Research And Implementation Of Real-time Pencil Sketch Drawing

Since the 1980s, non-photorealistic rendering (NPR) has become one of the most popular research topics in Computer Graphics. NPR is such a computer technology to generate the photos with manual drawing style, instead of realistic effect as photograph. So far, the researchers of related fields have present lots of NPR technologies to simulate drawing or physical materials for drawing, such as pen-and-ink, watercolor, charcoal, pencil drawing. Real-time pencil drawing is an important one among there technologies. This paper presents a real-time technique for rendering 3D meshes in the pencil drawing style.At first, this paper analyzes the NPR's generating process, mainly techniques and application fields and emphasizes the importance of GPU programming. During the preparation work, after describes the 3D mesh format this paper analyzes and implements the cartoon style rendering and hatching technique. The pencil sketch rendering technique of this paper will borrow ideas from cartoon rendering's edge detection and hatching's TAM.After analyze the characteristics of pencil sketch drawing, the paper incorporate them into the rendering process, which are fully implemented on GPU. For object contour, this paper researches and implements the contour detection and drawing based on image space according to G-buffer technique. In order to mimic the hand drawing style, the contours are perturbed and multi-rendered. For interior shading, this paper rotates the pencil strokes texture according to the principal curvature directions and then maps to the object surfaces. This paper also blends paper texture and interior shading to implements the effect of interaction between paper and pencil in a stroke.At last, this paper presents the system architecture of real-time pencil sketch drawing and rendering process on GPU. The experimental results show that the pencil sketch rendering technique of this paper is feasible and effective.