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== History ==
Canvas elements simplify the drawing of custom pixels to the screen as well as the modification of these pixels in real-time. There have been numerous requests for a canvas tag inside HTML documents which provided cusom drawability custom draw ability inside XUL (A Cross-Platform drawing management library). Unfortunately, XUL is client side based which only allows the modification of webpages web pages from the users user’s endpoint. The Canvas Tag was originally developed in order to create modifications to the browser from the server end. An on-screen Canvas object is basically a wrapper around the XUL engine that allows the visual manipulation of pixels on the webpage.
== Objective ==
== Rationale ==
The basis of the Canvas tag is to provide immediate drawing to the screen. The drawing can consist of regular 2D pixel manipulations as well as a proposed 3D model manipulationsmanipulation. In addition, it will provide a safe and simple application programming interface (API) to the OpenGL Layer. The OpenGL Layer is a library that handles the math required for 3D transformations. Unfortunately, OpenGL has the power to talk directly to the hardware therefore allowing direct manipulation of the hardware or possibly potential damage. Consequently, the OpenGL Layer will not be included in this project due to its complex nature and constant upkeep. In addition, the OpenGL API is extremely low-level and may be confusing when exposed to the internet. <br/> <br/>
However, the first step in creating a 3D Canvas element is to use a custom XML tag to specify the 3D objects on the screen as well as the drawing area available. In this case, the developer will be able to create 3D objects on the client's screen as well as provide logic to modify these objects in real-time. By using the Document Object Model (DOM) to interpret the XML language and retrieve the attributes of the objects, this causes the objects to be presented for modification purposes.
== The Document Object Model ==
The Document Object Model is an APi API that allows for the interpretation of HTML and XML documents. It provides a structual structural representation of the document, which enables for easy modification and visual representation of the webpage. In essence, it connects the markup langages languages to structual structural code inside the browser. The DOM is contained in a tree structure that allows for easy search and retrieval of HTML and XML tags and thier their properties. This technology allows the Canvas tags to be read and retrieved in an efficient manner.
== Use of XML 3D ==
The Canvas Tags are already handled by the browser and therefore do not need to be implemented. Rather, the tags that will create the 3D objects will be added to the current Canvas Framework to enable the creation of 3D objects in memory. For example, the <cube /> tag will create a 3D cube in memory. The Attributes associated with it, such as position, orientation and size are all modifiers that will be exposed within JavaScript. Each tag that is used inside the Canvas Tag will have similar properties that will also be available for modification in the JavaScript Code. <br /><br />
Within a 3D world, a programmer can add numerous transformations sequentially in order to place an object in a given place. It will provide a larger flexability flexibility aspect to the markup language:<br/>
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These are the basic principles that govern 3D controlls controls over an Object. An object can be anything from a simple primitive such as a Cube or Sphere to a complex Mesh that can be downloaded from the internet or from the client's computer. Furthermore, the usage of lighting and camera modifications will follows the same structure as the primitives.
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== Use of XML 3D in JavaScript ==
In order to draw the objects onto the screen, JavaScript will be used to call functions inside the core of Firefox. The API will be written to allow programmers to not only access the various attributes of the Objects but also write drawing logic. The webpage will initiate a call to a javaScript JavaScript function that will start the drawing/manipulation code. This part of the project is being handled by Vlad Vukicevic from Mozilla.
== Tag Reference ==
== Appendix ==
