Reflection Question

OpenGL OpenGL: Advanced Coding
1

Hi

I have seen some demos, which use real cool reflections.
Now AFAIK, there are two types of reflections.

  1. real ones (via stencil buffer or render to texture)
  2. cubemap reflections

I know how to do bumpmapped reflections with cubemaps and that looks pretty good, BUT some of those demos i´ve seen seem not to use this approach, because the reflections were too precise. That means the reflected objects were EXACTLY were they have to be, even when they are only an inch away from the (water) surface. I am not sure, if such a precise (bumpmapped) reflection is possible with cubemaps.

Therefore i´d like to know, if there is a way to use some kind of bumpmapping for such perfect reflections. Or do i only have to place the cubemap-creation-point at a very special position?

Thanks,
Jan.

2

The effect you are describing is implemented by loading the planar reflected rendering to a texture (by whatever means copytex rendertotexture etc.) and then texturing that onto the surface with either vertex texture coordinate peturbation or fragment texture peturbation.