Real-time Rendering Of Various Hairstyles

At present, virtual characters created by computers are widely used in movies, games and advertisements. Hair rendering has significant effects on rendering realistic human body. Hair styling and its real-time rendering have been very challenging problems in the area of computer graphics. Recently, fast development of programmable graphics hardware makes it possible to render various hairstyles in real-time.Based on current programmable graphics hardware, this thesis proposes a real-time algorithm to render human hair in multiple styles. Hair represented by surface is easy to model and friendly to hardware accelerated rendering, thus surface model was used to represent human hair. However, surface representation has limited support for hair styling. To overcome that, "Hair Style Function (HSF)" was proposed. HSF could help to simplify modeling procedure, reduce memory space required for storing complex hair model and increase rendering speed. HSF was considered as the most important contribution of this thesis.Besides, a luminance map and an alpha map were applied to a hair surface to represent complex hair distribution; Kajiya-Kay's classic hair lighting model [23] was used to compute anisotropic lighting of hair; an efficient self-shadow simulation method was introduced for self-shadowing and shadow volume [35] technique was used for globally shadowing.Most part of this algorithm was implemented in vertex shader and pixel shader of Graphics Process Unit (GPU) by using Microsoft Direct3D and HLSL (High-Level Shader Language). Experimental results show that our algorithm can achieve real-time rendering of various hairstyles in high quality on medium-end graphics hardware.