function scrollingcircles(y, speed, spacing, radius, color)
    for i = 1, 256, spacing do
        circfill((i-(gt*speed))%256-radius*2, y, radius, color)
    end
end

-- function scrollingcirclelines(y, speed, spacing, radius, color)
--     for i = 1, 256, spacing do
--         circ((i-(gt*speed))%256-radius*2, y, radius, color)
--     end
-- end

function scrollingsprite(sprite,x,y,w,h,speed,flip)
    flip = flip or false
    spr(sprite, (-gt*speed+x+w*8)%(128+w*8)-w*8, y, w, h, flip)
end


--ringed planet
function bgplanetmegasprite(x,y)
    --default values
    --x = 160-gt
    --y = 50

    palt(0,false)
    palt(13,true)
        spr(194,x+10,y+0,7,2)
        spr(201,x+10,y+16,7,2)
        spr(234,x+2,y+32,6,2)
    palt()
end


function drawbg()
    cls(0)
    camera(screenshakex/3, screenshakey/3)

    --stars
    for i = 1, 64, 1 do
        pset((((-gt*0.1)+i*4.3824)*(i/32))%128, sin(i*0.536382)*64+64, 4) --funny random star algorithm!!
    end

    --galaxies
    spr(120, 20, 30, 1, 1)
    spr(104, 108, 40, 1, 1)
    spr(104, 42, 74, 1, 1, true, true)

    --ringed planet
    bgplanetmegasprite(150-(gt)%300,50)
    
    --clouds
    scrollingcircles(-9, 24, 22, 22, 2)
    --small clouds
    scrollingsprite(88, 60, 10, 1, 1, 28)
    scrollingsprite(88, 120, 10, 1, 1, 28)
    scrollingsprite(88, 130, 12, 1, 1, 29)
    scrollingsprite(88, 160, 15, 1, 1, 30)--
    scrollingsprite(72, 145, 15, 1, 1, 30)--
    scrollingsprite(72, 20, 10, 1, 1, 28)
    scrollingsprite(72, 100, 10, 1, 1, 28)
    scrollingsprite(72, 170, 15, 1, 1, 30)
    --large clouds
    scrollingsprite(248, 40, 5, 2, 1, 35)
    scrollingsprite(248, 80, 5, 2, 1, 35)
    scrollingsprite(248, 180, 9, 2, 1, 38)
    scrollingsprite(248, 260, 9, 2, 1, 38)--
    scrollingsprite(232, 120, 7, 2, 1, 36)--
    scrollingsprite(232, 160, 7, 2, 1, 36)
    scrollingsprite(232, 240, 9, 2, 1, 38)
    --fg clouds
    scrollingcircles(-11, 40, 25, 20, 2)
    scrollingcircles(-12, 40, 25, 20, 4)


    camera(screenshakex/2, screenshakey/2)

    --landscape
    scrollingcircles(125, 72, 25, 20, 8)
    scrollingcircles(126, 72, 25, 20, 2)

    --landscape lines
    rectfill(0,112,128,128,8)
    line(0, 113, 128, 113, 2)
    line(0, 116, 128, 116, 2)
    line(0, 119, 128, 119, 2)

    for i = 1, 32, 1 do
        line(((-gt+i*2.5)*80)%128, 111, ((-gt+i*2.5)*80)%128*1.2-12.8, 125, 2)
    end

    --pine trees
    local treex = {10,30,20,50,62,70,80,95,100,120}
    for i = 1, 10, 1 do
        scrollingsprite(231,treex[i],94+sin(i/5.2323),1,2,72,(i%2==0))
    end
    --small buildings
    scrollingsprite(226,15,98,2,2,80)
    scrollingsprite(226,65,97,2,2,80)
    scrollingsprite(226,95,96,2,2,80)
    scrollingsprite(226,115,97,2,2,80)
    --totem poles
    scrollingsprite(230,25,99,1,2,84)
    scrollingsprite(230,65,100,1,2,83,true)
    scrollingsprite(230,85,101,1,2,83)
    --dead trees
    scrollingsprite(228,30,104,2,2,86)
    scrollingsprite(228,75,105,2,2,86,true)
    scrollingsprite(228,100,104,2,2,86)
    scrollingsprite(228,120,105,2,2,86,true)
    --large buildings (front)
    scrollingsprite(192,52,94,2,4,90)
    scrollingsprite(192,22,91,2,4,90)
    scrollingsprite(192,102,90,2,4,90)
    scrollingsprite(192,137,92,2,4,90)

    camera(screenshakex, screenshakey)

    scrollingcircles(150, 100, 30, 32, 8)
    scrollingcircles(151, 100, 30, 32, 2)
end