feat: Complete camera system w/o stretch goals

Author: Carter Hollman

game/src/camera.rs

@@ -0,0 +1 @@
+pub mod camera_plugin;

game/src/camera/camera_plugin.rs

@@ -0,0 +1,90 @@
+use bevy::{input::mouse::MouseWheel, prelude::*};
+
+pub struct CameraPlugin;
+
+//Component that marks our Camera's current target
+#[derive(Component)]
+pub struct CameraTarget;
+
+//Component that marks our main camera
+#[derive(Component)]
+pub struct MainCamera;
+
+impl Plugin for CameraPlugin{
+    fn build(&self, app: &mut App){
+        app.add_systems(Startup, setup_main_camera);
+        app.add_systems(Update, (update_camera, zoom_camera).chain());
+    }
+}
+
+
+//Sets up a 2d camera and attaches the MainCamera marker to it 
+fn setup_main_camera(
+    mut commands: Commands
+) {
+    commands.spawn(( 
+        Camera2dBundle::default(),
+        MainCamera    
+    ));
+}
+
+
+//Update camera function will have our main camera follow any entity with the CameraTarget tag
+fn update_camera(
+    mut camera_query : Query<&mut Transform, (With<MainCamera>, Without<CameraTarget>)>,
+    target_query: Query<&Transform, (With<CameraTarget>, Without<MainCamera>)>,
+){
+    //getting camera from query
+    let Ok(mut camera) = camera_query.get_single_mut() else{
+        return;
+    };
+
+    //getting target from query
+    let Ok(target) = target_query.get_single() else{
+        return;
+    };
+
+    //Gets the x and y coordinates of our target
+    let Vec3 {x,y,..} = target.translation;
+
+    //Stores the target x y with our camera z cuz our camera z not changing
+    let direction = Vec3::new(x,y,camera.translation.z);
+
+    //Debug statements if we want to use them :)
+    //info!("Camera: {:?}", camera);
+    //info!("Target: {:?}", target);
+
+    //Make our camera translation match our target translation
+    camera.translation = direction;
+}
+
+//Camera Zooming Function, uses MouseWheel Scrolling up/down for zooming in/out
+fn zoom_camera(
+    mut scroll_event : EventReader<MouseWheel>,
+    mut camera: Query<&mut OrthographicProjection, With<MainCamera>>
+){
+
+
+    //Zoom Sensitivity
+    let zoom_factor = 0.1;
+
+    //Amount to zoom in this update cycle
+    let mut zoom_amount = 0.0;
+
+
+    //For every event read in this cycle increase the zoom amount by 1 event * sensitivity
+    for event in scroll_event.read(){
+        zoom_amount += -event.y * zoom_factor
+    }
+
+    //If we have had any mouse scroll events in this update then apply it to the camera projection
+    if zoom_amount != 0.0{
+        //extracting the type of projection from camera, only ever going to be Orthographic since 2d but I don't know a better way lol
+        for mut projection in camera.iter_mut(){
+            projection.scale += zoom_amount;
+
+            //This statement makes sure that the amount of zoom is capped, can change if need be 
+            projection.scale = projection.scale.clamp(0.1,5.0);
+        }
+    }
+}

game/src/debug/debug_plugin.rs

@@ -1,4 +1,9 @@
 use bevy::prelude::*;
+use avian2d::prelude::*;
+use avian2d::math::*;
+
+use crate::movement::plugin::*;
+use crate::camera::camera_plugin::*;
 
 ///This plugin provides terminal debug capabilities
 ///By adding systems, requested information will be printed to the terminal
@@ -8,6 +13,7 @@ pub struct DebugPlugin;
 impl Plugin for DebugPlugin {
     fn build(&self, app: &mut App) {
         app.add_systems(Startup, print_debug_active_message);
+        app.add_systems(Startup, display_dudes);
     }
 }
 
@@ -16,3 +22,27 @@ impl Plugin for DebugPlugin {
 fn print_debug_active_message() {
     info!("The debugger is active!");
 }
+
+
+//Displays two pixel like sprites where one is stationary, then the other that has the CameraTarget component 
+//falls forever. Used to test camera system tracking and zooming. 
+fn display_dudes(mut commands : Commands){
+    commands.spawn((
+        SpriteBundle::default(),
+        
+        CharacterControllerBundle::new(Collider::capsule(12.5, 20.0)).with_movement(
+            1250.0,
+            0.92,
+            400.0,
+            (30.0 as Scalar).to_radians(),
+        ),
+        Friction::ZERO.with_combine_rule(CoefficientCombine::Min),
+        Restitution::ZERO.with_combine_rule(CoefficientCombine::Min),
+        ColliderDensity(2.0),
+        GravityScale(1.5),
+    )).insert(CameraTarget);
+
+    commands.spawn(
+        SpriteBundle::default()
+    );
+}

game/src/main.rs

@@ -1,11 +1,14 @@
 mod debug;
 mod movement;
+mod camera;
 
 use avian2d::prelude::*;
 use bevy::prelude::*;
 use bevy_ecs_ldtk::prelude::*;
 use debug::debug_plugin::DebugPlugin;
 use movement::plugin::CharacterControllerPlugin;
+use camera::camera_plugin::CameraPlugin;
+
 
 fn main() {
     App::new()
@@ -15,5 +18,7 @@ fn main() {
         .add_plugins(CharacterControllerPlugin)
         //user plugins
         .add_plugins(DebugPlugin)
+        .add_plugins(CameraPlugin)
         .run();
 }
+