GameDev Garden

Your First Game

One sitting, one playable game. Clone the Starter Template and open states/PlayState.lua — every block below goes there. It runs at every step.

git clone https://github.com/findingfocus/love2d-starter.git my-game
cd my-game
love .

Step 1 — Window + paddles (run this first)

File: states/PlayState.lua — set positions in enter, draw paddles in render.

local leftY, rightY = 250, 250
 
function PlayState:enter()
  leftY, rightY = 250, 250
end
 
function PlayState:render()
  love.graphics.rectangle("fill", 20, leftY, 15, 100)
  love.graphics.rectangle("fill", 765, rightY, 15, 100)
end

Run with love . — title screen, press Enter, two white bars. Win #1.

Step 2 — Move the left paddle

File: states/PlayState.lua — add update.

function PlayState:update(dt)
  local speed = 400
  if love.keyboard.isDown("w") then leftY = leftY - speed * dt end
  if love.keyboard.isDown("s") then leftY = leftY + speed * dt end
  -- right paddle: simple AI follows ball (added in step 4)
end

Step 3 — Ball that bounces

File: states/PlayState.lua — ball vars at top of file, move in update, draw in render.

local ballX, ballY = 400, 300
local ballDX, ballDY = 300, 200
 
function PlayState:update(dt)
  -- (keep paddle code from step 2)
  ballX = ballX + ballDX * dt
  ballY = ballY + ballDY * dt
  if ballY < 0 or ballY > 600 then ballDY = -ballDY end
end
 
function PlayState:render()
  -- (keep paddle drawing)
  love.graphics.circle("fill", ballX, ballY, 10)
end

Step 4 — Paddle collision + scoring

File: states/PlayState.lua — score vars + resetBall at top of file, merge into update / render.

local leftScore, rightScore = 0, 0
 
local function resetBall(dir)
  ballX, ballY = 400, 300
  ballDX = 300 * dir
  ballDY = 200 * (math.random() > 0.5 and 1 or -1)
end
 
function PlayState:enter()
  leftY, rightY = 250, 250
  leftScore, rightScore = 0, 0
  resetBall(1)
end
 
function PlayState:update(dt)
  -- movement + ball motion from above...
  -- simple right-paddle AI
  if ballY > rightY + 50 then rightY = rightY + 350 * dt end
  if ballY < rightY + 50 then rightY = rightY - 350 * dt end
 
  -- collide with left paddle
  if ballX < 35 and ballY > leftY and ballY < leftY + 100 then
    ballDX = math.abs(ballDX)
    ballX = 35
  end
  -- score
  if ballX < 0 then rightScore = rightScore + 1 resetBall(1) end
  if ballX > 800 then leftScore = leftScore + 1 resetBall(-1) end
end
 
function PlayState:render()
  love.graphics.rectangle("fill", 20, leftY, 15, 100)
  love.graphics.rectangle("fill", 765, rightY, 15, 100)
  love.graphics.circle("fill", ballX, ballY, 10)
  love.graphics.print(leftScore .. " : " .. rightScore, 380, 20)
end

TIP

Two-player mode: replace the AI with up/down keys for the right paddle. Instant party game.

When it breaks

SymptomFix
Ball tunnels through paddle at high speedClamp position on hit (ballX = 35) like above, or reduce speed
Paddle leaves screenAdd leftY = math.max(0, math.min(500, leftY)) at end of update
Everything moves too fast/slowYou forgot * dt — search for it

You shipped a game loop!

You now know: state, input, movement, collision, scoring, reset. Everything else is variations. And it’s already in the right home — states/PlayState.lua — so every Cookbook recipe drops straight in. Next:

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