How to Realize Multiple-Reflection Effect with Mirrors

Unity Engine
,
1

Hi~

I’m interested in realize multiple-reflection effect using flat mirrors, for example, by positioning two mirrors at a certain angle to reflect each other’s images. Here’s my current approach:

  1. I attach an Unlit/Texture shader to a Quad and create a new Render Texture, which I then assign to this material.
  2. Behind the Quad, I place an Orthographic Camera and set its Target Texture to the newly created Render Texture, adjusting the camera’s position and size accordingly.
  3. I invert the X scale of the Quad, say from X:20 Y:5 Z:6 to X:-20 Y:5 Z:6, to ensure the reflected image moves in the same direction as the object (otherwise, it moves in the opposite direction).

Currently, a single mirror setup works fine, but when I place another mirror opposite it, the reflected image seems to be odd. How should I modify my setup to achieve the desired effect?

Additionally, can Reflection Probes be used to achieve this kind of effect? If so, how should I proceed?

Thank you!

2

First, I don’t think orthographic camera’s result is correct if your main camera is perspective.

Then, multi-bounces reflection never do-able through reflection probe or camera-based planar reflection.

Last, you should try ray-tracing to get the correct result, you can write ray-tracing shader in URP or turn on ray-tracing features in HDRP. In HDRP the path tracing or recursive rendering feature is the key point of the multi-bounces reflection effect, but both of them are expensive and not available on mobile devices

https://docs.unity3d.com/Packages/com.unity.render-pipelines.high-definition@17.0/manual/ray-tracing.html

3

If I need to write Shader, it’s a bit beyond my abilities. But the solution idea and reference document are inspiring. Thank you very much!

4

I also want to read about multi reflection effect. The link you provide give beneficial information.