导　　师： 杨旭波

学科专业： 081202

授予学位： 硕士

作　　者： ;

机构地区： 上海交通大学

摘　　要： 非真实感渲染是当前计算机图形学研究中的热点问题之一。卡通渲染是非真实感渲染领域的一个重要研究方向。卡通渲染算法反映了非真实感渲染中涉及到的一些关键性的主题和技术。显示硬件的可编程性是显示硬件发展的主流。实时的卡通渲染技术在当前的影视娱乐与计算机游戏业界中有着广泛的应用。探讨利用着色器技术来实现实时卡通渲染算法有着重要的理论意义和应用价值。 与传统卡通绘制过程类似,本文作者的研究从卡通渲染的通着色和描边/(包括边缘检测和绘制两个部分/)两个过程入手。本文以三个部分,分别阐述了卡通着色算法、描边算法以及着色与边缘的合成方法的算法原理,以及使用现代着色器技术的实现细节。 在卡通着色算法部分,研究并实现了颜色查找表方法,纹理映射方法和点乘法。颜色查找方法首先建立好的包含场景所用颜色的颜色索引表,每个表项包含了高亮区域,漫反射区域及阴影区域的颜色,然后将表面漫反射值映射到该表项中的颜色。纹理映射方法则是使用一张纹理来取代颜色查找表,利用漫反射值作为纹理坐标访问这张纹理来获取表面颜色值。点乘法使用漫反射值来动态计算表面颜色条带和边缘的宽度,使用指定颜色值分别对其进行绘制。 在描边算法部分,研究并实现了表面角轮廓算法,过程几何轮廓算法,基于图像处理的方法以及直接绘制方法4大类方法。表面轮廓算法根据在轮廓边缘附近漫反射值接近于零的事实,使用纹理映射的方式绘制轮廓边缘。过程几何方法则是通过分别绘制正向表面和背向表面来获取轮廓线。基于图像处理的算法将像素着色器作为一个高效的图象处理单元,对G缓冲器进行边缘检测,然后对边缘图像进行增强。直接绘制方法将边缘的检测与绘制分开完成,能够处理各种 NPR /(Non-Photorealistic Rendering/) is one of the hotspots of current Computer Graphics research. Cartoon Rendering is an important researching area in NPR. The algorithm of Cartoon Rendering reflects some pivotal themes and technique of NPR. Programmability is the mainstream of current display hardware development. Real-time Cartoon Rendering has a wide application in current film entertainment and video game industry. The exploration of using shader to implement real-time Cartoon Rendering algorithm is of great importance in both theory and application. Being similar to the traditional cartoon making process, the research is divided into two parts named painting and inking. This paper used three parts to describe the algorithm behind cartoon painting, inking and combination of these two parts, and the implementation of using resent shader technique. This paper discussed three methods in painting part: color index table, texture mapping method and dot3 shading. In color index table method, there is a color table with items of all colors used in scene. Each item in the table includes the highlight, diffuse and shadow area colors. The diffuse value of lighting mode will be used as the index into the table. Texture mapping method replaces the table with a texture and uses the diffuse value as the texture coordinate to sample the texture. Dot3 shading uses the diffuse value to calculate the width of surface color band and the edge dynamically and uses the specified color to shading them. The inking algorithm is grouped by 4 categories: surface angle silhouette, procedural geometry silhouette, image-based outlining and direct drawing method. Surface angle silhouette is based on the fact that the diffuse value at the edge is nearly zero. This method uses texture to render the silhouette. Procedural geometry silhouette method draws front faces first and then back faces to make the silhouette visible. Image-based outlining uses the pixel shader as a effective image processing unit to process the G-buffers a

关 键 词： 非真实感渲染 卡通渲染 着色器技术 实时渲染

领　　域： [自动化与计算机技术] [自动化与计算机技术]