Optimize lighting in the Built-In Render Pipeline

To optimize the lights in your scene, avoid Unity using multiple render passes to render GameObjects, or doing too much work to render lighting. This reduces the number of the draw calls the CPU sends, and the number of vertices and pixels the GPU processes.

Do the following:

• Use lightmapping to light static objects, instead of realtime lights.
• Avoid combining meshes if they’re lit by different realtime per-pixel lights, because Unity calculates every light for every combined mesh.
• Avoid lighting GameObjects with multiple per-pixel lights.

Prioritize lights

To avoid lighting GameObjects with multiple per-pixel lights, prioritize which lights provide per-pixel lighting based on which GameObjects they light.

For example, in a driving game, prioritize the car headlights as a per-pixel light, but deprioritize the rear lights and distant lampposts.

To decrease the number of per-pixel lights, do any of the following:

• In the Light component Inspector window, set Render Mode to Not important. This sets the light as a per-vertex light or spherical harmonics (SH) light.
• In the Quality settings window, decrease Pixel Light Count. This excludes lights from the per-pixel light group.

To increase the number of per-pixel lights, do any of the following:

• In the Light component Inspector window, increase the Intensity. The brightest light is always a per-pixel light.
• In the Light component Inspector window, set Render Mode to Important. This sets the light as a per-pixel light.
• In the Quality settings window, increase Pixel Light Count. This includes more lights in the per-pixel light group.

Disable per-vertex and spherical harmonics (SH) lights

To disable per-vertex and SH lights in a custom shader, add the OnlyDirectional tag to the Pass in your ShaderLab code. For more information, refer to Pass tags in ShaderLab reference.

Additional resources

• Per-vertex and per-pixel lights
• Per-vertex and per-pixel lights in the Built-In Render Pipeline