Bloom Lighting

Target Platforms Mobile
1

Hello, I’m very new to Unity and am just going through Will Goldstone’s book at the moment.

I eventually want to move on to Unity iPhone and have a few ideas for games. I’ve been reading about the understandable limits of the platform and was wandering if there’s a way to fake the bloom lighting style seen in Ico on the PS2?

Could this be achieved with a lightmap?

Thanks in advance for any help.

Steve

2

Do you refer to bloom, ie, glow?

That’s usually achieved (essentially) by taking the higher levels of luminance on the rendered screen (so its a post effect, its 2d) and blurring it, then reapplying it as either additive or clamped-additive (screen).

Essentially, taking the render, pulling contrast, blur.

I am not aware of post-shaders working at all on Unity iPhone…

3

Hi JT,

thanks for your reply.

Yeah it’s also called glow. It’s one of the post processing filters included with Unity Pro.

I think with it’s limits I can’t imagine they’d work on the iPhone, I was just hoping there would be a way to fake the look. I see now that with it being a post effect it’s not something you can bake in to the lightmap.

I think I was just aiming too high wanting the beauty of Ico on the iPhone.

Thanks again.

Steve

4

Yeah, you wouldn’t be able to easily get any sort of bloom, except possibly on special cases, such as lights, or static objects…

Ie, if you have a big shiny ball in a room, and it never moves (so you always know where the highlights are), there’s no reason you couldn’t have a front-facing poly with an additive blob on it, and render it on a second camera (so that it doesn’t clip with the ball itself).

But like I said, special cases only, that sort of thing would require quite a lot of design to work right :slight_smile:

5

on iphone 1 and iphone 2 there isnt a way to do it correctly. you can fake it old school by using a particle at locations you know have bright colors.
on iphone 3 theoreticly you could do bloom as you can have programmed shaders on iphone 3. unity doesnt currently support a good method for that though. most high quality looking blooms blur the image and re-apply the blur to the screen in a good way… sometimes they add sometimes they lerp. a very fast method that doesnt look as clean but most games do is to use a low mip level of the final screen output. this will many times blur the bright spots enough but many times you dont have control so its not always usefull. i could see doing this second method on the iphone 3 but you would need to work it out yourself as i dont think unity can access mips on the iphone the way you would need.