View source for Blur filter

Best practices:

* Scale down before applying filter to increase blur radius
* Separate into horizontal + vertical passes to reduce number of texture lookups
* Use hardware filtering to reduce number of texture lookups
* Make sure blending happens in [[Gamma|linear RGB]] to avoid darkening

== See also ==

* https://www.codeproject.com/Articles/839187/An-investigation-of-fast-real-time-GPU-based-image
* https://iquilezles.org/www/articles/gamma/gamma.htm