIC-80

October 18, 2022

Basic setup

function init()
end

init()

function TIC()
 -- here lies our game loop
end

Game loop

function TIC()
    global.time=global.time+1
    input()
    if global.time%global.updateSpeed==0 then
        update()
    end
    draw()
end

General helper functions

function cos(x) return math.cos(x) end
function sin(x) return math.sin(x) end
function tan(x) return math.tan(x) end

function rnd(x,y) return math.random(x,y) end
function rndArray(a) return a[math.random(#a)] end

function ins(t,e) return table.insert(t,e) end
function rmv(t,e) return table.remove(t,e) end

-- get maximum of two numbers
function max(n1,n2) return math.max(n1,n2) end
function clamp(v,l,h) return math.min(math.max(v,l),h) end

It might be even easier to use the following shortcuts:

cos = math.cos
sin = math.sin
tan = math.tan
rnd = math.random
sqrt = math.sqrt
rad = math.rad
min = math.min
max = math.max
abs = math.abs

Specific helper functions

Color palette

For the standard color palette SWEETIE-16.

-- enum for sweetie-16 color palette
local COLOR = {
    BLACK = 0,
    PURPLE = 1,
    RED = 2,
    ORANGE = 3,
    YELLOW = 4,
    LIGHT_GREEN = 5,
    GREEN = 6,
    DARK_GREEN = 7,
    DARK_BLUE = 8,
    BLUE = 9,
    LIGHT_BLUE = 10,
    CYAN = 11,
    WHITE = 12,
    LIGHT_GREY = 13,
    GREY = 14,
    DARK_GREY = 15,
}

Physics

Simple collision

-- simple rectangle collision
function collide(a, b)
    -- get parameters from a and b
    local ax = a.x
    local ay = a.y
    local aw = 8
    local ah = 8
    local bx = b.x
    local by = b.y
    local bw = 8
    local bh = 8

    -- check collision
    if ax < bx + bw and ax + aw > bx and ay < by + bh and ah + ay > by then
        -- collision
        return true
    end
    -- no collision
    return false
end

Add velocity to object

function addVelocityToObject(o)
    o.x = o.x + o.vx
    o.y = o.y + o.vy
end

Apply friction to object

function applyFrictionToObject(o,fx,fy)
    o.vx = o.vx * fx
    o.vy = o.vy * fy
end

Apply gravity to object

function applyGravityToObject(o, g)
    o.vy = o.vy + g
    o.vy = min(max(o.vy, -3), 3)
end

Sprite Animations

-- time returns the number of milliseconds elapsed since the application began
-- // will auto round the result
-- as higher the animSpeed, as slower the animation will be
local animSpeed = 128
local spriteID = (time()//animSpeed)%2

Print text

With a border

c1 defines the inner color. c2 defines the border color.

function printf(t,x,y,c1,c2)
    local x=x or 0
    local y=y or 0
    local c1=c1 or 12
    local c2=c2 or 0

    print(t,x-1,y,c2)
    print(t,x,y-1,c2)
    print(t,x+1,y,c2)
    print(t,x,y+1,c2)
    print(t,x,y,c1)
end

With a shadow at the top

c1 defines the shadow color at the top. c2 defines the color of the text.

function printf(t,x,y,c1,c2)
    local x=x or 0
    local y=y or 0
    local c1=c1 or 12
    local c2=c2 or 0

    print(t,x,y,c1)
    print(t,x,y+1,c2)
end

Horizontally centered

f defines the flag indicating whether fixed width printing is required. s defines the scale.

function printhc(t,y,c,f,s)
    local f=f or false
    local s=s or 1
    local w=print(t,-8,-8)*s
    local x=(240-w)/2
    print(t,x,y,c,f,s)
end

Vertically centered

f defines the flag indicating whether fixed width printing is required. s defines the scale.

function printvc(t,x,c,f,s)
    local f=f or false
    local s=s or 1
    local w=print(t,-8,-8)*s
    local y=(136-6)/2
    print(t,x,y,c,f,s)
end

Centered

f defines the flag indicating whether fixed width printing is required. s defines the scale.

function printc(t,c,f,s)
    local f=f or false
    local s=s or 1
    local w=print(t,-8,-8)*s
    local x=(240-w)/2
    local y=(136-6)/2
    print(t,x,y,c,f,s)
end

Simple Scene Manager

-- global game table
G={
    runtime=0,
    SM={}
}

-- SCENE CLASS
local scene={}
function scene:new(o)
    o=o or {}
    self.__index=self
    setmetatable(o,self)
    o.timePassed=0
    return o
end

function scene:onExit() end
function scene:onEnter() end

-- SCENE MANAGER CLASS
local sceneManager={}
function sceneManager:create()
    self.__index=self
    o=setmetatable({},self)
    o.currentScene={}
    o.scenes={}
    return o
end

function sceneManager:addScene(s)
    table.insert(self.scenes,s)
end

function sceneManager:setCurrentScene(s)
    self.currentScene=s
end

function sceneManager:switchScene(s)
    if self.currentScene~=s then
        self.currentScene:onExit()
        self.currentScene=s
        self.currentScene:onEnter()
    end
end

-- main
local bootScene=scene:new({})
local mainMenuScene=scene:new({})

function init()
    G.SM=sceneManager:create()
    G.SM:addScene(bootScene)
    G.SM:addScene(mainMenuScene)
    G.SM:setCurrentScene(bootScene)
end

init()

function TIC()
    if btnp(6) then
        if G.SM.currentScene==bootScene then
            G.SM:switchScene(mainMenuScene)
        else
            G.SM:switchScene(bootScene)
        end
    end
    G.SM.currentScene:update()
    G.SM.currentScene:draw()
    G.runtime=G.runtime+1
    printhc("Press A to change the scene",100,4)
    rectb(0,0,240,130,4)
end

-- Boot Scene
bootScene.update=function()
    bootScene.timePassed=bootScene.timePassed+1
end

bootScene.draw=function()
    cls()
    printhc("Boot Scene",40,5)
    printhc("Scene time: " .. bootScene.timePassed,50,13)
    printhc("Global time: " .. G.runtime,60,14)
end

-- Main Menu Scene
mainMenuScene.update=function()
    mainMenuScene.timePassed=mainMenuScene.timePassed+1
end

mainMenuScene.draw=function()
    cls()
    printhc("Main Menu Scene",40,10)
    printhc("Scene time: " .. mainMenuScene.timePassed,50,13)
    printhc("Global time: " .. G.runtime,60,14)
end

-- short general helper functions
function max(n1,n2) return math.max(n1,n2) end
function printhc(t,y,c)
    local w=print(t,-8,-8)
    local x=(240-w)/2
    print(t,x,y,c)
end

Finite state machine

-- FINITE STATE MACHINE

-- Machine
local fsmBase={}

function fsmBase:new()
    self.__index=self
    o=setmetatable({},self)
    o.states={}
    o.curState=nil
    return o
end

function fsmBase:addState(s)
    self.states[s.name]=s
end

function fsmBase:setCurrentState(s)
    self.curState=s
end

function fsmBase:update()
    self.curState:onUpdate()
end

function fsmBase:switch(n)
    if self.curState.name~=n then
        self.curState:onExit()
        self.curState=self.states[n]
        self.curState:onEnter()
    end
end

-- Base State
local baseState={}

function baseState:new(n)
    self.__index=self
    o=setmetatable({},self)
    o.name=n
    return o
end

function baseState:onEnter() end
function baseState:onUpdate() end
function baseState:onExit() end

Simple particle system

-- SIMPLE PARTICLE CLASS
local particles = {}

local particle = {}
function particle:new(x,y)
    self.__index=self
    o = setmetatable({}, self)
    o.x = x
    o.y = y
    o.dx = rnd(-8,8)
    o.dy = rnd(0,0)
    o.life = rnd(2,40)
    o.color = rnd(0,15)
    return o
end

function particle:update()
    self.x = self.x + self.dx
    self.y = self.y + self.dy
    self.life = self.life - 1
    if self.life < 0 then
        local i = tblFind(particles,self)
        table.remove(particles,i)
    end
end

function particle:draw()
    pix(self.x,self.y,self.color)
end

-- main
function TIC()
    ins(particles,particle:new(118,58))
    updateParticles()
    drawParticles()
end

function updateParticles()
    for _,v in pairs(particles) do
        v:update()
    end
end

function drawParticles()
    for _,v in pairs(particles) do
        v:draw()
    end
end