# glassBackgroundEffect(in:displayMode:) Fills the view’s background with an automatic glass background effect and a shape that you specify. ``` nonisolated func glassBackgroundEffect(in shape: S, displayMode: GlassBackgroundDisplayMode = .always) -> some View where S : InsettableShape ``` ## Parameters `shape` An [`InsettableShape`](/documentation/SwiftUI/InsettableShape) instance that SwiftUI draws behind the view. `displayMode` When to display the glass background. The default is [`GlassBackgroundDisplayMode.always`](/documentation/SwiftUI/GlassBackgroundDisplayMode/always). ## Return Value A view with a glass background. ## Discussion Use this modifier to add a 3D glass background material that includes thickness, specularity, glass blur, shadows, and other effects. Because of its physical depth, the glass background influences z-axis layout. To ensure that the effect renders properly when you add it to a collection of views in a [`ZStack`](/documentation/SwiftUI/ZStack), add the modifier to the stack rather to one of the views in the stack. This includes when you create an implicit stack with view modifiers like [`overlay(alignment:content:)`](/documentation/SwiftUI/View/overlay(alignment:content:)) or [`background(alignment:content:)`](/documentation/SwiftUI/View/background(alignment:content:)). In those cases, you might need to create an explicit [`ZStack`](/documentation/SwiftUI/ZStack) inside the `content` closure to have a place to add the glass background modifier. Non closed shapes will be rendered as their convex hull. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)