Efficient direct lighting calculations for area lights with light portals
J. Romeu Huidobro (TU Delft - Electrical Engineering, Mathematics and Computer Science)
M. van de Ruit – Mentor (TU Delft - Computer Graphics and Visualisation)
E. Eisemann – Mentor (TU Delft - Computer Graphics and Visualisation)
C.M. Jonker – Graduation committee member (TU Delft - Interactive Intelligence)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Direct lighting calculation is an essential part of photorealistic rendering. Standard importance sampling techniques converge slowly in scenes where a light source is only visible through small openings as visibility is not considered. This problem is often addressed by manually placing light portals, marking the openings to the light. However, existing portal sampling techniques are not suitable for area lights since the portal is often times larger than the light itself. We present a novel portal sampling technique inspired by shadow volumes, which considers the light geometry to efficiently choose the optimal sampling strategy, depending on the location of the shading point. Our technique is unbiased, robust, applicable to many scenes, and easy to integrate into an existing renderer.