SimCity BuildIt and a lot of lights

How did the developers of SimCity BuildIt implement the car lantern effect so that the light is reflected on the buildings? How did they fake it, which allows to display a huge number of fake lights on the screen? And this is on mobiles.

 

I wouldn't be surprised if they're just projectors, or if it's making use of how much it can pack into a material, running in deferred mode, and using pooled deferred decals.

 

Probably emissive material.

 

For the buildings themselves and road lights, sure, but this is about the car headlights on the roads and buildings. My guess is leaning more towards it being deferred decals.

 

Ah, I can't read today... you're right, I slipped over the word car. The lantern effect made sense and got associated with the street lamps.
Sorry guys.

I go and get a coffee,

 

I made some research with RenderDoc.

There are 4 passes:
1. Render all light quads from top

2. Render objects from underground using texture from pass 1

3. Blur texture from pass 2. But I can't find where than they use this texture

4. Render final scene. Buildings using texture from pass 1

 

Can anyone reproduce this technique in Unity?

 

Unsure, but probably important to realise that this game is made in marmalade game studio, not unity, so there are going to be fundamental differences in terms of how you would go about achieving it.

Unfortunately marmalade game studio no longer is available for download so its probably going make reverse engineering their graphics etc more difficult than it would have been if it was available.

 

Yes, but you'll be better off asking for that in commercial collaboration as this is not very interesting.

Based on your breakdown, what they do is likely this:

1. Render light blobs onto render target. This one acts as a "glow texture"
2. Project render target onto the scene using planar projection. Basically they stretch the texture onto the visible part of the world, using X and Z as U and V respectively. With scale/offset.

The blurry texture is likely used for screen reflections or something similar.

This is definitely doable in unity.

The caveat of this appraoch is that passing cars will light up building from the first to the top floor, even if that building is a skyscraper. I.e. rather than being a "light point" a car will act as a "light column". You can notice this happening on the video.