ParalX.lua

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Example video

ParalX is a LunaLua library designed to create parallax background layers in Super Mario Bros X.

Installation

Place the file paralX.lua into the LuaScriptsLib folder. (Please note that this library relies on both Graphics.draw and the new rendering priorities which, as of writing this, are only available in development builds of LunaLua.)

How to use

To enable the ParalX library for a specific level, add this line to lunadll.lua:

local paralX = loadAPI("paralX");

This will load the ParalX API. From there, you can use paralX.create (table properties) to make Parallax layer objects.

Example

The following code was taken from this example level:

local paralX = loadSharedAPI("paralX")


-- Load the images
local fg0Img = Graphics.loadImage("fg0.png")
local fg1Img = Graphics.loadImage("fg1.png")

local bg0Img = Graphics.loadImage("bg0.png")
local bg1Img = Graphics.loadImage("bg1_alpha.png")
local pyramidBgImg = Graphics.loadImage("bg2.png")
local cloudBgImg = Graphics.loadImage("bg3_trans.png")
local skyBgImg = Graphics.loadImage("bg4.png")


-- Create the layers
function onStart ()
	fg0       = paralX.create ({image=fg0Img,                  y=-360,   priority=-1,                      repeatY=false,   paralXX=1.45,   paralXY=1.25})
	fg1       = paralX.create ({image=fg1Img,        x=-80,    y=-780,   priority=-0.5,   repeatX=false,   repeatY=false,   paralXX=2,      paralXY=1.5,     alpha=0.5})
	
	bg0       = paralX.create ({image=bg0Img,                  y=-80,    priority=-96,                     repeatY=false,   paralXX=0.6,    paralXY=0.6})
	bg1       = paralX.create ({image=bg1Img,        x= 80,    y=-60,    priority=-96.2,                   repeatY=false,   paralXX=0.45,   paralXY=0.35,    alpha=0.8})

	pyramidBg = paralX.create ({image=pyramidBgImg,  x=1464,   y=-120,   priority=-96.1,  repeatX=false,   repeatY=false,   paralXX=0.55,   paralXY=0.5})
	cloudBg   = paralX.create ({image=cloudBgImg,              y=-80,    priority=-96.3,                   repeatY=false,   paralXX=0.125,  paralXY=0.125,   speedX=0.0625})
	skyBg     = paralX.create ({image=skyBgImg,                y= 00,    priority=-96.4,  repeatX=false,   repeatY=false,   paralXX=0,      paralXY=0})
end

function onLoop ()
	pyramidBg.y = -120 + 32*math.sin (os.clock())
end

Documentation

Functions

cinematX coroutine functions
Type	Function/Field	Return values/Value type	Description
function	paralX.create (table properties)	nil	Creates a new parallax layer with its' properties defined via named arguments.

Properties

The following properties can be both defined in paralX.create (args) and accessed via parallaxObj.propertyName:

Name	Type	Is Optional?	Default Value	Description
image	LuaImageResource	no	nil	The image used; animations can be used as vertical sheets, though the frames property will need to be set accordingly (see below).
frames	number	yes	1	The number of frames in the animation.
animSpeed	number	yes	0.05	The rate at which the layer cycles through its' frames of animation.
alpha	number	yes	1	The transparency of the layer; 0 = invisible, 1 = completely opaque
sections	table of number	yes	{1, 2... 21}	The sections in which the parallax layer is shown.
priority	number	yes	-96	The depth at which the layer is shown; see this list for the sorting order.
x	number	yes	0	The horizontal offset of the layer.
y	number	yes	0	The vertical offset of the layer.
parallaxX	number	yes	0.75	The rate at which the layer pans horizontally with the camera; 0 = fixed position on the screen, 1 = pans with the level, >1 = pans more than the level, <0 = pans in reverse.
parallaxY	number	yes	0.75	The rate at which the layer pans vertically with the camera; 0 = fixed position on the screen, 1 = pans with the level, >1 = pans more than the level, <0 = pans in reverse.
speedX	number	yes	0	The horizontal speed of the layer independent of panning.
speedY	number	yes	0	The vertical speed of the layer independent of panning.
repeatX	boolean	yes	true	if true, the image is tiled horizontally.
repeatY	boolean	yes	true	if true, the image is tiled vertically.
gapX	number	yes	0	The horizontal separation between tiles.
gapY	boolean	yes	0	The vertical separation between tiles.