Merge pull request #48 from Jondolf/better-examples

Improve examples

README.md

@@ -83,7 +83,19 @@ fn setup(
 
 https://user-images.githubusercontent.com/57632562/230185604-b40441a2-48d8-4566-9b9e-be4825f4877e.mp4
 
-To see more complete examples of the various features of Bevy XPBD, check out the 2D and 3D examples in [/crates/bevy_xpbd_2d/examples](/crates/bevy_xpbd_2d/examples) and [/crates/bevy_xpbd_3d/examples](/crates/bevy_xpbd_3d/examples) respectively.
+## More examples
+
+You can find lots of 2D and 3D examples in [/crates/bevy_xpbd_2d/examples](/crates/bevy_xpbd_2d/examples) and [/crates/bevy_xpbd_3d/examples](/crates/bevy_xpbd_3d/examples) respectively.
+
+The examples support both `f32` and `f64` precisions, so the code contains some feature-dependent types like `Scalar` and `Vector`.
+In actual usage these are not needed, so you can just use `f32` or `f64` types depending on the features you have chosen.
+
+By default the examples use `f64`. To run the `f32` versions, you need to disable default features and manually choose the dimension
+and precision:
+
+```
+cargo run --example cubes --no-default-features --features 3d,f32
+```
 
 ## Current features
 

crates/bevy_xpbd_2d/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [features]
-default = [ "2d", "f32", "simd" ]
+default = [ "2d", "f64", "simd" ]
 2d = []
 f32 = [ "dep:parry2d" ]
 f64 = [ "dep:parry2d-f64" ]
@@ -24,8 +24,6 @@ bevy_prototype_debug_lines = { version = "0.10.1", optional = true }
 parry2d = { version = "0.13.1", optional = true }
 parry2d-f64 = { version = "0.13.1", optional = true }
 nalgebra = { version = "0.32.2", features = [ "convert-glam023" ] }
-console_error_panic_hook = "0.1.7"
-web-sys = "0.3.59"
 derive_more = "0.99"
 
 [dev-dependencies]
@@ -36,21 +34,25 @@ insta = "1.0"
 itertools = "0.10"
 
 [[example]]
-name = "chain2d"
-required-features = ["2d", "f32"]
+name = "chain_2d"
+required-features = ["2d"]
+
+[[example]]
+name = "collision_layers"
+required-features = ["2d"]
 
 [[example]]
 name = "fixed_joint_2d"
-required-features = ["2d", "f32"]
+required-features = ["2d"]
 
 [[example]]
 name = "move_marbles"
-required-features = ["2d", "f32"]
+required-features = ["2d"]
 
 [[example]]
 name = "prismatic_joint_2d"
-required-features = ["2d", "f32"]
+required-features = ["2d"]
 
 [[example]]
 name = "revolute_joint_2d"
-required-features = ["2d", "f32"]
+required-features = ["2d"]

crates/bevy_xpbd_2d/examples/chain_2d.rs

@@ -0,0 +1,87 @@
+#![allow(clippy::unnecessary_cast)]
+
+use bevy::{prelude::*, sprite::MaterialMesh2dBundle, window::PrimaryWindow};
+use bevy_xpbd_2d::prelude::*;
+use examples_common_2d::XpbdExamplePlugin;
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins)
+        .add_plugin(XpbdExamplePlugin)
+        .insert_resource(ClearColor(Color::rgb(0.05, 0.05, 0.1)))
+        .insert_resource(SubstepCount(50))
+        .insert_resource(Gravity(Vector::NEG_Y * 1000.0))
+        .add_startup_system(setup)
+        .add_system(follow_mouse)
+        .run();
+}
+
+#[derive(Component)]
+struct FollowMouse;
+
+fn setup(
+    mut commands: Commands,
+    mut materials: ResMut<Assets<ColorMaterial>>,
+    mut meshes: ResMut<Assets<Mesh>>,
+) {
+    commands.spawn(Camera2dBundle::default());
+
+    let particle_count = 100;
+    let particle_radius = 1.2;
+    let particle_mesh = MaterialMesh2dBundle {
+        mesh: meshes
+            .add(shape::Circle::new(particle_radius as f32).into())
+            .into(),
+        material: materials.add(ColorMaterial::from(Color::rgb(0.2, 0.7, 0.9))),
+        ..default()
+    };
+
+    // Spawn kinematic particle that can follow the mouse
+    let mut previous_particle = commands
+        .spawn((particle_mesh.clone(), RigidBody::Kinematic, FollowMouse))
+        .id();
+
+    // Spawn the rest of the particles, connecting each one to the previous one with joints
+    for i in 1..particle_count {
+        let current_particle = commands
+            .spawn((
+                particle_mesh.clone(),
+                RigidBody::Dynamic,
+                Position(i as Scalar * Vector::NEG_Y * (particle_radius * 2.0 + 1.0)),
+                MassPropertiesBundle::new_computed(&Collider::ball(particle_radius), 1.0),
+            ))
+            .id();
+
+        commands.spawn(
+            RevoluteJoint::new(previous_particle, current_particle)
+                .with_local_anchor_2(Vector::Y * (particle_radius * 2.0 + 1.0))
+                .with_compliance(0.0000001),
+        );
+
+        previous_particle = current_particle;
+    }
+}
+
+fn follow_mouse(
+    buttons: Res<Input<MouseButton>>,
+    windows: Query<&Window, With<PrimaryWindow>>,
+    camera: Query<(&Camera, &GlobalTransform)>,
+    mut follower: Query<&mut Position, With<FollowMouse>>,
+) {
+    if buttons.pressed(MouseButton::Left) {
+        let window = windows.single();
+        let (camera, camera_transform) = camera.single();
+        let mut follower_position = follower.single_mut();
+
+        // Set position of follower to cursor position in world coordinates
+        // https://bevy-cheatbook.github.io/cookbook/cursor2world.html
+        if let Some(pos) = window.cursor_position() {
+            let window_size = Vec2::new(window.width(), window.height());
+            let ndc = (pos / window_size) * 2.0 - Vec2::ONE;
+            let ndc_to_world =
+                camera_transform.compute_matrix() * camera.projection_matrix().inverse();
+            let world_pos = ndc_to_world.project_point3(ndc.extend(-1.0));
+            follower_position.0 = world_pos.truncate().adjust_precision();
+        }
+    }
+}