Archive for category programming
The next iteration of the S2BOC is online
Posted by visual77 in programming, sc2build on May 24, 2010
In my last update on the StarCraft II Build Order Calculator, I said that I was going to have this next version work on building queues, but I decided to work on the URL sharing instead. The newest version of the S2BOC still doesn’t account for queues, but you can now send someone the URL to share build orders.
This URL sharing is one of the most critical requirements of this system. This calculator is designed to aid strategy discussions and a key part of that is showing a friend your strategy. As you update your build order, the URL will be modified, so you can send the build order at any time and anyone going to that URL will see what you see.
This calculator also allows you to switch between Terran, Protoss and Zerg, albeit in a clunky way that will be addressed before the final build. In order to change race, change the URL to start the build order string (from # to the end of the URL) with T, P or Z. In both FireFox and Chrome, I had to refresh the page after changing the URL before the new race properly appeared.
StarCraft II Build Order Calculator
Sample Build (9 Pylon / 12 Gateway Protoss build)
Iterative Development for Economy Calculator
Posted by visual77 in gaming, programming, sc2build on May 19, 2010
This iterative build was to test the economy calculator at different time intervals. I created an array to store information on 5 basic protoss units – Nexus, Pylon, Gateway, Probe and Zealot. I then wrote some quick calculators to accept a time, in seconds, and return the amount of minerals available at that time. The display is fairly minimal, just showing economy, but various units and builds were constructed at certain times.
The calculation is based on finding out how many probes exist at this time, how long they have existed, and multiplying that by 5/6. 5/6 is the number of minerals gathered per second per harvester (before saturation, at least). Once I have found the total minerals gathered, I get a list of all units that have begun construction at that time and subtract it from the total and return it.
The formula for calculating wealth seems okay, but the initial array contained far more data than I ended up using and the formulas were a bit too hard coded. Things like MULE and Chrono Boost are not being accounted for, and supply count is ignored as well.
I like the idea of a function being passed a time value and returning a snapshot of the build status at that time, and the array storing the build information also containing when each item was started. This system would fairly easily allow new commands to be inserted mid way through the build.
I definitely need to make the calclations more dynamic, though. I’m also still unsure of how to handle the starting Nexus and 5 Probes. This system puts the build time at -100 and -17, respectively, and always adds 700 minerals to the mineral count.
All in all, this iteration did show some interesting ideas, particularly with where to store data on all of the units. I ended up sliding it in as an array inside the build class, but that seems impractical. I should probably set a race as a class, units as a class, buildings as a class and special abilities as a class. My next experimentation will involve testing those methods for viability.
StarCraft II Build Order Calculator
Posted by visual77 in gaming, programming, sc2build on May 18, 2010
I’ve recently begun work on a new project that should see the light of day in time for StarCraft II to launch on July 27. The project, being hosted over at http://sc2build.com, is the StarCraft II Build Order Calculator. The project aims to take the ease of use and share-friendly nature of World of Warcraft talent calculators and apply it to StarCraft II build orders.
The project is just beginning the iterative development phase, with some small scale tests of single aspects of the system. I began writing my notes on the site in plain text, but it quickly became apparent that I will have enough notes to require a full fledged blog.
Expect to see a flood of posts in the coming days as I think aloud on how to build this system and test various methods of implementation. I will be building it through iterative development, and as such there will be many micro tests in the coming weeks of single aspects of the system.
The first test that has already been pondered upon and attempted once is how to store the build order data in a URI without that URI becoming ungainly in length. You can see my notes on that test and see a sample of this one attempt in the iterative development section of that site.
Setting up dynamic themes on Kohana
Posted by visual77 in programming on April 14, 2010
It’s been a little over six months since I first began to use Kohana framework for all PHP development, and I thoroughly love the system. The only issue I’ve had with Kohana is the lack of built in, intuitive support for dynamic themes. I was unable to find an easy method to set up a theme that automatically wraps itself around all pages, while remaining dynamic enough to change certain elements on a page to page basis.
Over the past few days, I have been exploring methods to do this, with the following requirements:
- Keep all theme files separate from the application
- Require no changes to existing controllers and views to implement or change a theme
- Allow multiple applications on the same Kohana build to use the same theme
- Provide support for cascading themes
After a few failed attempts, I have found a solution that covers all four requirements and is pretty easy to implement. Of course, it is easier to implement this from the start, but if you have an existing Kohana site, it shouldn’t be too difficult to integrate this theming setup into the site. The concept of the theme is simple: create a theme as a module and then use hooks to implement the theme elements as appropriate.
How to flatten an array in PHP
Posted by visual77 in programming on March 23, 2010
In a recent Kohana project, I came across a somewhat odd PHP scenario – I had a multidimensional array that I needed to compress to a single dimensional array, but retaining all of the non array values. Basically, I need to make this change:
Array
(
to => Array
(
0 => stevep
1 => bobw
)
bcc => Array
(
0 => paulj
)
)
Array
(
0 => stevep
1 => bobw
2 => paulj
)
I looked around a bit for an existing PHP snippet to do just this, but they were all overly complex and used recursive callback functions. I had a feeling I could pull this off in a much more clean fashion. I toyed around a bit with the array functions and the ArrayObject library, and this is what I settled with:
$new_array = new ArrayObject(); array_walk_recursive($old_array, array($new_array, 'offsetSet')); $flattened_array = array_keys($new_array->getArrayCopy());
The big drawback is the way ArrayObect::offsetSet() accepts its parameters, compared to how array_walk_recursive() sends the callback parameters; they are reversed. This causes the values to become keys, which has the effect of canceling out duplicate values. If your script needs duplicate values to remain intact, then this solution won’t work for you. Otherwise, it should work out just fine.
Dealing with PHP and character encoding
Posted by visual77 in programming on February 16, 2010
How many times have you been presented with a character encoding glitch on a PHP site that you thought was working properly? You finished the site months ago with no issues, but now you are being told some weird character is showing up on that page? Chances are, that character is either Ã, Â or Ä, possibly followed by some other random character. If I’m right, keep reading. If not, I offer my deepest condolences, for you are knee deep in a character encoding issue that I cannot help you with.
So what is it that causes that à to show up? In short – you have UTF-8 encoded data set to display as ISO-8859-1. But the more important question is how to prevent this from happening in the future. The easy answer to that – store all data in the same format as the final display. Convert the encoding as soon as you receive the data, either through an input field, reading a file or any other method. Don’t put anything in your database unless you are sure it is in the right format.
First, an introduction to the three important character encodings that you are likely to deal with – ASCII, UTF-8 and ISO-8859-1. Character encoding is, in a nutshell, the exact method that characters are stored and displayed by a computer. Since computers only deal in binary, there must be some way to convert from binary into a character. Character encodings come in two flavors (at least, two flavors I’ll be discussing) – single byte and multi byte encodings. Single byte encodings, such as ASCII and ISO-8859-1, use a single byte to represent a character. For instance, the letter “M” in ASCII is represented as 0x4D, whereas the number 4 is 0×34.
A single byte is limited to only 256 possible values, which rapidly becomes a limitation when you want to use characters not typically seen in English, such as “ç” or “ß”, and when you begin thinking about Asian languages, you can quickly see there simply isn’t room for all characters. Multi byte encodings use one or more bytes to represent a character. Each byte still only has 256 possibilities, but 2 bytes have 65,536 possibilities. But, what if there is confusion as to whether or not you are using single or multi byte encoding? Is that short string “0x3C 0xA5″ supposed to be the UTF-8 character å or the ISO-8859-1 string ÃÑ? And there we are – a sudden bug has shown up.
ASCII is the oldest of the three and the most basic. The ASCII character set started out as just 128 characters, and very English-centric. You can see that the basic ASCII table is very restricted to the English speaking world. The extended ASCII table goes off into some weird directions and is rarely used. The full ASCII table is only 256 characters, and thus fits neatly into a single byte, and so it is a single byte encoding.
ISO-8859-1 is also a single byte encoding, but you can see that it is a bit better in the extended range to support many Latin based languages. Unlike ASCII, ISO-8859-1 can handle the majority of Latin based languages without too much issue. It fails when you go outside of the Latin based languages, however.
The third character encoding is UTF-8, which is designed to support over 1.1 million characters, more than enough for all existing languages (and a few dead ones). Unlike ASCII and ISO-8859-1, UTF-8 is not limited to a single byte, but can vary between 1 and 4 bytes, depending on the character being used.
One thing to take note of is that the first 128 characters of all three encodings are identical. This is why a character encoding issue on an English website can take so long to spot. You can go months not knowing that you have a character encoding issue because the only characters you used were the same in all 3 encodings – 0x4D is an M in ASCII, UTF-8 and ISO-8859-1.
On to the meat of this article – dealing with character encodings in PHP. Namely, how to detect and convert encodings.
The magic bullet of dealing with character encodings in PHP can be summed up in three functions – mb_detect_encoding(), mb_detect_order() and iconv(). The mb libraries are designed for working with multibyte languages and iconv is a function to convert from one encoding type to another. One nonobvious restriction to the multibyte languages is the lack of native support for ISO-8859-1, since that is a single byte language. mb_detect_order() can be used to specify the order of encodings to scan when attempting to detect an encoding on a string.
The basics of dealing with character encoding conversion in PHP is a simple three step process:
- Set the encoding types to scan (ASCII, UTF-8, ISO-8859-1). Luckily, this only has to be done once.
- Identify the encoding of the string to convert.
- Convert to the desired encoding type (I prefer UTF-8).
But, let’s cut to the crap. Sample code!
// tell the multibyte library which encodings to use
mb_detect_order('ASCII, UTF-8, ISO-8859-1');
// tell the browser that we are using UTF-8
header('content-type: text/plain; charset=UTF-8');
$string = "Fün wîth èñcøding!";
// UTF string displays properly
echo $string . "\r\n";
// convert to ISO-8859-1, which will confuse the browser
$string = iconv(
mb_detect_encoding($string),
'ISO-8859-1',
$string
);
echo $string . "\r\n";
// convert back to UTF-8, which the browser understands
$string = iconv(
mb_detect_encoding($string),
'UTF-8',
$string
);
echo $string . "\r\n";
How to unchunk data received through PHP sockets
Posted by visual77 in programming on February 12, 2010
When using the PHP socket functions to pull data from another website, you’ll often find yourself dealing with chunked data. Chunked data often looks like this:
1e this line is 30 characters lon 2c g, while this line is 44 characters long. an 21 d this line is 33 characters long
As you can see, each chunk is preceded by a hex string. This hex string corresponds to the string length of the following chunk. Line breaks are included in the chunk, as you can see in the second chunk. So to unchunk the string, you have to find every hex string that is preceded by, and followed by, a line break (or start of end of string), and if the following block of code is equal in length to the hex value, strip out the hex value.
I accomplished this with a regular expression and preg_replace_callback. In essence, it finds each block of code that follows this pattern:
- start of string / hex string on it’s own line
- anything
- hex string on it’s own line / end of string
Once it has found all of those patterns, it replaces only the ones where the hex value of #1 is equal to the string length of #2.
My unchunk function:
function unchunk($result) {
return preg_replace_callback(
'/(?:(?:\r\n|\n)|^)([0-9A-F]+)(?:\r\n|\n){1,2}(.*?)'
.'((?:\r\n|\n)(?:[0-9A-F]+(?:\r\n|\n))|$)/si',
create_function(
'$matches',
'return hexdec($matches[1]) == strlen($matches[2]) ?
$matches[2] :
$matches[0];'
),
$result
);
}
Greased PMA – Stripping the suck out of phpmyadmin’s SQL query window
Posted by visual77 in programming on February 10, 2010
Anyone who has used phpmyadmin‘s query window knows how frustratingly small the textarea is, and how difficult editing SQL query blocks can be. I wrote a Greasemonkey script to de-suck this query window. As of now, Greased PMA is version 0.1 and has the following features:
- Automatic resizing of the textarea to make best use of the window size
- Ctrl+Enter submits the query
- Tab inserts 4 spaces into the query
Click here to download Greased PMA version 0.1.
Update: While messing around at home on Vista / Chrome, I noticed that Greased PMA partially works on Chrome. I wasn’t expecting this to work outside of Firefox / Greasemonkey, but Chrome has a similar extension feature, it seems. The textarea resizing works, but the Ctrl+Enter submitting query and tab modification do not work. Perhaps this weekend I will debug those two functions on Chrome.
What makes a user want to buy digital content?
Posted by visual77 in gaming, programming, visual77 on January 21, 2010
As you can learn from a cursory glance at this site, I am a professional computer programmer. I also have side projects that I would like to one day monetize. One such side project is my planned Android app remind@home. On the other hand, I am a content consumer in the digital age, using the internet to acquire new content, sometimes in ways the content creator might not find appealing. Sometimes I pay for content (such as my recent Steam purchase of Dragon Age: Origins) and sometimes I do not pay for content (such as all apps I’ve installed on my Droid, except my podcast app BeyondPod).
Do I acquire content for free because I am cheap? Absolutely not. I buy when the content creator has provided sufficient incentives to buying. As a content creator, I strive to understand those reasons, both within myself and within others. For this reason, I have begun asking friends what a content creator can do to encourage a purchase. I am not concerned with preventing unauthorized downloads or free software that is asking for donations. I am only concerned with finding out what a content creator can do to encourage users to pay for their content. After my discussions with other techies, here are some of the ways a content creator can encourage users to pay:
Release a sample
Release a free sample that can be easily upgraded to the full version. This allows me to find out if I like your content before I commit money. iTunes and Amazon MP3 Store are examples of this from a music perspective, and game demos accomplish the same thing for game developers. If I am unsure of the quality of your product, I am unlikely to blindly commit money. Through Amazon MP3, I can sample every song on an album before I decide to buy. If you do not provide an easy to locate sample, I will still find a free way to sample the content. The alternative is an unauthorized acquisition of your content, and in that scenario I am unlikely to pay if I like the content. After all, why pay for what I already have? By placing barriers to sampling, you aren’t hindering my ability to sample, you are just putting yourself in a bad place if I like what I’ve sampled.
For PC game developers, this is even more critical. Unlike console games, PC games are not always playable on every PC. A demo not only lets me find out if I like the game, but it lets me find out if I can even run the game. There is nothing worse than paying $50 to find out my video card can’t handle your game. Just like in the music sampling example above, instead I can just acquire the game through other channels. If it doesn’t work, I still have my $50. If it does work, where does that leave you?
Continuously update your content
This rule applies more to software than any other form of content, but it is an important rule nonetheless. If I purchase software that is constantly updated, and only authorized copies can be updated directly from the developer, I have an incentive to pay. Fear not, all of the updates will be leaked through unauthorized channels, but the convenience of a built in updater cannot be understated. Imagine downloading a program to manage a database of clients and receiving a weekly update with bug fixes and occasional new features. These updates can come through two channels – an authorized update system that came with the purchase of the software, or a weekly hunt through P2P networks for the newest version. The convenience of a built in updater is easily worth the $50, assuming the updates are worthwhile. Releasing your software and then abandoning it gives me no incentive to purchase a copy. That just guarantees that the version available on a P2P network is the same as a legitimate copy, permanently.
Be easy to acquire
I’ve purchased over a dozen games from Steam simply because it is easy to pay for and acquire my game. The user interface for acquiring your content needs to be easy to use. If I am having trouble locating your content digitally through authorized channels, I’ll simply start looking through unauthorized channels. Make it easy enough that I never consider looking for alternate methods to get your content. Sometimes the issue isn’t how much your content costs, but how much of a hassle it is to locate and acquire.
As a content provider, make use of services like Amazon MP3 store, Audible and Steam. You don’t have to create your own system of distribution, but use a reliable distribution system. Users want convenience above all else when it comes to acquiring new content. The more convenient your distribution system is, the less likely a person is to seek alternate methods. There will always be those that simply don’t want to pay. There is almost nothing you can do about that crowd. Instead, focus on the crowd that is willing to pay. Find out what barriers are in their way and remove those barriers.
Offer your content digitally
This should go without saying. If you want people to pay you for your digital content, then offer that digital content. Rather than offer an explanation, I will just provide one of the conversations I had about this subject:
Steve: How often do you acquire unauthorized digital content?
Anonymous: Maybe twice a month, it really depends if theres an HBO or Showtime show I want to watch.
Steve: What could a content creator do to encourage you to buy?
Anonymous: Offer a place to buy it online. Just make it possible. Do it the day after not months later. I mean, I pay to torrent now, since I use usegroups. It’s access thats the issue, not price.
Steve: So the only reason HBO and Showtime aren’t getting your money is because they aren’t giving you a way to give it to them? Someone is getting the money, and if HBO or Showtime set up a good system, they’d have it. But, they are making it impossible for you to get, through them, what you can certainly get elsewhere.
Anonymous: Yeah.
Storing on/off switches through binary representation
Posted by visual77 in programming on January 5, 2010
As part of the Nightlife Project, you will have to store some data through binary representation in the payment_rates table. While doing the writeup on the MySQL schema, I decided that this section was too large to easily fit inside of that article and it should be its own article. The goal of this article is to explain how database schemas employ the principles of binary notation to store a sequence of on/off flags in a single field.
Imagine this scenario: You are the head of maintenance at an office and are trying to determine which lightbulbs get the most usage and should be replaced with high efficiency bulbs. In order to determine which gets the most usage, you walk through the building in the morning, at lunch and again at night and make a note of which bulbs are on and which are off. Once you’ve gathered your data, you store the information in a database and after 2 months, you will view the results and determine the top used bulbs and replace them with higher efficiency bulbs to save electricity.
After each walk through the building, you have a list of lights and a corresponding on/off value for each one. Your list may look something like this:
| Reception | Break Room | Bathroom | Office 1 | Office 2 | Office 3 | Office 4 | Hallway | Copy Room |
| On | Off | Off | Off | On | On | Off | On | Off |
The obvious way to store this data is to create a table called ‘lights’ and give it 10 fields – a timestamp (we need to know when this walk through occurred, after all) and a field for each of the 9 rooms. However, this obvious way has a few nasty shortcomings. What if you decide to add additional lights to be checked, such as desk lamps or the front walkway? Adding additional fields rarely ends well. This is also extremely inefficient, as you now have an 10 field table when a 2 field table would suffice.
Instead of storing it through this obvious, but inefficient method, instead you can convert that list of on/off switches into a binary string. Using the same data above, the binary string would look like this: 100011010. Each of the lights that are on is a 1 and each light that is off is a 0. Each character represents a room – the first position is reception, the second position is break room, etc. Converting this binary string to decimal, 100011010 becomes 282 (why?).
| Reception | Break Room | Bathroom | Office 1 | Office 2 | Office 3 | Office 4 | Hallway | Copy Room |
| 1 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 |
The key thing behind storing binary information in a database is this: no other combination of binary will equal that number. There is simply no other set of on/off values that will add up to 282. This lets us store an infinite amount of on/off values in a single integer slot, without ambiguity and always available for reading. As far as how you will read it, look into your language’s “bitwise and” and “bitwise or” operators. An example in PHP would be:
$user_permission = 6; // binary 0110
$view = 1; // binary 0001
$edit = 2; // binary 0010
$create = 4; // binary 0100
$delete = 8; // binary 1000
if($user_permission & $view)
echo 'user can view';
if($user_permission & $edit)
echo 'user can edit';
if($user_permission & $create)
echo 'user can create';
if($user_permission & $delete)
echo 'user can delete';
You can use a system like this for storing user permissions(which is how *nix permissions work), which days of the week an event occurs(the nightlife project will be doing this for storing payment rates), or any other piece of information that can be summed up in a series of on/off switches. Using binary storage is extremely efficient and flexible. Remember, however, that any additional fields to be added should be added to the left side of the string to preserve old data.