Cartoon Shader-based Real-time Rendering Technology Research

Cartoon rendering is a kind of non-photorealistic rendering technology, whose purpose is to generate the traditional cartoon-style rendering effects on 3D models and scenes by computer automatically. Cartoon rendering using the unchanged color and distinct contour to construct a virtual cartoon world, which having a distinctive cartoon-style visual effect. Compared with other rendering effect, cartoon-style effects make people feel more comfortable and kindly.Cartoon rendering technology is widely applied to the movie and animation, in addition, overseas there have been applying cartoon rendering technique to the computer and video game, which could generate cartoon style 3D scenes and get the distinct cartoon visual effects. It brings on a cartoon-style game industry development trend. But in China, we still relatively fall behind in the research of Computer Animation & Digital Entertainment field, comparing with our foreign competitor. Only a few colleges and universities such as Zhejiang University engage in the research of cartoon rendering and other non-photorealistic rendering technology.Because of my great interest in cartoons, animation, computer and video games for many years, I chose the cartoon rendering technology as my graduation issue subject. I offer a few commonplace remarks by way of introduction so that others may come up with valuable opinions. I wish this article to be a small kindling, could make more people think ,explore and research. the development of Computer Animation & Digital Entertainment in China.First, this article introduced the origin and development process of the term"cartoon", then provides an overview of cartoon rendering technology's origin, research status, and applications in practice, research problems and key sub-technologies. Also do a comparison between cartoon rendering and other non-photorealistic rendering technology. After that, this article use many chapters to do a detailed study of cartoon rendering, involved in several key sub-techniques, such as contour detection, contour rendering, shader programming, cartoon shading and so on.Programmable graphics pipeline is base on the fixed-function graphics pipeline, 45 adding the programmable transform and lighting modules in the geometric treatment phase, which named"vertex shader", as well as the programmable texture, filtering and hybrid module in the rasterization stage,which named"pixel shader". By programming the code of vertex shader and pixel shader, we can achieve even go beyond the work of fixed-function module.Contour lines are the foundation of cartoon-style rendering.The two or three-dimensional cartoon-style artwork usually use contour lines to outline the shape of model, and use thick lines to represent the important feature of the model when the exhibiting the model. In this paper, it present the contours definition and classification of non-photorealistic rendering(including cartoon rendering).And systematically pack up the mathematical description of a variety of contours,which including contour lines, creases and suggesting contour by using the math language.Then, on the basis of mathematical description of contours,this article combine the contour detection algorithm and the contour line drawing algorithm, implement the contour line extraction and real-time rendering of three-dimensional model, finally present experimental results.Cartoon shading means the process of calculating the cartoon-style illumination and choosing the color of all pixels, certainly this coloring effect is a little special and different from traditional realistic illumination model. This article begin from the simple illumination model and several classical shading model, then do the experiment of color shading methods including the pure gray shading, black and white gradient shading, cool and warm colour gradient shading, and so on. By presenting the experimental results directly, this article finds the suitable cartoon shading methods for cartoon rendering.Finally, we summarize our current work and propose the direction of improving and the future work.