# Screen Effects 2D

CRT, pixelate, and blur on a pure-2D scene via WorldEnvironment.

```{raw} html
<a class="example-run-button" href="../demos/features_2d_screen_effects.html">▶ Run in browser</a>

```

**Tags:** `2d` `post-processing` `crt` `pixelate` `blur`

Three built-in, cross-backend (desktop Vulkan + web WebGPU) screen-space post
effects that apply to a pure-2D scene through the same WorldEnvironment menu as
bloom/vignette:

  - CRT/scanlines  : darkens the image with a screen-space sine + a mild barrel
                     mask, like an old CRT tube.
  - Pixelate       : snaps the sample UV to a coarse block grid, so the frame
                     reads at a chunky "mosaic" resolution.
  - Blur           : a small box blur of the frame.

Each effect is gated by a flag bit: when its toggle is off it does no work at all
(zero cost), and a 2D scene with NONE of them enabled never enters the HDR path.

Controls:
    C            - Toggle CRT scanlines
    P            - Toggle pixelate
    B            - Toggle blur
    Up / Down    - Adjust the active knob (CRT intensity / block size / blur radius)
    Escape       - Quit

Run: uv run python examples/features/2d/screen_effects.py

## Source

```{literalinclude} ../../examples/features/2d/screen_effects.py
:language: python
:linenos:
```