From 46feec50bae25253ef79986fc4d73d9cd51ec0c8 Mon Sep 17 00:00:00 2001
From: mnmaita <47983254+mnmaita@users.noreply.github.com>
Date: Wed, 15 Nov 2023 01:47:31 +0100
Subject: [PATCH] Fixes camera boundary checks

---
 src/camera.rs | 51 ++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/src/camera.rs b/src/camera.rs
index 5012e6c..25e839e 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -39,29 +39,46 @@ fn update_camera(
 
 fn constrain_camera_position_to_level(
     mut camera_query: Query<(&Camera, &mut Transform), With<Camera2d>>,
+    #[cfg(debug_assertions)] mut gizmos: Gizmos,
 ) {
     let (camera, mut camera_transform) = camera_query.single_mut();
 
     if let Some(viewport_size) = camera.logical_viewport_size() {
         let level_dimensions = GRID_SIZE * TILE_SIZE;
-        let half_viewport_size = viewport_size * 0.5;
+        let viewport_size_remainder = viewport_size % TILE_SIZE;
+        let camera_boundary_size = (level_dimensions
+            - (viewport_size - viewport_size_remainder)
+            - viewport_size_remainder)
+            .clamp(Vec2::ZERO, Vec2::splat(f32::MAX));
+        let camera_boundary = Rect::from_center_size(-HALF_TILE_SIZE, camera_boundary_size);
 
-        camera_transform.translation.x = if viewport_size.x > level_dimensions.x {
-            0.0
-        } else {
-            let level_half_width = level_dimensions.x * 0.5;
-            let min = -level_half_width + half_viewport_size.x + HALF_TILE_SIZE.x;
-            let max = level_half_width - half_viewport_size.x - HALF_TILE_SIZE.x;
-            camera_transform.translation.x.clamp(min, max)
-        };
+        if camera_boundary.is_empty() {
+            if viewport_size.x > level_dimensions.x {
+                camera_transform.translation.x = 0.0;
+            }
+            if viewport_size.y > level_dimensions.y {
+                camera_transform.translation.y = 0.0;
+            }
+        }
 
-        camera_transform.translation.y = if viewport_size.y > level_dimensions.y {
-            0.0
-        } else {
-            let level_half_height = level_dimensions.y * 0.5;
-            let min = -level_half_height + half_viewport_size.y + HALF_TILE_SIZE.y;
-            let max = level_half_height - half_viewport_size.y - HALF_TILE_SIZE.y;
-            camera_transform.translation.y.clamp(min, max)
-        };
+        if camera_boundary.size() != Vec2::ZERO
+            && !camera_boundary.contains(camera_transform.translation.truncate())
+        {
+            let (min_x, max_x) = (camera_boundary.min.x, camera_boundary.max.x);
+            let (min_y, max_y) = (camera_boundary.min.y, camera_boundary.max.y);
+            camera_transform.translation.x = camera_transform.translation.x.clamp(min_x, max_x);
+            camera_transform.translation.y = camera_transform.translation.y.clamp(min_y, max_y);
+        }
+
+        #[cfg(debug_assertions)]
+        {
+            gizmos.rect_2d(
+                camera_boundary.center(),
+                0.,
+                camera_boundary.size(),
+                Color::RED,
+            );
+            gizmos.circle_2d(camera_transform.translation.truncate(), 10., Color::RED);
+        }
     }
 }