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UE3 Home > User Interfaces & HUDs > Scaleform GFx > Scaleform Content Guide

Scaleform Content Guide


The Scaleform GFx integration in Unreal Engine 3 enables the use of interfaces and menus built in Adobe Flash Professional to be used as heads-up displays (HUDs) and menus. This document is a content and design-focused guide for artists or level designers using the Scaleform GFx system. It will cover aspects of creating UIs using Scaleform and Flash as well as how to use those within levels in Unreal Engine 3.

Working with CLIK Components

In order to get the benefit of Scaleform's prebuilt collection of components, you need to know how to add them to your own scene. This is not a difficult task, but there are some gotchas to watch out for.

Adding new CLIK Object to your Library

To add new CLIK objects to your Library, you have two options: Copy an object out of a prebuilt file, or assign the GFx class to a movieclip.

Copy and paste method

  • In Adobe Flash Professional CS4, open CLIK_Components.fla, located in \UnrealEngine3\Development\Flash\CLIK\components.
  • Select one of the objects in the Library, copy it, and paste it into your file.
  • Open the Component Inspector (Shift+F7) to view the properties and values associated with the CLIK object you brought into your stage.

Assigning CLIK class to an existing movie clip

You are also able to assign any CLIK class to a movie clip. This is useful if you add custom functionality, or just need a simple button without state changes.

  • Right click the movie clip in the Library and choose Properties.
  • Enable Export for ActionScript via the check box.
  • In the class field, enter which class you want to use. (e.g gfx.controls.Button)
  • Click OK.
  • Right click once again on the object, but open "Component Definition...".
  • In the "class" field, enter the same class assigned in the Properties: gfx.controls.Button.
  • Click OK.

You movieclip should now be using the CLIK class, and has the same functionality as other CLIK objects.

ALERT! If you do not have the frame labels setup, you will not receive states for up, over, down, etc. These need to be set up properly in order to work, and in this case, it would be better to copy the object from the CLIK_Components file. You can define a custom class to a movie clip if you do not need it to follow the same rules and guidelines, for example: creating an invisible button.

Duplicating CLIK Objects - a Checklist

Duplicated components within your library will not retain their class and component class information, and will also have some auto-naming issues with the linkage identifier as well.

Here is quick checklist to ensure that the CLIK object is set up properly after duplication, or initial setup:

  • The CLIK class needs to be defined in its properties, and has Export for Action Script checked. When you duplicate within Adobe Flash, these properties are not copied from the original Library object you are duplicating.
  • Component definition also needs to be set, during duplication this information is not copied over from the original.
  • Ensure its identifier has the same name as the object name.

Content Best Practices

When developing Flash content for use with the Scaleform GFx integration in Unreal Engine 3, there are a number of considerations and optimizations that should be followed and implemented in order to get the best performance. This document details many of these best practices.

See the Scaleform GFx Content Best Practices page for a complete breakdown of what you need to keep in mind when it comes to using content in Scaleform UIs.

Scene Architecture

The way most Gears of War 3 scenes are laid out is a direct result of the limitations of the blur system. The gist of why backgrounds are set up the way they are is that the blur system does not work well on things that are semi-transparent. Thus, backgrounds are set up so the content of the scene can be blurred, but not the background. The background for the scenes are usually semi-transparent, and thus blurring backgrounds is avoided if possible. If a semi-transparent background is blurred, you get a nasty popping when the blur effect goes away, because the blend mode changes on a single frame, going from totally transparent to partially transparent. In short, it's ugly. So, to get around this, when a Gears scene is blurred (like when another scene appears over the top), it is blurred from the body down the chain, and not the background. To better illustrate this, below is an image showing how Gears scene hierarchies are set up now, which seems to be the best way:


Please also note that the Bag Clip, noted in red above, is very simple, but absolutely necessary. The problem is that if you blur something programmatically, you "break the timeline," which means animations will pop or be in an unpredictable state. So, an extra layer is added (which we term "bagging") to ensure that only a clip that is never directly animating on the timeline is blurred. The clips above and below this level can animate, but the actual level clip that is being blurred should never itself animate.

That is an important "gotcha" lesson though...if you EVER change a blur, alpha, or position variable via code on a clip that is animated on the timeline, it will NO LONGER behave predictably! It's one of the very hard lessons we learned in development, so please spare yourself the pain and don't do it! When in doubt, bag!

Using Kismet with Scaleform

Using Kismet to open and interact with Scaleform UIs makes it possible for designers to add another level of polish and interactivity to their levels.

Opening a Movie in Kismet

To open a movie from Kismet, simply create a new Open GFx Movie action (New Action > GFx UI > Open GFx Movie) and assign the SWF to the Movie property and the movie player class that should own the movie to the Movie Player Class property, as shown below:


The player to open the movie for should be linked to the Player Owner variable link.


If checked, the movie will by default capture input for the keys listed in the CaptureKeys array.
If CaptureInput is checked, the keys listed in this array will be sent to the GFx movie.
Should this movie be displayed even if the HUD is not shown (useful for most non-HUDuser interface movies).
Reference to the movie (SWF file imported into the engine as an asset) that you want to play.
(Advanced) If there is an UnrealScript class that encapsulates functionality for this movie that you wish to use, select it from this list. Otherwise, GFxMoviePlayer is the default option.
(Advanced) If you don't want to render this movie to the full screen, but rather to a render to texture resource so it can be used in the world, specify it here. If nothing is specified, the movie will render to the screen.
If checked, the movie will not play by default, and will have to manually be started by script.
If checked, the GFx movie will take control focus of the screen when it is opened.

Closing a Movie in Kismet

To close a movie through Kismet, you can use the Close GFx Movie action, though you first need to have saved a reference to the movie to close in an Object variable. This reference is obtained from the Movie Player variable link of the Open GFx Movie action when opening a new movie.



If checked, the movie is unloaded from memory when it is closed.

Calling an ActionScript function in Kismet

It is possible, in Kismet, to call an ActionScript method on an open SWF movie. For example, say the following ActionScript function was in a movie that was opened:

function myActionScriptMethod(MyString:String, MyBool:Boolean)
     // Do something interesting!

To invoke this ActionScript method from Kismet, create a new GFx Invoke ActionScript Kismet Action (right click on the Kismet workspace -> "Action" -> "GFx UI" -> "GFx Invoke ActionScript"). In the MethodName variable in the properties window, enter the name of the method you wish to call in ActionScript. ALERT! This is case sensitive, so if the capitalization is different than what is in ActionScript, the method will fail.


To pass parameters to the method, you must add an entry to the arguments array for each argument of the ActionScript function you wish to call. Each entry has four editable fields.

This specifies what type of parameter you wish to pass in that slot. The relevant types are AS_String (S), AS_Boolean (B), and AS_Number (N).
String data you wish to pass.
Boolean data you wish to pass.
Number data you wish to pass.

In our example above, there are two parameters for the myActionScriptMethod that we wish to pass; a string and a boolean. Therefore, there are two entries in our array. One with its type set to AS_String, and one with its type set to AS_Boolean, and the corresponding data fields are filled out for each.

Receiving ActionScript calls from GFx in Kismet

ActionScript can use FSCommands to trigger events in Kismet. These work the same as other events in kismet. For example:


To use this event in Kismet, create a new fscommand (right click on the Kismet workspace -> "Event" -> "GFx UI" -> "FsCommand"). Then enter your FsCommand and set the GFx Movie to use.


Getting and Setting Values

Values of variables belonging to objects within Scaleform movies opened through Kismet can be accessed or set using the GFx GetVariable and GFx SetVariable actions.



The name of the variable to get or set the value for.

Fonts in Scaleform

Fonts can be tricky when dealing with Scaleform for several reasons. One of these is that Flash has access to the full character set which means things will often work in the GFx player but not in UE3 because characters being used are missing from the UE3 fonts.

A good way to ensure you always have the characters you need in your fonts in UE3 is to create a master text file of all the glyphs required and use it as a wildcard when importing. With that, if you find you're missing characters you can update the text file, and right-click reimport a font easily in the Content Browser.

Contents of Epic's import text file for the default font (INT):

!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ €„ˆ›Œ‘’“”–—˜™›œ¡¢£¨©ª«­®°²³´¹º»¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÑÒÓÔÕÖØÙÚÛÜßàáâãäåæçèéêëìíîïñòóôõöøùúûüýÝ¥§Ÿ…A;a;C'c'C(c(D(d(E;e;E(e(L'l'??N'n'N(n(O"o"R(r(S's'ŠšT(t(U*u*U"u"Z'z'Z.z.Žž???????????????????????????????????????????????????????????????????A-a-A(a(??E-e-E(e(E.e.G(g(G,g,I-i-I;i;I.?K,k,L,l,L(l(N,n,O-o-O(o(ŒœR'r'R,r,S's'S,s,T,t,U-u-U*u*U;u; S,s,T,t,

In general, there are three possible workflows when it comes to fonts with Scaleform:

  • UFonts: Unreal bitmap fonts - Always fast to render! Support distance fields (monochrome only, great for scaling up, but cannot preserve sharp corners). RGBA bitmap (not as good at scaling, full color)
  • Embed vector font (fonts_en.swf, fonts_*.swf) - Sometimes fast to render. Dynamic font cache can lead to performance issues; not updated efficiently. No support for RGBA.
  • System font - Just like embedded font, but looked up from OS. Great for PC games that require full localization support.

The first method is a custom font path for using UE3 fonts while the other two are generic to Scaleform. More information on those can be found in Scaleform's documentation.

The game's Localization/GFxUI.int file maps the symbol name of the font to the actual font to use following one of these rules depending on which font path you decide to use:

  • UFonts - path to UFont resource; e.g. GearFonts.MyFont
  • Vector font - the name of the vector font exported from fonts_en.swf; e.g. Arial, Bold
  • System font - TODO

For example, the defaults for UDKGame are:

NormalFont=Bitstream Vera Sans
BoldFont=Bitstream Vera Sans,Bold
SmallFont=Bitstream Vera Sans
TitleFont=Bitstream Vera Sans,Bold

Common Font Error

> Missing font "$NormalFont" in "_level0.PauseMenuSP.PartyPanelLoaderPanel.PartyPanel.PPListItem1.PlayerIcon.textField". Search log:
>    Searching for font: "$NormalFont"
>       Movie resource: "$NormalFont"  not found.
>       Imports       : "$NormalFont"  not found.
>                     : "../UI_Common/gfxfontlib.swf", "..\UI_Common\UI_Common_Assets.swf".
>       Exported      : "$NormalFont"  not found.
>       Searching GFxFontProvider: "$NormalFont"  not found.
>    Font not found.
> Error: Resource for font id = 12 is not found in text field id = 52, def text = 'OPTION'
> Error: Resource for font id = 12 is not found in text field id = 52, def text = 'OPTION'
> Error: Resource for font id = 12 is not found in text field id = 59, def text = 'textField'

First of all, anyone who exports FLAs to SWFs must have the fonts installed on their system! After that, make sure you have compiled your dependencies. Flash files can be dependent on other Flash files, and you can create libraries with them. So, if you're testing a scene that is using symbols from another Flash file, it needs to be published first. Gears shares fonts in this way, so that only one copy of the font ever needs to be stored, which saves memory. If you use a similar system, you need to compile the Flash files in a particular order.

For instance:

  • UI_Common/fonts_en.fla - The fonts and glyphs for the language
  • UI_Common/gfxfontlib.fla - The library SWF that defines the font symbols ($NormalFont, $LargeFont, etc)
  • UI_Common/UI_Common_Assets.fla - Our shared common asset library of base widgets
  • UI_FrontEnd/UI_CommonFrontEndAssets.fla - Our shared front end assets

After you do this, you should have SWFs for all of these files. These contain things like the $NormalFont symbol and other things that the error spew says you're missing.

Testing and Debugging Scenes

Debugging Scaleform UIs is no easy chore in many cases, but there are some commands and settings that can help along the way.

Enabling or disabling of GFx rendering for debugging

During the transition from the old UI system to the new GFx UI system, it may be useful to disable GFx UI rendering if the new UI is being built concurrently with people using the old UI. Because of this, we added a simple boolean for debugging that allows you to disable the GFx UI from rendering and taking input. To change it, modify the following bool in your game's Engine.ini file:


If true, the GFx UI will not be rendered, nor will it take input.

Engine exec functions for testing

There are a few debugging functions added to make life easier for artists looking at SWF movies in the engine. Unless otherwise specified, these function work on the topmost movie currently being rendered by GFx.

  • GFxGotoAndPlay Path FrameLabel - Jumps the specified movie clip to the specified frame label, and plays.
  • GFxGotoAndStop Path FrameLabel - Jumps the specified movie clip to the specified frame label, and stops.
  • GFxInvoke Path FunctionName - Calls an ActionScript function with FunctionName on the specified path.
  • GFxRestartMovie - Restarts playback of the topmost movie being rendered.

Scaleform Import Pipeline

Importing your SWFs and any assets they use into Unreal is obviously a very important and necessary step in the process of UI creation with Scaleform. The process automatically imports images as textures as long as you have them set up correctly in Flash before publishing and there are certain other considerations you need to be aware of if your SWFs have dependencies on other movies or are used to share resources.

See the Scaleform GFx Import Pipeline page for complete details on setting up movies for import and importing them into Unreal Engine 3.