GTAV: how do they do reflections without RTX or DXR?

[magellan]

The reflections I've seen are definitely real time and reflecting what is seen across the street in storefront windows. The reflections are not high-res but they are there.

 

[mackerel]

Without looking in more detail there are two methods that might apply.

One is screen-space reflections. If the content being reflected is also on screen this is easy to do, but the downside is if the content being reflected is off screen, it doesn't exist any more and the reflection disappears.

The other trick I've seen is a generic fake reflection. If you know what is in the area you can create a generic fake environment to show as the reflection. It looks convincing enough and even moves with your viewpoint.

 

[magellan]

Without looking in more detail there are two methods that might apply.

One is screen-space reflections. If the content being reflected is also on screen this is easy to do, but the downside is if the content being reflected is off screen, it doesn't exist any more and the reflection disappears.

The other trick I've seen is a generic fake reflection. If you know what is in the area you can create a generic fake environment to show as the reflection. It looks convincing enough and even moves with your viewpoint.

I've seen generic fake reflections (e.g. in Dying Light) and at first that's what I figured was going on in GTAV, but when I look at the reflections they change depending on what's across the street and the buildings are recognizable and the colors change to match the buildings being reflected.

 

[Kenrou]

https://www.adriancourreges.com/blog/2015/11/02/gta-v-graphics-study-part-2/ ⇾ try this link, it's from 2015 but has a very detailed explanation of the various rendering methods, scroll down to Reflections