Hello,

I recently needed to use atan2 to convert position data into lon/lat coordinates in a fragment shader.

The outcome was kind of disturbing as it gives totally wrong values.

```
inline float2 posToRadial (float3 coords) {
coords = normalize(coords);
//calculate latitude:
float lat = acos(coords.y); //distance from zenit to äquator
//remaps [0;1] to [PI/2;0]
lat /= PI; //remap to [1/2;0]
lat*=2; //remap to [1;0]
//calculate longitude:
float lon = atan2(coords.z, coords.x)/PI; //lon around xz plane from -1 to 1
lon = lon/2+0.5; //remap lon from [-1; 1] to [0; 1] interval
return float2(lon, lat);
}
```

So I mapped this back to read textures with it and when i put in (-1, 0) which is the same as -PI/2 radians it gives me value 0xBC (processed as color and evaluated with color picker) instead of what should be 1/4.

I have rewritten the function for wolframalpha and there the values are correct.

And secondly I have written an atan2 debug shader:

```
fixed4 frag (v2f i) : SV_Target {
return (atan2(i.uv.y*2-1, i.uv.x*2-1)/UNITY_PI)/2+0.5;
}
```

This shows me that the borders are correct, but everything else is distributed like hell.

Thats it for now.

Hope someone can help, Ty!