HSV node

function init()
    setName("HSV")
    setDesc("Adjust HSV values")
    setSize(120,18+18+18+24+64+8+8+7+4)
    addOutput(24+32)
    addInput("Texture",24+64+8+8)
    addInputParameter("H","Hue",18+24+64+8+8,0,0,255)
    addInputParameter("S","Saturation",18+18+24+64+8+8,127,0,255)
    addInputParameter("V","Value",18+18+18+24+64+8+8,127,0,255)
end
-- Ugly way to use channels
function getChroma(R, G, B)
    m = math.min(math.min(R, G), B)
    M = math.max(math.max(R, G), B)
    return (M-m)
end
function rgbM(n, H, S, V)
    k = math.fmod((n + (H*6)), 6)
    out = V - (V*S*math.max(math.min(k,4-k,1),0))
    return out
end
function getHue(R, G, B)
    m = math.min(math.min(R, G), B)
    M = math.max(math.max(R, G), B)

    if (m == M) then
        return 0
    end
    if (M == R) then
        hue = (G-B)/(M-m)
    end
    if (M == G) then
        hue = 2+(B-R)/(M-m)
    end
    if (M == B) then
        hue = 4+(R-G)/(M-m)
    end

    hue = hue / 6

    if (hue < 0) then
        hue = hue + 1
    end
    if (hue > 1) then
        hue = hue - 1
    end

    return hue
end
function apply()
    x = 0
    y = 0
    tileSize = getTileSize()
    for i=0, tileSize*tileSize-1 do
        x = i%tileSize
        y = math.floor(i/tileSize)
        R, G, B = getValue(0,x,y,1) -- Scan Texture

        hmod = getValue(1,x,y,255)
        hnew = getHue(R, G, B) + hmod
        if (hnew > 1) then
            hnew = hnew - 1
        end
        if (hnew < 0) then
            hnew = hnew + 1
        end

        vmod = (getValue(3,x,y,255)*2) - 1
        vnew = math.min((math.max((math.max( (math.max(R, G)) , B) + vmod), 0)), 1)

        smod = (getValue(2,x,y,255)*2) - 1
        if(vnew == 0) then
            snew = (getChroma(R, G, B)) + smod
        else
            snew = (getChroma(R, G, B) / vnew) + smod
        end

        --convert to rgb
        outr = rgbM(5, hnew, snew, vnew)
        outg = rgbM(3, hnew, snew, vnew)
        outb = rgbM(1, hnew, snew, vnew)

        setPixel(0,x,y,outr,outg,outb)

    end
end