Using the Debug Overlays in LambDynamicLights for Minecraft

guide

LambDynamicLights includes a set of debug overlays that draw extra information directly in the world, which helps when you need to see what the dynamic lighting engine is doing. These overlays cover active lighting cells, behavior bounding boxes, chunk rebuilds, and light level radius. They are meant for diagnosing lighting problems, so expect them to be noisy and not something you leave on during normal play.

Where the Debug Options Live

The debug overlays are grouped together in the mod's settings. Each one is a toggle you can switch on or off independently, and each has a short tooltip explaining what it draws. Because they render in the world rather than in a menu, you will see the results immediately as you move around.

Active Dynamic Lighting Cells

Show Active Dynamic Lighting Cells draws every cell that the dynamic lighting engine currently considers active. The tooltip describes it as showing, in the world, all cells that are presently active in the engine. Turning this on is useful when you want to confirm which parts of the scene the engine is actually tracking at a given moment.

Display Radius of Dynamic Lighting Cells controls how far out those cell markers are shown. Increasing the radius lets you inspect cells further from your position; decreasing it keeps the view focused on what is nearby.

Behavior Bounding Boxes

Display Dynamic Light Behavior Bounding Box draws the bounding box of dynamic light behaviors in the world. The tooltip states that it shows the bounding box of dynamic light behaviors. This is handy when a light source is not behaving as expected and you want to see the region the behavior occupies.

Chunk Rebuilds

Display Dynamic Lighting Chunk Rebuilds shows every chunk rebuild that dynamic lighting updates cause. The tooltip says it displays, in the world, all chunk rebuilds triggered by dynamic lighting updates. Use this when you suspect lighting changes are forcing frequent rebuilds and want to see where they happen.

Light Level Radius

Display Radius of Dynamic Light Level sets how far the light level display extends. Adjust it to widen or narrow the area over which light levels are shown.

Several other options affect what the debug views will reveal, so they are worth checking while troubleshooting.

Toggle First-Person Lighting switches first-person dynamic lighting on or off. A note in the mod warns that you should disable this if you use shaders that already provide their own dynamic lighting.
Self Light Source enables first-person dynamic lighting, with the same recommendation to turn it off when a shader handles dynamic lighting itself.
Water Sensitivity Check enables a check for water-sensitive light sources, meaning some items stop emitting light while underwater.
Creeper Lighting and TNT Lighting each set the dynamic lighting mode for those entities: off, a constant luminance, or a dynamic luminance.
Entity and block entity dynamic lighting can each be enabled or disabled. Entity lighting is always active for players. A note advises disabling entities dynamic lighting when using Canvas, and another warns that dynamic lighting with Canvas is currently performance heavy.
Special Dynamic Light Sources covers beams from Beacons or End Gateways, firefly particles from Firefly Bushes, entities with the Glowing effect, Guardian lasers, and the Warden's sonic boom attack particles.

Operating the Overlays

Switch any overlay on or off through its toggle in the settings. If a control is bound to a hotkey rather than a menu entry, use the corresponding hotkey and set it in the controls menu. Debug overlays are diagnostic tools, so enable only the ones you need, check the behavior you are investigating, then turn them back off.