c# - Convert RenderTexture to Texture2D

Question

I need to save a RenderTexture object to a .png file that will then be used as a texture to wrap about a 3D object. My problem is right now I can't save a RenderTexture object using EncodeToPNG() because RenderTexture doesn't include that method. How can I convert a RenderTexture object into a Texture2D object? Thank you!

// Saves texture as PNG file.
using UnityEngine;
using System.Collections;
using System.IO;

public class SaveTexture : MonoBehaviour {

    public RenderTexture tex;

    // Save Texture as PNG
    void SaveTexturePNG()
    {
        // Encode texture into PNG
        byte[] bytes = tex.EncodeToPNG();
        Object.Destroy(tex);

        // For testing purposes, also write to a file in the project folder
        File.WriteAllBytes(Application.dataPath + "/../SavedScreen.png", bytes);
    }
}

Answer 1

Create new Texture2D, use RenderTexture.ReadPixels to read the pixels from RenderTexture into the new Texture2D. Finally, Call Texture2D.Apply(); to apply the changed pixels.

Texture2D toTexture2D(RenderTexture rTex)
{
    Texture2D tex = new Texture2D(512, 512, TextureFormat.RGB24, false);
    // ReadPixels looks at the active RenderTexture.
    RenderTexture.active = rTex;
    tex.ReadPixels(new Rect(0, 0, rTex.width, rTex.height), 0, 0);
    tex.Apply();
    return tex;
}

Usage:

public RenderTexture tex;
Texture2D myTexture = toTexture2D(tex);

---

You can make it an extension method (restore the previous active RenderTexture to avoid surprises):

public static class ExtensionMethod
{
    public static Texture2D toTexture2D(this RenderTexture rTex)
    {
        Texture2D tex = new Texture2D(rTex.width, rTex.height, TextureFormat.RGB24, false);
        var old_rt = RenderTexture.active;
        RenderTexture.active = rTex;

        tex.ReadPixels(new Rect(0, 0, rTex.width, rTex.height), 0, 0);
        tex.Apply();

        RenderTexture.active = old_rt;
        return tex;
    }
}

Usage:

public RenderTexture tex;
Texture2D myTexture = tex.toTexture2D();