From e6d6e50e1d44887bf979d3519fe1052e3fc864c5 Mon Sep 17 00:00:00 2001
From: Saverio Miroddi <saverio.pub2@gmail.com>
Date: Thu, 28 Jul 2022 22:57:44 +0200
Subject: [PATCH] Implement first version of camera stopping

Define points in the levels, where all the enemies (spawned) until then must be defeated before continuing.

The camera logic needs refinements (extra complexity) because for example, as of now, when there is a stop point, the players can't cross it, leaving a small part of the screen unusable by them.
---
 src/attack.rs   | 14 +++++++++---
 src/movement.rs | 60 ++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/src/attack.rs b/src/attack.rs
index 125e8356..1e678d1e 100644
--- a/src/attack.rs
+++ b/src/attack.rs
@@ -23,9 +23,10 @@ use crate::{
         self, ATTACK_HEIGHT, ATTACK_LAYER, ATTACK_WIDTH, ITEM_BOTTLE_NAME, ITEM_HEIGHT, ITEM_LAYER,
         ITEM_WIDTH, THROW_ITEM_ROTATION_SPEED,
     },
+    enemy::SpawnLocationX,
     input::PlayerAction,
     item::item_carried_by_player,
-    metadata::{FighterMeta, GameMeta, ItemMeta},
+    metadata::{FighterMeta, GameMeta, ItemMeta, LevelMeta},
     movement::{
         clamp_player_movements, LeftMovementBoundary, MoveInArc, MoveInDirection, Rotate, Target,
     },
@@ -296,6 +297,8 @@ fn player_flop(
         ),
         With<Player>,
     >,
+    enemy_spawn_locations_query: Query<&SpawnLocationX>,
+    level_meta: Res<LevelMeta>,
     fighter_assets: Res<Assets<FighterMeta>>,
     time: Res<Time>,
     left_movement_boundary: Res<LeftMovementBoundary>,
@@ -384,8 +387,13 @@ fn player_flop(
         )
         .collect::<Vec<_>>();
 
-    let players_movement =
-        clamp_player_movements(players_movement, &left_movement_boundary, &game_meta);
+    let players_movement = clamp_player_movements(
+        players_movement,
+        &enemy_spawn_locations_query,
+        &level_meta,
+        &left_movement_boundary,
+        &game_meta,
+    );
 
     for ((_, _, mut transform, _, _, _, _), player_dir) in query.iter_mut().zip(players_movement) {
         if let Some(player_dir) = player_dir {
diff --git a/src/movement.rs b/src/movement.rs
index c7500e72..51f6c235 100644
--- a/src/movement.rs
+++ b/src/movement.rs
@@ -11,8 +11,9 @@ use leafwing_input_manager::prelude::ActionState;
 use crate::{
     animation::Facing,
     consts::{self, LEFT_BOUNDARY_MAX_DISTANCE},
+    enemy::SpawnLocationX,
     input::PlayerAction,
-    metadata::GameMeta,
+    metadata::{GameMeta, LevelMeta},
     state::State,
     ArrivedEvent, DespawnMarker, Player, Stats,
 };
@@ -40,6 +41,8 @@ pub struct Knockback {
 pub fn knockback_system(
     mut commands: Commands,
     mut query: Query<(Entity, &mut Transform, &mut Knockback, Option<&Player>)>,
+    enemy_spawn_locations_query: Query<&SpawnLocationX>,
+    level_meta: Res<LevelMeta>,
     time: Res<Time>,
     game_meta: Res<GameMeta>,
     left_movement_boundary: Res<LeftMovementBoundary>,
@@ -85,7 +88,13 @@ pub fn knockback_system(
         })
         .collect::<Vec<_>>();
 
-    let player_dirs = clamp_player_movements(player_movements, &left_movement_boundary, &game_meta);
+    let player_dirs = clamp_player_movements(
+        player_movements,
+        &enemy_spawn_locations_query,
+        &level_meta,
+        &left_movement_boundary,
+        &game_meta,
+    );
 
     for ((_, transform, _, _), player_dir) in player_knockbacks.iter_mut().zip(player_dirs) {
         transform.translation += player_dir.unwrap().extend(0.);
@@ -103,6 +112,8 @@ pub fn player_controller(
         ),
         With<Player>,
     >,
+    enemy_spawn_locations_query: Query<&SpawnLocationX>,
+    level_meta: Res<LevelMeta>,
     time: Res<Time>,
     game_meta: Res<GameMeta>,
     left_movement_boundary: Res<LeftMovementBoundary>,
@@ -130,7 +141,13 @@ pub fn player_controller(
         })
         .collect::<Vec<_>>();
 
-    let player_dirs = clamp_player_movements(player_movements, &left_movement_boundary, &game_meta);
+    let player_dirs = clamp_player_movements(
+        player_movements,
+        &enemy_spawn_locations_query,
+        &level_meta,
+        &left_movement_boundary,
+        &game_meta,
+    );
 
     for ((mut state, _, mut transform, mut facing, _), dir) in
         query.iter_mut().zip(player_dirs.iter())
@@ -291,6 +308,7 @@ pub fn update_left_movement_boundary(
 /// Not a system, but a utility method!.
 ///
 /// player_movements: array of (location, direction vector).
+/// enemy_spawn_location_query: spawn locations of _alive_ enemies.
 ///
 /// WATCH OUT! All players must be included, even if they don't move, in which case, pass
 /// None as direction. This is because clamping is based on the position of _all_ the
@@ -298,11 +316,43 @@ pub fn update_left_movement_boundary(
 /// It's possible to pass an empty array; this can happen if the system doesn't guard the case
 /// where all the players are dead; an empty array will be returned.
 pub fn clamp_player_movements(
-    player_movements: Vec<(Vec3, Option<Vec2>)>,
+    mut player_movements: Vec<(Vec3, Option<Vec2>)>,
+    enemy_spawn_locations_query: &Query<&SpawnLocationX>,
+    level_meta: &LevelMeta,
     left_movement_boundary: &LeftMovementBoundary,
     game_meta: &GameMeta,
 ) -> Vec<Option<Vec2>> {
-    // In the first pass, we perform the absolute clamping (screen limits), and we collect the data
+    // In the first pass, we check the camera stop points. If a player is moving across a stop
+    // point, all the enemies up to that point must have been defeated, in order to move.
+
+    let current_stop_point = level_meta.stop_points.iter().find(|point_x| {
+        player_movements.iter().any(|(location, dir)| {
+            if let Some(dir) = dir {
+                location.x < **point_x && **point_x <= location.x + dir.x
+            } else {
+                false
+            }
+        })
+    });
+
+    if let Some(current_stop_point) = current_stop_point {
+        let any_enemy_behind_stop_point = enemy_spawn_locations_query
+            .iter()
+            .any(|SpawnLocationX(spawn_x)| spawn_x <= current_stop_point);
+
+        if any_enemy_behind_stop_point {
+            for (location, movement) in player_movements.iter_mut() {
+                if let Some(movement) = movement.as_mut() {
+                    // Can be simplified, but it's harder to understand.
+                    if location.x + movement.x > *current_stop_point {
+                        movement.x = 0.;
+                    }
+                }
+            }
+        }
+    }
+
+    // Then, we perform the absolute clamping (screen top/left/bottom), and we collect the data
     // required for the relative clamping.
 
     let mut min_new_player_x = f32::MAX;