fix the testcases

.gitignore

@@ -1 +1,2 @@
 /target
+/.vscode

Cargo.toml

@@ -7,10 +7,13 @@ default-run = "turtlers"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bevy = { version = "0.8", features = ["dynamic"] }
-bevy-inspector-egui = "0.12.1"
-bevy_prototype_lyon = "0.6"
-bevy_tweening = "0.5.0"
+bevy = { version = "0.11", features = ["dynamic_linking", "wayland"] }
+bevy-inspector-egui = "0.19"
+bevy_egui = "0.21"
+egui = "0.22"
+bevy_prototype_lyon = {version="0.9"}
+bevy_tweening = {version="0.8"}
+num-traits = "0.2"
 
 # Enable a small amount of optimization in debug mode
 [profile.dev]

TODO.md

@@ -0,0 +1 @@
+*[ ] Minimal example of filled animation

src/animation_step.rs

@@ -0,0 +1,59 @@
+use bevy::prelude::{Color, Commands, Query, Transform, With};
+use bevy_prototype_lyon::prelude::{Fill, Stroke};
+use bevy_tweening::Animator;
+
+use crate::{
+    turtle::{TurtleCommands, TurtleGraphElement, TurtleShape},
+    turtle_movement::TurtleStep,
+};
+
+pub(crate) fn run_animation_step(
+    commands: &mut Commands,
+    tcmd: &mut TurtleCommands,
+    turtle: &mut Query<&mut Animator<Transform>, With<TurtleShape>>,
+) {
+    loop {
+        match tcmd.get_next() {
+            Some(TurtleStep {
+                turtle_animation: Some(turtle_animation),
+                line_segment: Some(graph_element_to_draw),
+                line_animation: Some(line_animation),
+                fill,
+                stroke,
+            }) => {
+                let mut turtle = turtle.single_mut();
+                turtle.set_tweenable(turtle_animation);
+                let fill = fill.unwrap_or(Fill::color(Color::MIDNIGHT_BLUE));
+                let stroke = stroke.unwrap_or(Stroke::color(Color::BLACK));
+                match graph_element_to_draw {
+                    TurtleGraphElement::TurtleLine(line) => {
+                        commands.spawn((line, line_animation, fill, stroke));
+                    }
+                    TurtleGraphElement::Noop => (),
+                    TurtleGraphElement::TurtleCircle(circle) => {
+                        commands.spawn((circle, line_animation, fill, stroke));
+                    }
+                }
+                return;
+            }
+            // In case a rotation is performed the line drawing can be skipped
+            Some(TurtleStep {
+                turtle_animation: Some(turtle_animation),
+                line_segment: Some(_),
+                line_animation: None,
+                ..
+            }) => {
+                let mut turtle = turtle.single_mut();
+                turtle.set_tweenable(turtle_animation);
+                return;
+            }
+            Some(_) => {
+                println!("without animation");
+            }
+            None => {
+                println!("nothing to draw");
+                return;
+            }
+        };
+    }
+}

src/bin/animation.rs

@@ -1,143 +0,0 @@
-//! Create and play an animation defined by code that operates on the `Transform` component.
-
-use std::f32::consts::{FRAC_PI_2, PI};
-
-use bevy::prelude::*;
-
-fn main() {
-    App::new()
-        .add_plugins(DefaultPlugins)
-        .insert_resource(AmbientLight {
-            color: Color::WHITE,
-            brightness: 1.0,
-        })
-        .add_startup_system(setup)
-        .run();
-}
-
-fn setup(
-    mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
-    mut materials: ResMut<Assets<StandardMaterial>>,
-    mut animations: ResMut<Assets<AnimationClip>>,
-) {
-    // Camera
-    commands.spawn_bundle(Camera3dBundle {
-        transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
-        ..default()
-    });
-
-    // The animation API uses the `Name` component to target entities
-    let planet = Name::new("planet");
-    let orbit_controller = Name::new("orbit_controller");
-    let satellite = Name::new("satellite");
-
-    // Creating the animation
-    let mut animation = AnimationClip::default();
-    // A curve can modify a single part of a transform, here the translation
-    animation.add_curve_to_path(
-        EntityPath {
-            parts: vec![planet.clone()],
-        },
-        VariableCurve {
-            keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0],
-            keyframes: Keyframes::Translation(vec![
-                Vec3::new(1.0, 0.0, 1.0),
-                Vec3::new(-1.0, 0.0, 1.0),
-                Vec3::new(-1.0, 0.0, -1.0),
-                Vec3::new(1.0, 0.0, -1.0),
-                // in case seamless looping is wanted, the last keyframe should
-                // be the same as the first one
-                Vec3::new(1.0, 0.0, 1.0),
-            ]),
-        },
-    );
-    // Or it can modify the rotation of the transform.
-    // To find the entity to modify, the hierarchy  will be traversed looking for
-    // an entity with the right name at each level
-    animation.add_curve_to_path(
-        EntityPath {
-            parts: vec![planet.clone(), orbit_controller.clone()],
-        },
-        VariableCurve {
-            keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0],
-            keyframes: Keyframes::Rotation(vec![
-                Quat::from_axis_angle(Vec3::Y, 0.0),
-                Quat::from_axis_angle(Vec3::Y, FRAC_PI_2),
-                Quat::from_axis_angle(Vec3::Y, PI),
-                Quat::from_axis_angle(Vec3::Y, 3.0 * FRAC_PI_2),
-                Quat::from_axis_angle(Vec3::Y, 0.0),
-            ]),
-        },
-    );
-    // If a curve in an animation is shorter than the other, it will not repeat
-    // until all other curves are finished. In that case, another animation should
-    // be created for each part that would have a different duration / period
-    animation.add_curve_to_path(
-        EntityPath {
-            parts: vec![planet.clone(), orbit_controller.clone(), satellite.clone()],
-        },
-        VariableCurve {
-            keyframe_timestamps: vec![0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0],
-            keyframes: Keyframes::Scale(vec![
-                Vec3::splat(0.8),
-                Vec3::splat(1.2),
-                Vec3::splat(0.8),
-                Vec3::splat(1.2),
-                Vec3::splat(0.8),
-                Vec3::splat(1.2),
-                Vec3::splat(0.8),
-                Vec3::splat(1.2),
-                Vec3::splat(0.8),
-            ]),
-        },
-    );
-    // There can be more than one curve targeting the same entity path
-    animation.add_curve_to_path(
-        EntityPath {
-            parts: vec![planet.clone(), orbit_controller.clone(), satellite.clone()],
-        },
-        VariableCurve {
-            keyframe_timestamps: vec![0.0, 1.0, 2.0, 3.0, 4.0],
-            keyframes: Keyframes::Rotation(vec![
-                Quat::from_axis_angle(Vec3::Y, 0.0),
-                Quat::from_axis_angle(Vec3::Y, FRAC_PI_2),
-                Quat::from_axis_angle(Vec3::Y, PI),
-                Quat::from_axis_angle(Vec3::Y, 3.0 * FRAC_PI_2),
-                Quat::from_axis_angle(Vec3::Y, 0.0),
-            ]),
-        },
-    );
-
-    // Create the animation player, and set it to repeat
-    let mut player = AnimationPlayer::default();
-    player.play(animations.add(animation)).repeat();
-
-    // Create the scene that will be animated
-    // First entity is the planet
-    commands
-        .spawn_bundle(PbrBundle {
-            mesh: meshes.add(Mesh::from(shape::Icosphere::default())),
-            material: materials.add(Color::rgb(0.8, 0.7, 0.6).into()),
-            ..default()
-        })
-        // Add the Name component, and the animation player
-        .insert_bundle((planet, player))
-        .with_children(|p| {
-            // This entity is just used for animation, but doesn't display anything
-            p.spawn_bundle(SpatialBundle::default())
-                // Add the Name component
-                .insert(orbit_controller)
-                .with_children(|p| {
-                    // The satellite, placed at a distance of the planet
-                    p.spawn_bundle(PbrBundle {
-                        transform: Transform::from_xyz(1.5, 0.0, 0.0),
-                        mesh: meshes.add(Mesh::from(shape::Cube { size: 0.5 })),
-                        material: materials.add(Color::rgb(0.3, 0.9, 0.3).into()),
-                        ..default()
-                    })
-                    // Add the Name component
-                    .insert(satellite);
-                });
-        });
-}

src/bin/bevy_egui_test.rs

@@ -0,0 +1,112 @@
+use bevy::{app::AppExit, prelude::*};
+use bevy_egui::{egui, EguiContexts, EguiPlugin};
+use bevy_prototype_lyon::prelude::{
+    Fill, GeometryBuilder, Path, PathBuilder, ShapeBundle, ShapePlugin, Stroke,
+};
+
+#[derive(Default, Resource)]
+struct OccupiedScreenSpace {
+    left: f32,
+    top: f32,
+    right: f32,
+    bottom: f32,
+}
+
+#[derive(Default, Resource)]
+struct Line {
+    x: f32,
+    y: f32,
+}
+
+#[derive(Resource, Deref, DerefMut)]
+struct OriginalCameraTransform(Transform);
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins.set(WindowPlugin {
+            primary_window: Some(Window {
+                resolution: (800., 600.).into(),
+                title: "Turtle Window".to_string(),
+                present_mode: bevy::window::PresentMode::AutoVsync,
+                //decorations: false,
+                ..default()
+            }),
+            ..default()
+        }))
+        .add_plugins(EguiPlugin)
+        .add_plugins(ShapePlugin)
+        .init_resource::<OccupiedScreenSpace>()
+        .add_systems(Startup, setup_system)
+        .add_systems(Update, ui)
+        .add_systems(Update, update_path)
+        .run();
+}
+
+fn update_path(line: Res<Line>, mut path: Query<&mut Path>) {
+    for mut path in path.iter_mut() {
+        let mut path_builder = PathBuilder::new();
+        path_builder.move_to(Vec2::new(line.x, line.y));
+        path_builder.line_to(Vec2::new(100., 0.));
+        *path = path_builder.build();
+    }
+}
+
+fn ui(
+    mut egui_contexts: EguiContexts,
+    mut occupied_screen_space: ResMut<OccupiedScreenSpace>,
+    mut line: ResMut<Line>,
+    mut exit: EventWriter<AppExit>,
+) {
+    let mut style = (*egui_contexts.ctx_mut().style()).clone();
+    style.visuals.button_frame = false;
+    egui_contexts.ctx_mut().set_style(style);
+    occupied_screen_space.left = 0.0;
+    occupied_screen_space.right = egui::SidePanel::right("right_panel")
+        .resizable(false)
+        .show(egui_contexts.ctx_mut(), |ui| {
+            ui.add_space(7.);
+            ui.menu_button("Menu", |ui| {
+                if ui
+                    .add_sized([ui.available_width(), 30.], egui::Button::new("Exit"))
+                    .clicked()
+                {
+                    exit.send(AppExit);
+                }
+            })
+        })
+        .response
+        .rect
+        .width();
+    occupied_screen_space.top = 0.0;
+    occupied_screen_space.bottom = egui::TopBottomPanel::bottom("bottom_panel")
+        .resizable(false)
+        .show(egui_contexts.ctx_mut(), |ui| {
+            ui.add_sized(
+                ui.available_size(),
+                egui::Slider::new(&mut line.x, 0.0..=100.0),
+            );
+        })
+        .response
+        .rect
+        .height();
+}
+
+fn setup_system(mut commands: Commands) {
+    commands.spawn(Camera2dBundle::default());
+    commands.insert_resource(Line { x: 100., y: 100. });
+    let mut path_builder = PathBuilder::new();
+    path_builder.move_to(Vec2::new(200., 200.));
+    path_builder.line_to(Vec2::new(100., 0.));
+    let line = path_builder.build();
+    let fill = Fill::color(Color::MIDNIGHT_BLUE);
+    let stroke = Stroke::color(Color::BLACK);
+
+    commands.spawn((
+        ShapeBundle {
+            path: GeometryBuilder::build_as(&line),
+            ..default()
+        },
+        fill,
+        stroke,
+    ));
+}

src/bin/circle.rs

@@ -0,0 +1,142 @@
+use std::time::Duration;
+
+use bevy::prelude::*;
+use bevy_prototype_lyon::prelude::*;
+use bevy_tweening::{
+    component_animator_system, Animator, EaseFunction, Lens, Sequence, Tween, TweeningPlugin,
+};
+
+fn main() {
+    App::new()
+        .insert_resource(Msaa::Sample4)
+        .add_plugins(DefaultPlugins)
+        .add_plugins(ShapePlugin)
+        .add_plugins(TweeningPlugin)
+        .add_systems(Startup, setup_system)
+        .add_systems(Update, component_animator_system::<Path>)
+        .run();
+}
+
+fn setup_system(mut commands: Commands) {
+    let mut path_builder = PathBuilder::new();
+    path_builder.line_to(Vec2::new(100., 0.));
+    let ops = vec![
+        GElem::Circle {
+            center: Vec2::ZERO,
+            radii: Vec2::splat(100.),
+            angle: 90.,
+        },
+        GElem::Line {
+            start: Vec2::new(0., 100.),
+            target: Vec2::splat(200.),
+        },
+        GElem::Line {
+            start: Vec2::splat(200.),
+            target: Vec2::new(100., 0.),
+        },
+        GElem::Circle {
+            center: Vec2::ZERO,
+            radii: Vec2::splat(100.),
+            angle: -90.,
+        },
+        GElem::Line {
+            start: Vec2::new(0., -100.),
+            target: Vec2::new(200., -200.),
+        },
+        GElem::Line {
+            start: Vec2::new(200., -200.),
+            target: Vec2::new(100., 0.),
+        },
+    ];
+
+    let line = path_builder.build();
+
+    commands.spawn(Camera2dBundle::default());
+    let mut seq = Sequence::with_capacity(ops.len());
+    for (step, op) in ops.clone().into_iter().enumerate() {
+        let mut done = ops.clone();
+        done.truncate(step);
+        let next = Tween::new(
+            EaseFunction::QuadraticInOut,
+            Duration::from_millis(1000),
+            FilledAnimation { current: op, done },
+        );
+        seq = seq.then(next);
+    }
+    let animator = Animator::new(seq);
+    let fill = Fill::color(Color::MIDNIGHT_BLUE);
+    let stroke = Stroke::color(Color::BLACK);
+    commands
+        .spawn((
+            ShapeBundle {
+                path: GeometryBuilder::build_as(&line),
+                ..default()
+            },
+            fill,
+            stroke,
+        ))
+        .insert(animator);
+}
+
+#[derive(Clone, Copy)]
+enum GElem {
+    Circle {
+        center: Vec2,
+        radii: Vec2,
+        angle: f32,
+    },
+    Line {
+        start: Vec2,
+        target: Vec2,
+    },
+}
+
+impl GElem {
+    fn draw_to_builder(self, b: &mut PathBuilder) {
+        match self {
+            GElem::Circle {
+                center,
+                radii,
+                angle,
+            } => {
+                b.arc(center, radii, angle.to_radians(), 0.);
+            }
+            GElem::Line { target, start: _ } => {
+                b.line_to(target);
+            }
+        }
+    }
+}
+
+struct FilledAnimation {
+    current: GElem,
+    done: Vec<GElem>,
+}
+
+impl Lens<Path> for FilledAnimation {
+    fn lerp(&mut self, target: &mut Path, ratio: f32) {
+        let mut path_builder = PathBuilder::new();
+        path_builder.move_to(Vec2::new(100., 0.));
+        for x in &self.done {
+            x.draw_to_builder(&mut path_builder)
+        }
+
+        let part = match self.current {
+            GElem::Circle {
+                center,
+                radii,
+                angle,
+            } => GElem::Circle {
+                center,
+                radii,
+                angle: angle * ratio,
+            },
+            GElem::Line { target, start } => GElem::Line {
+                target: start + ((target - start) * ratio),
+                start,
+            },
+        };
+        part.draw_to_builder(&mut path_builder);
+        *target = path_builder.build();
+    }
+}

src/datatypes.rs

@@ -0,0 +1,8 @@
+use bevy::prelude::Vec2;
+
+pub mod angle;
+pub mod length;
+
+pub type Coordinate = Vec2;
+pub type Visibility = bool;
+pub type Speed = u32;

src/datatypes/angle.rs

@@ -0,0 +1,197 @@
+
+use std::{
+    f32::consts::PI,
+    ops::{Add, Div, Mul, Neg, Rem, Sub},
+};
+
+use bevy::reflect::Reflect;
+
+use crate::turtle::Precision;
+
+#[derive(Reflect, Copy, Clone, Debug, PartialEq, Eq)]
+pub enum AngleUnit<T: Default> {
+    Degrees(T),
+    Radians(T),
+}
+
+impl<T: Default> Default for AngleUnit<T> {
+    fn default() -> Self {
+        Self::Degrees(Default::default())
+    }
+}
+
+#[derive(Reflect, Copy, Default, Clone, Debug, PartialEq, Eq)]
+pub struct Angle<T: Default> {
+    value: AngleUnit<T>,
+}
+
+impl<T: Default + Clone + Rem<T, Output = T>> Rem<T> for Angle<T> {
+    type Output = Self;
+
+    fn rem(self, rhs: T) -> Self::Output {
+        match self.value {
+            AngleUnit::Degrees(v) => Self::Output::degrees(v % rhs),
+            AngleUnit::Radians(v) => Self::Output::radians(v % rhs),
+        }
+    }
+}
+
+impl<T: Default + Clone + Mul<T, Output = T>> Mul<T> for Angle<T> {
+    type Output = Self;
+
+    fn mul(self, rhs: T) -> Self::Output {
+        match self.value {
+            AngleUnit::Degrees(v) => Self::Output::degrees(v * rhs),
+            AngleUnit::Radians(v) => Self::Output::radians(v * rhs),
+        }
+    }
+}
+
+impl Angle<Precision> {
+    pub fn limit_smaller_than_full_circle(self) -> Self {
+        match self.value {
+            AngleUnit::Degrees(v) => Self {
+                value: AngleUnit::Degrees(v % 360.),
+            },
+            AngleUnit::Radians(v) => Self {
+                value: AngleUnit::Radians(v % (2. * PI)),
+            },
+        }
+    }
+}
+impl<T: Default + Clone + Div<T, Output = T>> Div<T> for Angle<T> {
+    type Output = Self;
+
+    fn div(self, rhs: T) -> Self::Output {
+        match self.value {
+            AngleUnit::Degrees(v) => Self::Output::degrees(v / rhs),
+            AngleUnit::Radians(v) => Self::Output::radians(v / rhs),
+        }
+    }
+}
+
+impl<T: Default + Clone + std::ops::Neg<Output = T>> Neg for Angle<T> {
+    type Output = Self;
+
+    fn neg(self) -> Self::Output {
+        match self.value {
+            AngleUnit::Degrees(v) => Self::Output::degrees(-v),
+            AngleUnit::Radians(v) => Self::Output::radians(-v),
+        }
+    }
+}
+
+impl<T: Default + Clone + std::ops::Neg<Output = T>> Neg for &Angle<T> {
+    type Output = Angle<T>;
+
+    fn neg(self) -> Self::Output {
+        match self.value.clone() {
+            AngleUnit::Degrees(v) => Self::Output::degrees(-v),
+            AngleUnit::Radians(v) => Self::Output::radians(-v),
+        }
+    }
+}
+
+impl<T: Default + Clone> Angle<T> {
+    pub fn degrees(value: T) -> Angle<T> {
+        Self {
+            value: AngleUnit::Degrees(value),
+        }
+    }
+    pub fn radians(value: T) -> Angle<T> {
+        Self {
+            value: AngleUnit::Radians(value),
+        }
+    }
+    pub fn value(&self) -> T {
+        match self.value.clone() {
+            AngleUnit::Degrees(v) => v,
+            AngleUnit::Radians(v) => v,
+        }
+    }
+}
+
+impl<T: Default + num_traits::float::Float> Angle<T> {
+    pub fn to_radians(self) -> Self {
+        match self.value {
+            AngleUnit::Degrees(v) => Self {
+                value: AngleUnit::Radians(v.to_radians()),
+            },
+            AngleUnit::Radians(_) => self,
+        }
+    }
+    pub fn to_degrees(self) -> Self {
+        match self.value {
+            AngleUnit::Degrees(_) => self,
+            AngleUnit::Radians(v) => Self {
+                value: AngleUnit::Degrees(v.to_degrees()),
+            },
+        }
+    }
+}
+
+impl<T: Add<Output = T> + Default + num_traits::float::Float> Add for Angle<T> {
+    type Output = Angle<T>;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        match (self.value, rhs.value) {
+            (AngleUnit::Degrees(v), AngleUnit::Degrees(o)) => Self::Output {
+                value: AngleUnit::Degrees(v + o),
+            },
+            (AngleUnit::Degrees(v), AngleUnit::Radians(o)) => Self::Output {
+                value: AngleUnit::Radians(v.to_radians() + o),
+            },
+            (AngleUnit::Radians(v), AngleUnit::Degrees(o)) => Self::Output {
+                value: AngleUnit::Radians(v + o.to_radians()),
+            },
+            (AngleUnit::Radians(v), AngleUnit::Radians(o)) => Self::Output {
+                value: AngleUnit::Radians(v + o),
+            },
+        }
+    }
+}
+
+impl<T: Sub<Output = T> + Default + num_traits::float::Float> Sub for Angle<T> {
+    type Output = Angle<T>;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        match (self.value, rhs.value) {
+            (AngleUnit::Degrees(v), AngleUnit::Degrees(o)) => Self::Output {
+                value: AngleUnit::Degrees(v - o),
+            },
+            (AngleUnit::Degrees(v), AngleUnit::Radians(o)) => Self::Output {
+                value: AngleUnit::Radians(v.to_radians() - o),
+            },
+            (AngleUnit::Radians(v), AngleUnit::Degrees(o)) => Self::Output {
+                value: AngleUnit::Radians(v - o.to_radians()),
+            },
+            (AngleUnit::Radians(v), AngleUnit::Radians(o)) => Self::Output {
+                value: AngleUnit::Radians(v - o),
+            },
+        }
+    }
+}
+
+#[test]
+fn convert_to_radians() {
+    let radi = Angle::radians(30f32.to_radians());
+    let degr = Angle::degrees(30f32);
+    let converted = degr.to_radians();
+    assert_eq!(radi, converted)
+}
+#[test]
+fn sum_degrees() {
+    let fst = Angle::degrees(30f32);
+    let snd = Angle::degrees(30f32);
+    let sum = fst + snd;
+    assert!((sum.value() - 60f32).abs() < 0.0001);
+    assert!((sum.to_radians().value() - 60f32.to_radians()).abs() < 0.0001);
+}
+#[test]
+fn sum_mixed() {
+    let fst = Angle::degrees(30f32);
+    let snd = Angle::radians(30f32.to_radians());
+    let sum = fst + snd;
+    assert!((sum.to_degrees().value() - 60f32).abs() < 0.0001);
+    assert!((sum.to_radians().value() - 60f32.to_radians()).abs() < 0.0001);
+}

src/datatypes/length.rs

@@ -0,0 +1,6 @@
+use bevy::reflect::Reflect;
+
+use crate::turtle::Precision;
+
+#[derive(Reflect, Default, Copy, Clone, Debug)]
+pub struct Length(pub Precision);

src/debug.rs

@@ -1,5 +1,5 @@
 use bevy::prelude::Plugin;
-use bevy_inspector_egui::WorldInspectorPlugin;
+use bevy_inspector_egui::quick::WorldInspectorPlugin;
 
 pub struct DebugPlugin;
 

src/main.rs

@@ -1,7 +1,12 @@
+mod animation_step;
+mod datatypes;
 mod debug;
+mod paths;
+mod primitives;
+mod structs;
 mod turtle;
 mod turtle_movement;
-mod turtle_shapes;
+mod turtle_state;
 use bevy::{prelude::*, window::close_on_esc};
 
 use bevy_prototype_lyon::prelude::*;
@@ -9,16 +14,17 @@ use turtle::TurtlePlugin;
 
 fn main() {
     App::new()
-        .insert_resource(Msaa { samples: 4 })
+        .insert_resource(Msaa::Sample4)
         .insert_resource(ClearColor(Color::BEIGE))
-        .insert_resource(WindowDescriptor {
-            width: 400.0,
-            height: 400.0,
-            title: "Turtle Window".to_string(),
+        .add_plugins(DefaultPlugins.set(WindowPlugin {
+            primary_window: Some(Window {
+                resolution: (800.,600.).into(),
+                //title: "Turtle Window".to_string(),
                 present_mode: bevy::window::PresentMode::AutoVsync,
                 ..default()
-        })
-        .add_plugins(DefaultPlugins)
+            }),
+            ..default()
+        }))
         .add_plugin(ShapePlugin)
         .add_plugin(debug::DebugPlugin)
         .add_plugin(TurtlePlugin)

src/paths/circle_star.rs

@@ -0,0 +1,46 @@
+use crate::{
+    datatypes::{angle::Angle, length::Length},
+    turtle::TurtleCommand,
+};
+
+#[allow(dead_code)]
+pub fn circle_star() -> Vec<TurtleCommand> {
+    vec![
+        TurtleCommand::Right(Angle::degrees(36.)),
+        TurtleCommand::Forward(Length(200.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Circle {
+            radius: Length(20.),
+            angle: Angle::degrees(324.),
+        },
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(200.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Circle {
+            radius: Length(20.),
+            angle: Angle::degrees(324.),
+        },
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(200.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Circle {
+            radius: Length(20.),
+            angle: Angle::degrees(324.),
+        },
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(200.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Circle {
+            radius: Length(20.),
+            angle: Angle::degrees(324.),
+        },
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(200.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Circle {
+            radius: Length(20.),
+            angle: Angle::degrees(324.),
+        },
+        TurtleCommand::Right(Angle::degrees(90.)),
+    ]
+}

src/paths/geometry_task.rs

@@ -0,0 +1,43 @@
+use crate::{
+    datatypes::{angle::Angle, length::Length},
+    turtle::TurtleCommand,
+};
+
+#[allow(dead_code)]
+pub fn geometry_task() -> Vec<TurtleCommand> {
+    let mut before = vec![
+        TurtleCommand::Forward(Length(100.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Backward(Length(100.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(100.)),
+        TurtleCommand::Right(Angle::degrees(45.)),
+    ];
+    for _ in 0..10 {
+        let mut dash = vec![
+            TurtleCommand::PenUp,
+            TurtleCommand::Forward(Length(5.)),
+            TurtleCommand::PenDown,
+            TurtleCommand::Forward(Length(5.)),
+        ];
+        before.append(&mut dash);
+    }
+    let mut after = vec![
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(50.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(100.)),
+        TurtleCommand::Right(Angle::degrees(90.)),
+        TurtleCommand::Forward(Length(50.)),
+        TurtleCommand::Right(Angle::degrees(45.)),
+        TurtleCommand::Forward(Length(100.)),
+        TurtleCommand::Left(Angle::degrees(120.)),
+        TurtleCommand::Forward(Length(100.)),
+        TurtleCommand::Left(Angle::degrees(120.)),
+        TurtleCommand::Forward(Length(100.)),
+        TurtleCommand::Right(Angle::degrees(150.)),
+        TurtleCommand::Forward(Length(100.)),
+    ];
+    before.append(&mut after);
+    before
+}

src/paths/mod.rs

@@ -0,0 +1,2 @@
+pub mod circle_star;
+pub mod geometry_task;

src/primitives.rs

@@ -0,0 +1,5 @@
+pub mod animation;
+pub mod bundles;
+pub mod components;
+pub mod turtle_primitives;
+pub mod turtle_shapes;

src/primitives/animation.rs

@@ -0,0 +1,72 @@
+use bevy::prelude::{Quat, Transform, Vec2};
+use bevy_prototype_lyon::{
+    prelude::{Path, PathBuilder, ShapePath},
+    shapes,
+};
+use bevy_tweening::Lens;
+
+use crate::{datatypes::angle::Angle, turtle::Precision};
+
+pub(crate) struct LineAnimationLens {
+    start: Vec2,
+    end: Vec2,
+}
+
+impl LineAnimationLens {
+    pub(crate) fn new(start: Vec2, end: Vec2) -> Self {
+        Self { start, end }
+    }
+}
+
+impl Lens<Path> for LineAnimationLens {
+    fn lerp(&mut self, target: &mut Path, ratio: f32) {
+        let line = shapes::Line(self.start, self.start + ((self.end - self.start) * ratio));
+        *target = ShapePath::build_as(&line);
+    }
+}
+
+pub(crate) struct CircleAnimationLens {
+    pub start_pos: Vec2,
+    pub center: Vec2,
+    pub radii: Vec2,
+    pub start: Angle<Precision>,
+    pub end: Angle<Precision>,
+}
+
+impl Lens<Path> for CircleAnimationLens {
+    fn lerp(&mut self, target: &mut Path, ratio: f32) {
+        let mut path_builder = PathBuilder::new();
+        path_builder.move_to(self.start_pos);
+        // The center point of the radius, then the radii in x and y direction, then the angle that will be drawn, then the x_rotation ?
+        path_builder.arc(
+            self.center,
+            self.radii,
+            (self.start + ((self.end - self.start) * ratio))
+                .to_radians()
+                .value(),
+            0.,
+        );
+        let line = path_builder.build();
+        *target = ShapePath::build_as(&line);
+    }
+}
+
+pub(crate) struct CircleMovementLens {
+    pub center: Vec2,
+    pub start: Transform,
+    pub end: Angle<Precision>,
+}
+
+impl Lens<Transform> for CircleMovementLens {
+    fn lerp(&mut self, target: &mut Transform, ratio: f32) {
+        let angle = self.end * ratio;
+        let mut rotated = self.start;
+
+        rotated.rotate_around(
+            self.center.extend(0.),
+            Quat::from_rotation_z(angle.to_radians().value()),
+        );
+
+        *target = rotated;
+    }
+}

src/primitives/bundles.rs

@@ -0,0 +1,128 @@
+use bevy::{
+    prelude::{default, Bundle, Component, Name, Vec2},
+    reflect::Reflect,
+};
+use bevy_prototype_lyon::{
+    entity::ShapeBundle,
+    prelude::{Fill, GeometryBuilder, PathBuilder, Stroke},
+    shapes::Line,
+};
+
+use crate::{
+    datatypes::angle::Angle,
+    turtle::{Colors, Precision, TurtleCommand, TurtleCommands},
+};
+
+use super::turtle_shapes;
+
+#[derive(Bundle, Reflect, Default)]
+pub struct TurtleDrawLine {
+    #[reflect(ignore)]
+    line: ShapeBundle,
+    name: Name,
+    marker: LineMarker,
+}
+
+#[derive(Component, Default, Reflect)]
+struct LineMarker;
+
+impl TurtleDrawLine {
+    pub(crate) fn new(start: Vec2, _end: Vec2, index: u64) -> Self {
+        let bundle = ShapeBundle {
+            path: GeometryBuilder::build_as(&Line(start, start)),
+            ..default()
+        };
+        Self {
+            line: bundle,
+            name: Name::new(format!("Line {}", index)),
+            marker: LineMarker,
+        }
+    }
+}
+
+#[derive(Bundle, Reflect, Default)]
+
+pub struct TurtleDrawCircle {
+    #[reflect(ignore)]
+    line: ShapeBundle,
+    name: Name,
+    marker: CircleMarker,
+}
+
+#[derive(Component, Default, Reflect)]
+struct CircleMarker;
+
+impl TurtleDrawCircle {
+    pub(crate) fn new(
+        center: Vec2,
+        radii: Vec2,
+        angle: Angle<Precision>,
+        index: u64,
+        start: Vec2,
+        end: Vec2,
+    ) -> Self {
+        let mut path_builder = PathBuilder::new();
+        path_builder.move_to(start);
+        // The center point of the radius - this is responsible for the orientation of the ellipse,
+        // then the radii in x and y direction - this can be rotated using the x_rotation parameter,
+        // then the angle - the part of the circle that will be drawn like (PI/2.0) for a quarter circle,
+        // then the x_rotation (maybe the rotation of the radii?)
+        path_builder.arc(center, radii, angle.to_radians().value(), 0.);
+        let line = path_builder.build();
+        println!("Draw Circle: {} {} {:?}", center, radii, angle);
+
+        let bundle = ShapeBundle {
+            path: GeometryBuilder::build_as(&line),
+            ..default()
+        };
+        Self {
+            line: bundle,
+            name: Name::new(format!("Circle {}", index)),
+            marker: CircleMarker,
+        }
+    }
+}
+
+#[derive(Bundle)]
+pub struct Turtle {
+    colors: Colors,
+    commands: TurtleCommands,
+    name: Name,
+    shape: ShapeBundle,
+}
+
+impl Default for Turtle {
+    fn default() -> Self {
+        let bundle = ShapeBundle {
+            path: GeometryBuilder::build_as(&turtle_shapes::turtle()),
+            ..default()
+        };
+        Self {
+            colors: Colors::default(),
+            commands: TurtleCommands::new(vec![]),
+            name: Name::new("Turtle"),
+            shape: bundle,
+        }
+    }
+}
+
+impl Turtle {
+    /*     pub fn set_color(&mut self, color: Color) {
+        self.colors.color = color;
+    }
+    pub fn set_fill_color(&mut self, color: Color) {
+        self.colors.fill_color = color;
+    }
+    pub fn get_colors(&self) -> &Colors {
+        &self.colors
+    }
+    pub fn forward(&mut self) -> &mut Self {
+        self.commands
+            .commands
+            .push(TurtleCommand::Forward(Length(100.0)));
+        self
+    } */
+    pub fn set_commands(&mut self, commands: Vec<TurtleCommand>) {
+        self.commands = TurtleCommands::new(commands);
+    }
+}

src/primitives/turtle_primitives.rs

@@ -0,0 +1,23 @@
+use bevy::prelude::Vec2;
+
+use crate::{datatypes::angle::Angle, turtle::Precision};
+
+pub struct TurtleAction {
+    heading: Angle<Precision>,
+    position: Vec2,
+    primitive: TurtleActionType,
+}
+
+pub enum TurtleActionType {
+    Straight {
+        target: Vec2,
+    },
+    Rotate {
+        angle: Angle<Precision>,
+    },
+    Circle {
+        center: Vec2,
+        radii: Vec2,
+        extent: Angle<Precision>,
+    },
+}

src/primitives/turtle_shapes.rs

@@ -3,31 +3,33 @@ use std::f32::consts::PI;
 use bevy::prelude::Vec2;
 use bevy_prototype_lyon::prelude::{Path, PathBuilder};
 
+use crate::turtle::Precision;
+
 pub fn turtle() -> Path {
-    let polygon = &[
-        [-2.5f32, 14.0f32],
-        [-1.25f32, 10.0f32],
-        [-4.0f32, 7.0f32],
-        [-7.0f32, 9.0f32],
-        [-9.0f32, 8.0f32],
-        [-6.0f32, 5.0f32],
-        [-7.0f32, 1.0f32],
-        [-5.0f32, -3.0f32],
-        [-8.0f32, -6.0f32],
-        [-6.0f32, -8.0f32],
-        [-4.0f32, -5.0f32],
-        [0.0f32, -7.0f32],
-        [4.0f32, -5.0f32],
-        [6.0f32, -8.0f32],
-        [8.0f32, -6.0f32],
-        [5.0f32, -3.0f32],
-        [7.0f32, 1.0f32],
-        [6.0f32, 5.0f32],
-        [9.0f32, 8.0f32],
-        [7.0f32, 9.0f32],
-        [4.0f32, 7.0f32],
-        [1.25f32, 10.0f32],
-        [2.5f32, 14.0f32],
+    let polygon: &[[Precision; 2]; 23] = &[
+        [-2.5, 14.0],
+        [-1.25, 10.0],
+        [-4.0, 7.0],
+        [-7.0, 9.0],
+        [-9.0, 8.0],
+        [-6.0, 5.0],
+        [-7.0, 1.0],
+        [-5.0, -3.0],
+        [-8.0, -6.0],
+        [-6.0, -8.0],
+        [-4.0, -5.0],
+        [0.0, -7.0],
+        [4.0, -5.0],
+        [6.0, -8.0],
+        [8.0, -6.0],
+        [5.0, -3.0],
+        [7.0, 1.0],
+        [6.0, 5.0],
+        [9.0, 8.0],
+        [7.0, 9.0],
+        [4.0, 7.0],
+        [1.25, 10.0],
+        [2.5, 14.0],
     ];
     let mut turtle_path = PathBuilder::new();
     turtle_path.line_to(Vec2::new(1.0, 1.0));

src/structs.rs

@@ -0,0 +1,69 @@
+use bevy_prototype_lyon::prelude::PathBuilder;
+
+use crate::{
+    datatypes::{
+        angle::Angle,
+        length::Length,
+        Coordinate,
+    },
+    turtle::Precision,
+};
+
+/**
+ * All the possibilities to draw something with turtle. All the commands can get the position, heading,
+ * color and fill_color from the turtles state.
+ */
+pub enum MoveCommand {
+    Forward(Length),
+    Backward(Length),
+    Circle { radius: Length, angle: Angle<f32> },
+    Goto(Coordinate),
+    Home,
+}
+
+/// Different ways to drop breadcrumbs on the way like a dot or a stamp of the turtles shape.
+
+pub enum Breadcrumb {
+    Dot,
+    Stamp,
+}
+
+/// Different ways that change the orientation of the turtle.
+pub enum OrientationCommand {
+    Left(Angle<Precision>),
+    Right(Angle<Precision>),
+    SetHeading,
+    LookAt(Coordinate),
+}
+
+/// A combination of all commands that can be used while drawing.
+pub enum DrawElement {
+    Draw(MoveCommand),
+    Move(MoveCommand),
+    Orient(OrientationCommand),
+    Drip(Breadcrumb),
+}
+
+pub enum DrawingSegment {
+    Single(DrawElement),
+    Outline(Vec<DrawElement>),
+    Filled(Vec<DrawElement>),
+}
+
+impl DrawingSegment {
+    pub fn draw(&self) {
+        match self {
+            DrawingSegment::Single(elem) => {
+                let mut path_builder = PathBuilder::new();
+            }
+            DrawingSegment::Outline(_) => todo!(),
+            DrawingSegment::Filled(_) => todo!(),
+        }
+    }
+}
+
+#[derive(PartialEq, Eq)]
+pub enum DrawState {
+    PenDown,
+    PenUp,
+}

src/turtle.rs

@@ -1,14 +1,23 @@
+pub mod builders;
+pub mod state;
+pub mod turtle;
 use std::time::Duration;
 
 use bevy::prelude::*;
-use bevy_inspector_egui::{Inspectable, RegisterInspectable};
-use bevy_prototype_lyon::{prelude::*, shapes::Line};
+use bevy_prototype_lyon::prelude::*;
 use bevy_tweening::{
-    lens::TransformPositionLens, Animator, EaseFunction, Sequence, Tween, TweenCompleted,
-    TweeningPlugin, TweeningType,
+    component_animator_system, lens::TransformScaleLens, Animator, EaseFunction, RepeatCount,
+    Tween, TweenCompleted, TweeningPlugin,
 };
 
-use crate::{turtle_movement::turtle_move, turtle_shapes};
+#[allow(unused_imports)]
+use crate::paths;
+use crate::{
+    animation_step::run_animation_step,
+    datatypes::{angle::Angle, length::Length},
+    primitives::bundles::{Turtle, TurtleDrawCircle, TurtleDrawLine},
+    turtle_movement::TurtleStep,
+};
 
 pub struct TurtlePlugin;
 
@@ -18,232 +27,193 @@ impl Plugin for TurtlePlugin {
             .add_startup_system(setup)
             .add_system(keypresses)
             .add_system(draw_lines)
-            .register_inspectable::<Colors>()
-            .register_inspectable::<TurtleCommands>();
+            .add_system(component_animator_system::<Path>)
+            .register_type::<Colors>()
+            .register_type::<TurtleCommands>();
     }
 }
-#[derive(Bundle)]
-pub struct Turtle {
-    colors: Colors,
-    commands: TurtleCommands,
-    name: Name,
-}
+pub type Precision = f32;
 
-impl Default for Turtle {
-    fn default() -> Self {
-        Self {
-            colors: Colors {
-                color: Color::DARK_GRAY,
-                fill_color: Color::BLACK,
-            },
-            commands: TurtleCommands::new(vec![
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Right(Angle(90.)),
-                TurtleCommand::Backward(Length(100.)),
-                TurtleCommand::Right(Angle(90.)),
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Right(Angle(45.)),
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Right(Angle(90.)),
-                TurtleCommand::Forward(Length(50.)),
-                TurtleCommand::Right(Angle(90.)),
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Right(Angle(90.)),
-                TurtleCommand::Forward(Length(50.)),
-                TurtleCommand::Right(Angle(45.)),
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Left(Angle(120.)),
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Left(Angle(120.)),
-                TurtleCommand::Forward(Length(100.)),
-                TurtleCommand::Right(Angle(150.)),
-                TurtleCommand::Forward(Length(100.)),
-            ]),
-            name: Name::new("Turtle"),
-        }
-    }
-}
-
-impl Turtle {
-    pub fn set_color(&mut self, color: Color) {
-        self.colors.color = color;
-    }
-    pub fn set_fill_color(&mut self, color: Color) {
-        self.colors.fill_color = color;
-    }
-    pub fn get_colors(&self) -> &Colors {
-        &self.colors
-    }
-    pub fn forward(&mut self) -> &mut Self {
-        self.commands
-            .commands
-            .push(TurtleCommand::Forward(Length(100.0)));
-        self
-    }
-}
-
-#[derive(Component, Inspectable)]
+#[derive(Component, Reflect)]
 pub struct TurtleCommands {
     commands: Vec<TurtleCommand>,
     lines: Vec<TurtleGraphElement>,
+    state: TurtleState,
+}
+#[derive(Reflect)]
+pub struct TurtleState {
+    pub start: Vec2,
+    pub heading: Angle<f32>,
+    pub speed: u64,
+    pub index: u64,
+    pub drawing: bool,
 }
 
 impl TurtleCommands {
-    fn new(commands: Vec<TurtleCommand>) -> Self {
+    pub fn new(commands: Vec<TurtleCommand>) -> Self {
         Self {
             commands,
             lines: vec![],
+            state: TurtleState {
+                start: Vec2::ZERO,
+                heading: Angle::degrees(0.),
+                speed: 2000,
+                index: 0,
+                drawing: true,
+            },
         }
     }
 }
 
 impl TurtleCommands {
-    fn generate_tweenable(&mut self) -> Sequence<Transform> {
-        self.lines.clear();
-        let mut seq = Sequence::with_capacity(self.commands.len());
-        let mut pos = Vec2::ZERO;
-        let mut ori: f32 = 0.;
-        for (index, op) in self.commands.iter().enumerate() {
-            match op {
+    pub(crate) fn get_next(&mut self) -> Option<TurtleStep> {
+        let index = self.state.index;
+        let next_index = index + 1;
+
+        if let Some(command) = self.commands.get(self.state.index as usize) {
+            let res = match command {
                 TurtleCommand::Forward(Length(x)) => {
-                    let (target, animation, line) = turtle_move(pos, ori, *x as f32, index as f32);
-                    self.lines.push(line);
-                    seq = seq.then(animation);
-                    pos = target;
+                    crate::turtle_movement::turtle_move(&mut self.state, *x as f32)
                 }
                 TurtleCommand::Backward(Length(x)) => {
-                    let (target, animation, line) = turtle_move(pos, ori, -*x as f32, index as f32);
-                    self.lines.push(line);
-                    seq = seq.then(animation);
-                    pos = target;
+                    crate::turtle_movement::turtle_move(&mut self.state, -*x as f32)
                 }
-                TurtleCommand::Left(Angle(x)) => {
-                    let (nori, tween, line) = crate::turtle_movement::turtle_turn(ori, *x as f32);
-                    ori = nori;
-                    seq = seq.then(tween);
-                    self.lines.push(line);
+                TurtleCommand::Left(angle) => {
+                    crate::turtle_movement::turtle_turn(&mut self.state, *angle)
                 }
-                TurtleCommand::Right(Angle(x)) => {
-                    let (nori, tween, line) = crate::turtle_movement::turtle_turn(ori, -*x as f32);
-                    ori = nori;
-                    seq = seq.then(tween);
-                    self.lines.push(line);
+                TurtleCommand::Right(angle) => {
+                    crate::turtle_movement::turtle_turn(&mut self.state, -angle)
+                }
+                TurtleCommand::PenUp => {
+                    self.state.drawing = false;
+
+                    TurtleStep {
+                        turtle_animation: None,
+                        line_segment: None,
+                        line_animation: None,
+                        fill: None,
+                        stroke: None,
+                    }
+                }
+                TurtleCommand::PenDown => {
+                    self.state.drawing = true;
+
+                    TurtleStep {
+                        turtle_animation: None,
+                        line_segment: None,
+                        line_animation: None,
+                        fill: None,
+                        stroke: None,
+                    }
+                }
+                TurtleCommand::Circle { radius, angle } => {
+                    crate::turtle_movement::turtle_circle(&mut self.state, radius.0 as f32, *angle)
                 }
-                TurtleCommand::PenUp => todo!(),
-                TurtleCommand::PenDown => todo!(),
-                TurtleCommand::Circle => todo!(),
                 TurtleCommand::Pause => todo!(),
+                TurtleCommand::BeginFill => todo!(),
+                TurtleCommand::EndFill => todo!(),
+            };
+            self.state.index = next_index;
+            Some(res)
+        } else {
+            None
         }
     }
-        seq
-    }
 }
 
-#[derive(Inspectable, Default)]
+#[derive(Reflect, Default)]
 pub enum TurtleGraphElement {
-    TurtleLine {
-        start: Vec2,
-        end: Vec2,
-    },
+    TurtleLine(TurtleDrawLine),
+    TurtleCircle(TurtleDrawCircle),
     #[default]
     Noop,
 }
 
-#[derive(Clone, Component, Inspectable)]
+#[derive(Clone, Component, Reflect)]
 pub struct TurtleShape;
 
-#[derive(Clone, Component, Inspectable)]
+#[derive(Clone, Component, Reflect, Default)]
 pub struct Colors {
     color: Color,
     fill_color: Color,
 }
 
-#[derive(Inspectable, Default)]
-pub struct Length(f64);
-#[derive(Inspectable, Default)]
-pub struct Angle(f64);
-
-#[derive(Component, Inspectable, Default)]
+#[derive(Component, Reflect, Default)]
 pub enum TurtleCommand {
     Forward(Length),
     Backward(Length),
-    Left(Angle),
-    Right(Angle),
+    Left(Angle<f32>),
+    Right(Angle<f32>),
     PenUp,
     PenDown,
+    BeginFill,
+    EndFill,
     #[default]
     Pause,
-    Circle,
+    Circle {
+        radius: Length,
+        angle: Angle<f32>,
+    },
 }
 
 fn setup(mut commands: Commands) {
-    let animator = Animator::new(Tween::new(
-        // Use a quadratic easing on both endpoints.
+    let animator = Animator::new(
+        Tween::new(
             EaseFunction::QuadraticInOut,
-        // Loop animation back and forth.
-        TweeningType::PingPong,
-        // Animation time (one way only; for ping-pong it takes 2 seconds
-        // to come back to start).
-        Duration::from_secs(1),
-        // The lens gives access to the Transform component of the Entity,
-        // for the Animator to animate it. It also contains the start and
-        // end values respectively associated with the progress ratios 0. and 1.
-        TransformPositionLens {
-            start: Vec3::ZERO,
-            end: Vec3::new(40., 40., 0.),
+            Duration::from_millis(500),
+            TransformScaleLens {
+                start: Vec3::new(1., 1., 0.),
+                end: Vec3::new(1.3, 1.3, 0.),
             },
+        )
+        .with_repeat_strategy(bevy_tweening::RepeatStrategy::MirroredRepeat)
+        .with_repeat_count(RepeatCount::Infinite),
+    );
+    commands.spawn(Camera2dBundle::default());
+    let mut turtle_bundle = Turtle::default();
+    let mut tcommands = vec![];
+    //for _ in 0..100 {
+    tcommands.append(&mut paths::geometry_task::geometry_task());
+    //tcommands.append(&mut paths::circle_star::circle_star());
+    //}
+    turtle_bundle.set_commands(tcommands);
+    commands.spawn((
+        turtle_bundle,
+        animator,
+        TurtleShape,
+        Fill::color(Color::MIDNIGHT_BLUE),
+        Stroke::color(Color::BLACK),
     ));
-    commands.spawn_bundle(Camera2dBundle::default());
-    commands
-        .spawn_bundle(Turtle::default())
-        .insert_bundle(GeometryBuilder::build_as(
-            &turtle_shapes::turtle(),
-            DrawMode::Outlined {
-                fill_mode: FillMode::color(Color::MIDNIGHT_BLUE),
-                outline_mode: StrokeMode::new(Color::BLACK, 1.0),
-            },
-            Transform::identity(),
-        ))
-        .insert(animator)
-        .insert(TurtleShape);
 }
 
 fn draw_lines(
     mut commands: Commands,
-    tcmd: Query<&TurtleCommands>,
+    mut tcmd: Query<&mut TurtleCommands>,
+    mut turtle: Query<&mut Animator<Transform>, With<TurtleShape>>,
     mut query_event: EventReader<TweenCompleted>, // TODO: howto attach only to the right event?
 ) {
-    for ev in query_event.iter() {
-        let index = ev.user_data;
-
-        for t in tcmd.iter() {
-            let t = t.lines.get(index as usize).unwrap();
-            match t {
-                TurtleGraphElement::TurtleLine { start, end } => {
-                    commands.spawn_bundle(GeometryBuilder::build_as(
-                        &Line(*start, *end),
-                        DrawMode::Outlined {
-                            fill_mode: FillMode::color(Color::MIDNIGHT_BLUE),
-                            outline_mode: StrokeMode::new(Color::BLACK, 1.0),
-                        },
-                        Transform::identity(),
-                    ));
-                }
-                TurtleGraphElement::Noop => (),
-            }
-        }
+    for _ev in query_event.iter() {
+        let mut tcmd = tcmd.single_mut();
+        run_animation_step(&mut commands, &mut tcmd, &mut turtle)
     }
 }
 
 fn keypresses(
+    mut commands: Commands,
     keys: Res<Input<KeyCode>>,
-    mut qry: Query<&mut Animator<Transform>, With<TurtleShape>>,
     mut tcmd: Query<&mut TurtleCommands>,
+    mut turtle: Query<&mut Animator<Transform>, With<TurtleShape>>,
 ) {
     if keys.just_pressed(KeyCode::W) {
         let mut tcmd = tcmd.single_mut();
-        let c = tcmd.generate_tweenable();
-        let mut shap = qry.single_mut();
-        shap.set_tweenable(c);
+        tcmd.state = TurtleState {
+            start: Vec2::ZERO,
+            heading: Angle::degrees(0.),
+            speed: 1,
+            index: 0,
+            drawing: true,
+        };
+
+        run_animation_step(&mut commands, &mut tcmd, &mut turtle);
     }
 }

src/turtle/builders.rs

@@ -0,0 +1,15 @@
+use bevy_prototype_lyon::prelude::PathBuilder;
+
+use super::state::TurtleState;
+
+/// A turtle that combines its commands to one closed shape with the `close()` command.
+pub struct ShapeBuilder {
+    state: TurtleState,
+    builder: PathBuilder,
+}
+
+/// A turtle that draws a filled shape. End the filling process with the `end()` command.
+pub struct FilledBuilder {
+    state: TurtleState,
+    builder: PathBuilder,
+}

src/turtle/state.rs

@@ -0,0 +1,28 @@
+use bevy::prelude::{Color, Transform};
+
+use crate::{
+    datatypes::{angle::Angle, Coordinate, Speed, Visibility},
+    structs::{DrawState, DrawingSegment},
+    turtle::Precision,
+};
+
+/// Describing the full state of a turtle.
+pub struct TurtleState {
+    drawing: Vec<DrawingSegment>,
+    position: Coordinate,
+    heading: Angle<Precision>,
+    color: Color,
+    draw_state: DrawState,
+    visible: Visibility,
+    shape_transform: Transform,
+    speed: Speed,
+}
+
+impl TurtleState {
+    pub fn add_segment(&mut self, seg: DrawingSegment) {
+        self.drawing.push(seg);
+    }
+    pub fn drawing(&self) -> bool {
+        self.draw_state == DrawState::PenDown
+    }
+}

src/turtle/turtle.rs

@@ -0,0 +1,72 @@
+use bevy::prelude::{Color, Component};
+
+use crate::{
+    structs::{DrawElement, DrawingSegment, MoveCommand},
+    turtle_state::TurtleDraw,
+};
+
+use super::state::TurtleState;
+
+/// A default turtle drawing lines each line is one Segment.
+#[derive(Component)]
+pub struct Turtle {
+    state: TurtleState,
+}
+
+pub struct FilledTurtle {
+    state: TurtleState,
+    drawing: Vec<DrawingSegment>,
+    color: Color,
+}
+
+impl Turtle {
+    pub fn begin_fill(self, color: Color) -> FilledTurtle {
+        FilledTurtle {
+            state: self.state,
+            drawing: vec![],
+            color,
+        }
+    }
+}
+
+impl TurtleDraw for Turtle {
+    fn forward(&mut self, length: crate::datatypes::length::Length) -> &mut Self {
+        let move_command = MoveCommand::Forward(length);
+        self.state
+            .add_segment(DrawingSegment::Single(if self.state.drawing() {
+                DrawElement::Draw(move_command)
+            } else {
+                DrawElement::Move(move_command)
+            }));
+
+        self
+    }
+
+    fn backward(&mut self, length: crate::datatypes::length::Length) -> &mut Self {
+        todo!()
+    }
+
+    fn circle(
+        &mut self,
+        radius: crate::datatypes::length::Length,
+        angle: crate::datatypes::angle::Angle<super::Precision>,
+    ) -> &mut Self {
+        todo!()
+    }
+
+    fn goto(&mut self, coordinate: crate::datatypes::Coordinate) -> &mut Self {
+        todo!()
+    }
+
+    fn home(&mut self) -> &mut Self {
+        todo!()
+    }
+
+    fn dot(&mut self, size: crate::datatypes::length::Length) -> &mut Self {
+        todo!()
+    }
+
+    fn stamp(&mut self, size: crate::datatypes::length::Length) -> &mut Self {
+        todo!()
+    }
+}

src/turtle_movement.rs

@@ -1,60 +1,146 @@
-use std::{f32::consts::PI, time::Duration};
+use std::time::Duration;
 
-use bevy::prelude::{Transform, Vec2};
+use bevy::prelude::{default, Color, Quat, Transform, Vec2, Vec3};
+use bevy_prototype_lyon::prelude::{Fill, Path, Stroke};
 use bevy_tweening::{
     lens::{TransformPositionLens, TransformRotateZLens},
-    EaseFunction, Tween, TweeningType,
+    Animator, EaseFunction, Tween,
 };
 
-use crate::turtle::TurtleGraphElement;
+use crate::{
+    datatypes::angle::Angle,
+    primitives::{
+        animation::{CircleAnimationLens, CircleMovementLens, LineAnimationLens},
+        bundles::{TurtleDrawCircle, TurtleDrawLine},
+    },
+    turtle::{Precision, TurtleGraphElement, TurtleState},
+};
 
-pub fn turtle_turn(
-    orientation: f32,
-    angle_to_turn: f32,
-) -> (f32, Tween<Transform>, TurtleGraphElement) {
-    let start = orientation;
-    let end = orientation + (angle_to_turn * PI / 180.);
-    let animation = Tween::new(
-        // Use a quadratic easing on both endpoints.
-        EaseFunction::QuadraticInOut,
-        // Loop animation back and forth.
-        TweeningType::Once,
-        // Animation time (one way only; for ping-pong it takes 2 seconds
-        // to come back to start).
-        Duration::from_millis(500),
-        // The lens gives access to the Transform component of the Entity,
-        // for the Animator to animate it. It also contains the start and
-        // end values respectively associated with the progress ratios 0. and 1.
-        TransformRotateZLens { start, end },
-    );
-    let line = TurtleGraphElement::Noop;
-    let orientation = end % (2. * PI);
-    (orientation, animation, line)
+pub struct TurtleStep {
+    pub turtle_animation: Option<Tween<Transform>>,
+    pub line_segment: Option<TurtleGraphElement>,
+    pub line_animation: Option<Animator<Path>>,
+    pub fill: Option<Fill>,
+    pub stroke: Option<Stroke>,
 }
 
-pub fn turtle_move(
-    position: Vec2,
-    orientation: f32,
-    length: f32,
-    index: f32,
-) -> (Vec2, Tween<Transform>, TurtleGraphElement) {
-    let start = position;
-    let end = position + (Vec2::from_angle(orientation) * length);
-    let turtle_movement_animation = Tween::new(
-        // accelerate and decelerate
+pub fn turtle_turn(state: &mut TurtleState, angle_to_turn: Angle<Precision>) -> TurtleStep {
+    let start = state.heading;
+    let end = state.heading + angle_to_turn;
+    let animation = Tween::new(
         EaseFunction::QuadraticInOut,
-        // Loop animation back and forth.
-        TweeningType::Once,
-        // later to be controlled by speed
-        Duration::from_millis(500),
-        // set the start and end of the animation
+        Duration::from_millis(state.speed),
+        TransformRotateZLens {
+            start: start.to_radians().value(),
+            end: end.to_radians().value(),
+        },
+    )
+    .with_completed_event(state.index as u64);
+    // Don't draw as the position does not change
+    let line = TurtleGraphElement::Noop;
+    // Update the state
+    state.heading = end.limit_smaller_than_full_circle();
+    TurtleStep {
+        turtle_animation: Some(animation),
+        line_segment: Some(line),
+        line_animation: None,
+        fill: None,
+        stroke: None,
+    }
+}
+
+pub fn turtle_move(state: &mut TurtleState, length: Precision) -> TurtleStep {
+    let start = state.start;
+    let end = state.start + (Vec2::from_angle(state.heading.to_radians().value()) * length);
+    let turtle_movement_animation = Tween::new(
+        EaseFunction::QuadraticInOut,
+        Duration::from_millis(state.speed),
         TransformPositionLens {
             start: start.extend(0.),
             end: end.extend(0.),
         },
     )
-    .with_completed_event(index as u64);
-    let line = TurtleGraphElement::TurtleLine { start, end };
+    .with_completed_event(state.index as u64);
+    let line = if state.drawing {
+        TurtleGraphElement::TurtleLine(TurtleDrawLine::new(start, end, state.index))
+    } else {
+        TurtleGraphElement::Noop
+    };
+    let line_animator = Animator::new(Tween::new(
+        EaseFunction::QuadraticInOut,
+        Duration::from_millis(state.speed),
+        LineAnimationLens::new(start, end),
+    ));
+    state.start = end;
+    TurtleStep {
+        turtle_animation: Some(turtle_movement_animation),
+        line_segment: Some(line),
+        line_animation: Some(line_animator),
+        fill: Some(Fill::color(Color::MIDNIGHT_BLUE)),
+        stroke: Some(Stroke::color(Color::BLACK)),
+    }
+}
 
-    (end, turtle_movement_animation, line)
+pub fn turtle_circle(
+    state: &mut TurtleState,
+    radius: Precision,
+    angle: Angle<Precision>,
+) -> TurtleStep {
+    let radii = Vec2::ONE * radius.abs();
+    let left_right = Angle::degrees(if radius >= 0. { 90. } else { -90. });
+    let center = state.start
+        + (Vec2::new(radius.abs(), 0.).rotate(Vec2::from_angle(
+            ((state.heading + left_right).to_radians()).value(),
+        )));
+
+    let turtle_movement_animation = Tween::new(
+        EaseFunction::QuadraticInOut,
+        Duration::from_millis(state.speed),
+        CircleMovementLens {
+            start: Transform {
+                translation: state.start.extend(0.),
+                rotation: Quat::from_rotation_z(state.heading.to_radians().value()),
+                scale: Vec3::ONE,
+            },
+            end: angle,
+            center,
+        },
+    )
+    .with_completed_event(state.index as u64);
+    let end_pos = center
+        + Vec2::new(radius.abs(), 0.).rotate(Vec2::from_angle(
+            (state.heading + angle - left_right).to_radians().value(),
+        ));
+    let line = if state.drawing {
+        TurtleGraphElement::TurtleCircle(TurtleDrawCircle::new(
+            center,
+            radii,
+            Angle::degrees(0.),
+            state.index,
+            state.start,
+            end_pos,
+        ))
+    } else {
+        TurtleGraphElement::Noop
+    };
+    let line_animator = Animator::new(Tween::new(
+        EaseFunction::QuadraticInOut,
+        Duration::from_millis(state.speed),
+        CircleAnimationLens {
+            start_pos: state.start,
+            center,
+            radii,
+            start: Angle::degrees(0.),
+            end: angle,
+        },
+    ));
+    state.start = end_pos;
+    state.heading = state.heading + angle;
+    TurtleStep {
+        turtle_animation: Some(turtle_movement_animation),
+        line_segment: Some(line),
+        line_animation: Some(line_animator),
+        fill: Some(Fill::color(Color::MIDNIGHT_BLUE)),
+        stroke: Some(Stroke::color(Color::BLACK)),
+    }
 }

src/turtle_state.rs

@@ -0,0 +1,61 @@
+use bevy::prelude::{Color, Transform};
+use bevy_prototype_lyon::prelude::PathBuilder;
+
+use crate::{
+    datatypes::{angle::Angle, length::Length, Coordinate, Speed, Visibility},
+    structs::DrawingSegment,
+    turtle::Precision,
+};
+
+/// Describing the full state of a turtle.
+pub struct TurtleState {
+    drawing: Vec<DrawingSegment>,
+    position: Coordinate,
+    heading: Angle<Precision>,
+    color: Color,
+    fill_color: Color,
+    visible: Visibility,
+    shape_transform: Transform,
+    speed: Speed,
+}
+
+/// A default turtle drawing lines each line is one Segment.
+pub struct Turtle {
+    state: TurtleState,
+}
+
+/// A turtle that combines its commands to one closed shape with the `close()` command.
+pub struct ShapeBuilder {
+    state: TurtleState,
+    builder: PathBuilder,
+}
+
+/// A turtle that draws a filled shape. End the filling process with the `end()` command.
+pub struct FilledBuilder {
+    state: TurtleState,
+    builder: PathBuilder,
+}
+
+pub trait TurtleDraw {
+    fn forward(&mut self, length: Length) -> &mut Self;
+    fn backward(&mut self, length: Length) -> &mut Self;
+    fn circle(&mut self, radius: Length, angle: Angle<Precision>) -> &mut Self;
+    fn goto(&mut self, coordinate: Coordinate) -> &mut Self;
+    fn home(&mut self) -> &mut Self;
+    fn dot(&mut self, size: Length) -> &mut Self;
+    fn stamp(&mut self, size: Length) -> &mut Self;
+}
+
+pub trait TurtleTurn {
+    fn left(&mut self, angle: Angle<Precision>) -> &mut Self;
+    fn right(&mut self, angle: Angle<Precision>) -> &mut Self;
+    fn look_at(&mut self, coordinate: Coordinate) -> &mut Self;
+}
+
+pub trait TurtleHistory {
+    fn reset(&mut self) -> &mut Self;
+    fn clear(&mut self) -> &mut Self;
+    fn undo(&mut self) -> &mut Self;
+
+    fn clear_stamps(&mut self) -> &mut Self;
+}