main.lua

Plank = {}
Plank.new = function(world, x, y, w, h, offset)
  body = love.physics.newBody(world, 0, 0, 0)
  body:setAngularDamping(1000)
  shape = love.physics.newRectangleShape(body, x, y, w, h)
  body:setMassFromShapes()
  return {
    shape = shape, body = body, offset = offset,
    force =
      function(self, t)
        return math.sin(self.offset * math.pi / 10 + t)
      end
  }
end

function load()
  world = love.physics.newWorld(760, 500)
  world:setGravity(0, 100)
  
  ballBody = love.physics.newBody(world, 740, 20)
  circleShape = love.physics.newCircleShape(ballBody, 30)
  circleShape:setRestitution(2)
  ballBody:setMassFromShapes()
  ballBody:setVelocity(-100, 0)
  
  border = love.physics.newBody(world, 0, 0, 0)
  borderShapeLeft = love.physics.newRectangleShape(border, 0, 200, 1, 400)
  borderShapeRight = love.physics.newRectangleShape(border, 760, 200, 1, 400)
  
  bars = {}
  for i = 1,25 do
    bars[i] = Plank.new(world, 30 * i - 10, 400, 20, 500, i)
  end
  t = 1
end

function update(dt)
  t = t + dt
  for _,bar in pairs(bars) do
    bar.body:setVelocity(0, 50 * bar:force(t))
  end
  world:update(dt)
end

function draw()
  love.graphics.setColor(255, 0, 0)
  love.graphics.circle(love.draw_fill, ballBody:getX(), ballBody:getY(), 30, 30)
  for _,bar in pairs(bars) do
    love.graphics.polygon(love.draw_fill, bar.shape:getPoints())
  end
  love.graphics.polygon(love.draw_line, borderShapeLeft:getPoints())
  love.graphics.polygon(love.draw_line, borderShapeRight:getPoints())
end