docs: added signals example!

Cargo.toml

@@ -9,6 +9,7 @@ repository = "https://github.com/AryanpurTech/BlueEngine"
 keywords = ["gamedev", "graphics", "3D", "2D"]
 categories = ["game-development", "gui", "graphics", "rendering"]
 license = "Apache-2.0"
+exclude = ["/examples"]
 
 [lib]
 name = "blue_engine"
@@ -97,6 +98,10 @@ path = "examples/utils/scissor.rs"
 name = "clear_color"
 path = "examples/utils/clear_color.rs"
 
+[[example]]
+name = "signals"
+path = "examples/utils/signals.rs"
+
 # Development ONLY
 [[example]]
 name = "dev"

examples/utils/signals.rs

@@ -0,0 +1,76 @@
+/*
+ * Signal example (could be used as template too) for Blue Engine
+ *
+ * The license is same as the one on the root.
+*/
+
+use blue_engine::{
+    header::{Engine, ObjectSettings},
+    primitive_shapes::triangle,
+    Signal,
+};
+
+/// An example plugin with custom fields and operations
+struct MyPlugin {
+    counter: u32,
+}
+impl MyPlugin {
+    fn new() -> Self {
+        Self { counter: 0 }
+    }
+
+    fn increment(&mut self) {
+        self.counter += 1;
+    }
+
+    fn reset(&mut self) {
+        self.counter = 0;
+    }
+}
+/// implemented the signals you need from the engine
+impl Signal for MyPlugin {
+    fn frame(
+        &mut self,
+        _renderer: &mut blue_engine::Renderer,
+        _window: &blue_engine::Window,
+        _objects: &mut blue_engine::ObjectStorage,
+        _camera: &mut blue_engine::CameraContainer,
+        input: &blue_engine::InputHelper,
+        _encoder: &mut blue_engine::CommandEncoder,
+        _view: &blue_engine::TextureView,
+    ) {
+        // operations that relate to the engine, and can call the
+        // internal fields and functions you need.
+        if input.key_pressed(blue_engine::KeyCode::Enter) {
+            self.increment();
+            println!("New counter value: {}", self.counter);
+        }
+    }
+}
+
+pub fn main() {
+    // initialize the engine
+    let mut engine = Engine::new().expect("win");
+
+    // add your objects and anything else you need
+    triangle(
+        "Triangle",
+        ObjectSettings::default(),
+        &mut engine.renderer,
+        &mut engine.objects,
+    )
+    .unwrap();
+
+    // initialize your plugin
+    let mut myplugin = MyPlugin::new();
+    // do any init operation you want
+    myplugin.reset();
+
+    // add it to the engine's signals
+    engine.signals.add_signal("my plugin", Box::new(myplugin));
+
+    // thats it, the engine will now run it on every frame or wherever you requested.
+    engine
+        .update_loop(move |_, _, _, _, _, _| {})
+        .expect("Error during update loop");
+}