Creating light probes for global illumination rendering of 3D scenes via two-stage search

The traditional Monte Carlo rendering method accurately renders 3D scenes but suffers from slow rendering speeds, limiting its suitability for high frame rate applications. Light probes offer a solution for achieving higher frame rates, but this method hardly simulates the accurate direction of light transmission. To address this, we made a virtual point lights(VPLs) irradiance map and created a two-stage search algorithm so that the light probes can simulate the correct light transmission direction. Firstly, we made a VPLs irradiance texture map through VPLs sampling. Then, using a two-stage search method, light probes obtain the irradiance value of the target point, the point where the light emitted from the small sphere of the light probe intersects the scene. Finally, each shading point utilizes nearby 8 light probes to calculate the irradiance value. Experiments show that our method achieves higher frame rates while maintaining good image quality.