bevy_post_process/effect_stack/
chromatic_aberration.rs

1use bevy_asset::Handle;
2use bevy_camera::Camera;
3use bevy_ecs::{
4    component::Component,
5    query::{QueryItem, With},
6    reflect::ReflectComponent,
7    resource::Resource,
8    system::lifetimeless::Read,
9};
10use bevy_image::Image;
11use bevy_reflect::{std_traits::ReflectDefault, Reflect};
12use bevy_render::{
13    extract_component::ExtractComponent, render_resource::ShaderType, sync_component::SyncComponent,
14};
15
16/// The raw RGBA data for the default chromatic aberration gradient.
17///
18/// This consists of one red pixel, one green pixel, and one blue pixel, in that
19/// order.
20pub(super) static DEFAULT_CHROMATIC_ABERRATION_LUT_DATA: [u8; 12] =
21    [255, 0, 0, 255, 0, 255, 0, 255, 0, 0, 255, 255];
22
23#[derive(Resource)]
24pub(crate) struct DefaultChromaticAberrationLut(pub(crate) Handle<Image>);
25
26/// Adds colored fringes to the edges of objects in the scene.
27///
28/// [Chromatic aberration] simulates the effect when lenses fail to focus all
29/// colors of light toward a single point. It causes rainbow-colored streaks to
30/// appear, which are especially apparent on the edges of objects. Chromatic
31/// aberration is commonly used for collision effects, especially in horror
32/// games.
33///
34/// Bevy's implementation is based on that of *Inside* ([Gjøl & Svendsen 2016]).
35/// It's based on a customizable lookup texture, which allows for changing the
36/// color pattern. By default, the color pattern is simply a 3×1 pixel texture
37/// consisting of red, green, and blue, in that order, but you can change it to
38/// any image in order to achieve different effects.
39///
40/// [Chromatic aberration]: https://en.wikipedia.org/wiki/Chromatic_aberration
41///
42/// [Gjøl & Svendsen 2016]: https://github.com/playdeadgames/publications/blob/master/INSIDE/rendering_inside_gdc2016.pdf
43#[derive(Reflect, Component, Clone)]
44#[reflect(Component, Default, Clone)]
45pub struct ChromaticAberration {
46    /// The lookup texture that determines the color gradient.
47    ///
48    /// By default (if None), this is a 3×1 texel texture consisting of one red
49    /// pixel, one green pixel, and one blue texel, in that order. This
50    /// recreates the most typical chromatic aberration pattern. However, you
51    /// can change it to achieve different artistic effects.
52    ///
53    /// The texture is always sampled in its vertical center, so it should
54    /// ordinarily have a height of 1 texel.
55    pub color_lut: Option<Handle<Image>>,
56
57    /// The size of the streaks around the edges of objects, as a fraction of
58    /// the window size.
59    ///
60    /// The default value is 0.02.
61    pub intensity: f32,
62
63    /// A cap on the number of texture samples that will be performed.
64    ///
65    /// Higher values result in smoother-looking streaks but are slower.
66    ///
67    /// The default value is 8.
68    pub max_samples: u32,
69}
70
71impl Default for ChromaticAberration {
72    fn default() -> Self {
73        Self {
74            color_lut: None,
75            intensity: 0.02,
76            max_samples: 8,
77        }
78    }
79}
80
81impl SyncComponent for ChromaticAberration {
82    type Target = Self;
83}
84
85impl ExtractComponent for ChromaticAberration {
86    type QueryData = Read<ChromaticAberration>;
87    type QueryFilter = With<Camera>;
88    type Out = Self;
89
90    fn extract_component(
91        chromatic_aberration: QueryItem<'_, '_, Self::QueryData>,
92    ) -> Option<Self::Out> {
93        // Skip the postprocessing phase entirely if the intensity is negligible.
94        if chromatic_aberration.intensity > 1e-4 {
95            Some(chromatic_aberration.clone())
96        } else {
97            None
98        }
99    }
100}
101
102/// The on-GPU version of the [`ChromaticAberration`] settings.
103///
104/// See the documentation for [`ChromaticAberration`] for more information on
105/// each of these fields.
106#[derive(ShaderType, Default)]
107pub struct ChromaticAberrationUniform {
108    pub(super) intensity: f32,
109    pub(super) max_samples: u32,
110    pub(super) unused_1: u32,
111    pub(super) unused_2: u32,
112}
bevy_post_process/effect_stack/chromatic_aberration.rs

bevy_post_process/effect_stack/
chromatic_aberration.rs
