---
title: TextureResource.Compression.ASTCBlockSize
framework: realitykit
role: symbol
role_heading: Enumeration
path: realitykit/textureresource/compression/astcblocksize
---

# TextureResource.Compression.ASTCBlockSize

The compressed block size.

## Declaration

```swift
enum ASTCBlockSize
```

## Overview

Overview note: RealityKit stores block pixel data in groups of 128 bits. For instance, a block4x4 bits per pixel is 128/(4*4) = 8 bit per pixel.

## Topics

### Compression block sizes

- [TextureResource.Compression.ASTCBlockSize.block4x4](realitykit/textureresource/compression/astcblocksize/block4x4.md)
- [TextureResource.Compression.ASTCBlockSize.block5x4](realitykit/textureresource/compression/astcblocksize/block5x4.md)
- [TextureResource.Compression.ASTCBlockSize.block5x5](realitykit/textureresource/compression/astcblocksize/block5x5.md)
- [TextureResource.Compression.ASTCBlockSize.block6x5](realitykit/textureresource/compression/astcblocksize/block6x5.md)
- [TextureResource.Compression.ASTCBlockSize.block6x6](realitykit/textureresource/compression/astcblocksize/block6x6.md)
- [TextureResource.Compression.ASTCBlockSize.block8x5](realitykit/textureresource/compression/astcblocksize/block8x5.md)
- [TextureResource.Compression.ASTCBlockSize.block8x6](realitykit/textureresource/compression/astcblocksize/block8x6.md)
- [TextureResource.Compression.ASTCBlockSize.block8x8](realitykit/textureresource/compression/astcblocksize/block8x8.md)
- [TextureResource.Compression.ASTCBlockSize.block10x10](realitykit/textureresource/compression/astcblocksize/block10x10.md)
- [TextureResource.Compression.ASTCBlockSize.block10x5](realitykit/textureresource/compression/astcblocksize/block10x5.md)
- [TextureResource.Compression.ASTCBlockSize.block10x6](realitykit/textureresource/compression/astcblocksize/block10x6.md)
- [TextureResource.Compression.ASTCBlockSize.block10x8](realitykit/textureresource/compression/astcblocksize/block10x8.md)
- [TextureResource.Compression.ASTCBlockSize.block12x10](realitykit/textureresource/compression/astcblocksize/block12x10.md)
- [TextureResource.Compression.ASTCBlockSize.block12x12](realitykit/textureresource/compression/astcblocksize/block12x12.md)

## Relationships

### Conforms To

- [Decodable](swift/decodable.md)
- [Encodable](swift/encodable.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Specifying the compression settings

- [default](realitykit/textureresource/compression/default.md)
- [none](realitykit/textureresource/compression/none.md)
- [astc(blockSize:quality:)](realitykit/textureresource/compression/astc(blocksize:quality:).md)
- [TextureResource.Compression.ASTCQuality](realitykit/textureresource/compression/astcquality.md)