Lighting and shadows play a crucial role in enhancing realism and immersion in WebXR applications. Three.js offers various lighting methods, but achieving high-quality visuals while maintaining performance requires optimization techniques.
Key Techniques for Shadows and Lighting in Three.js
- Shadow Mapping in Three.js
- Three.js provides shadow mapping techniques, including:
- BasicShadowMap – Fast but lacks soft shadows.
- PCFShadowMap (Percentage Closer Filtering) – Produces smoother shadows by blending samples.
- PCFSoftShadowMap – A more refined version of PCF for softer shadows.
- VSM (Variance Shadow Map) – Reduces shadow acne and improves shadow blur but requires more GPU memory.
- Real-Time Global Illumination
- Use light probes and baked lightmaps to simulate indirect lighting and reflections.
- Apply Screen Space Global Illumination (SSGI) for approximating real-world light behavior in real-time.
- Physically Based Rendering (PBR)
- Three.js supports PBR via the MeshStandardMaterial and MeshPhysicalMaterial shaders.
- Use HDR (High Dynamic Range) environments to enhance lighting realism.
- Combine Image-Based Lighting (IBL) with reflection maps for improved realism.
- Optimized Dynamic Lights
- Use directional light cascades for smoother outdoor lighting in VR.
- Reduce the number of active lights by dynamically enabling/disabling them based on user position.
- Precompute light data where possible and use baked lighting for static objects.
Use Cases in WebXR
- Day-Night Cycles in VR – Simulating natural lighting transitions for open-world VR experiences.
- Performance-Optimized Indoor Lighting – Combining baked lighting with dynamic shadows for realistic room illumination.
- Immersive Horror or Sci-Fi Environments – Using advanced shadow techniques for atmospheric effects like flickering lights.