using System; using System.Runtime.InteropServices; #if REAL_T_IS_DOUBLE using real_t = System.Double; #else using real_t = System.Single; #endif namespace Godot { [StructLayout(LayoutKind.Sequential)] public struct Quat : IEquatable { private static readonly Quat identity = new Quat(0f, 0f, 0f, 1f); public real_t x; public real_t y; public real_t z; public real_t w; public static Quat Identity { get { return identity; } } public real_t this[int index] { get { switch (index) { case 0: return x; case 1: return y; case 2: return z; case 3: return w; default: throw new IndexOutOfRangeException(); } } set { switch (index) { case 0: x = value; break; case 1: y = value; break; case 2: z = value; break; case 3: w = value; break; default: throw new IndexOutOfRangeException(); } } } public Quat CubicSlerp(Quat b, Quat preA, Quat postB, real_t t) { real_t t2 = (1.0f - t) * t * 2f; Quat sp = Slerp(b, t); Quat sq = preA.Slerpni(postB, t); return sp.Slerpni(sq, t2); } public real_t Dot(Quat b) { return x * b.x + y * b.y + z * b.z + w * b.w; } public Quat Inverse() { return new Quat(-x, -y, -z, w); } public real_t Length() { return Mathf.Sqrt(LengthSquared()); } public real_t LengthSquared() { return Dot(this); } public Quat Normalized() { return this / Length(); } public void Set(real_t x, real_t y, real_t z, real_t w) { this.x = x; this.y = y; this.z = z; this.w = w; } public void Set(Quat q) { x = q.x; y = q.y; z = q.z; w = q.w; } public Quat Slerp(Quat b, real_t t) { // Calculate cosine real_t cosom = x * b.x + y * b.y + z * b.z + w * b.w; var to1 = new real_t[4]; // Adjust signs if necessary if (cosom < 0.0) { cosom = -cosom; to1[0] = -b.x; to1[1] = -b.y; to1[2] = -b.z; to1[3] = -b.w; } else { to1[0] = b.x; to1[1] = b.y; to1[2] = b.z; to1[3] = b.w; } real_t sinom, scale0, scale1; // Calculate coefficients if ((1.0 - cosom) > Mathf.Epsilon) { // Standard case (Slerp) real_t omega = Mathf.Acos(cosom); sinom = Mathf.Sin(omega); scale0 = Mathf.Sin((1.0f - t) * omega) / sinom; scale1 = Mathf.Sin(t * omega) / sinom; } else { // Quaternions are very close so we can do a linear interpolation scale0 = 1.0f - t; scale1 = t; } // Calculate final values return new Quat ( scale0 * x + scale1 * to1[0], scale0 * y + scale1 * to1[1], scale0 * z + scale1 * to1[2], scale0 * w + scale1 * to1[3] ); } public Quat Slerpni(Quat b, real_t t) { real_t dot = Dot(b); if (Mathf.Abs(dot) > 0.9999f) { return this; } real_t theta = Mathf.Acos(dot); real_t sinT = 1.0f / Mathf.Sin(theta); real_t newFactor = Mathf.Sin(t * theta) * sinT; real_t invFactor = Mathf.Sin((1.0f - t) * theta) * sinT; return new Quat ( invFactor * x + newFactor * b.x, invFactor * y + newFactor * b.y, invFactor * z + newFactor * b.z, invFactor * w + newFactor * b.w ); } public Vector3 Xform(Vector3 v) { Quat q = this * v; q *= Inverse(); return new Vector3(q.x, q.y, q.z); } // Constructors public Quat(real_t x, real_t y, real_t z, real_t w) { this.x = x; this.y = y; this.z = z; this.w = w; } public Quat(Quat q) { x = q.x; y = q.y; z = q.z; w = q.w; } public Quat(Vector3 axis, real_t angle) { real_t d = axis.Length(); real_t angle_t = angle; if (d == 0f) { x = 0f; y = 0f; z = 0f; w = 0f; } else { real_t s = Mathf.Sin(angle_t * 0.5f) / d; x = axis.x * s; y = axis.y * s; z = axis.z * s; w = Mathf.Cos(angle_t * 0.5f); } } public static Quat operator *(Quat left, Quat right) { return new Quat ( left.w * right.x + left.x * right.w + left.y * right.z - left.z * right.y, left.w * right.y + left.y * right.w + left.z * right.x - left.x * right.z, left.w * right.z + left.z * right.w + left.x * right.y - left.y * right.x, left.w * right.w - left.x * right.x - left.y * right.y - left.z * right.z ); } public static Quat operator +(Quat left, Quat right) { return new Quat(left.x + right.x, left.y + right.y, left.z + right.z, left.w + right.w); } public static Quat operator -(Quat left, Quat right) { return new Quat(left.x - right.x, left.y - right.y, left.z - right.z, left.w - right.w); } public static Quat operator -(Quat left) { return new Quat(-left.x, -left.y, -left.z, -left.w); } public static Quat operator *(Quat left, Vector3 right) { return new Quat ( left.w * right.x + left.y * right.z - left.z * right.y, left.w * right.y + left.z * right.x - left.x * right.z, left.w * right.z + left.x * right.y - left.y * right.x, -left.x * right.x - left.y * right.y - left.z * right.z ); } public static Quat operator *(Vector3 left, Quat right) { return new Quat ( right.w * left.x + right.y * left.z - right.z * left.y, right.w * left.y + right.z * left.x - right.x * left.z, right.w * left.z + right.x * left.y - right.y * left.x, -right.x * left.x - right.y * left.y - right.z * left.z ); } public static Quat operator *(Quat left, real_t right) { return new Quat(left.x * right, left.y * right, left.z * right, left.w * right); } public static Quat operator *(real_t left, Quat right) { return new Quat(right.x * left, right.y * left, right.z * left, right.w * left); } public static Quat operator /(Quat left, real_t right) { return left * (1.0f / right); } public static bool operator ==(Quat left, Quat right) { return left.Equals(right); } public static bool operator !=(Quat left, Quat right) { return !left.Equals(right); } public override bool Equals(object obj) { if (obj is Vector2) { return Equals((Vector2)obj); } return false; } public bool Equals(Quat other) { return x == other.x && y == other.y && z == other.z && w == other.w; } public override int GetHashCode() { return y.GetHashCode() ^ x.GetHashCode() ^ z.GetHashCode() ^ w.GetHashCode(); } public override string ToString() { return String.Format("({0}, {1}, {2}, {3})", x.ToString(), y.ToString(), z.ToString(), w.ToString()); } public string ToString(string format) { return String.Format("({0}, {1}, {2}, {3})", x.ToString(format), y.ToString(format), z.ToString(format), w.ToString(format)); } } }