Löve ist ja schon nais

main.lua

paddleWidth = 10*2
paddleHeight = 200
ballRadius = 10
width = 800
height = 600

function love.load()
  love.physics.setMeter(64)
  world = love.physics.newWorld(0, 0, true)

  objects = {}
  objects.wall1 = {}
  objects.wall1.body = love.physics.newBody(world, 50/2, 613/2)
  objects.wall1.shape = love.physics.newRectangleShape(0, 0, 50, 613)
  objects.wall1.fixture = love.physics.newFixture(objects.wall1.body, objects.wall1.shape, 1)
  objects.wall1.fixture:setRestitution(1)

  objects.wall2 = {}
  objects.wall2.body = love.physics.newBody(world, 761/2+50, 50/2)
  objects.wall2.shape = love.physics.newRectangleShape(0, 0, 761, 50)
  objects.wall2.fixture = love.physics.newFixture(objects.wall2.body, objects.wall2.shape, 1)
  objects.wall2.fixture:setRestitution(1)

  objects.wall3 = {}
  objects.wall3.body = love.physics.newBody(world, 761/2+50, height-50/2)
  objects.wall3.shape = love.physics.newRectangleShape(0, 0, 761, 50)
  objects.wall3.fixture = love.physics.newFixture(objects.wall3.body, objects.wall3.shape, 1)
  objects.wall3.fixture:setRestitution(1)

  objects.paddle = {}
  objects.paddle.body = love.physics.newBody(world, width-20/2, height/2, "kinematic")
  w = paddleWidth
  h = paddleHeight
  objects.paddle.shape = love.physics.newPolygonShape( 0, -h/2,
                                                          -w/2, -h/6,
                                                          -w/2,  h/6,
                                                             0,  h/2,
                                                           w/2,  h/2,
                                                           w/2, -h/2)
  objects.paddle.fixture = love.physics.newFixture(objects.paddle.body, objects.paddle.shape, 1)
  objects.paddle.fixture:setRestitution(1)

  objects.ball = {}
  objects.ball.body = love.physics.newBody(world, width/2, height/2, "dynamic")
  objects.ball.shape = love.physics.newCircleShape(ballRadius)
  objects.ball.fixture = love.physics.newFixture(objects.ball.body, objects.ball.shape, 1) 
  objects.ball.fixture:setRestitution(1)
  objects.ball.fixture:setFriction(0)
  objects.ball.body:setLinearDamping(0)
  objects.ball.body:setMass(0.057)
  objects.ball.body:applyForce(500, 500)
  
  love.graphics.setBackgroundColor(0, 0, 0)
  love.graphics.setMode(width, height, false, true, 0)
end

function love.update(dt)
  world:update(dt)

  if love.keyboard.isDown("up") then
    newY = objects.paddle.body:getY() - 500 * dt
	  if newY - paddleHeight / 2 > objects.wall2.body:getY() + 50/2 then
	  	objects.paddle.body:setY(newY)
	  end
  elseif love.keyboard.isDown("down") then
	  newY = objects.paddle.body:getY() + 500 * dt
	  if newY + paddleHeight / 2 < objects.wall3.body:getY() - 50/2 then
	  	objects.paddle.body:setY(newY)
	  end
  end
  if love.keyboard.isDown(" ") then
	  objects.ball.body:setPosition(width/2, height/2)
  end
end

function love.draw()
  love.graphics.setColor(255, 255, 255)
  love.graphics.polygon("fill", objects.wall1.body:getWorldPoints(objects.wall1.shape:getPoints()))
  love.graphics.polygon("fill", objects.wall2.body:getWorldPoints(objects.wall2.shape:getPoints()))
  love.graphics.polygon("fill", objects.wall3.body:getWorldPoints(objects.wall3.shape:getPoints()))
  love.graphics.setColor(255, 0, 0)
  love.graphics.polygon("fill", objects.paddle.body:getWorldPoints(objects.paddle.shape:getPoints()))
  love.graphics.setColor(0, 255, 0)
  love.graphics.circle("fill", objects.ball.body:getX(), objects.ball.body:getY(), objects.ball.shape:getRadius())

end