# Project 360 video on the inside of a iso sphere / polygon sphere

I'm creating a game in Unity. I have a iso sphere or polygon sphere, and I want to project a 360 video on the inside of the polygon sphere.

I've learned thow to put a 360 video on the inside of a sphere, following this thread, but how can I do it inside a polygon sphere, since the 360 video was created based on a sphere but not a polygon sphere?

Shader "Flip Normals" {
Properties {
_MainTex ("Base (RGB)", 2D) = "white" {}
}
SubShader {

Tags { "RenderType" = "Opaque" }

Cull Off

CGPROGRAM

#pragma surface surf Lambert vertex:vert
sampler2D _MainTex;

struct Input {
float2 uv_MainTex;
float4 color : COLOR;
};

void vert(inout appdata_full v) {
v.normal.xyz = v.normal * -1;
}

void surf (Input IN, inout SurfaceOutput o) {
fixed3 result = tex2D(_MainTex, IN.uv_MainTex);
o.Albedo = result.rgb;
o.Alpha = 1;
}

ENDCG

}

Fallback "Diffuse"
}


## 1 Answer

The principle isn't really any different.

Inside the fragment shader you compute a latitude & longitude by converting the shaded point's offset from the center of the sphere from Cartesian to spherical coordinates.

Then you use that lat/long pair as the texture coordinate to look up into your video texture (assuming your video is in equirectangular projection - you'd use different formulas for other projections)

Even with a mesh that's already unwrapped in lat-long format, you should really do this mapping in the shader anyway - affine texture mapping alone can't handle the distortion at the poles of the sphere correctly.

• can you please provide a more detailed instruction? Or links to related links or tutorials where I can learn? I'm quite new to Unity and don't have much experience with shader to achieve this. – practicemakesperfect Apr 10 '18 at 23:33
• Yep - linked to one of my earlier answers. Don't forget to search; chances are you're not the first one to have a particular problem. ;) I've added a 360-video tag to the 11 questions we have on the subject so far to make them easier to find. – DMGregory Apr 10 '18 at 23:53