-- Arm on love2d

function love.load()
  love.graphics.setDefaultFilter("nearest", "nearest")

  img = love.graphics.newImage("circle02_64x64_take1_05_5bit32col_edit.png")

  scrw = love.graphics.getWidth()
  scrh = love.graphics.getHeight()
  bx = scrw / 2
  by = scrh / 2

  angles = {}
  pos_buf = {}
  for i = 1, 16 do
    angles[i] = 0
    pos_buf[i] = {bx, by}
  end

  ang = 0
  a0 = 15
  a1 = 30
end

function love.update(dt)
  ang = ang + 90 * dt

  mx, my = love.mouse.getPosition()
  a0 = 45 * (mx - (scrw / 2)) / (scrw / 2)
  a1 = 45 * (my - (scrh / 2)) / (scrh / 2)

  -- angles[1] = 0
  angles[1] = ang

  for i = 2, #angles do
    -- angles[i] = a1 + a1 * math.sin(math.rad(a0 * (i - 2)))
    angles[i] = a1 * math.sin(math.rad(ang * 0.75 + (i - 1) * a0))
  end

  local x = pos_buf[1][1]
  local y = pos_buf[1][2]
  local a = angles[1]

  -- local distance = 30
  local distance = 24 + 12 * math.cos(math.rad(ang * 1.4))

  for i = 2, #angles do
    a = a + angles[i]
    x = x + distance * math.cos(math.rad(a))
    y = y + distance * math.sin(math.rad(a))
    pos_buf[i] = {x, y}
  end
end

function love.draw()
  -- fill window background
  love.graphics.clear(0.4, 0.7, 0.8, 1.0)

  -- draw arm
  local ox, oy = img:getWidth() / 2, img:getHeight() / 2
  love.graphics.setColor(1.0, 1.0, 1.0, 1.0)
  for i = 1, #pos_buf do
    local px = pos_buf[i][1]
    local py = pos_buf[i][2]
    love.graphics.draw(img, px, py, 0, 1.0, 1.0, ox, oy)
  end

  love.graphics.print("a0=" .. tostring(a0), 2, 16)
  love.graphics.print("a1=" .. tostring(a1), 2, 32)

  -- draw FPS txet
  love.graphics.print("FPS: " .. tostring(love.timer.getFPS()), 2, 2)
end

function love.keypressed(key, isrepeat)
  if key == "escape" then
    -- ESC key to exit
    love.event.quit()
  end
end