ARPΔ : Accelerated ray-tracing photon differentials for real-time global illumination with combined specular and diffuse solutions

Abstract

This study introduces ARP , a novel photon mapping approach that employs photon differentials to achieve realtime global illumination on ray-tracing hardware. ARP dynamically adjusts photon bandwidth by adapting each photon’s footprint according to trajectory and interaction specifics, providing high-quality caustic and diffuse lighting with reduced photon count. The methodology integrates clamped adaptation and bounding box optimisations to manage photon footprints effectively, enhancing detail accuracy while maintaining high frame rates. Experimental results demonstrate ARPΔ’s competitive performance against established techniques, excelling in complex, caustic-rich scenes and achieving closer convergence to ground truth for near-field and detail shots. This work advances photon differential techniques, offering a ray-tracing hardware-compatible solution for real-time applications that balances computational efficiency with photorealistic illumination fidelity.