---
url: /api/effects/bloom/functions/bloom.md
---
# bloom()

```ts
function bloom(params?: {
  levels?: number;
  radius?: number;
  mix?: number;
}): CompositeEffectPass<{
  get uRadius(): number;
  get uMix(): number;
}>;
```

Creates a Bloom effect using a downsampling/upsampling pyramid.

Based on [Custom Bloom Post-Process in Unreal Engine](https://www.froyok.fr/blog/2021-12-ue4-custom-bloom/).

[Example: Bloom (builtin)](/examples/post-processing-builtin/bloom/)

## Parameters

### params?

Bloom configuration.

#### levels?

`number`

Number of mip levels for the bloom pyramid.

**Default**

```ts
8;
```

#### radius?

`number`

Blur radius for the upsampling stages.

**Default**

```ts
0.65;
```

#### mix?

`number`

Bloom intensity / mix factor.

**Default**

```ts
0.5;
```

## Returns

[`CompositeEffectPass`](../../../passes/compositeEffectPass/type-aliases/CompositeEffectPass.md)<{
get `uRadius`(): `number`;
get `uMix`(): `number`;
}>