simple dpad code.

dpad.lua

local DPad = {}

function DPad.create(radius)
	local dpad = display.newGroup()
	dpad.position = {x=0,y=0}
	dpad.angle = 0
	dpad.distance = 0
	local outterCircle = display.newCircle(dpad, 0, 0, radius )
	outterCircle:setFillColor(128,128,128)  
	outterCircle.alpha = 0.5
	local innerCircle = display.newCircle(dpad, 0, 0, radius/3 )
	innerCircle:setFillColor(128, 128, 128)
	innerCircle.alpha = 0.5

	outterCircle:addEventListener('touch',function(event)
		if event.phase == 'began' or event.phase == "moved" then
			display.getCurrentStage():setFocus( event.target, event.id )
			local x, y = event.target:localToContent( 0, 0 )
			x, y = event.x-x, event.y-y

			-- 내부원이 외부로 나가지 못하게.
			local dist = math.sqrt(x*x+y*y)
			if dist > radius - radius/3 then
				local ix= math.sin(math.atan2(x, y)) * (radius - radius/3)
				local iy= math.cos(math.atan2(x, y)) * (radius - radius/3)
				innerCircle.x, innerCircle.y = ix, iy
				dpad.position.x, dpad.position.y = ix/(radius-radius/3), iy/(radius-radius/3)
			else
				innerCircle.x, innerCircle.y = x, y
				dpad.position.x, dpad.position.y = x/(radius-radius/3), y/(radius-radius/3)
			end
--          print(dpad.position.x .. ' ' .. dpad.position.y)
		elseif event.phase == "ended" or event.phase == "cancelled" then
			dpad.position.x, dpad.position.y = 0, 0
			innerCircle.x, innerCircle.y = 0, 0
			display.getCurrentStage():setFocus( event.target, nil )
		end
	end)
	


	return dpad
end
return DPad