Example with CoronaSDK using PhysicsEditor & TexturePacker

Andreas Löw Get Sourcecode from GitHub

As requested on the Corona forum I created a small example using PhysicsEditor to create the shapes and TexturePacker for the sprite sheets.

I use the excellent SpriteGrabber class from the corona forum to split the sheet.

Overview over the important files

shapedefs.pes - PhysicsEditor file containing all the shapes
shapedefs.lua - Shape definitions file created by PhysicsEditor
spritesheet.tps - TexturePacker file to create the sprite sheets
spritesheet.lua - Sprite definition file ("old" format)
spritesheet.png - Png image containing the sprite data
SpriteGrabber.lua - Magenda's sprite grabber from corona forum
main.lua - The code driving the example

Initialisation of the physics module

local physics = require("physics")
physics.start()

Initializing SpriteGrabber with the sprite sheet

This code loads SpriteGrabber and then loads our sprite sheet.

local grabber = require("SpriteGrabber")
spriteSheet = grabber.grabSheet("spritesheet")

Setting up the background shape

To add a sprite you need to extract it from the sprite sheet, creating a sprite. Sprites can be addressed by their name:

local bkg = spriteSheet:grabSprite( "bkg_cor.png", true)

Creating a floor shape

With this code block you initialize a floor sprite, setting it's position. The bar is taking a rectangulars standard shape.

The second block initializes a second bar shape which sits above the other. With this the impression can be created that the sprite sinks in the floor a bit.

local bar = spriteSheet:grabSprite("bar.png", true)
bar.x = 160; bar.y = 430
physics.addBody( bar, "static", { friction=0.5, bounce=0.3 } )

-- create floor shape only for the looks
local bar2 = spriteSheet:grabSprite("bar2.png", true) 
bar2.x = 160; bar2.y = 440

Initialise the physics data

To load the physics data created with PhysicsEditor simply require the file and call the function physicsData:

-- load the physics data, scale factor is set to 1.0
local physicsData = (require "shapedefs").physicsData(1.0)

Setting debug drawing mode

This code enables hybrid drawing mode - it shows the shape itself but also overlays the shape's collition shapes.

physics.setDrawMode( "hybrid" )

Create some bodies

This function chooses a random object by it's name, creates a sprite using spriteSheet:grabSprite and then attaches a physics body which is retrieved from physicsData by calling addBody.

Finally the object is set to a random position allowing it to drop onto the scene:

function newItem()	
	names = {"orange", "drink", "hamburger", "hotdog", "icecream", "icecream2", "icecream3"};

	name = names[math.random(6)];

	-- set the graphics 
	obj = spriteSheet:grabSprite(name..".png", true);

	-- set the shape
	physics.addBody( obj, physicsData:get(name))	
	
	-- random start location
	obj.x = 60 + math.random( 160 )
	obj.y = -100
end

Finally this function is called from a timer, spawning more and more items over time:

local dropCrates = timer.performWithDelay( 500, newItem, 100 )

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Source code available for download

The source code is available on GitHub. Clone it using git:

git clone https://github.com/CodeAndWeb/CoronaSDK-TexturePacker-PhysicsEditor.git

or download one of the archives:

CoronaSDK-TexturePacker-PhysicsEditor.zip CoronaSDK-TexturePacker-PhysicsEditor.tar.gz