In the previous tutorial we looked at the basics of creating an application using the Defold engine, part of that included the built in Atlas type for displaying a sprite. In this tutorial we are going to look further into sprites. In case you are unaware, a sprite is simply a 2D graphic with position and is pretty fundamental to modern 2D games, even if sprites are actually faked in 3D.
There is an HD video version of this tutorial here.
In the previous tutorial we started with an Atlas created for us. This time we are going to create one from scratch. Don’t worry, it’s easy. So what exactly is an Atlas? It’s simply a collection of images in a single source. The Defold engine itself is resposible for determining the ideal layout for the best performance.
Creating and Populating an Atlas
Creating an Atlas is simple. In the Project Explorer, right click the folder you want to create the Atlas in and select New->Atlas File
Next name your Atlas file. In this case I’m going with walker. The extension is predictably enough .atlas. Then click Finish.
Now we need some Image files to put in our Atlas. In this case I am using a selection of images I created earlier but you can use whatever images you want. If you are a Patreon backer, they are available in the Patreon Dropbox in the folder Art\AnimatedCharacter\Spritesheets\Raw\walk. Whatever images you go with, simply drag and drop them to the images folder inside the main folder. If you don’t have such a folder, simply right click and create one.
Now make sure Walker.Atlas is open in the editor, then go over to the Outline view, right click Atlas and select Add Animation Group.
In the properties window, name the animation walk and set the default playback mode to Loop Forward.
Now right click the newly created Walk animation group and select Add Images. In the popup dialog, select all our newly added images. You can use CTRL or SHIFT to multiselect:
You will see that Defold automatically arranges all of our frames of animation together into a single atlas:
Be sure to save your Atlas before continuing. You can preview the animation by right clicking “walk” in the Outline then choosing Play/Stop Animation.
Creating a Sprite
Now that we’ve got our populated Atlas and a walk animation, how do we use it? We create a Sprite.
To do so open up your main level .collection file. In Outline right click Collection then choose Add Game Object:
I personally changed the ID of mine to walker. Now right click the newly created game object and select Add Component.
In the Add Component dialog, choose Sprite.
With the sprite selected in Outline, we now need to define some properties, specifically Image and Default animation.
For Image, it will bring up a dialog box, select our recently created Atlas. If the Atlas isnt shown, make sure everything has been saved.
Next select the Walk animation we defined earlier.
Now your game object Sprite will show in Collection.
In this case our sprite is centered about the atlas. You can move the sprite using the W key. ( E and R can be used for rotation and scaling as well ).
Each arrow represents the axis it will be moved along. Or you can position your mouse inside the square and move freely in any direction. Position your character then run your game (Ctrl + B) and you should see:
Creating a Tile Source
You can also use a tile source instead of an Atlas. A tile source is simply a grid of sprites already arranged into a single image. To use a tile source instead of selecting Atlas, you select Tile source. I wont be covering it in detail here ( I will cover tile sources later when we get to tile maps ), but if you want more details check the video where I did cover it.
You can also programmatically program the animation, get callbacks when animations complete, etc... but that requires knowledge of message passing... and that’s in the next tutorial!