64 lines
4.2 KiB
Markdown
64 lines
4.2 KiB
Markdown
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# Instancing
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You can use instancing to batch process multiple effects, if they have the same [Visual Effect Graph Asset](VisualEffectGraphAsset.md). This can lead to a significant improvement in performance.
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Instancing is enabled by default, except on Visual Effect Graph Assets that use features that do not support instancing. These include:
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- [GPU events](Events.md#gpu-events)
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- [Output Mesh](Context-OutputMesh.md)
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- [Output Event Handlers](OutputEventHandlers.md)
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## How instancing works
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Visual effects consist of data stored in buffers, and operations performed by shaders. Effects that use the same [Visual Effect Graph Asset](VisualEffectGraphAsset.md) perform the same operations.
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Instancing allocates data for these effects in shared buffers. A group of effects that share buffers is called a **batch**, and the effects are **instances** that belong to that batch.
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Every time a new effect is created, the instancing system looks for a slot in an existing batch. If there aren't any empty slots available, the instancing system creates a new full batch, and allocates the effect data there. Batches for each [Visual Effect Graph Asset](VisualEffectGraphAsset.md) have **fixed capacity**, which you can set automatically (by default) or manually.
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If instancing is disabled for an effect, the instancing system allocates a batch with a single instance.
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During the simulation update, effects that belong to the same batch can run some operations together.
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In the same way, during the rendering, effects can be grouped by batch, reducing CPU time.
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## Configuration
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The instancing feature is enabled by default, and does not require any configuration in most cases. However, to improve performance, you can adjust the batch capacity for each [Visual Effect Graph Asset](VisualEffectGraphAsset.md). You can also disable instancing on specific effects.
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### Adjust batch capacity
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You can adjust the batch capacity for each [Visual Effect Graph Asset](VisualEffectGraphAsset.md#visual-effect-asset-inspector). To adjust the capacity, navigate to the VFX asset’s Inspector, and in the Instancing section, select Instancing Mode.
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* **Automatic batch capacity**: Set batch capacity automatically, based on the contents of the effect and the build platform. This is the default mode.
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* **Custom batch capacity**: Set the capacity to a custom value. This is useful if you have a good estimation of how many effects should exist at the same time, or if you want to have a better control on how much memory is used.
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When you set a custom capacity, the effect uses the same value on all platforms. You should profile on different scenarios to ensure that there is no regression in performance.
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### Disable instancing
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You can disable instancing on a specific [Visual Effect Graph Asset](VisualEffectGraphAsset.md#visual-effect-asset-inspector) or [Visual Effect component](VisualEffectComponent.md#the-visual-effect-inspector), or across your whole project. Disabling instancing sets a batch capacity of 1 on each affected effect. You should only disable instancing for debugging purposes, or if you are confident that you don't need instancing.
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To disable instancing on a specific [Visual Effect Graph Asset](VisualEffectGraphAsset.md#visual-effect-asset-inspector):
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1. Navigate to the VFX asset’s Inspector.
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1. In the**Instancing** section, select **Instancing Mode**.
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1. Set **Instancing** mode to **Disabled**.
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To disable instancing on a specific [Visual Effect component](VisualEffectComponent.md#the-visual-effect-inspector):
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1. Navigate to the Visual Effect component’s Inspector.
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1. In the **Instancing** section, deactivate **Allow Instancing**.
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To disable instancing across your project:
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1. Open the [Visual Effect preferences](VisualEffectPreferences.md) ( Windows: **Edit > Preferences > Visual Effects**. macOS: **Unity > Settings > Visual Effects**).
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1. Deactivate **Instancing Enabled**.
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## Scripting API
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Instancing adds some scripting functionality through [VFX Manager scripting API](https://docs.unity3d.com/ScriptReference/VFX.VFXManager.html).
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Using this, you can access [additional information and stats](https://docs.unity3d.com/ScriptReference/VFX.VFXBatchedEffectInfo.html) for each Visual Effect Asset.
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