Download Manager Project - Bash scripting

The download manager is the project that I made for UNIX Scripts and Utilities course. I used bash scripting and dialog. Dialog is for the GUI of the project.

The reason that I chose this project is sometimes I download lecture slides of courses that I'm interested in. For example, since MIT opened the most of their courses, I want to download the lecture files to see how they go over the courses and what the homeworks are. Downloading whole files by clicking every link was exhausting. At this point my project is lending a hand to make things easier.

Actually you can download files from a web site by using wget command. To download specific types of files like pdf files, you can give the extension of the file with -A parameter. Let's see an exampe of this.

       wget -r -A.pdf http://www.cs.ozan.edu/~yildiz/prog101/

This command will download all pdf files in the given website which is supposed to include lecture slides or homeworks.

Since the aim of the project is using grep, sed, awk, cut and provide GUI to the user, I should have used something else. And I came up with this:

How does the script work?

• After a user enters comma-separated urls of web pages, the script keeps a list of urls by using awk command.
• The script has a loop to iterate over those urls.
• Then, the source of a web pages is downloaded with wget -k -O command. -k parameter is to convert all relative paths to absolute path.
• Then, grep extracts these absolute paths by looking file extensions and write them into a file. (The extensions of the files that are going to be downloaded is predefined.)
• Another loop downloads all files one by one. Also download bar is increasing when a file is downloaded.
• The script also keeps the history of the downloaded files.

And of course images of the project:

This is the part that user enters links.

Downloading screen. We are able to see the file that is being downloaded.

I put the codes to my gist. Click here to see the code. You can add new file extensions to be downloaded by modifying extensions variable.

Visualization of A* Algorithm - A Java Project

As I mentioned in the last post this semester I'm doing a Java project which is Visualization of A* Algorithm. Because of the exams, I couldn't spare time to improve it. I did some in this weekend. I redesigned the class structure because a class was doing things that it shouldn't do. I added one more class and it is more object-oriented right now.

When I did the first version - before the improvements above - I showed it to my professor. He wanted me to add the spreading of the algorithm in every step. In this way, we are able to see how the algorithm works. To do this, I had to sleep the algorithm for awhile in every step. And I added sleep into the function which finds the path. But it didn't work as I expected. Because GUI slept, too. After a little search, I found that I had to make thread programming to fix that problem. My program was executing in a single thread, when I sleep a function, GUI was sleeping, too. The thing that I have to do was dividing the program into two pieces, first is the piece that shows the GUI elements and the second is the piece that does calculations for algorithm.

I know a little bit of thread programming from my Operating Systems course. We also did a lab to learn better. We were using C, you can find the code for that here. In Java, thread programming was easier than I thought. After doing that, program was working correctly.

Now, I have to study to understand algorithm better. I am little bit confused because of heuristic part of algorithm. The heuristic is directly affecting the algorithm, choosing the right heuristic is the main issue of A*.

Here is some images from the project;

Initial position of starting and destination nodes. Later, users will be able to change their positions.

Spreading of algorithm. Light gray nodes are in closedList. Dark blue nodes are in openList. Calculating g value of neighbors is like this:

currentNode.g + 10 for horizontal and vertical neighbors

currentNode.g + 14 for diagonal neighbors
And Manhattan heuristic is used.

When I finish this project, I'm planning to open the source code. I will probably share the codes on Github.

Long Time No See

I haven't written something for more than a month. I have reasons for that. I've been busy with some paperwork for senior-year project which I will give more information in another post later.

What am I doing?

I'm busy with loving my Unix class. I always wanted to go little deep on the subjects of Unix. This is being happened in my Unix class and I'm happy with that. Moreover my professor gave me a GNU sticker. Woohoo!

I'm also spending time on my Java project which is a course project. I'm doing Visualization of A* Pathfinding Algorithm. We'll submit this project at the end of the semester. But I started early and did some improvements. Actually, this algorithm was another thing I always wanted to learn. I knew that this is also highly used in games. That's why I wanted to learn.

Finally, I will share a screenshot of that project which is an inevitable ending of my posts.

Sorry about the color choices. Green node is the starting node, red one is the destination node. Yellow ones are the walls that the path cannot pass through. Pink ones show the shortest path. User will be able to change the places of starting and destination nodes. Also they will be able to put walls wherever they want. 

G.I.F.T.

As I promise, I'm going write something about my new game: G.I.F.T. actually new version of the ice cube game. In G.I.F.T. we are controlling a kid and helping him to get his gift. Base mechanics remained same. We are controlling him by sliding on the surface. I've uploaded the game on kongreate and newgrounds. (Kongregate link - Newgrounds link to play the game.)

Here is how I converted an old game to a new one.

First, I started with changing the character. I wanted it to be a kid. And I started to draw something. First, I thought the kid as a stickman figure. But I didn't like that and I changed my idea. Then I applied some colors and I got this result:

This was my first attempt to draw something for my game.

Than I started to make tiles. In my mind, there was winter atmosphere for the game. For that reason, I made snowy tiles. And I used gradient effect for the background image. This is the tileset that I've made:

And a snowball which is an obstacle:

I know that they're not so good. But making them was so fun for me. Also, using them in a game was a great experience.

I also made some jumping sounds. It can be hardly noticed because its volume is low. That's because I recorded them by using a cheap microphone.

Now, some technical stuff:

I made all the levels as a different class which derives from FlxState. I chose this way because reseting was too easy. Just a line of code which is FlxG.resetState(). But I couldn't put a loop music to the game, because when it resets the game, it also resets the music. For that reason, maybe this decision wasn't that useful. I think whole game must be in just one state to fix this problem. Reseting can be done with setting all variables' values to thier first values. Another bad thing is that I wrote almost same things for the all of the levels. In the ice cube project, I wrote a Level class and derived all levels from this class. I think this way is better and more object-oriented.

I hope you have fun while playing G.I.F.T. and please rate and leave comments.

Ice Cube Has Gone

From the beginning, I didn't like the idea of ice cube game. But I liked the base mechanics of it. For that reason, instead of making new game I wanted to change and enhance it. I've been working on it for more than a week. The game has changed entirely. I think it's better than the previous idea.

I will give more information about the new idea soon. For now, I'm putting an image which reflects the game directly.

JURUMP - My first game

Yes, Jurump is my first game. Me and Efe Alaçamlı made it together. Click here to read his blog post about Jurump. (Link for the game is below this post.)

We made this game in fall, 2011 for the course called Introduction to Computer Games. This is the course which I meet game programming and love it. Obviously, this was my favourite course, I always looked forward to this course whole week. Other than those, another thing that I remember is how excited and enthusiastic I was. I hope these never ends.

Let's talk about the game now. It's side scrolling 2D platform game. We are trying to save Ali, who is the main character, from alien invasion. He is on the roof of the buildings during this escape. He shouldn't fall into the gaps between buildings and hit aliens. Also, there are four bonuses he can take. These are super jump, temporary protection, speed up and whistle. The goal of the game is finishing the levels faster.

We programmed this game in Java and used Slick2D library. This was a good and rough experience. I remember that we had trouble coding jumping. Because we wanted to simulate gravity in a right way. The character was shaking when he touches the ground. But we did some value changing and solved the problem.

And finally this game came out:

We made this "How to play" screen but some people didn't go there and they never used the bonuses. 

Click here to download the game. Java gives security warning, click no to play. 

An internship ends

It's been two weeks since the internship ended. But I can have a chance to write something at that moment. I've been busy with writing report and other stuff. In this post I will write about internship and the game that I made in this period.

Little information about game: It's a 2D platform game. The character is an ice cube. We're trying to get him to the north pole to make him live free there.

In my previous post I wrote

I'm having trouble designing the levels and making these levels hard.

As I wrote, I really tried to make the levels hard but when I watch people playing my game, those levels were VERY VERY HARD. They could finish the levels and proceed the game. I designed the difficulty of levels for my ability which was totally wrong. Because, while I was making the game, I played it a lot and I got used to controls and eveything. I understand that I missed a very important point which was playtesting. I should have done more playtesting. Maybe, the levels were not going to be that hard. I will put the game here, but I need to do some arrangements.

The game has lots of missing things. It's not fully completed (like my other game-ish things). But this time, there is a little bit much. Maybe I tried to complete some of them. But I really don't like to deal with a project after its deadline has passed. I rather want to make new things.

An image from third level

There are three weeks for college to start. Until that time, I want to find a game idea that I satisfied. Also I need to think something for my senior-year project.

See you soon.