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Export animations for mobile apps and game engines

Last updated on 19 January 2022

Create a sprite sheet or texture atlas and export your animations for mobile apps and game engines. Import a texture atlas to Unity or any of your favorite game engines by using the plug-in.

Overview

Animate enables you to create sprite sheet or texture atlas animations and export them for mobile apps and game engines.

Sprite Sheet

A sprite sheet is a bitmap image file that contains several smaller graphics in a tiled grid arrangement. By compiling several graphics into a single file, you enable Animate and other applications to use the graphics while only needing to load a single file. This loading efficiency can be helpful in situations such as game development where performance is especially important.

You can create a sprite sheet from a selection of any combination of movie clips, button symbols, graphic symbols, or bitmaps. You can select items in the Library panel or on the Stage, but not both. Each bitmap and each frame of the selected symbols appear as a separate graphic in the sprite sheet. If you export from the Stage, any transforms (scaling, skewing, and so on) you have applied to the symbol instance are preserved in the image output.

Texture atlas

Texture atlas is a collection of textures as a single large image or multiple images of the desired dimension. You can optimize your game by creating a texture atlas and using it in your game app.

In Animate, you can create a texture atlas from symbols such as movie clips, graphics, or buttons. You can select items in the Library panel or on the Stage, but not both. Each vector and each keyframe of the selected symbols appear as a separate bitmap in the texture atlas. If you export from the Stage, any transforms (scaling, skewing, and so on) you have applied to the symbol instance are preserved in the image output.

Difference between a sprite sheet and texture atlas

You can use either sprite sheet or texture atlas in your mobile apps as per your requirement. Some of the key differences between sprite sheet and texture atlas are provided in the following table.

Feature	Sprite Sheet	Texture Atlas
Performance in mobile apps	Low	High
Efficiency in loading app	High, as there is no computation	Low, as there is JSON file computation
Size	Occupies more size	Occupies less size
Quality of animation	Medium	High
Number of files generated	Two files: one bitmap and one json	Variable: Based on the image dimension.
Number of bitmaps generated	Based on number of frames used in sprite sheet, number of bitmap files can also increase resulting in the increase of sprite sheet size	Only unique bitmaps are generated in sprite, thus reducing the total size.

Creating a sprite sheet

To create a sprite sheet, perform the following steps:

Select one or more symbols in the Library or symbol instances on the Stage. The selection can also contain bitmaps.
Right-click the selection and choose Generate Sprite Sheet.

In the Generate Sprite Sheet dialog box, select the required options, and then click Export.

Export option	Description
Image dimension	The total size in pixels of the sprite sheet. The default setting is Autosize, which sizes the sheet to fit all the sprites you include.
Image format	The file format of the exported sprite sheet. PNG 8 bit and PNG 32-bit support using a transparent background (alpha channel). PNG 24 bit and JPG do not support transparent backgrounds. Generally, the visual difference between PNG 8 bit and PNG 32 bit is small. PNG 32-bit files are four times as large as 8-bit PNG bit files.
Border Padding	Padding around the edges of the sprite sheet, in pixels.
Shape Padding	Padding between each image within the sprite sheet, in pixels.
Algorithm	The technique used for packing the images into the sprite sheet. There are two options: Basic (default) MaxRects
Data Format	The internal format used for the image data. Choose the format that best suits your intended workflow for the sprite sheet after export.
Rotate	Rotates the sprites 90°. This option is only available for some data formats.
Trim	This option saves space on the sprite sheet by trimming unused pixels from each symbol frame added to the sheet.
Stack Frames	Selecting this option prevents duplicate frames within the selected symbols from being duplicated in the resulting sprite sheet.

Export animations to mobile apps or gaming engines

Animate helps you to export animations to gaming platforms and mobile applications. Want to view the animation on your mobile phones or game engine? Watch the tutorial at the end of this example and follow these steps.

In the Library, right click the movie clip.
Select Generate Sprite Sheet.
In the Sprite Sheet dialog box, select the required options.
Click Export.

How to export animations for mobile apps or gaming engines

Watch the video to know about other options to export animations.

Creating a texture atlas

Gaming developers can use Animate to orchestrate animations and export them as texture atlas to Unity game engine or any other favorite gaming platforms.

The process of generating a texture atlas in Animate and importing it in Unity is depicted in the following diagram:

flow-diagram-Texture-Atlas — An illustration depicting the workflow for generating texture atlas and importing it into Unity.

To generate texture atlas of your animation, perform the following steps:

In Animate, you can generate a texture atlas for a selected symbol from the Library or symbol instance on the stage.
Right-click the symbol and select Generate Texture Atlas from the menu. Generate Texture Atlas window appears.

Generate texture atlas

Choose the appropriate export options for texture atlas.

Export option	Description
Image dimension	The total size in pixels of the texture atlas. The default setting is Autosize, which sizes the sheet to fit all the images you include.
Optimize dimensions	When Optimize dimensions option is checked, it removes empty pixels from bitmaps and dimensions are not in power of two (default option). This is applicable for all the bitmaps generated. When Optimize dimensions option is unchecked, bitmaps are generated based on the selected dimensions.
Image format	The file format of the exported sprite sheet. PNG 8 bit and PNG 32-bit support using a transparent background (alpha channel). Generally, the visual difference between PNG 8 bit and PNG 32 bit is small. PNG 32-bit files are four times as large as 8-bit PNG bit files.
Resolution	Choose any value ranging from 0.3-3.0
Border Padding	Padding around the edges of the texture atlas, in pixels
Shape Padding	Padding between each image within the texture atlas, in pixels.
Algorithm	The technique used for packing the images into the texture atlas. There are two options: Basic MaxRects (default)
Data Format	The internal format used for the image data. The default is the JSON format.
Rotate	Rotates the images in 90°. This option is only available for some data formats.
Flatten skewed objects to bitmap	Select this option if you are using skewed transforms for your objects. Animate converts these objects into bitmap images as some of the game engines do not interpret skew transforms appropriately.
Optimize Animation.json file	When Optimize animation.json file option is checked, this option removes indentation, decomposed matrix and shortens the names used (default option). When Optimize animation.json file option is unchecked, this option exports with indentation and with meaningful names.

You can choose to export the symbol into multiple bitmaps based on the dimension.

Generate texture atlas for multiple bitmaps

For assets exceeding the size of selected image dimension, a warning is displayed.
To preview the texture atlas output, click Preview tab.

Preview the texture atlas after creating it
Click Browse and choose the destination path in your computer for the output file or enter the path in the text area and click Export.

The generated output folder for texture atlas contains the following files:

Animation.json

This file contains information about the Animation. Identical frames are optimized and consolidated in Animation.json file by default.

spritemap.json

This file contains information about spritesheet.png file.

spritemap.png

For the exported symbol, this file contains Bitmap representation of all the minimum unique textures required to reconstruct back the animation.

You can use the generated texture atlas in any game engines such as Unity with the suitable importer plug-in.

Importing texture atlas to Unity

You can import the Animate generated texture atlas files to your favorite game engines. To import the texture atlas files, you can create plug-ins corresponding to your game engines. A sample import plug-in is provided for Unity tool.

Import the texture atlas into Unity by performing the following steps:

In Unity, create a project at any specific location. At this location, a folder is created with Assets sub folder in it.
Create two sub folders under Assets as Resources and Editor.
Click here to download the sample import plug-in for Unity. Choose Unity Plugin from the Downloads tab and choose the corresponding version to download.

The unity-plugin.zip consists of Plugin.cs, WrapperPlugin.cs, AnimateEditor.cs, and Effect.shader files.

Download of the sample signifies your agreement to the Terms of Use and Online Privacy Policy.
Move the texture atlas files such as Animation.json, spritemap.json, spritemap.png, and the unity plug-in files such as Plugin.cs and Effect.shader to Assets > Resources.
Move the AnimateEditor.cs and WrapperPlugin.cs files to Assets folder.
In Unity, click AnimateEditor.cs file and drag it to Main Camera.
Play. Playing your project splits the sprite map to different sprites.
Move AnimateEditor.cs to Editor.
In Unity, click WrapperPlugin.cs file and drag it to Main Camera. Also, deselect or remove AnimateEditor.cs from Main Camera.
Play or publish the output as per your requirement.

You can even customize the plug-in by modifying the WrapperPlugin.cs file as per your requirement.

Unity plug-in supports color effects for Animate generated texture atlas files. Also, the plug-in supports masking through layers. The masking feature is applicable only for Unity 2017 release onwards.

Texture publishing

As an animator, you can continue to author content in vector format and export as vector or raster format for HTML 5 platforms. An option to export animations as a texture atlas has been added in publish settings to enhance the performance of the animations.

1. Create a canvas document. Select File>New to display the New Document window.

2. Select the Advanced tab and click HTML5 Canvas. A new FLA document opens.

3. Click File > Publish Settings. If Export document as texture is enabled in Basic tab, Image Settings tab shows Texture Publishing options. By default, all the symbols are included in Texture publishing. To selectively choose symbols for textures, click settings icon adjacent to it.

Though, this option may increase the size of the assets, it improves the performance. Also, you can increase the resolution of images in terms of 2x and 3x the original resolution of the images for targeting HiDPI displays. To change the resolution settings, click the spanner icon adjacent to Export document as texture option as shown in the screenshot below. Drag the numbers adjacent to Resolution to get the multiples of 2x and 3x.

By default, texture publishing is set at 2X resolution. Also, range for resolution can be changed from 0.3 - 3X.

Texture publishing is applicable only to HTML5 Canvas document type.

Choosing a vector or raster file is like a choice between file sizes and performance. HTML5 platforms are optimized for raster content. So, for some complex shapes, it is better to pre-convert vector images to raster. For some of the basic content, you can still use vector content. Animate provides this option to you through a partial symbol selection dialog. Partial symbol selection allows you to choose symbols that should be converted to raster while keeping the remaining as vectors.

To open partial symbol selection, click Change in Publish settings dialog and select a symbol from the list. By default, all symbols are selected.

Select the symbols of your choice from the list.

Improve graphics performance through Bitmap Textures

In Animate, bitmap textures improve the performance of animations in different platforms. Want to reduce the complexity of vectors with bitmap textures? Watch the tutorial at the end of this example and follow these steps.

In the Properties Inspector panel, click Publish Settings.
In the Basic tab, select the spanner icon adjacent to Export document as texture.
In the Image Settings tab, click Change and select the symbols of your choice.
Click OK.

How to publish your assets as bitmap textures to improve performance

Watch the video to know how animations with bitmap textures perform.

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