simple ecs systems!

Cargo.lock

@@ -621,6 +621,12 @@ dependencies = [
  "instant",
 ]
 
+[[package]]
+name = "fixedbitset"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
+
 [[package]]
 name = "flate2"
 version = "1.0.25"
@@ -1003,6 +1009,7 @@ dependencies = [
  "hecs",
  "image",
  "instant",
+ "petgraph",
  "specs",
  "tobj",
  "tracing",
@@ -1387,6 +1394,16 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "478c572c3d73181ff3c2539045f6eb99e5491218eae919370993b890cdbdd98e"
 
+[[package]]
+name = "petgraph"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4dd7d28ee937e54fe3080c91faa1c3a46c06de6252988a7f4592ba2310ef22a4"
+dependencies = [
+ "fixedbitset",
+ "indexmap",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.9"

Cargo.toml

@@ -23,4 +23,5 @@ instant = "0.1"
 async-trait = "0.1.65"
 specs = { version = "0.18.0", features = [ "derive" ] }
 hecs = "0.10.3"
-glam = { version = "0.24.0", features = ["bytemuck"] }
+glam = { version = "0.24.0", features = ["bytemuck"] }
+petgraph = "0.6.3"

src/ecs/components/transform.rs

@@ -15,14 +15,20 @@ impl Default for TransformComponent {
     }
 }
 
+impl From<Transform> for TransformComponent {
+    fn from(transform: Transform) -> Self {
+        Self {
+            transform
+        }
+    }
+}
+
 impl TransformComponent {
     pub fn new() -> Self {
         Self::default()
     }
     
     pub fn from_transform(transform: Transform) -> Self {
-        Self {
-            transform
-        }
+        Self::from(transform)
     }
 }

src/ecs/mod.rs

@@ -2,6 +2,7 @@ use std::collections::HashMap;
 
 use async_trait::async_trait;
 use hecs::World;
+use petgraph::{prelude::StableDiGraph, stable_graph::NodeIndex, visit::Topo};
 use tracing::warn;
 
 pub mod components;
@@ -52,6 +53,89 @@ impl SimpleSystem for SystemFnExecutor {
             }
         }
 
+        Ok(())
+    }
+}
+
+struct SystemGraphNode {
+    name: String,
+    dependent_on: Vec<String>,
+    system: Box<dyn SimpleSystem>,
+}
+
+struct SystemGraphEdge {
+    
+}
+
+pub struct SystemGraphExecutor {
+    graph: StableDiGraph<SystemGraphNode, SystemGraphEdge>,
+    node_refs: HashMap<String, NodeIndex>,
+}
+
+impl Default for SystemGraphExecutor {
+    fn default() -> Self {
+        Self {
+            graph: StableDiGraph::new(),
+            node_refs: HashMap::new(),
+        }
+    }
+}
+
+impl SystemGraphExecutor {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Adds a SimpleSystem to the SystemGraph.
+    ///  
+    /// WARN: Ensure that no cycles are created, this will cause the systems graph to not be sortable by topological sort,
+    /// and will cause a panic later on in the engine.
+    /// 
+    /// TODO: Return false if a cycle was created, making it impossible to know when to dispatch them. This will mean that the System would not of had been added.
+    pub fn add_system(&mut self, name: String, system: Box<dyn SimpleSystem>, dependencies: &[String]) -> bool {
+        let added_index =
+            self.graph.add_node(SystemGraphNode {
+                name: name.clone(),
+                dependent_on: dependencies.clone().to_vec(),
+                system,
+            });
+
+        // store name ref to the graph node
+        self.node_refs.insert(name, added_index);
+
+        // find the dependencies in node_refs and add edges directed towards the new node
+        for depend in dependencies.into_iter() {
+            let idx = self.node_refs
+                .get(depend)
+                .expect("Dependency not found!");
+
+            self.graph.add_edge(idx.clone(), added_index, SystemGraphEdge { });
+        }
+
+        true
+    }
+
+    pub(crate) fn execute_mut(&mut self, world: &mut World) {
+        let mut topo = Topo::new(&self.graph);
+
+        while let Some(nx) = topo.next(&self.graph) {
+            let node = self.graph.node_weight_mut(nx).unwrap();
+
+            match node.system.execute_mut(world) {
+                Ok(()) => {},
+                Err(e) => {
+                    warn!("System execution of {} resulted in an error! '{}'.", node.name, e);
+                    return;
+                }
+            }
+        }
+    }
+}
+
+impl SimpleSystem for SystemGraphExecutor {
+    fn execute_mut(&mut self, world: &mut World) -> anyhow::Result<()> {
+        SystemGraphExecutor::execute_mut(self, world);
+
         Ok(())
     }
 }

src/game.rs

@@ -13,7 +13,7 @@ use tracing_subscriber::{
 
 use winit::{window::{WindowBuilder, Window}, event::{Event, WindowEvent, KeyboardInput, ElementState, VirtualKeyCode}, event_loop::{EventLoop, ControlFlow}};
 
-use crate::{render::{renderer::{Renderer, BasicRenderer}, render_job::RenderJob}, input_event::InputEvent, ecs::{components::{mesh::MeshComponent, transform::TransformComponent}, SystemFnExecutor, SimpleSystem}};
+use crate::{render::{renderer::{Renderer, BasicRenderer}, render_job::RenderJob}, input_event::InputEvent, ecs::{components::{mesh::MeshComponent, transform::TransformComponent}, SystemFnExecutor, SimpleSystem, SystemGraphExecutor}};
 
 struct TickCounter {
     counter: u32,
@@ -69,24 +69,43 @@ impl TickCounter {
     }
 }
 
+struct JiggleEntitiesSystem {
+
+}
+
+impl SimpleSystem for JiggleEntitiesSystem {
+    fn execute_mut(&mut self, world: &mut World) -> anyhow::Result<()> {
+        for (_eid, (transform, )) in world.query_mut::<(&mut TransformComponent,)>() {
+            transform.transform.translate_vec3(glam::Vec3::new(0.0, 0.001, 0.0));
+        }
+
+        Ok(())
+    }
+}
 
 struct GameLoop {
     window: Arc<Window>,
     renderer: Box<dyn Renderer>,
     
     world: Arc<Mutex<World>>,
-    system_fn_executor: SystemFnExecutor,
+    /// higher priority systems
+    engine_systems: Vec<Box<dyn SimpleSystem>>,
+    systems: Vec<Box<dyn SimpleSystem>>,
     fps_counter: TickCounter,
 }
 
 impl GameLoop {
-    pub async fn new(window: Arc<Window>, world: Arc<Mutex<World>>) -> GameLoop {
+    pub async fn new(window: Arc<Window>, world: Arc<Mutex<World>>, user_systems: Vec<Box<dyn SimpleSystem>>) -> GameLoop {
+        /* let mut graph_exec = SystemGraphExecutor::new();
+        graph_exec.add_system("jiggle_entities".to_string(), Box::new(JiggleEntitiesSystem {}), &[]); */
+        
         Self {
             window: Arc::clone(&window),
             renderer: Box::new(BasicRenderer::create_with_window(window).await),
 
             world,
-            system_fn_executor: SystemFnExecutor::new(),
+            engine_systems: vec![],
+            systems: user_systems,
             fps_counter: TickCounter::new(),
         }
     }
@@ -101,7 +120,14 @@ impl GameLoop {
 
     async fn update(&mut self) {
         let mut world = self.world.lock().await;
-        self.system_fn_executor.execute_mut(&mut world).unwrap(); // always returns Ok(())
+
+        for esystem in self.engine_systems.iter_mut() {
+            esystem.execute_mut(&mut world).unwrap();
+        }
+
+        for system in self.systems.iter_mut() {
+            system.execute_mut(&mut world).unwrap();
+        }
     }
 
     async fn input_update(&mut self, event: &InputEvent) -> Option<ControlFlow> {
@@ -208,12 +234,14 @@ impl GameLoop {
 
 pub struct Game {
     world: Option<Arc<Mutex<World>>>,
+    systems: Option<Vec<Box<dyn SimpleSystem>>>
 }
 
 impl Default for Game {
     fn default() -> Self {
         Self {
             world: None,
+            systems: Some(vec![]),
         }
     }
 }
@@ -247,13 +275,25 @@ impl Game {
         self
     }
 
+    pub fn with_system<S>(&mut self, system: S) -> &mut Self
+    where
+        S: SimpleSystem + 'static
+    {
+        let systems = self.systems.as_mut().unwrap();
+        systems.push(Box::new(system));
+
+        self
+    }
+
     pub async fn run(&mut self) {
         let world = self.world.take().expect("ECS World was never given to Game!");
 
         let event_loop = EventLoop::new();
         let window = Arc::new(WindowBuilder::new().build(&event_loop).unwrap());
 
-        let mut g_loop = GameLoop::new(Arc::clone(&window), world).await;
+        let systems = self.systems.take().unwrap();
+
+        let mut g_loop = GameLoop::new(Arc::clone(&window), world, systems).await;
 
         event_loop.run(move |event, _, control_flow| {
             g_loop.run_sync(event, control_flow);

src/main.rs

@@ -11,10 +11,11 @@ use ecs::components::transform::TransformComponent;
 use game::Game;
 use hecs::World;
 
+use crate::ecs::SystemFnExecutor;
 use crate::render::material::Material;
 use crate::render::texture::Texture;
 use crate::ecs::components::camera::CameraComponent;
-use crate::math::Angle;
+use crate::math::{Angle, Transform};
 //use specs::*;
 
 #[derive(Debug, Default)]
@@ -77,7 +78,7 @@ async fn main() {
             shader_id: 0,
             texture: diffuse_texture
         }),
-        TransformComponent::new(),
+        TransformComponent::from(Transform::from_translation(0.005, 0.0, 0.0)),
     ));
 
     let mut camera = CameraComponent::new();
@@ -86,8 +87,21 @@ async fn main() {
     camera.transform.rotate_z(Angle::Degrees(-90.0));
     world.spawn((camera,));
 
+    let jiggle_system = |world: &mut World| -> anyhow::Result<()> {
+        for (_eid, (transform, )) in world.query_mut::<(&mut TransformComponent,)>() {
+            let t = &mut transform.transform;
+            t.translate_vec3(glam::Vec3::new(t.x() * -1.0, 0.001, 0.0));
+        }
+
+        Ok(())
+    };
+
+    let mut fn_exec = SystemFnExecutor::new();
+    fn_exec.add_system("jiggle", Box::new(jiggle_system));
+    
     Game::initialize().await
         .with_world(world)
+        .with_system(fn_exec)
         .run().await;
 
     /* world.register::<Point2d>();

src/math/transform.rs

@@ -65,6 +65,16 @@ impl Transform {
         Self::from_matrix(matrix)
     }
 
+    pub fn from_translation_vec(translation: Vec3) -> Self {
+        let matrix = glam::Mat4::from_scale_rotation_translation(Vec3::new(1.0, 1.0, 1.0), Quat::IDENTITY, translation);
+
+        Self::from_matrix(matrix)
+    }
+
+    pub fn from_translation(x: f32, y: f32, z: f32) -> Self {
+        Self::from_translation_vec(Vec3::new(x, y, z))
+    }
+
     pub fn translate_vec3(&mut self, vec: Vec3) -> &mut Self {
         let translation = glam::Mat4::from_translation(vec);
         self.matrix *= translation;
@@ -163,4 +173,16 @@ impl Transform {
 
         self
     }
+
+    pub fn x(&self) -> f32 {
+        self.get_translation().x
+    }
+
+    pub fn y(&self) -> f32 {
+        self.get_translation().y
+    }
+
+    pub fn z(&self) -> f32 {
+        self.get_translation().z
+    }
 }