From 567c422f8cd42eba2437f9a8c2522716a1649be7 Mon Sep 17 00:00:00 2001
From: hazel <hazel@hazelthats.me>
Date: Mon, 26 Jan 2026 22:04:39 +0100
Subject: celesteia archive, last updated april 9th 2024

Signed-off-by: hazel <hazel@hazelthats.me>
---
 .../systems/physics/PhysicsWorldCollisionSystem.cs | 83 ++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 source/game/systems/physics/PhysicsWorldCollisionSystem.cs

(limited to 'source/game/systems/physics/PhysicsWorldCollisionSystem.cs')

diff --git a/source/game/systems/physics/PhysicsWorldCollisionSystem.cs b/source/game/systems/physics/PhysicsWorldCollisionSystem.cs
new file mode 100644
index 0000000..ba8da22
--- /dev/null
+++ b/source/game/systems/physics/PhysicsWorldCollisionSystem.cs
@@ -0,0 +1,83 @@
+using System;
+using Celesteia.Game.Components;
+using Celesteia.Game.Components.Physics;
+using Celesteia.Game.Planets;
+using Microsoft.Xna.Framework;
+using MonoGame.Extended;
+using MonoGame.Extended.Entities;
+using MonoGame.Extended.Entities.Systems;
+
+namespace Celesteia.Game.Systems.Physics {
+    public class PhysicsWorldCollisionSystem : EntityUpdateSystem {
+        private ChunkMap _chunkMap;
+
+        public PhysicsWorldCollisionSystem(ChunkMap chunkMap) : base(Aspect.All(typeof(TargetPosition), typeof(PhysicsEntity), typeof(CollisionBox))) {
+            _chunkMap = chunkMap;
+        }
+
+        private ComponentMapper<Transform2> transformMapper;
+        private ComponentMapper<TargetPosition> targetPositionMapper;
+        private ComponentMapper<PhysicsEntity> physicsEntityMapper;
+        private ComponentMapper<CollisionBox> collisionBoxMapper;
+
+        public override void Initialize(IComponentMapperService mapperService)
+        {
+            transformMapper = mapperService.GetMapper<Transform2>();
+            targetPositionMapper = mapperService.GetMapper<TargetPosition>();
+            physicsEntityMapper = mapperService.GetMapper<PhysicsEntity>();
+            collisionBoxMapper = mapperService.GetMapper<CollisionBox>();
+        }
+
+        public override void Update(GameTime gameTime)
+        {
+            foreach (int entityId in ActiveEntities) {
+                Transform2 transform = transformMapper.Get(entityId);
+                TargetPosition targetPosition = targetPositionMapper.Get(entityId);
+                PhysicsEntity physicsEntity = physicsEntityMapper.Get(entityId);
+                CollisionBox collisionBox = collisionBoxMapper.Get(entityId);
+
+                collisionBox.Update(targetPosition.Target);
+
+                int minX = (int)MathF.Floor(collisionBox.Bounds.Center.X - (collisionBox.Bounds.Width / 2f));
+                int maxX = (int)MathF.Ceiling(collisionBox.Bounds.Center.X + (collisionBox.Bounds.Width / 2f));
+
+                int minY = (int)MathF.Floor(collisionBox.Bounds.Center.Y - (collisionBox.Bounds.Height / 2f));
+                int maxY = (int)MathF.Ceiling(collisionBox.Bounds.Center.Y + (collisionBox.Bounds.Height / 2f));
+                
+                bool collLeft = false;
+                bool collRight = false;
+                bool collUp = false;
+                bool collDown = false;
+
+                for (int i = minX; i < maxX; i++)
+                    for (int j = minY; j < maxY; j++) {
+                        RectangleF? blockBox = _chunkMap.TestBoundingBox(i, j);
+                        if (blockBox.HasValue) {
+                            RectangleF inter = RectangleF.Intersection(collisionBox.Bounds, blockBox.Value);
+
+                            if (inter.IsEmpty) continue;
+
+                            if (inter.Width < inter.Height) {
+                                collLeft = blockBox.Value.Center.X < collisionBox.Bounds.Center.X;
+                                collRight = blockBox.Value.Center.X > collisionBox.Bounds.Center.X;
+
+                                targetPosition.Target += new Vector2(blockBox.Value.Center.X < collisionBox.Bounds.Center.X ? inter.Width : -inter.Width, 0f);
+                            } else {
+                                collUp = blockBox.Value.Center.Y < collisionBox.Bounds.Center.Y;
+                                collDown = blockBox.Value.Center.Y > collisionBox.Bounds.Center.Y;
+
+                                targetPosition.Target += new Vector2(0f, blockBox.Value.Center.Y < collisionBox.Bounds.Center.Y ? inter.Height : -inter.Height);
+                            }
+
+                            collisionBox.Update(targetPosition.Target);
+                        }
+                    }
+                
+                physicsEntity.CollidingDown = collDown;
+                physicsEntity.CollidingUp = collUp;
+                physicsEntity.CollidingLeft = collLeft;
+                physicsEntity.CollidingRight = collRight;
+            }
+        }
+    }
+}
\ No newline at end of file
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