Add Int32Matrix4x4 struct.

This allows matrices to be represented as a value type, and additionally allows avoiding array allocations when calculating rotations.

OpenRA.Game/Graphics/Util.cs

@@ -323,12 +323,31 @@ namespace OpenRA.Graphics
 			return mtx;
 		}
 
-		public static float[] MakeFloatMatrix(int[] imtx)
+		public static float[] MakeFloatMatrix(Int32Matrix4x4 imtx)
 		{
-			var fmtx = new float[16];
-			for (var i = 0; i < 16; i++)
-				fmtx[i] = imtx[i] * 1f / imtx[15];
-			return fmtx;
+			var multipler = 1f / imtx.M44;
+			return new float[]
+			{
+				imtx.M11 * multipler,
+				imtx.M12 * multipler,
+				imtx.M13 * multipler,
+				imtx.M14 * multipler,
+
+				imtx.M21 * multipler,
+				imtx.M22 * multipler,
+				imtx.M23 * multipler,
+				imtx.M24 * multipler,
+
+				imtx.M31 * multipler,
+				imtx.M32 * multipler,
+				imtx.M33 * multipler,
+				imtx.M34 * multipler,
+
+				imtx.M41 * multipler,
+				imtx.M42 * multipler,
+				imtx.M43 * multipler,
+				imtx.M44 * multipler,
+			};
 		}
 
 		public static float[] MatrixAABBMultiply(float[] mtx, float[] bounds)

OpenRA.Game/OpenRA.Game.csproj

@@ -106,6 +106,7 @@
     <Compile Include="Actor.cs" />
     <Compile Include="CacheStorage.cs" />
     <Compile Include="FileSystem\IPackage.cs" />
+    <Compile Include="Primitives\Int32Matrix4x4.cs" />
     <Compile Include="LogProxy.cs" />
     <Compile Include="Map\MapGrid.cs" />
     <Compile Include="Map\MapPlayers.cs" />

OpenRA.Game/Primitives/Int32Matrix4x4.cs

@@ -0,0 +1,72 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2018 The OpenRA Developers (see AUTHORS)
+ * 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;
+
+namespace OpenRA
+{
+	public struct Int32Matrix4x4 : IEquatable<Int32Matrix4x4>
+	{
+		public readonly int M11, M12, M13, M14, M21, M22, M23, M24, M31, M32, M33, M34, M41, M42, M43, M44;
+
+		public Int32Matrix4x4(
+			int m11, int m12, int m13, int m14,
+			int m21, int m22, int m23, int m24,
+			int m31, int m32, int m33, int m34,
+			int m41, int m42, int m43, int m44)
+		{
+			M11 = m11;
+			M12 = m12;
+			M13 = m13;
+			M14 = m14;
+
+			M21 = m21;
+			M22 = m22;
+			M23 = m23;
+			M24 = m24;
+
+			M31 = m31;
+			M32 = m32;
+			M33 = m33;
+			M34 = m34;
+
+			M41 = m41;
+			M42 = m42;
+			M43 = m43;
+			M44 = m44;
+		}
+
+		public static bool operator ==(Int32Matrix4x4 me, Int32Matrix4x4 other)
+		{
+			return
+				me.M11 == other.M11 && me.M12 == other.M12 && me.M13 == other.M13 && me.M14 == other.M14 &&
+				me.M21 == other.M21 && me.M22 == other.M22 && me.M23 == other.M23 && me.M24 == other.M24 &&
+				me.M31 == other.M31 && me.M32 == other.M32 && me.M33 == other.M33 && me.M34 == other.M34 &&
+				me.M41 == other.M41 && me.M42 == other.M42 && me.M43 == other.M43 && me.M44 == other.M44;
+		}
+
+		public static bool operator !=(Int32Matrix4x4 me, Int32Matrix4x4 other) { return !(me == other); }
+
+		public override int GetHashCode() { return M11 ^ M22 ^ M33 ^ M44; }
+
+		public bool Equals(Int32Matrix4x4 other) { return other == this; }
+		public override bool Equals(object obj) { return obj is Int32Matrix4x4 && Equals((Int32Matrix4x4)obj); }
+
+		public override string ToString()
+		{
+			return
+				"[" + M11 + " " + M12 + " " + M13 + " " + M14 + "],[" +
+				"[" + M21 + " " + M22 + " " + M23 + " " + M24 + "],[" +
+				"[" + M31 + " " + M32 + " " + M33 + " " + M34 + "],[" +
+				"[" + M41 + " " + M42 + " " + M43 + " " + M44 + "]";
+		}
+	}
+}

OpenRA.Game/WRot.cs

@@ -41,58 +41,61 @@ namespace OpenRA
 			return new WRot(Roll, Pitch, yaw);
 		}
 
-		public int[] AsQuarternion()
+		void AsQuarternion(out int x, out int y, out int z, out int w)
 		{
 			// Angles increase clockwise
-			var r = new WAngle(-Roll.Angle / 2);
-			var p = new WAngle(-Pitch.Angle / 2);
-			var y = new WAngle(-Yaw.Angle / 2);
-			var cr = (long)r.Cos();
-			var sr = (long)r.Sin();
-			var cp = (long)p.Cos();
-			var sp = (long)p.Sin();
-			var cy = (long)y.Cos();
-			var sy = (long)y.Sin();
+			var roll = new WAngle(-Roll.Angle / 2);
+			var pitch = new WAngle(-Pitch.Angle / 2);
+			var yaw = new WAngle(-Yaw.Angle / 2);
+			var cr = (long)roll.Cos();
+			var sr = (long)roll.Sin();
+			var cp = (long)pitch.Cos();
+			var sp = (long)pitch.Sin();
+			var cy = (long)yaw.Cos();
+			var sy = (long)yaw.Sin();
 
 			// Normalized to 1024 == 1.0
-			return new int[4]
-			{
-				(int)((sr * cp * cy - cr * sp * sy) / 1048576), // x
-				(int)((cr * sp * cy + sr * cp * sy) / 1048576), // y
-				(int)((cr * cp * sy - sr * sp * cy) / 1048576), // z
-				(int)((cr * cp * cy + sr * sp * sy) / 1048576)  // w
-			};
+			x = (int)((sr * cp * cy - cr * sp * sy) / 1048576);
+			y = (int)((cr * sp * cy + sr * cp * sy) / 1048576);
+			z = (int)((cr * cp * sy - sr * sp * cy) / 1048576);
+			w = (int)((cr * cp * cy + sr * sp * sy) / 1048576);
 		}
 
-		public int[] AsMatrix()
+		public void AsMatrix(out Int32Matrix4x4 mtx)
 		{
-			var q = AsQuarternion();
+			int x, y, z, w;
+			AsQuarternion(out x, out y, out z, out w);
 
 			// Theoretically 1024 *  * 2, but may differ slightly due to rounding
-			var lsq = q[0] * q[0] + q[1] * q[1] + q[2] * q[2] + q[3] * q[3];
+			var lsq = x * x + y * y + z * z + w * w;
 
 			// Quaternion components use 10 bits, so there's no risk of overflow
-			var mtx = new int[16];
-			mtx[0] = lsq - 2 * (q[1] * q[1] + q[2] * q[2]);
-			mtx[1] = 2 * (q[0] * q[1] + q[2] * q[3]);
-			mtx[2] = 2 * (q[0] * q[2] - q[1] * q[3]);
-			mtx[3] = 0;
+			mtx = new Int32Matrix4x4(
+				lsq - 2 * (y * y + z * z),
+				2 * (x * y + z * w),
+				2 * (x * z - y * w),
+				0,
 
-			mtx[4] = 2 * (q[0] * q[1] - q[2] * q[3]);
-			mtx[5] = lsq - 2 * (q[0] * q[0] + q[2] * q[2]);
-			mtx[6] = 2 * (q[1] * q[2] + q[0] * q[3]);
-			mtx[7] = 0;
+				2 * (x * y - z * w),
+				lsq - 2 * (x * x + z * z),
+				2 * (y * z + x * w),
+				0,
 
-			mtx[8] = 2 * (q[0] * q[2] + q[1] * q[3]);
-			mtx[9] = 2 * (q[1] * q[2] - q[0] * q[3]);
-			mtx[10] = lsq - 2 * (q[0] * q[0] + q[1] * q[1]);
-			mtx[11] = 0;
+				2 * (x * z + y * w),
+				2 * (y * z - x * w),
+				lsq - 2 * (x * x + y * y),
+				0,
 
-			mtx[12] = 0;
-			mtx[13] = 0;
-			mtx[14] = 0;
-			mtx[15] = lsq;
+				0,
+				0,
+				0,
+				lsq);
+		}
 
+		public Int32Matrix4x4 AsMatrix()
+		{
+			Int32Matrix4x4 mtx;
+			AsMatrix(out mtx);
 			return mtx;
 		}
 

OpenRA.Game/WVec.cs

@@ -46,19 +46,20 @@ namespace OpenRA
 
 		public WVec Rotate(WRot rot)
 		{
-			return Rotate(rot.AsMatrix());
+			Int32Matrix4x4 mtx;
+			rot.AsMatrix(out mtx);
+			return Rotate(ref mtx);
 		}
 
-		public WVec Rotate(int[] rotationMatrix)
+		public WVec Rotate(ref Int32Matrix4x4 mtx)
 		{
-			var mtx = rotationMatrix;
 			var lx = (long)X;
 			var ly = (long)Y;
 			var lz = (long)Z;
 			return new WVec(
-				(int)((lx * mtx[0] + ly * mtx[4] + lz * mtx[8]) / mtx[15]),
-				(int)((lx * mtx[1] + ly * mtx[5] + lz * mtx[9]) / mtx[15]),
-				(int)((lx * mtx[2] + ly * mtx[6] + lz * mtx[10]) / mtx[15]));
+				(int)((lx * mtx.M11 + ly * mtx.M21 + lz * mtx.M31) / mtx.M44),
+				(int)((lx * mtx.M12 + ly * mtx.M22 + lz * mtx.M32) / mtx.M44),
+				(int)((lx * mtx.M13 + ly * mtx.M23 + lz * mtx.M33) / mtx.M44));
 		}
 
 		public WAngle Yaw

OpenRA.Mods.Common/Graphics/RangeCircleRenderable.cs

@@ -17,8 +17,8 @@ namespace OpenRA.Mods.Common.Graphics
 	public struct RangeCircleRenderable : IRenderable, IFinalizedRenderable
 	{
 		const int RangeCircleSegments = 32;
-		static readonly int[][] RangeCircleStartRotations = Exts.MakeArray(RangeCircleSegments, i => WRot.FromFacing(8 * i).AsMatrix());
-		static readonly int[][] RangeCircleEndRotations = Exts.MakeArray(RangeCircleSegments, i => WRot.FromFacing(8 * i + 6).AsMatrix());
+		static readonly Int32Matrix4x4[] RangeCircleStartRotations = Exts.MakeArray(RangeCircleSegments, i => WRot.FromFacing(8 * i).AsMatrix());
+		static readonly Int32Matrix4x4[] RangeCircleEndRotations = Exts.MakeArray(RangeCircleSegments, i => WRot.FromFacing(8 * i + 6).AsMatrix());
 
 		readonly WPos centerPosition;
 		readonly WDist radius;
@@ -58,8 +58,8 @@ namespace OpenRA.Mods.Common.Graphics
 			var offset = new WVec(radius.Length, 0, 0);
 			for (var i = 0; i < RangeCircleSegments; i++)
 			{
-				var a = wr.Screen3DPosition(centerPosition + offset.Rotate(RangeCircleStartRotations[i]));
-				var b = wr.Screen3DPosition(centerPosition + offset.Rotate(RangeCircleEndRotations[i]));
+				var a = wr.Screen3DPosition(centerPosition + offset.Rotate(ref RangeCircleStartRotations[i]));
+				var b = wr.Screen3DPosition(centerPosition + offset.Rotate(ref RangeCircleEndRotations[i]));
 
 				if (contrastWidth > 0)
 					wcr.DrawLine(a, b, contrastWidth / wr.Viewport.Zoom, contrastColor);