# Generating a sphere-normal-map in code OR importing 16 bit textures

Hey, so, I was trying to make an extreme fisheye-lens, kind of like in this video:

http://vimeo.com/90312869#at=0

I tried this by feeding a cubemap from a camera into a shader, which I then fed into another camera with Graphics.Blit.
This worked perfectly, except that the way I got the fisheye effect was using a texture generated in Maya with a sphere of reflected normals, so I could get almost a full 360 degree view. (Basically a mathematically perfect, reflecting sphere with no fresnel reflecting another sphere encapsulating it colored by it’s normalized coordinates in space).

From that I got this result:

It seems the precision of 8bit normals isn’t enough (duh…), so my question is if anyone has any suggestion on how to generate the normals within Unity, or have a way of importing 16bit (or even 32bit) textures, maybe through hacks or something?

For generating, I have played with this formula:

x = sin(theta)cos(phi)
y = sin(theta)sin(phi)
z = cos(theta)

With theta being the V-coordinate, and phi being the U-coordinate, either mulitplied with pi or 2x pi, or switched around (spent 4-5 hours on that yesterday).

It turned out too angular though, and I don’t know if it’s just my poor math, or I need a different approach.

Too angular? Do you mean that the normals aren’t smoothly distributed? (I can imagine something ‘angular’ happening if you calculate the normals per-vertex, not per fragment) Or something else?

Perhaps you should show an example of what goes wrong there too. Because I do think that calculating your normals in the shader probably gives the prettiest results.

On a related note, you might be interested in Aras’s blogpost about encoding/decoding normal maps for storage in 8bit/channel texture.

Thankyou, and sorry about that, I will promptly post a picture!

Here we go:

In all honesty I don’t really understand the formula. I get that it somewhat treats the u and v as axial and polar (right words?) angles to find the position, but I don’t understand how to tweak it, so it might be what I am looking for, just set up wrong.

Also, reading through Aras’ blog now, VERY interesting. Probably hard to use for this case though.