How to save a png using Unity WebCamTexture

Question

I want to save a picture using the device native camera. Currently I cannot get the image to save to file. I have a rawimage which's texture is the native device camera image. I am taking the bytes from that rawimage and encoding to png. Then I write the png to file on my computer.

    public WebCamTexture webCamTexture;
    public RawImage myImage;

    public void start () {
        webCamTexture = new WebCamTexture ();
        myImage.texture = webCamTexture;
        myImage.transform.localScale = new Vector3 (1,-1,1);
        webCamTexture.Play ();

        int width =  (int)GameObject.Find("myImage").GetComponent<Rect>      ().width;
        int height = (int)GameObject.Find("myImage").GetComponent<Rect>().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 ();
        System.IO.File.WriteAllBytes(Application.dataPath + "/"+"imgcap.png",bytes);

        Object.Destroy (tex);
    }

Answer 1

using System;
using System.IO;
using System.Runtime.InteropServices;
using UnityEngine;

public class WebCamScreenShot : MonoBehaviour
{
    public static int fileCounter = 0;

    WebCamTexture webCamTexture;

    public string path = "C:/temp/UnityScreenShots";

    public string fileNamePrefix = "image_";

    void Start()
    {
        var devices = WebCamTexture.devices;

        if (devices.Length < 1) throw new System.Exception("No webcams was found");

        var device = devices[0];

        webCamTexture = new WebCamTexture(device.name);
        webCamTexture.requestedFPS = 30;
        webCamTexture.requestedWidth = 320;
        webCamTexture.requestedHeight = 240;
        webCamTexture.Play();

        if (webCamTexture.width < 1 || webCamTexture.height < 1) throw new System.Exception("Invalid resolution");
    }

    public void SaveToPNG()
    {
        string zeros =
            (fileCounter < 10000 ? "0000" :
                (fileCounter < 1000 ? "000" :
                    (fileCounter < 100 ? "00" :
                        (fileCounter < 10 ? "0" : ""))));

        string image_path = path + $"/{ fileNamePrefix + zeros + fileCounter }.png";

        byte[] data = ScreenshotWebcam( webCamTexture );

        File.WriteAllBytes(image_path, data);

        fileCounter ++ ;
    }
    static byte[] ScreenshotWebcam(WebCamTexture wct)
    {
        Texture2D colorTex = new Texture2D(wct.width, wct.height, TextureFormat.RGBA32, false);

        byte[] colorByteData = Color32ArrayToByteArray(wct.GetPixels32());

        colorTex.LoadRawTextureData(colorByteData);
        colorTex.Apply();

        return colorTex.EncodeToPNG();
    }

    static byte[] Color32ArrayToByteArray(Color32[] colors)
    {
        // https://stackoverflow.com/a/21575147/2496170

        if (colors == null || colors.Length == 0) return null;

        int lengthOfColor32 = Marshal.SizeOf(typeof(Color32));

        int length = lengthOfColor32 * colors.Length;

        byte[] bytes = new byte[length];

        GCHandle handle = default(GCHandle);

        try
        {
            handle = GCHandle.Alloc(colors, GCHandleType.Pinned);
            IntPtr ptr = handle.AddrOfPinnedObject();
            Marshal.Copy(ptr, bytes, 0, length);
        }
        finally
        {
            if (handle != default(GCHandle)) handle.Free();
        }

        return bytes;
    }
}