Feature request for Sprite trimming.

When cutting out sprites from a sprite sheet it would be nice to be able to set how tight "auto slicing" and "trim" will cut.

In my current game I have some rectangular sprites - if there is no buffer around the edges the edges will get very jagged (especially on low res devices) due to the straight edges of the sprites being on the outer edge of a piece of mesh.

Se the difference in this example:



Currently I have two manually tedious ways to deal with this issue.
a) Move the sprite sizes out a bit manually in the sprite editor (get unbearable when having many sprites that also animates)
b) Make some border around my sprites in GIMP that is (almost) invisible that will make Unity not cut so thighly.

Hope this makes sense

Cheers,
Jesper Rasmussen

 

You might be able to fix this with code by adding this to the Start function of a script on a sprite:

Code (csharp):

1.  
2. int border = 8; // Border tickness
3.  
4. Rect spriteRect = GetComponent<SpriteRenderer>().sprite.rect;
5. spriteRect = new Rect(spriteRect.x - border, spriteRect.y - border, spriteRect.width + (border * 2), spriteRect.height + (border * 2));
6.  

I didn't actually try this so I don't know for sure if it works but it should.

 

Btw. I have tried the "Extrude Edges" option in the Importer settings ... but I cannot see any difference in results no matter the setting.

 

Unfortunately I see an issue with your idea DSSiege ....

I'm using Unity's sprite packer - thus the sprites are already packed very close together, and if we extend the borders as you suggest we'd end up with having pieces of the surrounding sprites shown in the edges.

I think that the easiest solution is to do it at slice time

 

You're right, I didn't think of that... I only have Unity Free so I didn't think of the Sprite packer...

 

This issue surfaces when the sprite have one or more straight (axis aligned) edges (which is then cut too close).

It is most visible when:

1) the sprite is rotated at low angles (as in the example) ... or
2) when moving the sprite (at sub pixel coordinates) the outer edge will flicker like hell

 

Hurray .. found an easy solution to this issue

Enable Anti Aliasing (i use 2x multi sample) in Edit->Project Settings->Quality

And voila ! ... no more ugly edges !

 

Well, that solution does work, but it will be at the cost of performance. Anti-aliasing after the fact is much more intensive than a little bit of border on the edges. If you end up needing more performance and have the time to spend, I'd recommend adding a couple of pixels around each of the sprites by hand - you'll get a pretty decent FPS bump from disabling anti-aliasing. And your initial feature request is still a good one.

 

@StarManta I totally agree ...

But for my current project where the sprite count is fairly low (max ~500) I don't think a little aa is that costly (I hope

I think it is by far the easiest solution until Unity adds this feature

 

I don't believe the performance cost of AA has any relation to the number of sprites in a scene. All the same, if your project has performance to spare, then by all means..

 

I really should test it shouldn't I ??

... ok, I will test it ... and return with some real numbers ... soonish



Just to be certain we're talking about the same thing.

The AA part of the Quality is described thus in the documentation ...

"Anti aliasing improves the appearance of polygon edges, so they are not “jagged”, but smoothed out on the screen. However, it incurs a performance cost for the graphics card and uses more video memory (there’s no cost on the CPU though). The level of anti-aliasing determines how smooth polygon edges are (and how much video memory does it consume)."

I don't think it is mentioned anywhere in the 2D sections of Unity ... but for now it solves my issues.

Also notice that is is not a pro feature