docs: Add bloom example

examples/bloom.rs

@@ -0,0 +1,51 @@
+//! This example shows that bevy_smud works with bloom enabled
+//!
+//! Note that you could probably achieve chieper and higher quality bloom-like
+//! effects by creating a custom fill.
+
+use bevy::{core_pipeline::bloom::BloomSettings, prelude::*};
+// The prelude contains the basic things needed to create shapes
+use bevy_smud::prelude::*;
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins)
+        .add_plugin(SmudPlugin)
+        .add_startup_system(setup)
+        .run();
+}
+
+fn setup(mut commands: Commands, mut shaders: ResMut<Assets<Shader>>) {
+    // add_sdf_expr expects a wgsl expression
+    // p is the position of a fragment within the sdf shape, with 0, 0 at the center.
+    // Here we are using the built-in sd_circle function, which accepts the
+    // radius as a parameter.
+    let circle = shaders.add_sdf_expr("sd_circle(p, 70.)");
+
+    commands.spawn(ShapeBundle {
+        shape: SmudShape {
+            color: Color::TOMATO,
+            sdf: circle,
+            // The frame needs to be bigger than the shape we're drawing
+            // Since the circle has radius 70, we make the half-size of the quad 80.
+            frame: Frame::Quad(80.),
+            fill: SIMPLE_FILL_HANDLE.typed(),
+            ..default()
+        },
+        ..default()
+    });
+
+    commands.spawn((
+        Camera2dBundle {
+            camera: Camera {
+                hdr: true,
+                ..default()
+            },
+            ..default()
+        },
+        BloomSettings {
+            threshold: 0.2,
+            ..default()
+        },
+    ));
+}