Author Archives: Kenneth Larsen

File Server and Client Using Sockets in C++

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File transfer

Sending the client to itself, effectively overwriting it while its running.

Find downloads at the bottom of this post!
I wanted to make an application in C++ using sockets and threads to test myself and get familiar with C++. It took me a couple of days and this is what I came up with.
It is an application to easily transmit a file in a LAN.
It works by running “server ” in a CLI, this will start the server which will advertise its presence and transmit its file to anyone who connects to it. By “advertise” I mean it will open a UDP socket to listen for incoming broadcasts from clients.
On another computer you run the client from a CLI which will query for file servers in the LAN by broadcasting a UDP packet to the file server UDP port, present its findings and you can then choose which file to download.

Background

I first started working with sockets in Visual Basic 6 when I was 12 years old. I started out creating a chat application, which at that point took me weeks and never worked properly.
In the past couple of years I’ve been diving back in to it, by creating a lot of unfinished multiplayer games with .NET(C# and VB) and GameMaker. I love LAN games and I really wish there were more of them, but it seems I am not patient enough to create them, at least not alone.
I’m currently taking a course in networking in which we’ve implemented a chat application in Python. It is extremely easy to set up sockets in Python and can even be accomplished by running the Python environment in a terminal, which makes it really cool for debugging.
I’m really eager to try out network programming in Unity3D as it seems completely different from what I am used to; it uses RPCs as far as I can tell.

Code

I use the Boost library to achieve a cross platform implementation of sockets and threads. This did not work out. I spent hours trying to compile the project with MinGW, I eventually gave up and tried with Visual Studio which I got working rather quickly. But then the applications started crashing and acting weird because apparently sockets are only thread safe in Boost if you’re using Linux and some other bugs I don’t have the patience to uncover cropped up, like the client randomly appending characters to filenames and ports when splitting them. I successfully sent and received files from Windows<->Linux and Windows<->Windows, albeit with crashes, but that’s the best I can do without rewriting the entire thing. And it’d probably be easier to just write a Windows specific solution rather than using Boost. But for some reason it still felt really awesome sending a file from a Linux laptop to a Windows desktop.
I haven’t put much weight on the structure of the code and spent most of the time digging around in Boost documentation. Right now it works, but it is really cluttered and a lot of stuff could probably be removed, since it is only there because I thought it would work at some point in time, but it didn’t and I am too lazy to refactor the code, since this was just a test.
I only wrote one file per executable, no header, no classes, no nothing(so a lot of something, I guess). I commented every section of the code to make it easier to understand for people wanting to learn.
I also learned about static linking from making this project. It’s something I guess you don’t know about when you’ve grown up with IDEs and very high level languages which handle most of the linking hassle for you. But apparently you can just put whatever libraries you’re using in the compiled executable, which will make it larger but also self contained, i.e. no darn dependencies!
Dependencies have always been a bitch for me; I couldn’t show off my first games when I was a kid since they would only run on my own PC(GameMaker was a dream come true). Sometimes I find it hard to find dependencies and package them properly; to this day I still don’t know how to deploy MonoDevelop/GTK projects short of just including the entirety of MonoDevelop in the package, which really sucks since I wanted to use it for a Linux/Windows game. I wonder how Unity3D does it?

Ideas for expansion

  • Multiple file servers on one host: You could alter the server so that if the UDP port is taken it will send its filename and endpoint to the UDP port so the currently running fileserver can advertise its presence for it. You could also just make a single fileserver handle more files, but that would make it more complicated and defeat the purpose of the project, i.e. easy file transfer.
  • More customizability: Most of the options are hardcoded; port numbers, buffer size, etc., simply because I was too lazy to handle arguments.

Download

Without further ado:

Linux binaries

Windows binaries(UNSTABLE!)

Commented source files

Creating 3D models(And some life story)

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FishDesktop2(Click picture for wallpaper!)
I got really inspired watching time-lapse videos of people creating 3D assets so I decided to model, rig and texture a 3D model for real, i.e. extruding, cutting, welding, UV mapping by hand and carefully skinning the model. This is my first real attempt at creating a 3D model.

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Save Us, Unity3D vs GameMaker comparison

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I’m still early in the process of porting an old game from GameMaker to Unity3D. I thought I’d compare them graphically, since I’ve reached a point where most of the 3D modeling is done.

Overall I think going full 3D adds a little immersiveness to the game and makes everything look a little nicer, while I loose a bit of aesthetic, but that’s purely because of my lack of skill with 3D modeling. In any case, porting to Unity3D will make me able to make Save Us into a browser game, thereby reaching a larger audience.

Compare2
I think this scene made it out the best. Because of the bad graphics and stupid looking characters, the atmosphere was completely broken in the old version. The new version has a much creepier feel to it. You can’t see it in the picture, but imagine the cloaks of the characters flailing gently in the air. I wish I could’ve done a better job of modeling and texturing them though.

Compare3
The old version was more stylized here. I had more control since everything was just 2D sprites. The sheep don’t look nearly as good in the new version and I’m not sure if the intensity of the grass in the new version is too high. In any case, the aesthetic could probably be saved by a fullscreen shader, which I can’t utilize unless I pay 1500$ for Unity Pro. On the plus side the claw is way more awesome now, it’s really come alive because of its animations. I really need to add a hatch to the robot.

Compare1
I completely re-did the bad guys. In the old version they had a genie like shape; floating in the air with a tail thing. I did that so I wouldn’t have to render an animated walk cycle from 8 different angles. This is not a problem in the new version, so I made them four legged with inverted knees on the back legs for added creepiness.

Compare4
I really like this screenshot. The yellowish dots are eyes; I made a shader with an emissive texture so that the eyes of the bad guys glow in the dark.

Fresnel shader in Unity(With source)

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FresnelShader

I was just messing around with shaders in Unity while working on a game. I’ve never really tried making a shader before because I feel the math is intimidating, but it is actually pretty simple once you get into it. I’ve always liked the fresnel effect; it looks cool for microbiological illustrations and it’s nice for highlighting stuff.

The way it works is that you take the dot product of the direction vector of the camera and the normal of the current pixel being rendered on the model(See picture below). The dot product will go from 1 to 0(assuming that we’re dealing with unit vectors(we are)) the closer these vectors are to being perpendicular and the closer these vectors are to being perpendicular the closer the pixel is to the edge of the model being rendered in relation to the camera. You then take the inverse of the dot product, i.e. 1 – (cameraDirection · normal), and you multiply it with the color you want. The color then gets more intense the closer you get to the edge of the model, as you can see in the picture above. If you add a bump map to this, the surface normals get distorted and the fresnel effect distorts with it, which looks really cool as you can see in the bottom two spheres on the right, in the picture above.

Normals

The white lines are the normals of the sphere; the outward direction of the face.

Anyway, feel free to use it in your own projects as much as you want, link in the comments if you wanna show off something you’ve made with it. Here’s the source:

Shader "Custom/FresnelShader" {
	Properties {
	 	_Shininess ("Shininess", Range (0.01, 3)) = 1

	 	_MyColor ("Shine Color", Color) = (1,1,1,1) 

		_MainTex ("Base (RGB)", 2D) = "white" {}

		_Bump ("Bump", 2D) = "bump" {}

	}
	SubShader {
		Tags { "RenderType"="Opaque" }
		LOD 200

		CGPROGRAM
		#pragma surface surf Lambert

		sampler2D _MainTex;
		sampler2D _Bump;
		float _Shininess;
		fixed4 _MyColor; 

		struct Input {
			float2 uv_MainTex;
			float2 uv_Bump;
			float3 viewDir;
		};

		void surf (Input IN, inout SurfaceOutput o) {
			half4 c = tex2D (_MainTex, IN.uv_MainTex);
			o.Normal = UnpackNormal(tex2D(_Bump, IN.uv_Bump));
			half factor = dot(normalize(IN.viewDir),o.Normal);
			o.Albedo = c.rgb+_MyColor*(_Shininess-factor*_Shininess);
			o.Emission.rgb = _MyColor*(_Shininess-factor*_Shininess);
			o.Alpha = c.a;
		}
		ENDCG
	} 
	FallBack "Diffuse"
}

Save Us, Unity3D remake

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I’m currently in the process of converting my old competition game to a full 3D browser game using Unity3D.

SaveUs1
Checking if importing in unity is easy(It is) and trying out some basic behavior for the sheep things(Walk to a random point, when you get there: Choose a new point. Obstacle? Choose a new a point). And yes, I’m well aware of the fact that they are extremely creepy.

SaveUs2
Adding the player(Robot thing) and setting up the top-down camera with look. I read that you can use curves, specifically AnimationCurve, as a public variable in Unity and Unity will provide a curve editor! I used this to make a hover effect for the robot by changing the y-position with a smooth curve thereby making it bob. I read it from this post from SauropodStudio(Looking forward to Castle Story).

SaveUs3
Attached two lights to the robot(Second one at the feet for hover effect) and updated floor texture. Also, notice how much the shadows add to making it look like the sheep are more grounded, and not just added to the background. It’s just a 2 polygon square, 0.01 units above the ground, with a black gradient circle texture:
Shadow

SaveUs4
Re-did the sheep things, or rather, I spent a huge amount of time merging and welding polygons from the old sheep(From the first Save Us game) to make a new sheep with a single textured and rigged surface. Since they were only gonna be rendered to a sprite, the old sheep consisted of hundreds of high polygon spheres, I had to degrade the quality a lot for performance. They are less frightening but jaggy, but I fixed that in the next picture using some phong shading(Bascially checking a box in Unity).

SaveUs5
Added trees, sadly not my own generated ones, since it was quicker to just create a new one with splines rather than writing an export function for my tree generator(Well, probably not). I should just port the tree generator to Unity since they’re both C#! Great idea me 😀

Home Theater PC for free

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HTPC

What you need, if you want the HTPC(Home Theater PC) for free:

  • A TV with VGA or HDMI input(Possibly audio input jack or speaker system).
  • A wireless router.
  • An old PC(Possibly laptop, if you’re wiling to plug it in every time you want to watch stuff).
  • A smartphone(Only necessary for easily portable remote control).
  • A USB with about 1 GB free space or a writable DVD.
  • Willingness to “just fucking Google it”.

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Save Us

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    Save Us 1

    Save Us 1
    Save Us 2

    Save Us 2

    The upgrade menu.
    Save Us 3

    Save Us 3

    This was early on in development. The core machanics were done.
    Save Us 4

    Save Us 4

    Improved graphics.
    Save Us 5

    Save Us 5

    First upgrade implemented.

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    Church of Denmark

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    I am no longer a member of the Church of Denmark. I’ve been a member all my life, but I’ve never believed in anything. (If you’re not interested in reading a somewhat aimless rant on religion, don’t continue reading). Continue reading →