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# MTLTextureSparseTier.tier1

Indicates support for sparse textures tier 1.

```
case tier1
```

## Discussion

Tier 1 sparse textures allow the following:

- Partial memory backing at sparse tile granularity.
- Defined behavior for accessing an unbacked texture region.
- Shader feedback on texture access to determine memory backing.

An unbacked texture region indicates a region within the texture that doesn’t
have memory backing at a given point in time. Accessing an unbacked texture
region produces the following results:

- Reading returns zero (transparent black) for pixel formats with an alpha (A) channel.
- Reading return zero in RGB and one in alpha (A) channels (opaque black) otherwise.
- Writing produces no result.

---

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