SBR Shooting and Bouncing Ray

SBR (Shooting and Bouncing Ray) is a technique used in computer graphics, specifically in rendering algorithms, to simulate the behavior of light as it interacts with surfaces in a virtual scene. It is a global illumination method that aims to capture indirect lighting effects, such as diffuse inter-reflections and color bleeding.

The SBR algorithm works by tracing rays of light from the light sources in the scene and simulating their interaction with the surfaces. These rays are called shooting rays. When a shooting ray hits a surface, it can generate one or more bouncing rays, which represent the light that is reflected or scattered off the surface.

The shooting rays are typically traced from the light sources toward the surfaces in the scene. When a shooting ray intersects with a surface, the algorithm determines the reflective and refractive properties of the surface to calculate the amount of light that is reflected and transmitted. The reflected light contributes to the indirect illumination in the scene.

Bouncing rays are generated when a shooting ray hits a surface. These rays are traced in a direction determined by the reflective or scattering properties of the surface. Bouncing rays continue to propagate through the scene until they either reach the maximum allowed number of bounces or are absorbed by a surface. Each time a bouncing ray hits a surface, it can generate additional bouncing rays, simulating the multiple reflections and scattering of light within the scene.

The SBR algorithm collects the contribution of each bouncing ray at the surface where it originated and accumulates it to compute the indirect illumination. The process is repeated for each shooting ray, and the accumulated contributions are combined with the direct illumination from the light sources to produce the final image.

SBR can produce high-quality renderings with realistic lighting effects, but it can be computationally expensive due to the large number of rays that need to be traced and the multiple bounces that need to be simulated. Various optimizations and acceleration techniques, such as spatial data structures (e.g., bounding volume hierarchies or octrees) and importance sampling, are often employed to make the algorithm more efficient.

Overall, SBR is a powerful technique for simulating global illumination in computer graphics, allowing for the accurate representation of indirect lighting effects and enhancing the realism of rendered images.