-<!--
-/**-->
-
-# Texture Atlases {#textureatlases}
-
-## Example demo application
-
-![ ](../assets/img/texture-atlas/image-wall.jpg)
-![ ](image-wall.jpg)
-
-
-Application above is running slow as there are many small individual images displayed (50)
-
-| Metric | Result | Explanation |
-|--------|--------|-------------|
-| Launch time | Slow | Has to perform: 50 file open requests and multiple reads for each image |
-| Memory consumption| High | Has to create:50 Dali::Image objects,50 OpenGL Textures|
-| Rendering | Slow | Has to perform: 50 glBindTexture calls per frame ( each OpenGL calls takes time) 50 a frame = 3000 calls per second @60 FPS.Texture switching is a major state change in the GPU|
-
-
-
-## Solutions to problem: Use a Texture Atlas
-
-A texture atlas is simply one larger image that contains smaller images. A texture atlas is sometimes called a
-sprite sheet, bitmap sheet or texture pack.
-
-![ ](../assets/img/texture-atlas/atlas.jpg)
-![ ](atlas.jpg)
-
-Dali::ImageActor has the ability to display a portion of an image using ImageActor::PixelArea setting.
-For example to display the first 3 image in the atlas
-
-![ ](../assets/img/texture-atlas/example-javascript-code.jpg)
-![ ](example-code.jpg)
-
-### Result of using an Atlas
-
-| Metric | Result | Explanation |
-|--------|--------|-------------|
-| Launch time | Fast | Has to perform: - 1 file open request |
-| Memory consumption| Low | Has to create: 1 Dali::Image objects 1 OpenGL Textures|
-| Rendering | Fast | HHas to perform: 1 glBindTexture calls per frame ( each OpenGL calls takes time) 1 a frame = 6- calls per second @60 FPS.|
-
-
-## Atlas creation guide
-
-Many tools exist for creating texture atlases.
-In the following example we are using a tool called TexturePacker as DALi has an exporter script for it.
-The exporter automatically generates a source file that has the ImageActor::PixelArea pre-defined.
-
-- Download http://www.codeandweb.com/texturepacker
-- Launch TexturePacker
-- Go to the menu File -> Preferences
-- Set the "Exporter directory" to be the location of dali-toolkit/texture-atlas-exporter
-
-![ ](../assets/img/texture-atlas/texture-packer-preferences.jpg)
-![ ](texture-packer-preferences.jpg)
-
-- Restart the application!
-- Select DALi 3D framework for new project
-
-![ ](../assets/img/texture-atlas/texture-packer-startup.jpg)
-![ ](texture-packer-startup.jpg)
-
-- Create the atlas
-![ ](../assets/img/texture-atlas/texture-packer-add-sprites.jpg)
-![ ](texture-packer-add-sprites.jpg)
-- Click publish to produce the files
-![ ](../assets/img/texture-atlas/texture-packer-publish.jpg)
-![ ](texture-packer-publish.jpg)
-
-
-
-## Using the generated cpp ( contains JavaScript code as well)
-
-The generated cpp file contains 3 different ways of describing the atlas.
-Copy and paste the section that best suits your application.
-- Lookup table. Includes code for storing the table in a std::map for fast lookup.
-- constants.
-- JavaScript property map
-
-### Using the JavaScript generated property map
-
-The property map should be cut and paste in to your application. It just looks like
-
-~~~{.js}
-var ATLAS_IMAGE_LIST : [
- { name: "add_user_usericon_bg", x: 2, y:109, w:105, h:105, blendMode:dali.BLENDING_ON },
- { name: "app_background", x: 180, y:183, w:1, h:1, blendMode:dali.BLENDING_OFF },
- { name: "btn_arrow_left", x: 141, y:183, w:11, h:20, blendMode:dali.BLENDING_ON },
- { name: "btn_arrow_right", x: 154, y:183, w:11, h:20, blendMode:dali.BLENDING_ON },
- { name: "icn_app_foc", x: 194, y:2, w:72, h:72, blendMode:dali.BLENDING_ON },
- { name: "icn_app_nor", x: 109, y:109, w:72, h:72, blendMode:dali.BLENDING_ON }
- ]
-var atlas = new dali.ResourceImage( { url: "atlas_filename.png" });
-
-// display the user icon using the size / position data in the ATLAS_IMAGE_LIST
-var userIconData = ATLAS_IMAGE_LIST[0];
-var userIconRect = [ userIconData.x, userIconData.y,userIconData.w,userIconData.h];
-
-var btnArrowLeft = new dali.ImageActor( atlas, userIconRect );
-btnArrowLeft.setBlendMode(userIconData.blendMode);
-
-~~~
-
-![ ](example-javascript-code.jpg)
-
-
-### Using the lookup table in C++
-
-Cut and paste the lookup table code into your application.
-
-~~~{.cpp}
-
-// The following code is automatically generated when TexturePacker publishes to a cpp file.
-const char* ATLAS_FILE_NAME( "my_first_atlas.png" ); ///< Atlas image filename
-
-// Structure to hold image name and position within the atlas.
-struct ImageInfo
-{
- const char* name;
- unsigned int x,y,w,h;
- Dali::BlendingMode::Type blendMode; // only enable blending if image has alpha
-};
-
-
-// lookup table
-const ImageInfo ImageAtlas[]=
-{
- { "blocks-ball", 2, 198, 51, 51, BlendingMode::ON },
- { "bubble-ball", 288, 74, 32, 32, BlendingMode::ON },
- { "gallery-small-52", 2, 2, 128, 128, BlendingMode::OFF },
- { "icon-change", 219, 2, 37, 34, BlendingMode::ON },
- { "icon-cluster-carousel", 180, 2, 37, 34, BlendingMode::ON }
-};
-
-const ImageInfo* GetImageInfo(const char* name)
-{
- typedef std::map< const char*, const ImageInfo* > LookupMap;
- static LookupMap lookup;
- if( lookup.empty() )
- {
- for( unsigned int i = 0; i < ATLAS_IMAGE_COUNT; ++i)
- {
- lookup[ ImageAtlas[i].name ] = &ImageAtlas[i];
- }
- }
- LookupMap::const_iterator iter = lookup.find(name);
- if( iter != lookup.end() )
- {
- return (*iter).second;
- }
- DALI_ASSERT_ALWAYS(0 && "image name not found in atlas");
- return NULL;
-}
-
-~~~
-
-To use the lookup table you can do something like this:
-
-~~~{.cpp}
-// Example function on how to get an image info from the table
-
-std::string fileName = std::string( DALI_IMAGE_DIR ) + ATLAS_FILE_NAME;
-Image imageImage = Image::New( fileName );
-
-const ImageInfo* info(NULL);
-
-info = GetImageInfo("blocks-ball");
-if( info)
-{
- ImageActor ballActor = ImageActor::New( imageAtlas, ImageActor::PixelArea( info->x, info->y, info->w, info->h) );
- ballActor->SetBlendMode( info->blendMode );
-}
-info = GetImageInfo("bubble-ball");
-if( info)
-{
- ImageActor bubbleActor = ImageActor::New( imageAtlas, ImageActor::PixelArea( info->x, info->y, info->w, info->h) );
- bubbleActor->SetBlendMode( info->blendMode );
-}
-
-~~~
-
-### Using the constant definitions (C++)
-
-1. Cut and paste the constant definition code into your application.
-
-You'll notice the code below won't compile because C++ variables can't have a dash character.
-E.g. BLOCKS-BALL, BUBBLE-BALL will cause errors. Do a search and replace for - and replace with underscores.
-This is one reason why using lookup table which holds the filename as a string maybe easier to use.
-
-~~~{.cpp}
-
-// The following code is automatically generated when TexturePacker publishes to a cpp file.
-const char* ATLAS_FILE_NAME( "my_first_atlas.png" );
-
-
-// Structure to hold position / blend mode within the atlas.
-struct ImageInfo
-{
- ImageInfo(unsigned int x,unsigned int y,unsigned int w,unsigned int h, Dali::BlendingMode::Type mode)
- :pixelArea(x,y,w,h),blendMode(mode)
- {}
- ImageActor::PixelArea pixelArea;
- Dali::BlendingMode::Type blendMode; // only enable blending if image has alpha
-};
-
-
-const ImageInfo BLOCKS-BALL( 2, 198, 51, 51 ,BlendingMode::ON );
-const ImageInfo BUBBLE-BALL( 288, 74, 32, 32 ,BlendingMode::ON );
-const ImageInfo GALLERY-SMALL-52( 2, 2, 128, 128 ,BlendingMode::OFF );
-~~~
-
- 2. To use it, you can copy example code from the generated cpp file which looks
-like this
-
-~~~{.cpp}
-void LoadAtlasImages()
-{
- std::string fileName = std::string(DALI_IMAGE_DIR) + ATLAS_FILE_NAME;
- Image atlasImage = Image::New( fileName );
- ImageActor Blocksball = ImageActor::New( atlasImage, BLOCKS_BALL.pixelArea);
- Blocksball.SetBlendMode( BLOCKS_BALL.blendMode );
-
- ImageActor Bubbleball = ImageActor::New( atlasImage, BUBBLE_BALL.pixelArea);
- Bubbleball.SetBlendMode( BUBBLE_BALL.blendMode );
- ...
-~~~
-
-
-## Atlas creation tips
-
-- Compress the atlas - \link texturecompression Compressing Textures \endlink
-- Avoid adding large images to the Atlas.
-- E.g. don't add background images to it. Medium to large images should be kept seperate.
-
-![ ](../assets/img/texture-atlas/atlas-size.jpg)
-![ ](atlas-size.jpg)
-
-
-- Try to ensure the atlas contains only images that are frequently used. There's no point in having images taking up GPU texture memory if they're not displayed.
-- Avoid very large atlases. Try to create multiple atlases based on how they are used within your application.
-Alternatively Texture packer has the option to split atlases ( search help for Multipack)
-
-
-
-@class _Guide_TextureAtlases
-
-*/
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