debug_frustum

The "frustum" provider for @builtin::modules.debugViz: appends one cyan wireframe frustum per scene Camera into the shared debug-visualization batch, every edit-mode tick.

debugViz.registerProvider("frustum", require("@builtin::modules.debug_frustum").tick)

DebugViz.component registers this provider automatically — attach it to one entity to draw every enabled camera's view frustum alongside whatever other providers are registered.

How it works

tick(emit) queries every entity carrying a Camera and, for each enabled one, builds its 8 near/far corners in the camera's local space:

• half-height at a given distance is tan(fov / 2) * distance; half-width is half-height * aspect.
• the camera looks down its local -Z axis (entity(id).transform.forward is documented as "local -Z axis in world space"), so the near/far planes sit at local z = -near / z = -far.
• each corner is position + forward * dist + right * (±halfWidth) + up * (±halfHeight), using the entity's world position and world-space forward/right/up axes — no separate quaternion math needed.

Camera has no aspect field, so the aspect ratio is read live from getViewportSize() (the window's real aspect, matching what the viewport camera sees), falling back to a 16:9 default if the viewport size isn't readable. The 12 edges (4 near, 4 far, 4 connecting) are appended via emit.line.

API

• debug_frustum.tick(emit) — append one wireframe frustum per enabled scene camera into the shared batch.