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Preloading Textures into Memory

Decompress images ahead of time to avoid performance issues during gameplay.


A major advantage to SpriteKit is that it performs a lot of memory management for you automatically. When rendering a new frame of animation, SpriteKit determines whether a texture is needed to render the current frame. If a texture is needed but is not prepared for rendering, SpriteKit loads the texture data from the file, transforms the data into a format that the graphics hardware can use, and uploads it to the graphics hardware.

This process happens automatically in the background, but it isn’t free. If too many unloaded textures are needed at once, it may be impossible to load all the textures in a single frame of animation, causing the frame rate to stutter. To avoid this problem, you need to preload textures into memory, particularly in larger or complex games.

Preload Texture Objects

This code shows how to preload an array of SKTexture objects. The preload(_:withCompletionHandler:) method calls the completion handler after all of the textures are loaded into memory. In this example, all of the textures for a particular level of the game are preloaded in a single operation. When the textures are all in memory, the completion handler is called. It creates the scene and presents it. (You need to add code to provide these texture objects to the scene; that code isn’t shown here).

SKTexture.preload(textureArrayForLevel1) {
    // The textures are loaded into memory. Start the level.
    let gameScene = GamePlayScene(size: CGSize(width: 768, height: 1024))
    if let spriteView = view as? SKView {

Choose a Time to Preload

Because you are intimately familiar with the design of your game or app, you are the best person to know when new textures are needed. The exact design of your preloading code is going to depend on your game engine. Here are a few possible designs to consider:

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