此答案已针对最新的bevy = "0.9.1"更新，并使用默认着色器。
下面的代码演示如何：
1.定义bevy::render::pipeline::PrimitiveTopology::TriangleList的折点位置
1.为顶点指定 * 顶点法线 * 和 *UV坐标
1.使用我们定义的3个顶点创建三角形
它是基于bevy中内置的形状，可以在这里找到。

use bevy::prelude::*;
use bevy::render::mesh::{self, PrimitiveTopology};

fn main() {
    App::new()
        .insert_resource(Msaa { samples: 4 })
        .add_plugins(DefaultPlugins)
        .add_startup_system(setup)
        .run();
}

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    let mut mesh = Mesh::new(PrimitiveTopology::TriangleList);

    // Positions of the vertices
    // See https://bevy-cheatbook.github.io/features/coords.html
    mesh.insert_attribute(
        Mesh::ATTRIBUTE_POSITION,
        vec![[0., 0., 0.], [1., 2., 1.], [2., 0., 0.]],
    );

    // In this example, normals and UVs don't matter,
    // so we just use the same value for all of them
    mesh.insert_attribute(Mesh::ATTRIBUTE_NORMAL, vec![[0., 1., 0.]; 3]);
    mesh.insert_attribute(Mesh::ATTRIBUTE_UV_0, vec![[0., 0.]; 3]);

    // A triangle using vertices 0, 2, and 1.
    // Note: order matters. [0, 1, 2] will be flipped upside down, and you won't see it from behind!
    mesh.set_indices(Some(mesh::Indices::U32(vec![0, 2, 1])));

    commands.spawn(PbrBundle {
        mesh: meshes.add(mesh),
        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
        ..default()
    });

    commands.spawn(PointLightBundle {
        point_light: PointLight {
            intensity: 1500.0,
            shadows_enabled: true,
            ..default()
        },
        transform: Transform::from_xyz(4.0, 8.0, 4.0),
        ..default()
    });

    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..default()
    });
}

你必须根据你的使用情况定义你自己的 * 位置 ， 紫外线 * 和 * 法线 *。有些着色器不需要所有这些网格属性。

@frankenapps答案已针对bevy = 0.7更新

use bevy::prelude::*;
use bevy::render::mesh::{self, PrimitiveTopology};

fn main() {
    App::new()
        .insert_resource(Msaa { samples: 4 })
        .add_plugins(DefaultPlugins)
        .add_startup_system(setup)
        .run();
}

/// set up a simple 3D scene
fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    ) {
    let vertices = [
        ([0.0, 0.0, 0.0], [0.0, 1.0, 0.0], [1.0, 1.0]),
        ([1.0, 2.0, 1.0], [0.0, 1.0, 0.0], [1.0, 1.0]),
        ([2.0, 0.0, 0.0], [0.0, 1.0, 0.0], [1.0, 1.0]),
    ];

    let indices = mesh::Indices::U32(vec![0, 2, 1, 0, 3, 2]);

    let mut positions = Vec::new();
    let mut normals = Vec::new();
    let mut uvs = Vec::new();
    for (position, normal, uv) in vertices.iter() {
        positions.push(*position);
        normals.push(*normal);
        uvs.push(*uv);
    }

    let mut mesh = Mesh::new(PrimitiveTopology::TriangleList);
    mesh.set_indices(Some(indices));
    mesh.insert_attribute(Mesh::ATTRIBUTE_POSITION, positions);
    mesh.insert_attribute(Mesh::ATTRIBUTE_NORMAL, normals);
    mesh.insert_attribute(Mesh::ATTRIBUTE_UV_0, uvs);

    // add entities to the world
    // plane
    commands.spawn_bundle(PbrBundle {
        mesh: meshes.add(mesh),
        material: materials.add(Color::rgb(0.3, 0.5, 0.3).into()),
        ..default()
    });
    // light
    commands.spawn_bundle(PointLightBundle {
        point_light: PointLight {
            intensity: 1500.0,
            shadows_enabled: true,
            ..default()
        },
        transform: Transform::from_xyz(4.0, 8.0, 4.0),
        ..default()
    });
    // camera
    commands.spawn_bundle(PerspectiveCameraBundle {
        transform: Transform::from_xyz(-2.0, 2.5, 5.0)
            .looking_at(Vec3::ZERO, Vec3::Y),
            ..default()
    });
}