New here? What’s IwGame? IwGame is an open source free to use cross platform game engine for iPhone, iPad, Android, Bada, Playbook, Symbian, Windows Mobile, LG-TV, Windows and Mac, built on top of the Marmalade SDK. You can find out more and download the SDK from our IwGame Engine page.
The Universe conspired against me this week, first of all landing me with a nice flu, followed directly by some horrible sickness bug that featured projectile vomiting of the likes only seen in movies such as the Exorcist! Thankfully the Universe decided to give me a break this week so an IwGame Engine update got finished.
Most of the changes this week are XOML related as this is the general direction we want to take the game engine. A good mix of XOML mark-up and solid coding should make games and media apps very quick and easy to develop.
Oh and we got a new logo for the IwGame Engine woohoo! Feel free to use the logo in any of your IwGame powered products, or if you want to link to us.
Ok, onto the list of iwGame Engine changes for v0.29:
- New style system added to XOML. Actors and scenes can now use a style to reduce repetition
- Actors and scenes now handle events such as OnSuspend, OnTapped, OnBeginTouch etc.. When an event fires it executes a collection of actions
- Actions added to XOML to allow definition of collections of actions that can be executed. Many default actions are suppported such as ChangeScene, KillScene, PlayTimeline, PlaySound etc.. Custom actions can also be added toextend the system
- CIwGame now handles touch begin touch, end touch and tapped events
- CIwGame now has new Postdraw() method for adding in custom post draw rendering
- Actors can now be made tappable and now handle OnTapped(), OnBeginTouch() and OnEndTouchEvents()
- Actors have new HitTest() method that can be used to check if a point is inside the actors visual
- XOML now supports creation of cameras
- XOML now supports creation of variables and update of variables using actions, supports string, bool, int, float, vec2, vec3 and vec4
- XOML files can now load other XOML files with new LoadXOML tag as well as LoadXOML action
- Scenes now support a type field
- CIwGameBitmapSprite now supports image transforms (flips. mirrors etc) which can be also applied to actors visuals using FlipX and FlipY attributes
- You now change the current time of a CIwGameAnimInstance and CIwGameAnimTimeline
- Bug Fix – Actor visibile state now works properly
- Bug Fix – CIwGameShape::setShape() now works
- Bug Fix – Transform is now reset after CIwGameAdsView finishes rendering
- Bug Fix – JPEG file detection fixed, was not detecting certain types of JPEG files
- Bug Fix – CIwGameString::FindNext() crash fixed
Quite a few changes and bug fixes. Note that someo f the bug fixes directly affected IwGameAds so an update to that API will be released shortly.
Lets take a look at the changes in more detail.
XOML got variables, but why? Well, there are a number of reasons:
- We want to be able to define values that can be read by the main code
- We want to change these values via actions
- When we implement the UI system we are looking to add data binding capabilities that will rely on values
You can declare a variable in XOML like this:
<Variable Name="PlayerName" Type="string" Value="Player One" /> <Variable Name="PlayerScore" Type="int" Value="0" /> <Variable Name="PlayColour" Type="vec4" Value="255, 128, 64, 8" />
You can later modify the value of that variable using a SetVar action, more on this later.
Each scene contains its own variables collection and the global resource system also contains a global variables collection.
XOML now supports the styling of actors and scenes using the new Style tag. XOML styles enable you to create a set of properties and values that are common across a range of objects then apply tat style the to them all. Hers a quick
<Style Name="BasicActorStyle"> <Set Property="Size" Value="60, 60" /> <Set Property="Angle" Value="0" /> <Set Property="SrcRect" Value="0, 0, 36, 40" /> <Set Property="Image" Value="Sprites" /> <Set Property="Timeline" Value="Player1Intro1" /> <Set Property="Shape" Value="PlayerShape" /> <Set Property="Box2dMaterial" Value="BounceyBall" /> <Set Property="CollisionFlags" Value="1, 1, 1" /> </Style>
<TestActor Name=”Player2″ Style=”BasicActorStyle” Position=”0, -150″ />
The TestActor Player2 will be assigned all of the values in the properties defined in the style saving you a whole bunch of typing as well as making your mark-up much more readable and easier to maintain.
XOML Events And Actions
Actors and scenes now support various events that can fire off user defined actions. The following events are currently defined:
- OnSuspend – Called when a scene is suspended
- OnResume – Called when a scene is resumed
- OnTapped – Called when the user taps an actor
- OnBeginTouch – Called when the user begins to touch an actor
- OnEndTouch – Called when the user stops touching an actor
More will be added as we think of them or when requested. You can also add your own custom events youself. Check out the CIwGameActor class for a reference on how to do this.
Events wouldn’t really be much use unless we could carry out some kind of action when the event occurred. Actions are defined in XOML using the Actions tag, heres an example:
<Scene Name="GameScene3" Style="GenericSceneStyle" OnSuspend="SuspendActions"> <Actions Name="SuspendActions"> <Action Method="SetTimeline" Param1="SceneTransition1" /> <Action Method="PlaySound" Param1="explosion" /> </Actions> </Scene>
You actually create a group of actions that are all executed when the action is called by an event.
The following actions are currently supported:
- ChangeScene – Changes the currently focused scene to the specified scene
- SuspendScene – Suspends the specified sceme
- ResumeScene– Resumes the specified sceme
- HideScene– Hides the specified sceme
- ShowScene– Shows the specified sceme
- ActivateScene – Activates the specified sceme
- DeactivateScene – Deactivates the specified sceme
- KillScene – Destroys and removes the specified sceme from the game, all contained resources amd actors will be also be destroyed
- HideActor – Hides the specified actor
- ShowActor – Shows the specified actor
- ActivateActor – Activates the specified actor
- DeactivateActor – Deactivates the specified actor
- KillActor – Kills and removes the specified actor
- PlayTimeline – Plays the specified timeline. If no timeline is supplied then the current actor / scenes timeline will be restarted (depends on where the action was defined)
- StopTimeline – Stops the specified timeline. If no timeline is supplied then the current timeline will be stopped. (depends on where the action was defined)
- SetTimeline – Changes to the specified timeline. If no timeline is supplied then the current timeline will changed and restarted. (depends on where the action was defined)
- PlaySound – Starts playing a sound effect
- PlayMusic – Starts the playing specified music file
- StopMusic – Stops the music player playing
- LoadXOML – Loads a XOML file into scene or globally. If a scene is provided then the XOML will be loaded into that scene
- SetVar – Sets the value of a variable
Again, more will be added as we think of them or when requested. You can also add your own custom actions youself. Check out the CIwGameXomlAction_Actors class for a reference on how to do this.
Coupled together the events and actions system provide a very powerful way of creating fully interactive content without having to write a single line of code.
Loading Other XOML Files
It is now possible to load other XOML files from a XOML file using the new LoadXOML tag. Heres an example:
<LoadXOML File="Common.xml" /> <LoadXOML File="Sceme2.xml" /> <LoadXOML File="Scene3.xml" />
You can also (as shown in the actions section) load a XOML file from an action.
Using this system you can create fully interactive navigation based content. Think adventure games, books, magazines and informational apps etc..
Cameras can now be defined in XOML and attached to scenes. You can also switch a scenes camera using the animation system.
Image Transforms for Sprites and Actors
Sprites and actors can now use an image transform allowing you to flip the source image used to render the object. The ne FlipX and FlipY attributes are now available in XOML.
Well thats it for this update. IwGame now has some very cool features that should hopefully make game / app development much easier and quicker for everyone.
We are going to assess the possibility of wrapping up Marmalades cool UI system with XOML very soon, will keep you all posted on how that goes. I am also looking at producing a new article on in-app purchasing with the Marmalade SDK, which will form the basis of in-app purchasing for the IwGame engine.