bevy_fast_light 0.7.1

/*
 * File: light.rs
 * Author: Leopold Johannes Meinel (leo@meinel.dev)
 * -----
 * Copyright (c) 2026 Leopold Johannes Meinel & contributors
 * SPDX ID: Apache-2.0
 * URL: https://www.apache.org/licenses/LICENSE-2.0
 */

//! Different light types and modules for rendering.
//!
//! This first renders a light map to a scalable texture and then composes this to the screen texture.
//!
//! This is the third and fourth render stage of [`FastLightPlugin`](crate::prelude::FastLightPlugin).

mod extract;
mod node;
mod pipeline;
mod plugin;
mod prepare;

pub(super) mod prelude {
    pub(super) use super::extract::{
        ExtractedAmbientLight2d, ExtractedLight2dMeta, ExtractedPointLight2d,
    };
    pub(super) use super::node::{Light2dCompositeNode, Light2dNode};
    pub(super) use super::pipeline::{Light2dCompositePipeline, Light2dPipeline};
    pub(crate) use super::plugin::{Light2dCompositeLabel, Light2dLabel, Light2dPlugin};
    pub(super) use super::prepare::Light2dTextures;
    pub(crate) use super::{AmbientLight2d, PointLight2d};
}

use bevy::{
    camera::{
        primitives::Aabb,
        visibility::{Visibility, VisibilityClass, add_visibility_class},
    },
    color::Color,
    ecs::component::Component,
    math::Vec3A,
    reflect::Reflect,
    render::sync_world::SyncToRenderWorld,
    transform::components::Transform,
};

/// Ambient light for fullscreen lighting in a 2D environment.
///
/// This is meant to be added to a [`Camera2d`](bevy::camera::Camera2d).
///
/// ## Formula
///
/// color = src_color * ([`AmbientLight2d::color`] * [`AmbientLight2d::intensity`] + light_color).
///
/// ## Note
///
/// Only a single [`AmbientLight2d`] should ever exist, otherwise extraction will be skipped.
#[derive(Component, Reflect, Clone, Copy)]
#[require(SyncToRenderWorld)]
pub struct AmbientLight2d {
    /// The [`Color`] of the light.
    pub color: Color,
    /// The intensity of the light.
    pub intensity: f32,
}
impl Default for AmbientLight2d {
    /// This is visually the same as without [`AmbientLight2d`].
    fn default() -> Self {
        Self {
            color: Color::WHITE,
            intensity: 1.,
        }
    }
}

/// Point light for area lighting in a 2D environment.
///
/// ## Formula
///
/// color = src_color * (ambient_color + [`PointLight2d::color`] * [`PointLight2d::intensity`] * attenuation).
///
/// ## Note
///
/// attenuation is influenced by [`PointLight2d::inner_radius`] and [`PointLight2d::outer_radius`].
#[derive(Component, Reflect, Clone, Copy)]
#[require(SyncToRenderWorld, Transform, Visibility, VisibilityClass)]
#[component(on_add = add_visibility_class::<Self>)]
pub struct PointLight2d {
    /// The [`Color`] of the light.
    pub color: Color,
    /// The intensity of the light.
    pub intensity: f32,
    /// The inner radius of the light.
    ///
    /// `attenuation` is always 1 (actually it is disregarded entirely).
    pub inner_radius: f32,
    /// The outer radius of the light.
    ///
    /// `attenuation` starts at 1 and then decreases smoothly if outside of [`PointLight2d::inner_radius`] until it reaches 0.
    pub outer_radius: f32,
}
impl PointLight2d {
    fn aabb(&self) -> Aabb {
        Aabb {
            center: Vec3A::ZERO,
            half_extents: Vec3A::new(self.outer_radius, self.outer_radius, 0.),
        }
    }
}
impl Default for PointLight2d {
    fn default() -> Self {
        Self {
            color: Color::WHITE,
            intensity: 1.,
            inner_radius: 0.,
            outer_radius: 64.,
        }
    }
}