Monday, February 13, 2017

Take a Unity Screenshot with Alpha

This script takes a screenshot and saves it to the user desktop. It has options to use an alpha background, and also upscale the image. Useful for taking pictures of a scene or model for composition by artists.

using UnityEngine;
using System.IO;
using System;

[RequireComponent (typeof(Camera))]
public class CaptureWithAlpha : MonoBehaviour
    public int UpScale = 4;
    public bool AlphaBackground = true;

    Texture2D Screenshot ()
        var camera = GetComponent<Camera> ();
        int w = camera.pixelWidth * UpScale;
        int h = camera.pixelHeight * UpScale;
        var rt = new RenderTexture (w, h, 32);
        camera.targetTexture = rt;
        var screenShot = new Texture2D (w, h, TextureFormat.ARGB32, false);
        var clearFlags = camera.clearFlags;
        if (AlphaBackground) {
            camera.clearFlags = CameraClearFlags.SolidColor;
            camera.backgroundColor = new Color (0, 0, 0, 0);
        camera.Render (); = rt;
        screenShot.ReadPixels (new Rect (0, 0, w, h), 0, 0);
        screenShot.Apply ();
        camera.targetTexture = null; = null;
        DestroyImmediate (rt);
        camera.clearFlags = clearFlags;
        return screenShot;

    [ContextMenu ("Capture Screenshot")]
    public void SaveScreenshot ()
        var path = Environment.GetFolderPath (Environment.SpecialFolder.Desktop);
        var filename = "SS-" + DateTime.Now.ToString ("") + ".png";
        File.WriteAllBytes (Path.Combine (path, filename), Screenshot ().EncodeToPNG ());

Friday, February 03, 2017

Building fast, quality network server programs with Go.

I've been investigating and learning Go. There is a lot of high quality tools out there, for example:

- xo generates types and functions to match your SQL schema, and

- goa lets you design a REST api using a DSL, then generate the code to implement that API!

Compile time for Go is super fast, and so is the built executable. I'm using vim for the IDE, and it has excellent support for Go, including autocompletion which is great when you're learning the language.

Wednesday, January 25, 2017

A HTTP server embedded inside Unity3D.

Just 514 lines of code. Uses sockets only, no other dependencies.

Example Component:

public class FileUpload : MonoBehaviour, IWebResource
    public string path = "/upload";
    public TextAsset html;
    EmbeddedWebServerComponent server;

    void Start ()
        server = GetComponent<EmbeddedWebServerComponent>();
        server.AddResource(path, this);
    public void HandleRequest (Request request, Response response)
        response.statusCode = 200;
        response.message = "OK.";

Tuesday, January 24, 2017

A widget to list Github repositories.

<div id="github-activity"></div>
<script type="text/javascript">
window.renderGitHubWidget = function(github) {
    var html = '<div class="widget"><ul>';
    for (var i=0; i<; i++) {
        var item =[i];
        var url = item.html_url;
        if(item.fork) continue; 
        var repo = '<a href="' + url + '" target="_blank">' + + '</a>';
        html += "<li>" + repo + " <br/>" + item.description+ "</li>"
    html += '</ul></div>';
    var el = document.createElement('div');
    el.innerHTML = html;
    var URL = '';
    var script = document.createElement('script');
    script.setAttribute('type', 'text/javascript');
    script.setAttribute('src', URL);

Tuesday, January 03, 2017

Notes on the Unity3D UNET HLAPI

The NetworkManager instantiates a Player prefab. This is your Player Object.

In a two player game, your GameObjects exist conceptually in 3 places, and logically in 2 places. An object exists on each game client, and on the game server. If the game server is also a client, it is called a host, and it shares the GameObject with the client.

By default:
- only methods on components on the Player Object can have the [Command] attribute.
- you can only call [Command] methods from other methods on the Player Object.

It is hard to see which code is server code, and which is client code. I recommend using the [Server] and [Client] attributes liberally to add this information to the source code. When this attribute cannot be applied to a method (only NetworkBehaviours support this attribute) then add the attribute inside a comment.

The NetworkTransform does not provide interpolation when in Transform mode, only when using RigidBody mode. You will need to write this code yourself using [SyncVar].

For fast iterative development, keep the NetworkManager in your development scene, and add the NetworkManagerHUD component. Set this scene as your startup scene, then Build and Run, choose Host or Client from the GUI, then press Play in the editor, and choose Host or Client.

NetworkServer.Spawn only create an instance on the client, and sets it's transform component to match the server. You will have to do any other configuration on this object via a secondary [ClientRpc] call.

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