High-Performance Occlusion Culling in Large-Scale WebGL Scenes

Rendering complex architectural models or expansive interactive CAD environments in the browser suffers when hidden objects are rasterized. Implementing hardware-accelerated occlusion culling ensures only visible geometry enters the graphics pipeline.

1. Frustum Culling vs. Hardware Occlusion Queries

While CPU-based frustum culling removes objects outside the camera field of view, hardware occlusion queries ask the GPU if any pixels of an object bounding box pass the depth test before issuing draw calls for detailed meshes.

2. Hierarchical Z-Buffer (HZB) Culling on GPU

Generating a mipmapped depth pyramid from the previous frame allows compute shaders to test bounding boxes against low-resolution depth textures, discarding occluded geometry in a single dispatch pass.

3. Spatial Partitioning with Dynamic BVH

Organizing scene objects into spatial Bounding Volume Hierarchies minimizes the number of visibility tests required per frame, enabling smooth 60 FPS rendering of dense industrial models.