GPU기반 실시간 굴절 물체 렌더링 방법
GPU based Real-Time Rendering method for refractive object
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참고문헌
초록
본 논문에서는 굴절(refractive) 물체의 광학적 현상들을 실시간으로 표현하는 GPU(Graphics Processing Unit) 기반 렌더링 알고리즘이 제안되었다. 일반적으로 굴절 물체에 대한 광학적 현상들을 렌더링할 때 포톤 매핑(Photon Mapping)이 널리 쓰이지만, 포톤 매핑 방법은 계산량이 많기 때문에 게임 등과 같은 실시간 응용분야에는 적합하지 않다. 본논문에서는 굴절 물체의 앞면, 뒷면의 깊이값의 차이와 굴절 레이(ray)를 이용해 탈출지점을 구하며, 탈출지점의 법선벡터를 근사하여 빛이 굴절 물체를 통과하면서 발생하는 커스틱스(caustics)현상과 굴절현상을 렌더링한다. 굴절 물체의반사(reflection) 현상은 프레넬 항(Fresnel term)을 근사(approximation)해서 효율적으로 표현하였다. 또한 HDRI(High Dynamic Range Image)로 환경맵을 구성하여 자연광이 굴절 물체를 통해 굴절되어 보이는 현상을 생성하였다.
Abstract
This paper presents a novel GPU based real-time rendering algorithm for lighting effects of refractive object. Although photon mapping method is widely used to generate reflection effects, it is unsuitable for real-time applications such as game owing to its high computational load. After computing an exit position of the refraction ray on the object with the difference of depth values of the front face and the back, we approximate the normal vector of the exit position and render the caustics effect and the refractions due to light participating the refractive object. In addition, reflection effects are generated efficiently using Fresnel term's approximation. In order to represent natural lights refracted through refractive object, we construct an environment map composed by HDRI (High Dynamic Range Image).
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