ReadonlyrendererReadonlycameraReadonlysceneReadonlyboundsReadonlybufferPre-allocated Vector2 receiver for getDrawingBufferSize.
Borrow contract: This Vector2 is owned by SceneManager (a single
shared instance) and is mutated on every camera-materials update.
Downstream consumers MUST treat it as read-only and scoped to the
current call. To retain the value across frames, .copy() it into
private storage — never store the reference itself, or a subsequent
resize will silently mutate your "saved" value.
Ctx supplied by SceneManager. The materials helpers read these refs but never mutate the host class.
_bufferSizeis a pre-allocated Vector2 owned by SceneManager so resize callbacks don't allocate on every frame.