From 7ef5a7370457e0fa076056fa0e0d33f8d790e15b Mon Sep 17 00:00:00 2001
From: Elijah Voigt <elijah.caine.mv@gmail.com>
Date: Sat, 18 Oct 2025 22:30:03 -0700
Subject: [PATCH] not perfect, but gooder movement

---
 src/bin/tetris/main.rs | 255 ++++++++++++++++++++---------------------
 1 file changed, 123 insertions(+), 132 deletions(-)

diff --git a/src/bin/tetris/main.rs b/src/bin/tetris/main.rs
index 554612f..43f4364 100644
--- a/src/bin/tetris/main.rs
+++ b/src/bin/tetris/main.rs
@@ -21,7 +21,6 @@ fn main() {
             Update,
             (
                 kb_input.run_if(on_event::<KeyboardInput>),
-                update_position,
                 falling
                     .run_if(in_state(Falling::On))
                     .run_if(clock_cycle(1.0)),
@@ -31,19 +30,16 @@ fn main() {
                         .or(any_component_added::<Orientation>)
                         .or(any_component_changed::<Orientation>),
                 ),
-                shape_block_movement.run_if(
-                    any_component_added::<RelativePosition>
-                        .or(any_component_changed::<RelativePosition>)
-                        .or(any_component_changed::<GridPosition>),
-                ),
+                update_relative_position,
+                update_position.after(update_relative_position),
                 sync_singleton_to_ui::<Shape>.run_if(any_component_changed::<Shape>),
                 sync_singleton_to_ui::<Orientation>.run_if(any_component_changed::<Orientation>),
-                check_collision.run_if(any_component_changed::<GridPosition>),
                 add_piece.run_if(not(any_with_component::<Shape>)),
                 clear_line.run_if(any_component_changed::<LineBlocks>),
             ),
         )
         .add_systems(Update, draw_grid)
+        .add_observer(deactive_shape)
         .run();
 }
 
@@ -115,7 +111,7 @@ struct Line(u8);
 #[derive(Component, Debug)]
 struct Block;
 
-#[derive(Component, Event, Debug)]
+#[derive(Component, Event, Debug, Clone, Copy)]
 #[require(GridPosition)]
 struct RelativePosition {
     x: i8,
@@ -124,31 +120,19 @@ struct RelativePosition {
 
 impl RelativePosition {
     fn up() -> Self {
-        RelativePosition {
-            x: 0,
-            y: 1,
-        }
+        RelativePosition { x: 0, y: 1 }
     }
 
     fn down() -> Self {
-        RelativePosition {
-            x: 0,
-            y: -1,
-        }
+        RelativePosition { x: 0, y: -1 }
     }
 
     fn left() -> Self {
-        RelativePosition {
-            x: -1,
-            y: 0,
-        }
+        RelativePosition { x: -1, y: 0 }
     }
 
     fn right() -> Self {
-        RelativePosition {
-            x: 1,
-            y: 0,
-        }
+        RelativePosition { x: 1, y: 0 }
     }
 }
 
@@ -206,12 +190,23 @@ impl GridPosition {
         self.x == other.x && self.y.saturating_sub(1) == other.y
     }
 
-    fn add_offset(&self, RelativePosition { x: x1, y: y1 }: &RelativePosition) -> Result<Self, GameError> {
-        let x = self.x.checked_add_signed(*x1 as i32).ok_or(GameError::OutOfBoundsLeft)?;
-        let y = self.y.checked_add_signed(*y1 as i32).ok_or(GameError::OutOfBoundsDown)?;
-        if x >= X_MAX { // TODO: y > Y_MAX?
+    fn add_relative(
+        &self,
+        RelativePosition { x: x1, y: y1 }: &RelativePosition,
+    ) -> Result<Self, GameError> {
+        let x = self
+            .x
+            .checked_add_signed(*x1 as i32)
+            .ok_or(GameError::OutOfBoundsLeft)?;
+        let y = self
+            .y
+            .checked_add_signed(*y1 as i32)
+            .ok_or(GameError::OutOfBoundsDown)?;
+        if x >= X_MAX {
+            // TODO: y > Y_MAX?
             Err(GameError::OutOfBoundsRight)
         } else {
+            debug!("Moving to {x},{y}");
             Ok(GridPosition { x, y })
         }
     }
@@ -514,7 +509,7 @@ fn set_piece(
     visuals: Res<Visuals>,
 ) {
     query.iter().for_each(|(e, s, o)| {
-        debug!("{e:?} {s:?} {o:?}");
+        debug!("Setting piece: {e:?} {s:?} {o:?}");
 
         let mesh = visuals.mesh.clone();
         let mat = visuals.material.clone();
@@ -525,7 +520,9 @@ fn set_piece(
                 .entity(e)
                 .with_related_entities::<ShapeBlock>(|parent| {
                     positions.into_iter().for_each(|rp| {
-                        parent.spawn((Mesh2d(mesh.clone()), MeshMaterial2d(mat.clone()), rp, Block));
+                        parent
+                            .spawn((Mesh2d(mesh.clone()), MeshMaterial2d(mat.clone()), rp, Block))
+                            .observe(movement);
                     });
                 });
         } else {
@@ -537,11 +534,42 @@ fn set_piece(
     });
 }
 
-fn update_position(mut query: Query<(&GridPosition, &mut Transform), Changed<GridPosition>>) {
-    query.iter_mut().for_each(|(gp, mut t)| {
+fn update_position(
+    mut changed: Query<
+        (Entity, &GridPosition, &mut Transform),
+        Or<(Added<GridPosition>, Changed<GridPosition>)>,
+    >,
+) {
+    changed.iter_mut().for_each(|(e, gp, mut t)| {
+        let v3: Vec3 = gp.into();
+        debug!(
+            "Updating {e} with grid position {:?} to coordinates {:?}",
+            gp, v3
+        );
+
         debug_assert!(gp.x < X_MAX, "block x > x_max");
         t.translation = gp.into();
-        debug!("Updating position {:?}", t.translation);
+    });
+}
+
+fn update_relative_position(
+    shape: Single<&GridPosition, With<ShapeBlocks>>,
+    mut query: Query<
+        (Entity, &mut GridPosition, &RelativePosition),
+        (
+            Without<ShapeBlocks>,
+            Or<(Added<RelativePosition>, Changed<RelativePosition>)>,
+        ),
+    >,
+) {
+    query.iter_mut().for_each(|(e, mut gp, rp)| {
+        debug!(
+            "Updating {e} grid position to {:?} + {:?} = {:?}",
+            gp,
+            rp,
+            gp.add_relative(rp).unwrap()
+        );
+        *gp = (*shape).add_relative(rp).unwrap();
     });
 }
 
@@ -568,13 +596,13 @@ fn kb_input(
                         }
                         KeyCode::ArrowDown => {
                             commands.entity(e).trigger(RelativePosition::down());
-                        },
+                        }
                         KeyCode::ArrowLeft => {
                             commands.entity(e).trigger(RelativePosition::left());
-                        },
+                        }
                         KeyCode::ArrowRight => {
                             commands.entity(e).trigger(RelativePosition::right());
-                        },
+                        }
                         KeyCode::Space => next.set(match curr.get() {
                             Falling::On => Falling::Off,
                             Falling::Off => Falling::On,
@@ -607,28 +635,11 @@ fn draw_grid(mut gizmos: Gizmos) {
 
 fn falling(mut shape: Query<Entity, With<Shape>>, mut commands: Commands) {
     shape.iter_mut().for_each(|e| {
+        info!("Making {:?} fall", e);
         commands.entity(e).trigger(RelativePosition::down());
     });
 }
 
-// Re-implement parenting for movement, but on the grid structure
-fn shape_block_movement(
-    shape: Query<
-        &GridPosition,
-        (
-            With<ShapeBlocks>,
-            Without<RelativePosition>,
-        ),
-    >,
-    mut blocks: Query<(&mut GridPosition, &RelativePosition), With<ShapeBlock>>,
-) {
-    shape.iter().for_each(|shape_gp| {
-        blocks.iter_mut().for_each(|(mut block_gp, block_rp)| {
-            *block_gp = shape_gp.add_offset(block_rp).expect("Cannot move there...");
-        });
-    });
-}
-
 // Run condition that returns `true` every `n` seconds
 // TODO: Update a resource with the current tick
 fn clock_cycle(n: f32) -> impl FnMut(Res<Time>, Local<f32>) -> bool {
@@ -643,58 +654,12 @@ fn clock_cycle(n: f32) -> impl FnMut(Res<Time>, Local<f32>) -> bool {
     }
 }
 
-/// Check if the active piece is about to collide with the ground
-fn check_collision(
-    active: Query<(&GridPosition, Entity), (With<Block>, With<RelativePosition>)>,
-    shape: Single<(&GridPosition, Entity), With<ShapeBlocks>>,
-    inactive: Query<&GridPosition, (With<Block>, Without<RelativePosition>)>,
-    lines: Query<(&Line, Entity)>,
-    mut commands: Commands,
-) {
-    // TODO: Easy optimizations
-    let hit = active.iter().any(|(a, _e)| {
-        debug!("Checking: {:?}", a);
-        // Check if active shape is at floor
-        let hit_floor = a.y == 0;
-        // Check if active peice is near other blocks
-        let hit_block = inactive.iter().any(|b| {
-            debug!("Checking against: {:?}", b);
-            a.is_colliding_with(b)
-        });
-
-        hit_floor || hit_block
-    });
-
-    if hit {
-        info!("hit detected!");
-
-        let blocks: Vec<Entity> = active
-            .iter()
-            .map(|(gp, e)| commands.entity(e).remove::<RelativePosition>().id())
-            .collect();
-
-        debug_assert_eq!(blocks.len(), 4, "Shapes should have 4 blocks");
-
-        info!("De-relating blocks {:?} and shape {:?}", blocks, *shape);
-        let (_shape_pos, shape_e) = *shape;
-        commands
-            .entity(shape_e)
-            .remove_related::<ShapeBlock>(blocks.as_slice())
-            .despawn();
-
-        active.iter().for_each(|(GridPosition { y, .. }, block_e)| {
-            lines.iter().for_each(|(Line(i), line_e)| {
-                if *y == *i as u32 {
-                    commands.entity(line_e).add_one_related::<LineBlock>(block_e);
-                }
-            });
-        });
-    }
-}
-
 fn add_piece(mut commands: Commands) {
     // TODO: Choose a different piece
-    commands.spawn((Orientation::default(), GridPosition::default(), Shape::T)).observe(movement).observe(rotation);
+    commands
+        .spawn((Orientation::default(), GridPosition::default(), Shape::T))
+        .observe(movement)
+        .observe(rotation);
 }
 
 /// When a line reaches 10 blocks, clear it
@@ -713,51 +678,77 @@ fn clear_line(
 
 fn movement(
     trigger: Trigger<RelativePosition>,
-    mut shapes: Query<&mut GridPosition, With<Shape>>,
-    mut active: Query<&mut GridPosition, (With<RelativePosition>, Without<Shape>)>,
-    inactive: Query<&GridPosition, (Without<RelativePosition>, Without<Shape>)>,
-    blocks: Query<&ShapeBlocks>,
+    mut grid_positions: Query<&mut GridPosition, Or<(With<RelativePosition>, With<Shape>)>>,
+    parent: Query<&ShapeBlocks>,
+    inactive: Query<
+        &GridPosition,
+        (
+            Without<RelativePosition>,
+            Without<Shape>,
+        ),
+    >,
     mut commands: Commands,
 ) {
-    // Find any errors
-    for block in blocks.iter_descendants(trigger.target()) {
-        // Get the child's grid position
-        let gp = active.get(block).unwrap();
+    // Do a bunch of checks if this move is valid
+    for block in parent.iter_descendants(trigger.target()) {
+        let block_gp = grid_positions.get(block).unwrap();
 
-        match gp.add_offset(trigger.event()) {
-            // If this would go out of bounds to the left or right, prevent this move
+        match block_gp.add_relative(trigger.event()) {
             Err(GameError::OutOfBoundsLeft) | Err(GameError::OutOfBoundsRight) => {
-                return
+                // Hit the left/right wall, just ignore this move
+                return;
             }
-            // If this would go out of bounds down, or cause a collision, remove the active
-            // component from the piece
-            Err(GameError::OutOfBoundsDown) | Err(GameError::Collision) => {
-                // remove active component
+            Err(GameError::OutOfBoundsDown) => {
                 commands.entity(trigger.target()).remove::<Shape>();
-                return
+                return;
+            }
+            Err(GameError::Collision) => {
+                // Do nothing. add_relative does not return this variant
             }
-            Ok(new_gp) => {
-                // If any children collide with the new position, remove the active component
-                if inactive.iter().any(|other_gp| new_gp == *other_gp) {
+            Ok(new_block_gp) => {
+                let collision = inactive
+                    .iter()
+                    .any(|inactive_block_gp| new_block_gp == *inactive_block_gp);
+
+                if collision {
                     commands.entity(trigger.target()).remove::<Shape>();
-                    return
                 }
             }
         }
     }
 
-    // If the above checks went ok, we can move
-    let mut gp = shapes.get_mut(trigger.target()).unwrap();
-    *gp = gp.add_offset(trigger.event()).unwrap();
+    // Move shape itself
+    if let Ok(mut shape_gp) = grid_positions.get_mut(trigger.target()) {
+        *shape_gp = shape_gp.add_relative(trigger.event()).unwrap();
+    }
+
+    // Move the blocks of this shape
+    parent.iter_descendants(trigger.target()).for_each(|block| {
+        info!("Propogating movement {:?} to child {:?}", trigger.event(), block);
+        commands.entity(block).trigger(*trigger.event());
+    });
 }
 
-fn rotation(
-    trigger: Trigger<Orientation>,
-    mut q: Query<(&mut Orientation, &mut GridPosition)>,
-) {
-    let (mut o, mut _gp) = q.get_mut(trigger.target()).unwrap();
+fn rotation(trigger: Trigger<Orientation>, mut q: Query<&mut Orientation>) {
+    let mut o = q.get_mut(trigger.target()).unwrap();
     // If children would go out of bounds to the left
     // If children would not go out of bounds to the right
     // If children would not go out of bounds to the down
     *o = trigger.event().clone();
 }
+
+// TODO: Just despawn?
+fn deactive_shape(
+    trigger: Trigger<OnRemove, Shape>,
+    parent: Query<&ShapeBlocks>,
+    mut commands: Commands,
+) {
+    let v: Vec<Entity> = parent.iter_descendants(trigger.target()).collect();
+    parent.iter_descendants(trigger.target()).for_each(|block| {
+        commands.entity(block).remove::<RelativePosition>();
+    });
+    commands
+        .entity(trigger.target())
+        .remove_related::<ShapeBlock>(v.as_slice())
+        .despawn();
+}