Good day. I am Xor and I write shaders for a living.
I recently heard that Construct users were using an old blur shader I wrote in 2015, which is clunky and slow.
So I wanted to offer a better solution. Here's my fast "disk blur":
DOWNLOAD ADDON
DOWNLOAD DEMO
This method produces the best results when applied directly to an object with no effects or color adjustments before it. This way it can utilize mipmapping (downsampling) for high-radius blurring.
Alternatively, if you need to apply this to a lot of objects you should apply the effect to the layer instead. You won't be able to use mipmapping, so to make it smooth at a high-radius, you'll want to apply the disk blur multiple times at increasing radii:
This should produce similar results to mipmapping on the entire layer.
Hope this helps. Thanks