-- a vlorb consists of six gromlings[A
-- 1  2
-- 4  8
-- 16 Q
-- these are characters 0x80 through 0x9f in the cc charset
-- which is only 2^5 characters though. for the sixth bit you flip the colours
-- of that vlorb.

-- on colour, off colour, gromlings 1 through 6 (bools)
-- returns text colour, bg color, and vlorbchar
local function vlorb(onc,offc, g1,g2,g3,g4,g5,g6)
	local textc,bgc = onc,offc
	if g6 then textc,bgc=bgc,textc end
	local vlorbchar = 0x80
	-- ~= on booleans is xor
	-- if g6 set then flip all the other bits
	if g1 ~= g6 then vlorbchar=vlorbchar+1  end
	if g2 ~= g6 then vlorbchar=vlorbchar+2  end
	if g3 ~= g6 then vlorbchar=vlorbchar+4  end
	if g4 ~= g6 then vlorbchar=vlorbchar+8  end
	if g5 ~= g6 then vlorbchar=vlorbchar+16 end
	return textc,bgc,string.char(vlorbchar)
end

local function should_be_on(col)
	return col[1]+col[2]+col[3] > 1.5
end

-- todo: refactor common stuff into a common file
local function disp(R,img,scrx,scry,w,h,imgx,imgy)
	-- w and h are image coords
	scrx = scrx or 1
	scry = scry or 1
	w = w or img.width
	h = h or img.width
	imgx = imgx or 1
	imgy = imgy or 1

	local sw = math.ceil(w/2)
	local sh = math.ceil(h/3)

	for soffx=0,sw do
		for soffy=0,sh do
			local ioffx=soffx*2
			local ioffy=soffy*3
			R.setCursorPos(scrx+soffx,scry+soffy)
			local gs = {}
			for goffy=0,2 do
				for goffx=0,1 do
					local ic = img[imgy+ioffy+goffy][imgx+ioffx+goffx] or {0,0,0}
					table.insert(gs,should_be_on(ic))
				end
			end
			local tc,bc,ch = vlorb(colors.white,colors.black,table.unpack(gs))
			R.setTextColor(tc)
			R.setBackgroundColor(bc)
			R.write(ch)
		end
	end
end


	
	

return {vlorb=vlorb,disp=disp}