-- Draw video alpha

function love.load()
  -- load bg image
  bgimg = love.graphics.newImage("bg.jpg")
  
  -- load video(.ogv)
  maskvideo = love.graphics.newVideo("mask.ogv")
  rgbvideo = love.graphics.newVideo("rgb.ogv")
  maskvideo:play()
  rgbvideo:play()
end

function love.update(dt)
end

function love.draw()
  -- loop video play
  if not rgbvideo:isPlaying() then
    maskvideo:rewind()
    rgbvideo:rewind()
    maskvideo:play()
    rgbvideo:play()
  end
  
  -- canvas clear
  love.graphics.clear(0, 0, 0, 1)

  -- draw bg
  love.graphics.setColor(1, 1, 1, 1)
  love.graphics.draw(bgimg, 0, 0)

  -- draw video
  love.graphics.setBlendMode("subtract")
  love.graphics.draw(maskvideo, 0, 0)
  
  love.graphics.setBlendMode("add")
  love.graphics.draw(rgbvideo, 0, 0)

  -- draw text
  love.graphics.setBlendMode("alpha")
  love.graphics.setColor(1, 1, 1, 1)
  love.graphics.print("ESC to exit.", 8, 4)
end

function love.keypressed(key, scancode, isrepeat)
  if key == "escape" then
    love.event.quit()
  end
end