From a45d42c07af52cc19187fa656a33c2b6439638e8 Mon Sep 17 00:00:00 2001
From: xfy <i@rua.plus>
Date: Fri, 10 Jul 2026 10:20:38 +0800
Subject: [PATCH] feat: full-screen quad + BlackHoleMaterial pipeline

---
 assets/shaders/black_hole.wgsl | 11 +++++++++++
 src/main.rs                    |  7 ++-----
 src/render/material.rs         | 17 +++++++++++++++++
 src/render/mod.rs              |  4 ++++
 src/render/plugin.rs           | 33 +++++++++++++++++++++++++++++++++
 5 files changed, 67 insertions(+), 5 deletions(-)
 create mode 100644 assets/shaders/black_hole.wgsl
 create mode 100644 src/render/material.rs
 create mode 100644 src/render/mod.rs
 create mode 100644 src/render/plugin.rs

diff --git a/assets/shaders/black_hole.wgsl b/assets/shaders/black_hole.wgsl
new file mode 100644
index 0000000..b2897ea
--- /dev/null
+++ b/assets/shaders/black_hole.wgsl
@@ -0,0 +1,11 @@
+#import bevy_sprite::mesh2d_vertex_output::VertexOutput
+
+@group(#{MATERIAL_BIND_GROUP}) @binding(0) var<uniform> time: f32;
+
+@fragment
+fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
+    // Gradient from time, just to prove the uniform flows.
+    let t = (sin(time) + 1.0) * 0.5;
+    let col = mix(vec3<f32>(0.02, 0.02, 0.05), vec3<f32>(0.08, 0.04, 0.12), t);
+    return vec4<f32>(col, 1.0);
+}
diff --git a/src/main.rs b/src/main.rs
index c22d663..0f7cd96 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ use bevy::window::WindowPlugin;
 
 #[cfg(target_arch = "wasm32")]
 mod web;
+mod render;
 
 fn main() {
     // On web, abort startup if WebGPU isn't available and show a message.
@@ -24,10 +25,6 @@ fn main() {
             }),
             ..default()
         }))
-        .add_systems(Startup, setup)
+        .add_plugins(render::BlackHolePlugin)
         .run();
 }
-
-fn setup(mut commands: Commands) {
-    commands.spawn(Camera2d);
-}
diff --git a/src/render/material.rs b/src/render/material.rs
new file mode 100644
index 0000000..40b5d88
--- /dev/null
+++ b/src/render/material.rs
@@ -0,0 +1,17 @@
+use bevy::prelude::*;
+use bevy::reflect::TypePath;
+use bevy::render::render_resource::AsBindGroup;
+use bevy::shader::ShaderRef;
+use bevy::sprite_render::Material2d;
+
+#[derive(Asset, TypePath, AsBindGroup, Debug, Clone)]
+pub struct BlackHoleMaterial {
+    #[uniform(0)]
+    pub time: f32,
+}
+
+impl Material2d for BlackHoleMaterial {
+    fn fragment_shader() -> ShaderRef {
+        "shaders/black_hole.wgsl".into()
+    }
+}
diff --git a/src/render/mod.rs b/src/render/mod.rs
new file mode 100644
index 0000000..d6739ef
--- /dev/null
+++ b/src/render/mod.rs
@@ -0,0 +1,4 @@
+pub mod plugin;
+pub mod material;
+
+pub use plugin::BlackHolePlugin;
diff --git a/src/render/plugin.rs b/src/render/plugin.rs
new file mode 100644
index 0000000..44b1a27
--- /dev/null
+++ b/src/render/plugin.rs
@@ -0,0 +1,33 @@
+use bevy::prelude::*;
+use bevy::sprite_render::Material2dPlugin;
+
+use super::material::BlackHoleMaterial;
+
+pub struct BlackHolePlugin;
+
+impl Plugin for BlackHolePlugin {
+    fn build(&self, app: &mut App) {
+        app.add_plugins(Material2dPlugin::<BlackHoleMaterial>::default())
+            .add_systems(Startup, spawn_fullscreen_quad)
+            .add_systems(Update, update_time);
+    }
+}
+
+fn spawn_fullscreen_quad(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<BlackHoleMaterial>>,
+) {
+    commands.spawn(Camera2d);
+    commands.spawn((
+        Mesh2d(meshes.add(Rectangle::new(2.0, 2.0))),
+        MeshMaterial2d(materials.add(BlackHoleMaterial { time: 0.0 })),
+        Transform::default(),
+    ));
+}
+
+fn update_time(time: Res<Time>, mut materials: ResMut<Assets<BlackHoleMaterial>>) {
+    for (_, mat) in materials.iter_mut() {
+        mat.time = time.elapsed_secs();
+    }
+}