Photon Mapping
Photon mapping is a global illumination algorithm in computer graphics that simulates realistic lighting effects, such as caustics, color bleeding, and soft shadows, by tracing photons from light sources and storing them in a spatial data structure called a photon map. It is a two-pass technique where the first pass emits photons from lights and records their interactions with surfaces, and the second pass uses this data during rendering to compute indirect illumination efficiently. This method is particularly effective for handling complex light transport phenomena that are challenging for other rendering techniques.
Developers should learn photon mapping when working on applications requiring photorealistic rendering, such as architectural visualization, film production, or video games with advanced graphics, as it provides accurate simulations of light behavior in scenes with reflective or refractive materials. It is especially useful for rendering caustics (e.g., light focusing through glass or water) and diffuse interreflections, making it a key tool in ray tracing and path tracing pipelines for achieving high visual fidelity. However, it can be computationally intensive, so it's best applied in offline rendering contexts or with optimizations for real-time use.