feat: debug terrain painting

src/game/camera.rs

@@ -13,6 +13,7 @@ pub struct GameCameraPlugin;
 impl Plugin for GameCameraPlugin {
     fn build(&self, app: &mut App) {
         app.register_inspectable::<CameraFollow>()
+            .register_type::<GameCamera>()
             .add_startup_system(camera_setup)
             .add_system_to_stage(CoreStage::PostUpdate, camera_system);
     }
@@ -31,6 +32,10 @@ impl Default for FollowMovement {
     }
 }
 
+#[derive(Default, Component, Reflect, Inspectable)]
+#[reflect(Component)]
+pub struct GameCamera;
+
 #[derive(Default, Component, Reflect, Inspectable)]
 #[reflect(Component)]
 pub struct CameraFollow {
@@ -55,6 +60,7 @@ fn camera_setup(mut commands: Commands) {
             },
             ..default()
         },
+        GameCamera,
     ));
 }
 

src/terrain2d.rs

@@ -3,7 +3,10 @@ use std::collections::{
     HashMap,
 };
 
-use bevy::prelude::*;
+use bevy::{
+    prelude::*,
+    render::{camera::RenderTarget, view::window},
+};
 use bevy_prototype_debug_lines::DebugLines;
 
 mod chunk2d;
@@ -14,7 +17,10 @@ pub use chunk2d::*;
 pub use terrain_gen2d::*;
 pub use texel2d::*;
 
-use crate::util::{math::*, Vector2I};
+use crate::{
+    game::camera::GameCamera,
+    util::{math::*, Vector2I},
+};
 
 pub struct Terrain2DPlugin;
 
@@ -23,6 +29,7 @@ impl Plugin for Terrain2DPlugin {
         app.register_type::<TerrainChunk2D>()
             .insert_resource(Terrain2D::new())
             .add_event::<TerrainEvent2D>()
+            .add_system(debug_painter)
             .add_system_to_stage(
                 CoreStage::PostUpdate,
                 dirty_rect_visualizer.before(emit_terrain_events),
@@ -34,6 +41,70 @@ impl Plugin for Terrain2DPlugin {
     }
 }
 
+fn debug_painter(
+    mut terrain: ResMut<Terrain2D>,
+    windows: Res<Windows>,
+    input: Res<Input<MouseButton>>,
+    camera_query: Query<(&Camera, &GlobalTransform), With<GameCamera>>,
+) {
+    if !input.pressed(MouseButton::Left) && !input.pressed(MouseButton::Right) {
+        return;
+    }
+
+    // REM: Dirty and hopefully temporary
+    // https://bevy-cheatbook.github.io/cookbook/cursor2world.html#2d-games
+    // get the camera info and transform
+    // assuming there is exactly one main camera entity, so query::single() is OK
+    let (camera, camera_transform) = camera_query.single();
+
+    // get the window that the camera is displaying to (or the primary window)
+    let window = if let RenderTarget::Window(id) = camera.target {
+        windows.get(id).unwrap()
+    } else {
+        windows.get_primary().unwrap()
+    };
+
+    // check if the cursor is inside the window and get its position
+    let world_pos = if let Some(screen_pos) = window.cursor_position() {
+        // get the size of the window
+        let window_size = Vec2::new(window.width() as f32, window.height() as f32);
+
+        // convert screen position [0..resolution] to ndc [-1..1] (gpu coordinates)
+        let ndc = (screen_pos / window_size) * 2.0 - Vec2::ONE;
+
+        // matrix for undoing the projection and camera transform
+        let ndc_to_world = camera_transform.compute_matrix() * camera.projection_matrix().inverse();
+
+        // use it to convert ndc to world-space coordinates
+        let world_pos = ndc_to_world.project_point3(ndc.extend(-1.0));
+
+        // reduce it to a 2D value
+        world_pos.truncate()
+    } else {
+        return;
+    };
+
+    let origin = Vector2I::from(world_pos);
+    let radius: i32 = 12;
+    let id = match (
+        input.pressed(MouseButton::Left),
+        input.pressed(MouseButton::Right),
+    ) {
+        (true, false) => 1,
+        (_, _) => 0,
+    };
+
+    for y in origin.y - (radius - 1)..origin.y + radius {
+        for x in origin.x - (radius - 1)..origin.x + radius {
+            let dx = (x - origin.x).abs();
+            let dy = (y - origin.y).abs();
+            if dx * dx + dy * dy <= (radius - 1) * (radius - 1) {
+                terrain.set_texel(&Vector2I { x, y }, id)
+            }
+        }
+    }
+}
+
 /**
     Visualize dirty rects
 */

src/terrain2d/chunk2d.rs

@@ -553,7 +553,8 @@ pub fn chunk_collision_sync(
         (With<TerrainChunkCollisionSync2D>, Changed<TerrainChunk2D>),
     >,
     chunk_query: Query<(Entity, &TerrainChunk2D), With<TerrainChunkCollisionSync2D>>,
-    child_collider_query: Query<&Children, With<Collider>>,
+    child_query: Query<&Children>,
+    collider_query: Query<&Collider>,
 ) {
     let mut updated_chunks = vec![];
 
@@ -585,9 +586,11 @@ pub fn chunk_collision_sync(
 
     for (entity, chunk) in updated_chunks.iter() {
         // Remove old colliders
-        for children in child_collider_query.get(*entity) {
+        for children in child_query.get(*entity) {
             for child in children {
-                commands.entity(*child).despawn_recursive()
+                if let Ok(_) = collider_query.get(*child) {
+                    commands.entity(*child).despawn_recursive()
+                }
             }
         }
 

src/util/vector2_i32.rs

@@ -17,6 +17,15 @@ impl Vector2I {
     }
 }
 
+impl From<Vec2> for Vector2I {
+    fn from(vec: Vec2) -> Self {
+        Self {
+            x: vec.x as i32,
+            y: vec.y as i32,
+        }
+    }
+}
+
 impl From<Vector2I> for Vec2 {
     fn from(vec: Vector2I) -> Self {
         Vec2 {