Jamie's Blog

My employer gives us a week off for the holidays, so I’d been trying to decide what to do with all of the time. Although I originally didn’t want to work on any programming projects, I wound up working on a few. One of them was inspired by a play of the iOS game Train Yard. I was paying particular attention to the loading screen when I noticed it had been created using Cocos2d. I’d seen articles about the engine before, so I decided to take another look at the Website. I was curious about what other game engines were in popular use. Besides Unity, I didn’t notice any that were more popular than Cocos2d. I decided to investigate further and found a tutorial on the site.

Before I knew it, I was working through the tutorial. The API was simple, straight-forward, and intuitive, and I was soon done. Still, I wanted to use it for my own project. Unfortunately, the holidays were winding down, and Spring term classes will start soon, so time is very limited.

As a prepubescent child, I played a shareware game where balloons would rise on the screen. You’d use your mouse to draw a bowstring, flying an arrow horizontally through the balloon field, timing the ascent of a balloon. It’s this game that immediately came to mind when I tried to think of simple games. The satisfaction of that balloon popping noise made me long to play. (A satisfaction only outpaced by the sound of popping bubble-wrap.)

So, I decided to work on a game like that other game, and started on making balloons float up. I went to http://openclipart.org and found a great balloon-popping sound at http://soundbible.com. I started out by using CCActions, a CCSequence composed of CCMoveUp and CCCallFuncND to perform cleanup. The balloons would randomly spawn at a certain interval below the screen, and rise to a height above the screen, out of the viewport, and be removed from the layer.

Somewhere along the line, I decided that an bow and arrow would be unnecessary, and that touching a balloon would be enough to pop it. At the same time, I’d target the game at children. I implemented procedures to detect a balloon touch, show a particle effect upon touch, play the popping noise, and remove the balloon from the layer immediately.

Play-testing confirmed this mechanic was a little boring in of itself. I figured that popping balloons should release things stored inside, so you should be able to earn points for popping balloons and touching a “treasure item” dropped from the balloon, things like: diamonds, coins, and treasure boxes. I also added clouds in the background, a timer, and score display, the concept of rounds, and a game over state.

I got this working, but it didn’t seem especially targeted towards children. Lisa, my wife, tried it and confirmed as much. We talked about marking each balloon with a letter, and using the balloons to spell words or elsewise learn about words.

After thinking for a bit, I decided that balloons marked with a letter would release a word starting with that letter. When you touched the word dropped by a balloon, that word would be spoken aloud. I downloaded Audacity, and had Lisa recite a list of words. I spliced them and loaded them into my project Resources folder. Once I got the code working, so that the word sound would play when the word was touched, the audio seemed to low, like it had not been normalized. Even after reducing the volume of the background music and popping sound, the words weren’t loud enough. We’ll have to redo the word sounds at some point.

At this point, I’m mostly done, but may add some more graphics and clean up the code. This project has been a great introduction to Cocos2D and Objective-C programming, in general.

Check out game footage below and the complete source code, including assets, on Github: http://github.com/jamiely/ios-balloon-burst

I tried setting up Rubygame on Snow Leopard this time last year. I had many difficulties setting up SDL. I had some time to kill so I tried to set it up again, this time on my new MacBook Air running Lion.

This old blog post from 2005 helped me this time around: http://inquirylabs.com/blog2005/?p=21 to nail down the requirements. Instead of following the installation instructions here, I used Homebrew to set things up.

One of the key requirements is rubysdl, ruby bindings for the SDL multimedia library, and the rsdl gem. The following Gist is a rubysdl Homebrew formula that will help install the required packages: https://gist.github.com/1394440. The SGE formula is not part of the included formulas. I forked the following Gist to provide SGE: https://gist.github.com/1394414/.

# install the sge graphics lib
wget https://gist.github.com/raw/1394414/4a6bfa4a8bab179ebe263b1d044a4322c7628f60/sge.rb
brew install sge

# install rubysdl ruby sdl bindings
wget https://raw.github.com/gist/1394440/8a71160306ad277f08fbad3eaf028b2e8700f2f1/rubysdl.rb
brew install rubysdl

# install the required gem
gem install rsdl
gem install rubygame

Afterwards, most of the rubygame samples ran fine, but the ones requiring opengl had issues. I installed ruby 1.9.2 using rbenv, compiled a new dynamic library libruby.dylib, based on the 1.9.2 source. Then, I cloned this repo providing an upgraded ruby-opengl gem: https://github.com/theymaybecoders/ruby-opengl.

# clone the repo
git clone https://github.com/theymaybecoders/ruby-opengl
cd ruby-opengl

# make sure that the libruby.1.9.1.dylib compiled from the
# ruby 1.9.2 source is present in the gcc class path. For
# me, it was ~/.rbenv/versions/1.9.2-p290/lib/libruby.dylib
# use build option --enable-shared

rake

# build the gem
rake gem

# install the gem
gem install pkg/ruby-opengl-0.60.1.gem

Afterwards, the rubygame opengl samples compiled fine.

My wife loves PopCap’s game Alchemy. It’s a dominoes-like game, where you match up alchemic symbols and various colors. The object of the game is to turn each board-square from lead to gold. I have been wanting to try out the limejs game library, which is based on Google’s Closure compiler, so I decided to write a quick implementation of the game. You can find the source on Github.

You can try out the game online. To play, place pieces adjacent to other pieces which match in symbol or color. A placed piece must match all the pieces adjacent to it. A wild card piece, denoted with the ‘*’ symbol, matches all pieces. Filling a row or column with pieces will mark the corresponding spaces as cleared. The object of the game is to get each space marked as cleared.

Edit (20100214 11:00 PM): Added win condition and box showing how many spaces cleared.
Edit (20100215 11:00 PM): Added leveling. The board starts small with few pieces and keeps getting bigger with each round.

I did a quick matrix to compare various mobile JS frameworks in late May. It is probably a little outdated, especially with the recent Sencha merger, and I did not know DashCode could create web applications at the time, but maybe it will help someone. Enjoy! http://bit.ly/d6Gsaj

Here’s a great wrapper that really simplifies working with KeyChain in iOS http://log.scifihifi.com/post/55837387/simple-iphone-keychain-code. The code is on GitHub as well http://github.com/ldandersen/scifihifi-iphone/tree/master/security/.

Apple’s official documentation is here, and there is also a sample project, but it’s not a good example for getting up and running quickly. The version of the project (last updated 10/2009) doesn’t even run on the simulator.

A coworker and I have been doing some work on visualizations of wiki updates. The server-side code, written in Ruby, stores changes from a media-wiki feed.

Media-wiki Changes Feed

I got a chance to use the Google Visualization API, which is really simple and useful for a wide variety of domains.

He also turned me on to HAML, which offers a concise, structured way of specifying HTML.

Project Page: http://github.com/hectcastro/mediawiki-usage/
Demo: http://www.angelforge.org/mediawiki-usage/

Media-wiki Changes Visualization

I was working on the Drupal OrgChart module tonight, specifically the rendering of the chart image via GraphViz, and I got stuck for at least an hour on a trifle! I planned to use the PEAR library for GraphViz (Image_GraphViz) and I wrote a function using the class it provides. I run the procedure and get weird errors about not being able to find files and such. After debugging for awhile, I find out that there is a property binPath that is not present. I had expected this to point to my install of GraphViz, which I knew to be especially important because it was in a weird macports directory.

It turns out that I had not installed the version I needed! I didn’t realize the version I wanted was beta, and to download a beta package, you need to explicitly state so in the PEAR command.

sudo pear install Image_GraphViz-beta
#instead of
sudo pear install Image_GraphViz

After downloading the most recent package, it turned out my code worked almost perfectly. What a waste of a night!

The past few days, I also worked on a few other modifications. I removed the requirement for a “subordinate_id” field. Also, I made the profile field names options in the administrative settings page.

The project page is here: http://code.google.com/p/drupal-orgchart/.

I decided to try out some Ruby stuff this weekend. I wanted to do a quick little game with the rubygame gem, but I got some weird error attempting to install it on my 64-bit Snow Leopard Intel Mac Powerbook. I abandoned the effort, since I hate to expend time in system administration and installation.

Next, I decided to try running through a Rails demo. I wanted to use MySQL instead of the default SQLite, but got an error, whose text is below, when I tried installing the mysql gem. I resolved it by using the command string that follows, which I found on a MySQL website forum post.  I think the main issue was that I had a non-standard installation of mysql on my machine via macports, so I had to specify the locations of the various MySQL directories in the gem install command.

Error:
cdERROR:  Error installing mysql:
ERROR: Failed to build gem native extension.

/usr/local/bin/ruby extconf.rb --with-mysql-dir=/opt/local/bin
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lmygcc... no
checking for mysql_query() in -lmysqlclient... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Command:

sudo gem install --include-dependencies mysql -- --with-mysql-dir=/opt/local/bin --with-mysql-config=/opt/local/bin/mysql_config5

Here’s a function for Gaussian/Banker’s Rounding in Javascript adapted from code written by Michael Boon at http://boonedocks.net/.

This can be useful if you’re working with Microsoft languages such as VBScript, which use Banker’s Rounding by default in their Round function. Javascript has no built-in gaussian rounding and, instead, uses Arithmetic rounding. For more information on this, see Wikipedia’s article on rounding, specifically, the Round to Even section.

/*
    Adapted from <a href="http://boonedocks.net/code/bround.inc.phps">http://boonedocks.net/code/bround.inc.phps</a>
Provided under the GNU General Public License
    Contact me for use outside the bounds of that license

    ---------------------------------------------------------------
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; either version 2
    of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    The GNU General Public License can be found at:

http://www.gnu.org/copyleft/gpl.html

*/
<a href="http://boonedocks.net/code/bround.inc.phps"></a>
Number.prototype.gaussianRound = Number.prototype.bankersRound = function bround(iDec) {
    return Math.gaussianRound ( this, iDec );
};

Math.gaussianRound = Math.bankersRound = function (dVal, iDec) {

    // banker's style rounding or round-half-even
    // (round down when even number is left of 5, otherwise round up)
    // dVal is value to round
    // iDec specifies number of decimal places to retain

    var
		dFuzz=0.00001, // to deal with floating-point precision loss
		iRoundup=0, // amount to round up by
		iSign= dVal != 0.0 ? Math.floor ( dVal/ Math.abs( dVal ) ) : 1;

	dVal=Math.abs(dVal);

    // get decimal digit in question and amount to right of it as a fraction
    dWorking = dVal * Math.pow ( 10.0, iDec + 1 ) -
		Math.floor ( dVal * Math.pow ( 10.0, iDec ) ) * 10.0;

	iEvenOddDigit =
		Math.floor ( dVal * Math.pow ( 10.0, iDec) ) -
		Math.floor ( dVal * Math.pow ( 10.0, iDec-1 ) ) * 10.0;

    if ( Math.abs ( dWorking - 5.0 ) &lt; dFuzz)
		iRoundup= iEvenOddDigit &amp; 1 ? 1 : 0; // even testing using bitwise and
    else
		iRoundup= dWorking &gt; 5.0 ? 1 : 0;

    return iSign * ( ( Math.floor ( dVal * Math.pow (10.0,iDec ) ) + iRoundup )/ Math.pow(10.0,iDec) );
};

Awesome JS graphics library compatible with JQuery and Prototype.

JSXGraph » Examples