//! Skinned mesh example with mesh and joints data defined in code. //! Example taken from use std::f32::consts::*; use bevy::{ math::ops, prelude::*, render::{ mesh::{ skinning::{SkinnedMesh, SkinnedMeshInverseBindposes}, Indices, PrimitiveTopology, VertexAttributeValues, }, render_asset::RenderAssetUsages, }, }; use rand::{Rng, SeedableRng}; use rand_chacha::ChaCha8Rng; fn main() { App::new() .add_plugins(DefaultPlugins) .insert_resource(AmbientLight { brightness: 3000.0, ..default() }) .add_systems(Startup, setup) .add_systems(Update, joint_animation) .run(); } /// Used to mark a joint to be animated in the [`joint_animation`] system. #[derive(Component)] struct AnimatedJoint(isize); /// Construct a mesh and a skeleton with 2 joints for that mesh, /// and mark the second joint to be animated. /// It is similar to the scene defined in `models/SimpleSkin/SimpleSkin.gltf` fn setup( mut commands: Commands, asset_server: Res, mut meshes: ResMut>, mut materials: ResMut>, mut skinned_mesh_inverse_bindposes_assets: ResMut>, ) { // Create a camera commands.spawn(( Camera3d::default(), Transform::from_xyz(2.5, 2.5, 9.0).looking_at(Vec3::ZERO, Vec3::Y), )); // Create inverse bindpose matrices for a skeleton consists of 2 joints let inverse_bindposes = skinned_mesh_inverse_bindposes_assets.add(vec![ Mat4::from_translation(Vec3::new(-0.5, -1.0, 0.0)), Mat4::from_translation(Vec3::new(-0.5, -1.0, 0.0)), ]); // Create a mesh let mesh = Mesh::new( PrimitiveTopology::TriangleList, RenderAssetUsages::RENDER_WORLD, ) // Set mesh vertex positions .with_inserted_attribute( Mesh::ATTRIBUTE_POSITION, vec![ [0.0, 0.0, 0.0], [1.0, 0.0, 0.0], [0.0, 0.5, 0.0], [1.0, 0.5, 0.0], [0.0, 1.0, 0.0], [1.0, 1.0, 0.0], [0.0, 1.5, 0.0], [1.0, 1.5, 0.0], [0.0, 2.0, 0.0], [1.0, 2.0, 0.0], ], ) // Add UV coordinates that map the left half of the texture since its a 1 x // 2 rectangle. .with_inserted_attribute( Mesh::ATTRIBUTE_UV_0, vec![ [0.0, 0.00], [0.5, 0.00], [0.0, 0.25], [0.5, 0.25], [0.0, 0.50], [0.5, 0.50], [0.0, 0.75], [0.5, 0.75], [0.0, 1.00], [0.5, 1.00], ], ) // Set mesh vertex normals .with_inserted_attribute(Mesh::ATTRIBUTE_NORMAL, vec![[0.0, 0.0, 1.0]; 10]) // Set mesh vertex joint indices for mesh skinning. // Each vertex gets 4 indices used to address the `JointTransforms` array in the vertex shader // as well as `SkinnedMeshJoint` array in the `SkinnedMesh` component. // This means that a maximum of 4 joints can affect a single vertex. .with_inserted_attribute( Mesh::ATTRIBUTE_JOINT_INDEX, // Need to be explicit here as [u16; 4] could be either Uint16x4 or Unorm16x4. VertexAttributeValues::Uint16x4(vec![ [0, 0, 0, 0], [0, 0, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], [0, 1, 0, 0], ]), ) // Set mesh vertex joint weights for mesh skinning. // Each vertex gets 4 joint weights corresponding to the 4 joint indices assigned to it. // The sum of these weights should equal to 1. .with_inserted_attribute( Mesh::ATTRIBUTE_JOINT_WEIGHT, vec![ [1.00, 0.00, 0.0, 0.0], [1.00, 0.00, 0.0, 0.0], [0.75, 0.25, 0.0, 0.0], [0.75, 0.25, 0.0, 0.0], [0.50, 0.50, 0.0, 0.0], [0.50, 0.50, 0.0, 0.0], [0.25, 0.75, 0.0, 0.0], [0.25, 0.75, 0.0, 0.0], [0.00, 1.00, 0.0, 0.0], [0.00, 1.00, 0.0, 0.0], ], ) // Tell bevy to construct triangles from a list of vertex indices, // where each 3 vertex indices form an triangle. .with_inserted_indices(Indices::U16(vec![ 0, 1, 3, 0, 3, 2, 2, 3, 5, 2, 5, 4, 4, 5, 7, 4, 7, 6, 6, 7, 9, 6, 9, 8, ])); let mesh = meshes.add(mesh); // We're seeding the PRNG here to make this example deterministic for testing purposes. // This isn't strictly required in practical use unless you need your app to be deterministic. let mut rng = ChaCha8Rng::seed_from_u64(42); for i in -5..5 { // Create joint entities let joint_0 = commands .spawn(Transform::from_xyz( i as f32 * 1.5, 0.0, // Move quads back a small amount to avoid Z-fighting and not // obscure the transform gizmos. -(i as f32 * 0.01).abs(), )) .id(); let joint_1 = commands.spawn((AnimatedJoint(i), Transform::IDENTITY)).id(); // Set joint_1 as a child of joint_0. commands.entity(joint_0).add_children(&[joint_1]); // Each joint in this vector corresponds to each inverse bindpose matrix in `SkinnedMeshInverseBindposes`. let joint_entities = vec![joint_0, joint_1]; // Create skinned mesh renderer. Note that its transform doesn't affect the position of the mesh. commands.spawn(( Mesh3d(mesh.clone()), MeshMaterial3d(materials.add(StandardMaterial { base_color: Color::srgb( rng.gen_range(0.0..1.0), rng.gen_range(0.0..1.0), rng.gen_range(0.0..1.0), ), base_color_texture: Some(asset_server.load("textures/uv_checker_bw.png")), ..default() })), SkinnedMesh { inverse_bindposes: inverse_bindposes.clone(), joints: joint_entities, }, )); } } /// Animate the joint marked with [`AnimatedJoint`] component. fn joint_animation( time: Res