# Objective
fix crash / misbehaviour when `DeferredPrepass` is used without
`DepthPrepass`.
- Deferred lighting requires the depth prepass texture to be present, so
that the depth texture is available for binding. without it the deferred
lighting pass will use 0 for depth of all meshes.
- When `DeferredPrepass` is used without other prepass markers, and with
any materials that use `OpaqueRenderMode::Forward`, those entities will
try to queue to the `Opaque3dPrepass` render phase, which doesn't exist,
causing a crash.
## Solution
- check if the prepass phases exist before queueing
- generate prepass textures if `Opaque3dDeferred` is present
- add a note to the DeferredPrepass marker to note that DepthPrepass is
also required by the default deferred lighting pass
- also changed some `With<T>.is_some()`s to `Has<T>`s