stride3d.stride-docs/en/manual/graphics/textures/streaming.md

Streaming

Beginner Artist Programmer

When you stream textures, Xenko only loads them when they're needed. This significantly decreases the time it takes to load a game or scene, uses less memory, and makes your game easier to scale.

[!Note] Currently, only textures can be streamed.

How Xenko streams textures

Instead of loading a texture when Xenko loads the scene (with all its mipmaps), Xenko only loads it when it's used (eg a model using the texture is onscreen).

When the texture is no longer needed (ie no objects that use the texture are onscreen), Xenko unloads it.

Currently, there's no loading priority for textures. For example, Xenko doesn't load textures based on distance; instead, Xenko loads them all in sequence.

Using streaming with mipmaps

If mipmaps (different-resolution versions of textures displayed at different distances) are enabled in the texture properties, the lower-resolution mipmaps load first, as they're smaller in size. The gif below shows this process happening in slow motion.

In most situations, the process is very quick. We recommend you enable mipmaps for streaming as it means lower-resolution versions of textures act as placeholders until the higher-quality versions can load, reducing pop-in.

When not to use streaming

Streaming is enabled by default for all textures. You might want to disable streaming on important textures you always want to display immediately and in high quality, such as:

• splash screens

• textures on player models

• textures used in particles (particles often have a short lifespan, so might disappear before the texture loads)

Enable or disable streaming on a texture

1. In the Asset View, select the texture.

   

2. In the Property Grid, under Format, use the Stream check box.

   

Global streaming settings

You can access the global streaming settings in the Game Settings asset. These settings apply to all textures that have streaming enabled.

For instructions about how to access the global streaming settings, see the Game Settings page.

Properties

Property	Description
Streaming	Enable streaming
Update interval	How frequently Xenko updates the streaming. Smaller intervals mean the streaming system reacts faster, but use more CPU and cause more memory fluctuations.
Max resources per update	The maximum number of textures loaded or unloaded per streaming update. Higher numbers reduce pop-in but might slow down the framerate.
Resource timeout (ms)	How long resources stay loaded after they're no longer used (when the memory budget is exceeded)
Memory budget (in MB)	When the memory used by streaming exceeds this budget, Xenko unloads unused textures. You can increase this to keep more textures loaded when you have memory to spare, and vice versa.

Access the streaming manager in code

Use Streaming.

For example, to disable streaming globally, use:

Streaming.EnableStreaming = false;

To start streaming a texture:

Streaming.StreamResources(myTexture);

To disable streaming at load time:

var texture = Content.Load<Texture>("myTexture", ContentManagerLoaderSettings.StreamingDisabled);

Options

There are three StreamingOptions:

• The KeepLoaded option keeps the texture in memory even when the memory budget is exceeded.

• If mipmaps are enabled, the ForceHighestQuality option loads only the highest-quality version of the texture.

• The KeepLoaded option keeps the texture in memory even when it's not used.

For example:

var myOptions = new StreamingOptions() { KeepLoaded = true };
Streaming.StreamResources(myTexture, myOptions);

To change the StreamingOptions at runtime, use SetResourceStreamingOptions. For example:

var myNewOptions = new StreamingOptions() { KeepLoaded = false };
Streaming.SetResourceStreamingOptions(myTexture, myNewOptions);

See also

• StreamingManager API
• Textures index
• Texture compression
• Game Settings