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some matrix-related number extensions

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Ellpeck 2020-07-19 23:12:12 +02:00
parent e427305490
commit ec370479ef
1 changed files with 52 additions and 1 deletions
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53
MLEM/Extensions/NumberExtensions.cs
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@ -4,7 +4,7 @@ using MLEM.Misc;
namespace MLEM.Extensions { namespace MLEM.Extensions {
/// <summary> /// <summary>
/// A set of extensions for dealing with <see cref="float"/>, <see cref="Vector2"/>, <see cref="Vector3"/>, <see cref="Vector4"/>, <see cref="Point"/>, <see cref="Rectangle"/> and <see cref="RectangleF"/> /// A set of extensions for dealing with <see cref="float"/>, <see cref="Vector2"/>, <see cref="Vector3"/>, <see cref="Vector4"/>, <see cref="Point"/>, <see cref="Matrix"/>, <see cref="Rectangle"/> and <see cref="RectangleF"/>
/// </summary> /// </summary>
public static class NumberExtensions { public static class NumberExtensions {
@ -143,5 +143,56 @@ namespace MLEM.Extensions {
return rect; return rect;
} }
/// <summary>
/// Turns the given 3-dimensional vector into a 2-dimensional vector by chopping off the z coordinate.
/// </summary>
/// <param name="vector">The vector to convert</param>
/// <returns>The resulting 2-dimensional vector</returns>
public static Vector2 ToVector2(this Vector3 vector) {
return new Vector2(vector.X, vector.Y);
}
/// <summary>
/// Returns the 3-dimensional translation of the given matrix.
/// </summary>
/// <param name="matrix">The matrix</param>
/// <returns>The translation of the matrix</returns>
public static Vector3 Translation(this Matrix matrix) {
return new Vector3(matrix.M41, matrix.M42, matrix.M43);
}
/// <summary>
/// Returns the 3-dimensional scale of the given matrix.
/// </summary>
/// <param name="matrix">The matrix</param>
/// <returns>The scale of the matrix</returns>
public static Vector3 Scale(this Matrix matrix) {
float xs = Math.Sign(matrix.M11 * matrix.M12 * matrix.M13 * matrix.M14) < 0 ? -1 : 1;
float ys = Math.Sign(matrix.M21 * matrix.M22 * matrix.M23 * matrix.M24) < 0 ? -1 : 1;
float zs = Math.Sign(matrix.M31 * matrix.M32 * matrix.M33 * matrix.M34) < 0 ? -1 : 1;
Vector3 scale;
scale.X = xs * (float) Math.Sqrt(matrix.M11 * matrix.M11 + matrix.M12 * matrix.M12 + matrix.M13 * matrix.M13);
scale.Y = ys * (float) Math.Sqrt(matrix.M21 * matrix.M21 + matrix.M22 * matrix.M22 + matrix.M23 * matrix.M23);
scale.Z = zs * (float) Math.Sqrt(matrix.M31 * matrix.M31 + matrix.M32 * matrix.M32 + matrix.M33 * matrix.M33);
return scale;
}
/// <summary>
/// Returns the rotation that the given matrix represents, as a <see cref="Quaternion"/>.
/// Returns <see cref="Quaternion.Identity"/> if the matrix does not contain valid rotation information.
/// </summary>
/// <param name="matrix">The matrix</param>
/// <returns>The rotation of the matrix</returns>
public static Quaternion Rotation(this Matrix matrix) {
var (scX, scY, scZ) = matrix.Scale();
if (scX == 0.0 || scY == 0.0 || scZ == 0.0)
return Quaternion.Identity;
return Quaternion.CreateFromRotationMatrix(new Matrix(
matrix.M11 / scX, matrix.M12 / scX, matrix.M13 / scX, 0,
matrix.M21 / scY, matrix.M22 / scY, matrix.M23 / scY, 0,
matrix.M31 / scZ, matrix.M32 / scZ, matrix.M33 / scZ, 0,
0, 0, 0, 1));
}
} }
} }