--[[
basically draws an image with

aaa bbb aaa bbb ...
ccc bbb ccc bbb
aaa bbb aaa bbb
ccc bbb ccc bbb
aaa bbb aaa bbb
ccc bbb ccc bbb
...

if you know the luminance of a and c, and b columns blends in perfectly, then the luminance of b is the average of that of a and c

keys:

escape - quit
f - toggle fullscreen. this is borderless windowed so it shouldn't overwrite any LUT you have loaded.
q,a - increase/decrease a
w,s - increase/decrease b
e,d - increase/decrease c
c,z - increase/decrease the precision of adjusting a,b,c
x - swap columns
t - change color to white
r - red
g - green
b -blue

]]

function love.load()
    a = 0
    b = 190
    c = 255
    p = 1
    seed = 3.14159
    col = 2
    z = 0

    love.keyboard.setKeyRepeat(true)
    love.graphics.setBackgroundColor(0, 0, 0)
    love.window.setMode(1600,900,{resizable=true})
    --love.window.setFullscreen(true, "desktop")
end

function setcol(c)
    if col == 0 then
        love.graphics.setColor(c, c, c)
    elseif col == 1 then
        love.graphics.setColor(c, 0, 0)
    elseif col == 2 then
        love.graphics.setColor(0, c, 0)
    elseif col == 3 then
        love.graphics.setColor(0, 0, c)
    end
end

function love.draw()
    math.randomseed(seed)
    setcol(b)
    for x = 100,1800,100 do
        for y = 100, 1100 do
            love.graphics.rectangle("fill", x+z*50, y, 49, 1)
        end
    end

    setcol(a)
    for x = 150,1850,100 do
        for y = 99,1100,2 do
            love.graphics.rectangle("fill",x-z*50,y,49,1)
        end
    end

    setcol(c)
    for x = 150,1850,100 do
        for y = 100,1100,2 do
            love.graphics.rectangle("fill",x-z*50,y,49,1)
        end
    end

    love.graphics.setColor(255, 255, 255)
    love.graphics.print(a.." "..b.." "..c.." "..p, 100, 10)
end

function love.keypressed(key)
--lua y u no switch??
    if key == 'q' then --increase/decrease colors
        a = a + p
    elseif key == 'a' then
        a = a - p
    elseif key == 'w' then
        b = b + p
    elseif key == 's' then
        b = b - p
    elseif key == 'e' then
        c = c + p
    elseif key == 'd' then
        c = c - p

    elseif key == 'z' then --increase/decrease precision
        p = p / 4
    elseif key == 'c' then
        p = p * 4

    elseif key == 't' then --change color
        col = 0
    elseif key == 'r' then
        col = 1
    elseif key == 'g' then
        col = 2
    elseif key == 'b' then
        col = 3

    elseif key == 'x' then --swap columns
        z = 1 - z

    elseif key == "f" then
        love.window.setFullscreen(not love.window.getFullscreen( ), "desktop")
    elseif key == 'escape' then
        love.event.quit()
    end

    if a > 255 then a = 255
    elseif a < 0 then a = 0 end
    if b > 255 then b = 255
    elseif b < 0 then b = 0 end
    if c > 255 then c = 255
    elseif c < 0 then c = 0 end

    if p > 64 then p = 64
    elseif p < 1/64 then p = 1/64 end

    seed = math.random()
end