Add left-handed spherical and cylindrical billboards

src/libraries/System.Numerics.Vectors/ref/System.Numerics.Vectors.cs

@@ -77,7 +77,9 @@ public partial struct Matrix4x4 : System.IEquatable<System.Numerics.Matrix4x4>
         public System.Numerics.Vector3 Translation { readonly get { throw null; } set { } }
         public static System.Numerics.Matrix4x4 Add(System.Numerics.Matrix4x4 value1, System.Numerics.Matrix4x4 value2) { throw null; }
         public static System.Numerics.Matrix4x4 CreateBillboard(System.Numerics.Vector3 objectPosition, System.Numerics.Vector3 cameraPosition, System.Numerics.Vector3 cameraUpVector, System.Numerics.Vector3 cameraForwardVector) { throw null; }
+        public static System.Numerics.Matrix4x4 CreateBillboardLeftHanded(System.Numerics.Vector3 objectPosition, System.Numerics.Vector3 cameraPosition, System.Numerics.Vector3 cameraUpVector, System.Numerics.Vector3 cameraForwardVector) { throw null; }
         public static System.Numerics.Matrix4x4 CreateConstrainedBillboard(System.Numerics.Vector3 objectPosition, System.Numerics.Vector3 cameraPosition, System.Numerics.Vector3 rotateAxis, System.Numerics.Vector3 cameraForwardVector, System.Numerics.Vector3 objectForwardVector) { throw null; }
+        public static System.Numerics.Matrix4x4 CreateConstrainedBillboardLeftHanded(System.Numerics.Vector3 objectPosition, System.Numerics.Vector3 cameraPosition, System.Numerics.Vector3 rotateAxis, System.Numerics.Vector3 cameraForwardVector, System.Numerics.Vector3 objectForwardVector) { throw null; }
         public static System.Numerics.Matrix4x4 CreateFromAxisAngle(System.Numerics.Vector3 axis, float angle) { throw null; }
         public static System.Numerics.Matrix4x4 CreateFromQuaternion(System.Numerics.Quaternion quaternion) { throw null; }
         public static System.Numerics.Matrix4x4 CreateFromYawPitchRoll(float yaw, float pitch, float roll) { throw null; }

src/libraries/System.Numerics.Vectors/tests/Matrix4x4LeftHandChangedBasisTests.cs

@@ -0,0 +1,58 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Numerics.Tests
+{
+    public class Matrix4x4LeftHandChangedBasisTests : Matrix4x4RightHandTests
+    {
+        protected override string CreateLookAtMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateLookAtLeftHanded)}";
+        protected override Matrix4x4 CreateLookAt(Vector3 cameraPosition, Vector3 cameraTarget, Vector3 cameraUpVector)
+        {
+            return LeftHandToRightHand * Matrix4x4.CreateLookAtLeftHanded(
+                ChangeRightHandToLeftHand(cameraPosition),
+                ChangeRightHandToLeftHand(cameraTarget),
+                ChangeRightHandToLeftHand(cameraUpVector)) * RightHandToLeftHand;
+        }
+
+        protected override string CreateLookToMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateLookToLeftHanded)}";
+        protected override Matrix4x4 CreateLookTo(Vector3 cameraPosition, Vector3 cameraDirection, Vector3 cameraUpVector)
+        {
+            return LeftHandToRightHand * Matrix4x4.CreateLookToLeftHanded(
+                ChangeRightHandToLeftHand(cameraPosition),
+                ChangeRightHandToLeftHand(cameraDirection),
+                ChangeRightHandToLeftHand(cameraUpVector)) * RightHandToLeftHand;
+        }
+
+        protected override string CreateViewportMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateViewportLeftHanded)}";
+        protected override Matrix4x4 CreateViewport(float x, float y, float width, float height, float minDepth, float maxDepth)
+        {
+            return LeftHandToRightHand * Matrix4x4.CreateViewportLeftHanded(x, y, width, height, -minDepth, -maxDepth) * RightHandToLeftHand;
+        }
+
+        protected override string CreateBillboardMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateBillboardLeftHanded)}";
+        protected override Matrix4x4 CreateBillboard(Vector3 objectPosition, Vector3 cameraPosition, Vector3 cameraUpVector, Vector3 cameraForwardVector)
+        {
+            return LeftHandToRightHand * Matrix4x4.CreateBillboardLeftHanded(
+                ChangeRightHandToLeftHand(objectPosition),
+                ChangeRightHandToLeftHand(cameraPosition),
+                ChangeRightHandToLeftHand(cameraUpVector),
+                ChangeRightHandToLeftHand(cameraForwardVector)) * RightHandToLeftHand;
+        }
+
+        protected override string CreateConstrainedBillboardMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateConstrainedBillboardLeftHanded)}";
+        protected override Matrix4x4 CreateConstrainedBillboard(
+            Vector3 objectPosition,
+            Vector3 cameraPosition,
+            Vector3 rotateAxis,
+            Vector3 cameraForwardVector,
+            Vector3 objectForwardVector)
+        {
+            return LeftHandToRightHand * Matrix4x4.CreateConstrainedBillboardLeftHanded(
+                ChangeRightHandToLeftHand(objectPosition),
+                ChangeRightHandToLeftHand(cameraPosition),
+                ChangeRightHandToLeftHand(rotateAxis),
+                ChangeRightHandToLeftHand(cameraForwardVector),
+                ChangeRightHandToLeftHand(objectForwardVector)) * RightHandToLeftHand;
+        }
+    }
+}

src/libraries/System.Numerics.Vectors/tests/Matrix4x4LeftHandTests.cs

@@ -0,0 +1,113 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Xunit;
+
+namespace System.Numerics.Tests
+{
+    public class Matrix4x4LeftHandTests : Matrix4x4OrientationAwareTests
+    {
+        [Fact]
+        public void Matrix4x4CreateLookAtLeftHandedTest()
+        {
+            Vector3 cameraPosition = new Vector3(10.0f, 20.0f, 30.0f);
+            Vector3 cameraTarget = new Vector3(3.0f, 2.0f, -4.0f);
+            Vector3 cameraUpVector = new Vector3(0.0f, 1.0f, 0.0f);
+
+            Matrix4x4 expected = new Matrix4x4();
+            expected.M11 = -0.979457f;
+            expected.M12 = -0.0928268f;
+            expected.M13 = -0.179017f;
+
+            expected.M21 = +0.0f;
+            expected.M22 = +0.887748f;
+            expected.M23 = -0.460329f;
+
+            expected.M31 = +0.201653f;
+            expected.M32 = -0.450873f;
+            expected.M33 = -0.869511f;
+
+            expected.M41 = +3.74498f;
+            expected.M42 = -3.30051f;
+            expected.M43 = +37.0821f;
+            expected.M44 = +1.0f;
+
+            Matrix4x4 actual = CreateLookAt(cameraPosition, cameraTarget, cameraUpVector);
+            Assert.True(MathHelper.Equal(expected, actual), $"{CreateLookAtMethodName} did not return the expected value.");
+        }
+
+        [Fact]
+        public void Matrix4x4CreateLookToLeftHandedTest()
+        {
+            Vector3 cameraPosition = new Vector3(10.0f, 20.0f, 30.0f);
+            Vector3 cameraDirection = new Vector3(-7.0f, -18.0f, -34.0f);
+            Vector3 cameraUpVector = new Vector3(0.0f, 1.0f, 0.0f);
+
+            Matrix4x4 expected = new Matrix4x4();
+            expected.M11 = -0.979457f;
+            expected.M12 = -0.0928268f;
+            expected.M13 = -0.179017f;
+
+            expected.M21 = +0.0f;
+            expected.M22 = +0.887748f;
+            expected.M23 = -0.460329f;
+
+            expected.M31 = +0.201653f;
+            expected.M32 = -0.450873f;
+            expected.M33 = -0.869511f;
+
+            expected.M41 = +3.74498f;
+            expected.M42 = -3.30051f;
+            expected.M43 = +37.0821f;
+            expected.M44 = +1.0f;
+
+            Matrix4x4 actual = CreateLookTo(cameraPosition, cameraDirection, cameraUpVector);
+            Assert.True(MathHelper.Equal(expected, actual), $"{CreateLookToMethodName} did not return the expected value.");
+        }
+
+        [Fact]
+        public void Matrix4x4CreateViewportLeftHandedTest()
+        {
+            float x = 10.0f, y = 20.0f;
+            float width = 3.0f, height = 4.0f;
+            float minDepth = 100.0f, maxDepth = 200.0f;
+
+            Matrix4x4 expected = Matrix4x4.Identity;
+            expected.M11 = width * 0.5f;
+            expected.M22 = -height * 0.5f;
+            expected.M33 = maxDepth - minDepth;
+            expected.M41 = x + expected.M11;
+            expected.M42 = y - expected.M22;
+            expected.M43 = minDepth;
+
+            Matrix4x4 actual = CreateViewport(x, y, width, height, minDepth, maxDepth);
+            Assert.True(MathHelper.Equal(expected, actual), $"{CreateViewportMethodName} did not return the expected value.");
+        }
+
+        protected override string CreateLookAtMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateLookAtLeftHanded)}";
+        protected override Matrix4x4 CreateLookAt(Vector3 cameraPosition, Vector3 cameraTarget, Vector3 cameraUpVector)
+            => Matrix4x4.CreateLookAtLeftHanded(cameraPosition, cameraTarget, cameraUpVector);
+
+        protected override string CreateLookToMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateLookToLeftHanded)}";
+        protected override Matrix4x4 CreateLookTo(Vector3 cameraPosition, Vector3 cameraDirection, Vector3 cameraUpVector)
+            => Matrix4x4.CreateLookToLeftHanded(cameraPosition, cameraDirection, cameraUpVector);
+
+        protected override string CreateViewportMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateViewportLeftHanded)}";
+        protected override Matrix4x4 CreateViewport(float x, float y, float width, float height, float minDepth, float maxDepth)
+            => Matrix4x4.CreateViewportLeftHanded(x, y, width, height, minDepth, maxDepth);
+
+        protected override string CreateBillboardMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateBillboardLeftHanded)}";
+        protected override Matrix4x4 CreateBillboard(Vector3 objectPosition, Vector3 cameraPosition, Vector3 cameraUpVector, Vector3 cameraForwardVector)
+            => Matrix4x4.CreateBillboardLeftHanded(objectPosition, cameraPosition, cameraUpVector, cameraForwardVector);
+
+        protected override string CreateConstrainedBillboardMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateConstrainedBillboardLeftHanded)}";
+
+        protected override Matrix4x4 CreateConstrainedBillboard(
+            Vector3 objectPosition,
+            Vector3 cameraPosition,
+            Vector3 rotateAxis,
+            Vector3 cameraForwardVector,
+            Vector3 objectForwardVector)
+            => Matrix4x4.CreateConstrainedBillboardLeftHanded(objectPosition, cameraPosition, rotateAxis, cameraForwardVector, objectForwardVector);
+    }
+}

src/libraries/System.Numerics.Vectors/tests/Matrix4x4OrientationAwareTests.cs

@@ -0,0 +1,40 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Numerics.Tests
+{
+    public abstract class Matrix4x4OrientationAwareTests
+    {
+        protected static Matrix4x4 RightHandToLeftHand =
+            new(1, 0, 0, 0,
+                 0, 1, 0, 0,
+                 0, 0, -1, 0,
+                 0, 0, 0, 1);
+
+        // The basis change is a self-inverse
+        protected static Matrix4x4 LeftHandToRightHand = RightHandToLeftHand;
+
+        protected static Vector3 ChangeRightHandToLeftHand(Vector3 v) => new(v.X, v.Y, -v.Z);
+        protected static Vector3 ChangeLeftHandToRightHand(Vector3 v) => new(v.X, v.Y, -v.Z);
+
+        protected abstract string CreateLookAtMethodName { get; }
+        protected abstract Matrix4x4 CreateLookAt(Vector3 cameraPosition, Vector3 cameraTarget, Vector3 cameraUpVector);
+
+        protected abstract string CreateLookToMethodName { get; }
+        protected abstract Matrix4x4 CreateLookTo(Vector3 cameraPosition, Vector3 cameraDirection, Vector3 cameraUpVector);
+
+        protected abstract string CreateViewportMethodName { get; }
+        protected abstract Matrix4x4 CreateViewport(float x, float y, float width, float height, float minDepth, float maxDepth);
+
+        protected abstract string CreateBillboardMethodName { get; }
+        protected abstract Matrix4x4 CreateBillboard(Vector3 objectPosition, Vector3 cameraPosition, Vector3 cameraUpVector, Vector3 cameraForwardVector);
+
+        protected abstract string CreateConstrainedBillboardMethodName { get; }
+        protected abstract Matrix4x4 CreateConstrainedBillboard(
+            Vector3 objectPosition,
+            Vector3 cameraPosition,
+            Vector3 rotateAxis,
+            Vector3 cameraForwardVector,
+            Vector3 objectForwardVector);
+    }
+}

src/libraries/System.Numerics.Vectors/tests/Matrix4x4RightHandChangedBasisTests.cs

@@ -0,0 +1,58 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Numerics.Tests
+{
+    public class Matrix4x4RightHandChangedBasisTests : Matrix4x4LeftHandTests
+    {
+        protected override string CreateLookAtMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateLookAt)}";
+        protected override Matrix4x4 CreateLookAt(Vector3 cameraPosition, Vector3 cameraTarget, Vector3 cameraUpVector)
+        {
+            return RightHandToLeftHand * Matrix4x4.CreateLookAt(
+                ChangeLeftHandToRightHand(cameraPosition),
+                ChangeLeftHandToRightHand(cameraTarget),
+                ChangeLeftHandToRightHand(cameraUpVector)) * LeftHandToRightHand;
+        }
+
+        protected override string CreateLookToMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateLookTo)}";
+        protected override Matrix4x4 CreateLookTo(Vector3 cameraPosition, Vector3 cameraDirection, Vector3 cameraUpVector)
+        {
+            return RightHandToLeftHand * Matrix4x4.CreateLookTo(
+                ChangeLeftHandToRightHand(cameraPosition),
+                ChangeLeftHandToRightHand(cameraDirection),
+                ChangeLeftHandToRightHand(cameraUpVector)) * LeftHandToRightHand;
+        }
+
+        protected override string CreateViewportMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateViewport)}";
+        protected override Matrix4x4 CreateViewport(float x, float y, float width, float height, float minDepth, float maxDepth)
+        {
+            return RightHandToLeftHand * Matrix4x4.CreateViewport(x, y, width, height, -minDepth, -maxDepth) * LeftHandToRightHand;
+        }
+
+        protected override string CreateBillboardMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateBillboard)}";
+        protected override Matrix4x4 CreateBillboard(Vector3 objectPosition, Vector3 cameraPosition, Vector3 cameraUpVector, Vector3 cameraForwardVector)
+        {
+            return RightHandToLeftHand * Matrix4x4.CreateBillboard(
+                ChangeLeftHandToRightHand(objectPosition),
+                ChangeLeftHandToRightHand(cameraPosition),
+                ChangeLeftHandToRightHand(cameraUpVector),
+                ChangeLeftHandToRightHand(cameraForwardVector)) * LeftHandToRightHand;
+        }
+
+        protected override string CreateConstrainedBillboardMethodName => $"{nameof(Matrix4x4)}.{nameof(Matrix4x4.CreateConstrainedBillboard)}";
+        protected override Matrix4x4 CreateConstrainedBillboard(
+            Vector3 objectPosition,
+            Vector3 cameraPosition,
+            Vector3 rotateAxis,
+            Vector3 cameraForwardVector,
+            Vector3 objectForwardVector)
+        {
+            return RightHandToLeftHand * Matrix4x4.CreateConstrainedBillboard(
+                ChangeLeftHandToRightHand(objectPosition),
+                ChangeLeftHandToRightHand(cameraPosition),
+                ChangeLeftHandToRightHand(rotateAxis),
+                ChangeLeftHandToRightHand(cameraForwardVector),
+                ChangeLeftHandToRightHand(objectForwardVector)) * LeftHandToRightHand;
+        }
+    }
+}