EditorUtility.CompressCubemapTexture

Description

Compress a cubemap texture.

Use this function to explicitly compress a cube map texture into specified format.

using UnityEngine;
using UnityEditor;

public class CompressCubemapTextureExample : AssetPostprocessor
{
    // Automatically Compress all imported cube map textures to the project to RGB24
    void OnPosprocessTexture(Cubemap t)
    {
        EditorUtility.CompressCubemapTexture(t, TextureFormat.RGB24, TextureCompressionQuality.Normal);
    }
}