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== 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 manipulations. 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.
== Security Considerations The Document Object Model ==
The Document Object Model is an APi that allows for the interpretation of HTML and XML documents. It provides a structual representation of the document, which enables for easy modification and visual representation of the webpage. In essence, it connects the markup langages to structual 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 properties. This technology allows the Canvas tags to be read and retrieved in an efficient manner.
== Use of XML 3D ==
The Canvas 3D Tags will be based upon the syntax of its counterpart, the 2D Canvas tags. Essentially, the syntax will be similar to the following:<br/> <pre><canvas> -- size is size of a size, orientation is a quaternion <cube position="x y z" orientation= The Document Object Model "a b c d" size="4"/> -- size is radius <sphere position="x y z" size="5"/></canvas></pre> 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 aspect to the markup language:<br/>
<pre>
<canvas>
-- either with an explicit matrix
<transform matrix="m1..m16">
<cube size="5"/>
</transform>
-- or with position and/or orientation
<transform position="x y z" orientation="a b c d">
<cube size="5"/>
</transform>
</canvas>
</pre>
<pre><canvas> -- create a light <light type="spot" color= Use of XML 3D "blue" position="x y z" orientation="a b c d" /></canvas></pre>
== Use of XML 3D in JavaScript ==
== Tag Reference ==
== Appendix ==