Acta Scientiarum Naturalium Universitatis Pekinensis ›› 2022, Vol. 58 ›› Issue (1): 113-122.DOI: 10.13209/j.0479-8023.2021.051

Previous Articles     Next Articles

Research on Key Techniques of Smoothing Transition of LOD Texture Blending and Antialiasing Based on Shader

JIANG Zhan1, LI Mei1,†, SUN Zhenming2, MAO Shanjun1   

  1. 1. Institute of Remote Sensing and Geographical Information System, Peking University, Beijing 100871 2. School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083
  • Received:2021-01-25 Revised:2021-03-26 Online:2022-01-20 Published:2022-01-20
  • Contact: LI Mei, E-mail: mli(at)pku.edu.cn

基于着色器的LOD纹理混合与反走样平滑过渡关键技术研究

姜展1, 李梅1,†, 孙振明2, 毛善君1   

  1. 1. 北京大学遥感与地理信息系统研究所, 北京 100871 2. 中国矿业大学(北京)能源与矿业学院, 北京 100083
  • 通讯作者: 李梅, E-mail: mli(at)pku.edu.cn
  • 基金资助:
    国家自然科学基金(51774281)和国家重点研发计划(2016YFC0803108)资助

Abstract:

Aiming at the problem of LOD (level of detail) popping and aliasing when the LOD Level is switched, this paper proposes a shader-based smooth transition algorithm for LOD texture blending and antialiasing. According to the distance between the 3D model and the viewpoint, the opaque mask algorithm based on Alpha test and weighted adjacent frames antialiasing algorithm are used to generate transition materials between LODs to achieve smooth transition for LOD switching. It can not only improve the texture quality, but also ensure the fluency and authenticity of loading 3D scene. The experimental results show that, compared with the smoothing method of Unreal Engine 4, the average GPU time of the proposed algorithm is reduced by more than 8%, and the frame rate is increased by more than 8%. Compared with the existing texture smooth transition methods, this algorithm can optimize the GPU rendering performance, stabilize and improve the frame rate and maintain good visual effect, effectively solve the popping problem when the LOD Level is switched.

Key words: popping, smooth transition of LOD, Alpha test, geometric antialiasing, shading antialiasing, temporal anti-aliasing (TAA)

摘要:

针对场景切换时产生的LOD (level of detail)纹理突变和走样问题, 提出一种基于着色器的LOD纹理混合与反走样平滑过渡算法。该算法根据三维模型和视点的距离, 运用基于Alpha测试的不透明蒙版算法和加权邻帧反走样算法, 在LOD间生成过渡材质, 实现三维模型LOD切换的平滑过渡, 不仅能够改善纹理质量, 而且能够保证三维场景加载的流畅性与真实性。实验结果表明, 与Unreal Engine 4 (UE4)自带的平滑算法相比, 算法的GPU平均耗时减少8%以上, 帧率提高 8%以上。与现有纹理平滑过渡方法相比, 该算法能够优化GPU渲染性能, 稳定并提高画面帧率, 保持良好的视觉效果, 有效地解决LOD层级切换时的突变问题。

关键词: 纹理突变, LOD平滑过渡, Alpha测试, 几何走样, 着色走样, 时间反走样(TAA)