The processing.js project was started by John Resig who wanted to utilize the HTML5 canvas element and take advantage of the Java Processing language. It took about seven months to get a working version, consisting of 5000 lines of code but it was not a complete port of the Processing language. The project, similarly to other open source products, was released with the hope that a developer community will converge around it and contribute to development. In September 2009, we began the work to complete the port to JavaScript. In order to facilitate an architecture for participation the source code had to be readily available and the inner workings of the project and the missing functionality must be publicized. To this end the source code was made available publicly on GitHub and an issue tracking system was used to manage the large number of issues needed to be resolved in order to complete the port. A review process was setup to ensure that the code submitted was of sufficient quality.

"The Mozilla experience howeverFrom it's inception, suggests that proprietary products may not Processing.js was designed to be well-suited to distributed development if they have tightly-coupled architectures. There is more than just a need to create an “architecture for participation,” one that promotes ease rewrite of understanding the Java functions provided by limiting module size, and ease of contribution " - (MacCormack, Rusnak and Baldwin 2004)Processing to JavaScript. In September 2009, we began John Resig wrote the work to complete the port to JavaScriptoriginal Processing. In order js parser to facilitate an architecture scan a Processing sketch for participation a number hints of things needed to happen. First Java code and foremost the source convert that code had to be readily availableJavaScript. Secondly However, if the inner workings of parser encountered JavaScript code, it would leave the project and the missing functionality must be publicized and a dialog startedcode intact. To this end This method allowed not only for the source conversion of existing Processing code was made available publicly on GitHub and an issue tracking system was used to manage JavaScript but the large number injection of issues needed JavaScript into Processing sketches as well. By allowing JavaScript to be resolved in order exist within a Processing Sketch intact,Java and JavaScript code can exist together without any need to complete declare the portlanguage you are using. A review process was setup Old sketches written for Processing will work but new sketches written for Processing.js can not only have Processing code but can make use of JavaScript to ensure that interact with other elements of the code submitted was of sufficient qualitywebpage.

Processing.js is more than just a Processing parser re-written in JavaScript. It is designed in a way that connects the Processing language (also known as P5) with web technologies such as JavaScript, the HTML5 canvas element, JQuery, and various web services. Furthermore, Processing.js is built in such a way as to allow easy integration of new technologies as they emerge. It is designed to be fast and to take advantage of recent JavaScript developments to ensure that the platform is responsive. While syntactically JavaScript and Java are fairly similar, there are some fundamental differences that has made this conversion challenging. The first is that we wanted to do this conversion dynamically in real time. The code produced by the converter needed to be fully object oriented and we had to provide support to all native Java functions and objects that are supported by Processing. We also had to take into account the differences between working with web resources vs local resources. Furthermore we had to consider how we would handle some fundamental differences between Java and JavaScript such as typed vs. typeless variables, function overloading and variable name overloading. The original code for Processing.js used regular expressions to convert Java into JavaScript when it was encountered. It did this by scanning for hints of Java code within the entire sketch and then replaced the Java code with its JavaScript equivalent. Due to the difference in how Java and JavaScript accessed object properties from methods inside an object, the with statement was used as a simple solution to avoid having to prepend all function calls with "this." or "Processing.". However, the use of the with statement also meant that the JavaScript generated would fall off Trace /*cite trace paper here... do we need to talk about trace in the back ground section???*/ making the code run slower than it needed to in some browsers. Later this method of scanning the entire sketch was replaced by the creation of an abstract syntax tree that broke up the code into smaller pieces. Each piece then had the regular expressions applied to change it. This made it was easier to apply the regular expressions correctly without accidentally converting code that was already working. It also made it easier to create proper inheritance structures and attach properties and methods to the correct object in the hierarchy chain as smaller pieces of code was being converted at any one time. ==Browser Unification== One important feature provided by Processing.js is that it hides the differences between browsers. Web standards are often loosely defined, and thus variations can exist. These variations not only exist between different browser vendors but can even exist between versions of the same browser on different platforms. Something as simple as key events can vary widely between browsers. Processing.js hides a large number of these differences from the user by creating a unified method of handling events. Regardless of the browser/platform, the functions for handling events within Processing.js are handled the same way.

While syntactically JavaScript and Java Different browser makers are fairly similaralso at various stages of implementation for various newer technologies. For example, there WebGL provides typed arrays which are some fundamental differences that has made this conversion challengingmuch faster than traditional JavaScript arrays. The first is While these typed arrays are implemented for WebGL, they can be used outside of that we wanted to do this conversion dynamically in real time. The code produced by the converter needed to be fully object oriented context also and we had to can provide support to all native Java functions and objects (such as Strings) that are supported by Processingtremendous speed improvement. We also had However, not every browser supports WebGL at this time thus a fallback to take into account regular JavaScript arrays is necessary if the differences between working with web resources vs local resources. Furthermore we had to consider how we would handle some fundamental differences between Java and JavaScript such as typed vs. typeless variables, function overloading and variable name overloadingfeature does not exist.

From it's inceptionBy hiding these differences between browser makers from the user, Processing.js was designed provides a means for game developers to be more than just a rewrite of make games without worry about the Java functions provided by Processing to JavaScriptdifferences between browsers. John Resig wrote If a feature exists that can make the original rendering smoother and faster, Processing.js parser to scan a Processing sketch for hints will make use of Java code and convert that code it to JavaScriptincrease performance. However, if the parser encountered JavaScript code, If it would leave the code intact. This method allowed does not only for the conversion of existing Processing code exist a fallback mechanism is available to JavaScript but the injection of JavaScript into Processing sketches as well. This simple idea means that within a processing sketch Java and JavaScript code can exist together without any need allow it to declare the language you are usingstill run.

The introduction of the <canvas> tag into the HTML5 specification allowed Processing to be ported to JavaScript, thus enabling users to run 2D sketches within the browser without additional plug-ins. At the time when porting began, there was no plug-in free method of delivering 3D content. This limited Processing.js to its 2D functions. WebGL, A JavaScript API that is based on OpenGL ES 2.0, is now being implemented by Firefox, Chrome and Safari. It is now has become a viable candidate for use in Processing.js to render 3D sketches. Additionally, since WebGL closely matches OpenGL which is used by Processing, it substantially aided the porting processof the 3D Processing functions was relatively straight forward.

===Differencesbetween OpenGL and WebGL===The matter of porting Processing (which uses OpenGL/*1.x?? if it was opengl 2.0 it would have been even easier right?*/) was simplified because the WebGL interface is similar that of OpenGL, but there are a number of differences between the interfaces. Arguably, the The single largest difference between WebGL and OpenGL 1.x is that like OpenGL ES 2.0, the fixed-function pipeline was been removed. Because of this, not all Processing source code could not be ported directly. Instead, user-defined vertex and fragment shaders were necessary to write for lighting operations. Since some shapes in Processing aren't lit and others were, multiple shaders were written. One shader exists for lit objects such as boxes and spheres, another less complex shader was written for unlit objects such as lines and points.

Because typed arrays are only available for pre-release browsers, they cannot currently be used in 2D sketches. Once they become implemented in browsers, a significant amount of the Processing.js code base can make use of these structures, increasing performance throughout the library. ===Specification Changes and Browser Inconsistencies===As the specification is concurrently implemented in different browsers, several inconsistencies between browsers have appeared. These range from minor issues, such as Minefield and Chrome/Chromium return "function" while WebKit returns "object" when the type of a typed array is queried. Another is the way WebGL's readPixels() function is implemented. This function isn't used extensively in the library itself/* andor, but it is used mike said its in the Processing.js reference testing framework. ===Problems===WebGL provides a close match to OpenGL for incorporating 3D into Processing.js, but it does present some issues when trying to port over code. There are interface differences, changes to the interface are common, and some functionality isn't available at all such as point smoothing.  ==Browser Unification== One important feature provided by Processing.js is that it hides the differences between browsers. Web standards are often loosely defined, and thus variations can exist. These variations not only exist between different browser vendors but can even exist between versions of the same browser on different platforms. Something as simple as key events can vary widely between browsers. Processing.js hides all these intricacies from the user keeping it simple for content creators. ???*/