GPUDrivenForwardPlus

GPUDrivenForwardPlus is a GPU-driven clustered forward lighting system for Unity URP,

designed specifically for scenes that require more than the default per-camera visible light budget.

URP’s built-in Forward+ pipeline is optimized around a fixed per-camera visible light limit,

which works well for many projects but becomes a constraint in light-dense scenes.

GPUDrivenForwardPlus is built with a different design goal: enabling a single camera

to reliably process up to 64 additional lights with fully deterministic GPU behavior.

This is achieved by assigning lights to view-space clusters on the GPU.

Each Cluster AABB is strictly limited to a maximum of 8 additional lights, ensuring

that every pixel evaluates only a small, fixed number of lights.

As a result:

• A single camera can handle up to 64 additional lights
• Shading cost is strictly bounded per cluster (max 8 lights)
• Lighting cost becomes independent of object count
• Lighting cost becomes independent of draw call count
• Performance remains predictable and stable on mobile GPUs

The system uses a forward lighting pipeline (not deferred) and is compatible with

URP Lit and SimpleLit workflows. A minimal custom Forward+ shader example is included for extension and integration.