opengl - possibility of a mirroring shader?

Question

Until today, when I wanted to create reflections (a mirror) in opengl, I rendered a view into a texture and displayed that texture on the mirroring surface.

What i want to know is, are there any other methods to create a mirror in opengl?

And 2. can this be done lonely in shaders (e.g. geometry shader) ?

Answer 1

Ray-tracing. You can write a ray-tracer in the fragment shader (every fragment follows a ray). Ray-tracers can perfectly deal with reflection (mirroring) on all kinds of surfaces.

You can find an OpenGL example here and a WebGL example including mirroring here.