Journal of the Korea Computer Graphics Society (한국컴퓨터그래픽스학회논문지)

Korea Computer Graphics Society (한국컴퓨터그래픽스학회)
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A Soft Shadow Technique for a Real-time Mobile Ray Tracing Hardware

실시간 모바일 레이트레이싱 하드웨어를 위한 소프트 쉐도우 생성 기법

  • Kwon, Hyuck-Joo (Department of Electrical and Electronic Engineering, Yonsei University) ;
  • Hong, Dukki (Department of Computer Engineering, Sejong University) ;
  • Park, Woo-Chan (Department of Computer Engineering, Sejong University) ;
  • Lee, Sanghoon (Department of Electrical and Electronic Engineering, Yonsei University)
  • 권혁주 (연세대학교 전기전자공학과) ;
  • 홍덕기 (세종대학교 컴퓨터공학과) ;
  • 박우찬 (세종대학교 컴퓨터공학과) ;
  • 이상훈 (연세대학교 전기전자공학과)
  • Received : 2017.06.24
  • Accepted : 2017.07.06
  • Published : 2017.07.14
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Abstract

In this paper, a novel soft shadow method is suggested to support realistic shadows in mobile ray tracing. In ray tracing, soft shadow is generally generated by sampling a shadow ray. As this sampling method increases the number of rays to be processed, it has undermined the performance. We designed the proposed soft shadow processing method and hardware architecture to overcome this problem through selective shadow generation and triangle address caching for minimizing the performance degradation caused by sampling. The proposed hardware architecture can be integrated into a mobile ray-tracing hardware and was evaluated in terms of its performance on the FPGA. Based on the results, the rendering performance about 4, 8, and 16 samples were improved, respectively, by 40%, 50%, and 56% on average compared to the previous method, and it was found that the real-time soft shadow processing is feasible with the proposed hardware architecture.

본 논문에서는 실시간 모바일 레이트레이싱에서 사실적인 그림자를 생성하기 위한 새로운 그림자 생성 기법을 제시한다. 일반적으로 레이트레이싱에서는 그림자 광선을 샘플링 하여 부드러운 그림자를 생성한다. 지금까지 이런 생성 방법은 처리해야 할 광선의 수를 증가시키기 때문에 성능 저하의 요인이 되어왔다. 제안하는 소프트 쉐도우 생성 기법과 하드웨어 구조는 선택적 그림자 생성과 삼각형 주소 캐싱을 통해 샘플링에 의한 성능 저하를 최소화시킴으로써 이런 문제를 해결하였다. 제안된 하드웨어 구조는 모바일 레이트레이싱 하드웨어에 통합 가능한 수준이며, FPGA상에서 성능 평가 되었다. 평가 결과 제안된 기법의 성능은 4, 8, 그리고 16 샘플에 대해서 이전 기법 대비 평균 40%, 50% 그리고 56% 수준으로 향상 되었으며, 우리는 제안된 하드웨어 구조를 통해 실시간으로 소프트 쉐도우를 생성할 수 있음을 확인하였다.

Keywords

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