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# astc(blockSize:quality:)

Compresses the imported image with ASTC.

```
static func astc(blockSize: TextureResource.Compression.ASTCBlockSize, quality: TextureResource.Compression.ASTCQuality = .fast) -> TextureResource.Compression
```

## Discussion

If the device doesn’t support ASTC pixel formats,
RealityKit applies compression as part of the `.reality` file
export.

> Note: Remove an unused alpha channel from the source image to
> get better compression quality.

---

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