Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

OpenRA.Game/Traits/World/ScreenShaker.cs

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+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.Graphics;
+
+namespace OpenRA.Traits
+{
+	[TraitLocation(SystemActors.World)]
+	public class ScreenShakerInfo : TraitInfo
+	{
+		public readonly float2 MinMultiplier = new(-3, -3);
+		public readonly float2 MaxMultiplier = new(3, 3);
+
+		public override object Create(ActorInitializer init) { return new ScreenShaker(this); }
+	}
+
+	public class ScreenShaker : ITick, IWorldLoaded
+	{
+		readonly ScreenShakerInfo info;
+		WorldRenderer worldRenderer;
+		readonly List<ShakeEffect> shakeEffects = [];
+		int ticks = 0;
+
+		public ScreenShaker(ScreenShakerInfo info)
+		{
+			this.info = info;
+		}
+
+		void IWorldLoaded.WorldLoaded(World w, WorldRenderer wr) { worldRenderer = wr; }
+
+		void ITick.Tick(Actor self)
+		{
+			if (shakeEffects.Count > 0)
+			{
+				worldRenderer.Viewport.Scroll(GetScrollOffset(), true);
+				shakeEffects.RemoveAll(t => t.ExpiryTime == ticks);
+			}
+
+			ticks++;
+		}
+
+		public void AddEffect(int time, WPos position, int intensity)
+		{
+			AddEffect(time, position, intensity, new float2(1, 1));
+		}
+
+		public void AddEffect(int time, WPos position, int intensity, float2 multiplier)
+		{
+			shakeEffects.Add(new ShakeEffect { ExpiryTime = ticks + time, Position = position, Intensity = intensity, Multiplier = multiplier });
+		}
+
+		float2 GetScrollOffset()
+		{
+			return GetMultiplier() * GetIntensity() * new float2(
+				(float)Math.Sin(ticks * 2 * Math.PI / 4),
+				(float)Math.Cos(ticks * 2 * Math.PI / 5));
+		}
+
+		float2 GetMultiplier()
+		{
+			return shakeEffects.Aggregate(float2.Zero, (sum, next) => sum + next.Multiplier)
+				.Constrain(info.MinMultiplier, info.MaxMultiplier);
+		}
+
+		float GetIntensity()
+		{
+			var cp = worldRenderer.Viewport.CenterPosition;
+			var intensity = 100 * 1024 * 1024 * shakeEffects.Sum(
+				e => (float)e.Intensity / (e.Position - cp).LengthSquared);
+
+			return Math.Min(intensity, 10);
+		}
+	}
+
+	struct ShakeEffect
+	{
+		public int ExpiryTime;
+		public WPos Position;
+		public int Intensity;
+		public float2 Multiplier;
+	}
+}