Implementing simple ray-traced shadows
As we mentioned in the introduction, shadow mapping techniques have been a staple of real-time rendering for many years. Before the introduction of ray tracing capabilities in GPUs, using other techniques was simply too expensive.
This hasn’t prevented the graphics community from coming up with clever solutions to increase the quality of results while maintaining a low cost. The main issue with traditional techniques is that they are based on capturing depth buffers from the point of view of each light. This works well for objects that are near the light and camera, but as we move further away, depth discontinuities lead to artefacts in the final result.
Solutions to this problem include filtering the result – for instance, using Percentage Closer Filtering (PCF) or Cascade Shadow Maps (CSM). This technique requires capturing multiple depth slices – the cascades to maintain enough resolution as we move further away from...
