diff --git a/agb/src/display/blend.rs b/agb/src/display/blend.rs index 68848dcb..5275242b 100644 --- a/agb/src/display/blend.rs +++ b/agb/src/display/blend.rs @@ -49,6 +49,47 @@ pub struct Blend { fade_weight: u16, } +/// When making many modifications to a layer, it is convenient to operate on +/// that layer directly. This is created by the [Blend::layer] function and +/// operates on that layer. +pub struct BlendLayer<'blend> { + blend: &'blend mut Blend, + layer: Layer, +} + +impl BlendLayer<'_> { + /// Set whether a background is enabled for blending on this layer. + pub fn set_background_enable(&mut self, background: BackgroundID, enable: bool) -> &mut Self { + self.blend + .set_background_enable(self.layer, background, enable); + + self + } + + /// Set whether objects are enabled for blending on this layer. + pub fn set_object_enable(&mut self, enable: bool) -> &mut Self { + self.blend.set_object_enable(self.layer, enable); + + self + } + + /// Set whether the backdrop contributes to the blend on this layer. + /// The backdrop is transparent colour, the colour rendered when nothing is + /// in it's place. + pub fn set_backdrop_enable(&mut self, enable: bool) -> &mut Self { + self.blend.set_backdrop_enable(self.layer, enable); + + self + } + + /// Set the weight for the blend on this layer. + pub fn set_blend_weight(&mut self, value: Num) -> &mut Self { + self.blend.set_blend_weight(self.layer, value); + + self + } +} + const BLEND_CONTROL: *mut u16 = 0x0400_0050 as *mut _; const BLEND_ALPHAS: *mut u16 = 0x0400_0052 as *mut _; @@ -93,6 +134,13 @@ impl Blend { self.reset_targets().reset_fades().reset_weights() } + /// Creates a layer object whose functions work only on that layer, + /// convenient when performing multiple operations on that layer without the + /// need of specifying the layer every time. + pub fn layer(&mut self, layer: Layer) -> BlendLayer { + BlendLayer { blend: self, layer } + } + /// Set whether a background is enabled for blending on a particular layer. pub fn set_background_enable( &mut self,