Sprite Mesh Type: Full Rect vs Tight (Mobile Performance)

Hey all,

I am making a mobile game where obviously performance is always a concern. I see when you import an image and set it to a Sprite, you get the option to choose it's Mesh Type. Full Rect or Tight.

Full Rect : Rectangle mesh equal to the user specified sprite size.
Tight : Tight mesh based on pixel alpha values. As many excess pixels are cropped as possible.

In other worse, Full Rect is 1 big quad (rectangle) that wraps the entire image. It will include any transparency around the edges. Tight will use many triangles to almost go around the edges of your image to limit the amount of whitespace/transparency included.

I have read that Full Rect will have a lot less triangles whereas Tight will have much more. The advantage to Tight is there will be a lot less overdraw and alpha blending (it doesn't need to draw/calculate empty alpha pixels.

Some sites I read claim for mobile to just use Tight as Alpha Blending and Overdraw is expensive. I am not sure changing every single sprite in my game to Tight is the best option. What about images that are square in size and have little to no transparency around the edges? Seems to make sense those I'd leave at Full Rect.

Anyone know?

Thanks!

 

Well, unless I am missing something, I need to make everything a Full Rect. Since I use Unity's Sprite Sheets, the Tight mesh type seems to grab parts of adjacent sprites (you can see parts of the other sprites around the edges).

If anyone has any solutions or experience in this area it would be appreciated!

 

Ya sure. So if I change some of my game icons to use a "tight" mesh type, this is how it shows up in my game :



Those red bits under my arrow icon should not be there. They are part of a different image in the sprite sheet (I assume)

I am trying to find out how to see the Sprite Atlas Unity creates for me, but the "Pack Preview" button doesn't seem to do anything (It used to show a zoomed in view of the sprite sheet, doesn't anymore, not sure why)

 

Hmm, I just saw this post.



I disabled "tight packing" in the Atlas Unity creates and the issue goes away.

 

In order to use Tight Packed sprites in the UI you should enable Use Sprite Mesh in the image component:

It's still there but maybe hidden at the bottom. Click that double line with Left mouse button to expand it or with Right mouse button to zoom it:

 

Thanks man, you were right