Is there a simple blur image effect for mobile

Unity Engine
1

Hi there,

Just wondering if there is a simple image blur effect that could be used on mobile.
There used to be this one - Unity - Manual: Blur (Optimized)
It seems if I look for that, everything suggests using the new stack, but that seems like it will be a little too harsh for my mobile project.
(also there isn’t a full screen blur effect in the post process stack)

Any suggestions?
Thanks!
Pete

2

For blur on mobile you will need to do a few tricks in order to be performant. I made my own effect based on those two guides:
https://software.intel.com/en-us/blogs/2014/07/15/an-investigation-of-fast-real-time-gpu-based-image-blur-algorithms
http://rastergrid.com/blog/2010/09/efficient-gaussian-blur-with-linear-sampling/

Before that I tried an asset (Gaussian Blur | VFX Shaders | Unity Asset Store), but it was to performance heavy for mobile. Not quite sure if there is a good asset out there now.

3

@petey do you need a complete blur or Depth Of Field? What is your case?

4

If blur is your only image effect that is required - I recommend you write up your own blur shader. It should go something like:
-Downsample image to about 1/4 resolution
-Perform a 2-pass horizontal/vertical gaussian blur (or box blur works as well)

If you use other effects like Bloom - you should combine the blur with your bloom so you don’t need to perform extra instructions. For instance, PRISM (linked in my sig) gives you a checkbox inside the bloom effect if you just want to blur the whole screen - it uses the already-generated bloom texture for this, so there is 0 extra performance hit if you’re already using bloom.

5

Downsampling by a relative amount like 1/4 of the resolution makes a very distinct appearance on different devices. Hi-rez devises will have smaller blur, low-rez devices will have larger blur. This is what we see in the FxPro package - bloom looks completely different on different resolutions. The difference becomes much more apparent on devices with the same screen sizes, but different DPIs.
This is usually not an issue on PC targets because it’s mostly 1080 pixels height, so blur and bloom look mostly the same.

I strongly encourage to blur some fixed resolution instead. This is the technique that’s used in Sleek Render and it really enables completely consistently-looking bloom on the whole range of devices.

2 Likes
6

I converted the bluroptimized effect you speak of to the new stack:

3 Likes