So, I’m mapping an earth texture to an Icosphere, and ran into the standard issue of the vertices of triangles on the texture boundary spanning and interpolating the entire texture causing a big ugly seam.

I fixed this with the standard fragment shader solution:

```
float4 frag(v2f i) : COLOR {
float3 tc = i.tex;
float3 norm;
float3 p;
p.x = i.pass_xy_position.x;
p.y = i.pass_xy_position.y;
p.z = i.pass_xy_position.z;
norm.x = sqrt(p.x*p.x + p.y*p.y + p.z*p.z);
tc.x = (PI + atan2(p.z, p.x)) / (2 * PI);
tc.y = (PI / 2 + asin(p.y / norm.x)) / PI;
float4 color = tex2D(decal, tc);
return color;
}
```

but I’m still left with a single pixel-wide seam at the texture longitude boundary, and some small distortions around the poles. I’ve tried a couple of different textures from the NASA Blue Earth site, and see the same issue. Any help would be greatly appreciated.