yield new WaitForEndOfFrame ();

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    IEnumerator Example() {
        yield return new WaitForEndOfFrame();
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example() as IEnumerator:
        yield WaitForEndOfFrame()

// Saves screenshot as PNG file.
import System.IO;
// Take a shot immediately
function Start() {
    UploadPNG();
}
function UploadPNG() {
    // We should only read the screen bufferafter rendering is complete
    yield WaitForEndOfFrame();
    // Create a texture the size of the screen, RGB24 format
    var width = Screen.width;
    var height = Screen.height;
    var tex = new Texture2D( width, height, TextureFormat.RGB24, false );
    // Read screen contents into the texture
    tex.ReadPixels( Rect(0, 0, width, height), 0, 0 );
    tex.Apply();
    // Encode texture into PNG
    var bytes = tex.EncodeToPNG();
    Destroy( tex );
    // For testing purposes, also write to a file in the project folder
    // File.WriteAllBytes(Application.dataPath + "/../SavedScreen.png", bytes);
    // Create a Web Form
    var form = new WWWForm();
    form.AddField("frameCount", Time.frameCount.ToString());
    form.AddBinaryData("fileUpload",bytes);
    // Upload to a cgi script
    var w = WWW("http://localhost/cgi-bin/env.cgi?post", form);
    yield w;
    if (w.error != null)
        print(w.error);
    else
        print("Finished Uploading Screenshot");
}

using System.IO;
using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Start() {
        UploadPNG();
    }
    IEnumerator UploadPNG() {
        yield return new WaitForEndOfFrame();
        int width = Screen.width;
        int height = Screen.height;
        Texture2D tex = new Texture2D(width, height, TextureFormat.RGB24, false);
        tex.ReadPixels(new Rect(0, 0, width, height), 0, 0);
        tex.Apply();
        byte[] bytes = tex.EncodeToPNG();
        Destroy(tex);
        WWWForm form = new WWWForm();
        form.AddField("frameCount", Time.frameCount.ToString());
        form.AddBinaryData("fileUpload", bytes);
        WWW w = new WWW("http://localhost/cgi-bin/env.cgi?post", form);
        yield return w;
        if (w.error != null)
            print(w.error);
        else
            print("Finished Uploading Screenshot");
    }
}

import System.IO
import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Start():
        UploadPNG()

    def UploadPNG() as IEnumerator:
        yield WaitForEndOfFrame()
        width as int = Screen.width
        height as int = Screen.height
        tex as Texture2D = Texture2D(width, height, TextureFormat.RGB24, false)
        tex.ReadPixels(Rect(0, 0, width, height), 0, 0)
        tex.Apply()
        bytes as (byte) = tex.EncodeToPNG()
        Destroy(tex)
        form as WWWForm = WWWForm()
        form.AddField('frameCount', Time.frameCount.ToString())
        form.AddBinaryData('fileUpload', bytes)
        w as WWW = WWW('http://localhost/cgi-bin/env.cgi?post', form)
        yield w
        if w.error != null:
            print(w.error)
        else:
            print('Finished Uploading Screenshot')

// Shows alpha channel contents in the game view.
private var mat : Material;
// After the frame is completely rendered, we'll
// draw a full screen quad that extracts the alpha channel.
function Start() {
    while (true) {
        yield WaitForEndOfFrame();
        if( !mat ) {
            mat = new Material( "Shader \"Hidden/Alpha\" {" +
                "SubShader {" +
                "    Pass {" +
                "        ZTest Always Cull Off ZWrite Off" +
                "        Blend DstAlpha Zero" +
                "        Color (1,1,1,1)" +
                "    }" +
                "}" +
                "}"
            );
        }
        GL.PushMatrix ();
        GL.LoadOrtho ();
        for (var i = 0; i < mat.passCount; ++i) {
            mat.SetPass (i);
            GL.Begin( GL.QUADS );
            GL.Vertex3( 0, 0, 0.1 );
            GL.Vertex3( 1, 0, 0.1 );
            GL.Vertex3( 1, 1, 0.1 );
            GL.Vertex3( 0, 1, 0.1 );
            GL.End();
        }
        GL.PopMatrix ();
    }
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    private Material mat;
    IEnumerator Start() {
        while (true) {
            yield return new WaitForEndOfFrame();
            if (!mat)
                mat = new Material("Shader \"Hidden/Alpha\" {" + "SubShader {" + "    Pass {" + "        ZTest Always Cull Off ZWrite Off" + "        Blend DstAlpha Zero" + "        Color (1,1,1,1)" + "    }" + "}" + "}");
            
            GL.PushMatrix();
            GL.LoadOrtho();
            int i = 0;
            while (i < mat.passCount) {
                mat.SetPass(i);
                GL.Begin(GL.QUADS);
                GL.Vertex3(0, 0, 0.1F);
                GL.Vertex3(1, 0, 0.1F);
                GL.Vertex3(1, 1, 0.1F);
                GL.Vertex3(0, 1, 0.1F);
                GL.End();
                ++i;
            }
            GL.PopMatrix();
        }
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    private mat as Material

    def Start() as IEnumerator:
        while true:
            yield WaitForEndOfFrame()
            if not mat:
                mat = Material((((((((('Shader "Hidden/Alpha" {' + 'SubShader {') + '    Pass {') + '        ZTest Always Cull Off ZWrite Off') + '        Blend DstAlpha Zero') + '        Color (1,1,1,1)') + '    }') + '}') + '}'))
            GL.PushMatrix()
            GL.LoadOrtho()
            i as int = 0
            while i < mat.passCount:
                mat.SetPass(i)
                GL.Begin(GL.QUADS)
                GL.Vertex3(0, 0, 0.1F)
                GL.Vertex3(1, 0, 0.1F)
                GL.Vertex3(1, 1, 0.1F)
                GL.Vertex3(0, 1, 0.1F)
                GL.End()
                ++i
            GL.PopMatrix()