NPR.js : A JavaScript library for Interactive Non- Photorealistic Rendering in WebGL

Background and Motivation Non-photorealistic rendering (NPR) is the area of computer graphics that is concerned with rendering images in styles other than photorealism, such as a variety of art-based styles. Stylized rendering in general may have a number of perceived advantages, the most obvious being the potential for a diversity of visual appeal. Other motivations include visual clarity (illustrative diagrams are frequently simpler to comprehend than photographs or photorealistically rendered models), or practical asset limitation (applying a visual style other than photorealism may reduce the need for detailed textures and geometry). We present a library of utilities for applying art-based NPR effects to 3d models in WebGL. The goals of the project are to provide a reasonable variety of customizable effects, as well as utilities for authoring and prototyping effects and assets for these effects. Our work is motivated primarily by the visual possibilities of art-based rendering for digital art. Of particular interest is the application of NPR techniques to real-time digital art such as games, but increasingly including other forms such as installation art, interactive visualization for performance, and web-based work involving any or all of the aforementioned. Recent developments in web standards (HTML5) allow for dynamic multimedia content using only standard HTML and JavaScript that previously required the use of browser plugins such as Adobe Flash. This has given rise to a large number of multimedia web experiments and applications. The integration of these technologies into the web standard serves a purpose further than just allowing a theoretically greater dissemination of such content to devices without common plugins. By embedding this functionality into the fabric of the web, HTML5 multimedia can interact with the DOM (Document Object Model) directly, which in turn would allow for a wide range of possibilities for the future of web content.