Overview
Clustered Shading extends tiled light culling by slicing depth, producing smaller 3D regions with more accurate light lists.
SpecializedSource checked
Clustered Shading
Groups screen space and depth into clusters so lights are culled in three dimensions.
Quick Facts
Compact metadata for implementation and discovery.
- Category
- Rendering
- Difficulty
- Advanced
- Family
- GPU Rendering Optimization
- Tier
- Specialized
- Status
- Verified
- Review
- Source Checked
- Sources
- 1
- Formulas
- 1
- Relationships
- 4
- Code example
- Ready
- Visualization
- Ready
Core Concepts
view-space clusterdepth slicelight assignmentlocal light list
Quick facts
Complexity
Runtime and memory behavior at a glance.
Best
O(clusters + lights)
Average
O(clusters * lights + shaded pixels)
Worst
O(clusters * lights + shaded pixels)
Space
O(cluster light lists)
When to Use
- Use when tiled rendering includes too many irrelevant lights because depth varies strongly.
- Use when dense real-time lighting is a central requirement.
When Not to Use
- Avoid when the added cluster setup cost outweighs saved shading work.
- Avoid when the renderer cannot provide the buffers, samples, or lighting data the technique needs.
What It Does
- Partitions view space into clusters
- Assigns lights to 3D clusters
- Shades pixels with cluster-local lights
Use Cases
- Dense real-time lighting
- Forward-plus renderers
- VR scenes with depth variation
Inputs
- Camera frustum
- Depth slices
- Light bounds
Outputs
- Per-cluster light lists
Key Formulas (1)
Cluster index
cluster = tilex + tiley · tilesx + depthslice · tilesx · tilesy
cluster = tile_x + tile_y * tiles_x + depth_slice * tiles_x * tiles_yMaps a pixel tile and depth slice to a cluster light list.
Pseudocode
- 1.Divide the view frustum into screen tiles and depth slices
- 2.Build cluster bounds
- 3.Assign each light to intersecting clusters
- 4.During shading, find the pixel's cluster
- 5.Loop only over that cluster's lights
Canonical Example
- Input
- pixel depth = far slice, screen tile = (3, 2)
- Output
- cluster lights = far lights in that tile
- Explanation
- The pixel ignores near lights that overlap the same screen tile but not its depth slice.
Implementation Notes
- Debug cluster indices with false-color views before checking lighting.
- Debug with simple geometry, known lights, and visualized intermediate buffers.
- Keep a tiny example with expected output beside the implementation.
Common Pitfalls
- Incorrect depth-slice mapping can assign pixels to the wrong light lists.
- Coordinate-space mismatches often cause artifacts that look like math errors.
- Not defining boundary, empty, or degenerate inputs before implementation.
Interactive Mechanism Walkthrough
Spatial Primitive & Sweep-Line CanvasShow a camera frustum cut into 3D clusters, each with its own light list.
Step 1 of 5: Divide the view frustum into screen tiles and depth slices
rendering-pipelineNotes
Depth slicing improves culling for scenes with lights at different distances.
Sources (1)
What each reference supports for this entry.
Clustered Deferred and Forward Shading
PaperEurographics/HPG paper introducing clustered shading for light assignment.
Open sourceExplore Next
Good next jumps from the relationship graph, ranked for useful discovery.
Relationships
View full relationship pageAlternative toDeferred Shading
Clustered shading can keep forward-rendering material flexibility.
Improves onTiled Rendering
Clustered shading extends tiled ideas into 3D clusters.
Related Algorithms
Tags
GraphicsShadingScreen-SpaceOptimization