{graphics: g} = love

class ParalaxBg

layers: 4

speed: 1

lazy sprite: -> imgfy "images/ground.png"

new: =>

@sprite\set_wrap "repeat", "clamp"

@base_offsets = setmetatable {}, __index: (key) =>

r = rand 0, 100

@[key] = r

r

update: (dt) =>

draw: (viewport, bounds) =>

w,h = @sprite\width!, @sprite\height!

vw = viewport.w

for l=@layers,1,-1

t = (@layers - (l - 1)) / @layers

COLOR\push { t * 255, t * 255, t * 255 }

scale = math.sqrt t

real_w = w * scale

times = math.floor(vw / real_w) + 2

q = g.newQuad 0, 0, w * times, h, w, h

g.push!

g.translate viewport.x, bounds.h

px = -(l - 1) / @layers + 1

g.translate -((@base_offsets[l] + viewport.x) * px % real_w), (l - 1) * -10

g.scale scale, scale

@sprite\draw q, 0, -h

g.pop!

COLOR\pop!

{ :ParalaxBg }