OpenSimMirror/libraries/ModifiedBulletX/ModifiedBulletX/LinearMath/MatrixOperations.cs

117 lines
3.9 KiB
C#

/*
Bullet for XNA Copyright (c) 2003-2007 Vsevolod Klementjev http://www.codeplex.com/xnadevru
Bullet original C++ version Copyright (c) 2003-2007 Erwin Coumans http://bulletphysics.com
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
using System;
using System.Collections.Generic;
using System.Text;
using MonoXnaCompactMaths;
namespace XnaDevRu.BulletX
{
internal static class MatrixOperations
{
public static void SetRotation(ref Matrix m, Quaternion q)
{
float d = q.LengthSquared();
BulletDebug.Assert(d != 0);
float s = 2f / d;
float xs = q.X * s, ys = q.Y * s, zs = q.Z * s;
float wx = q.W * xs, wy = q.W * ys, wz = q.W * zs;
float xx = q.X * xs, xy = q.X * ys, xz = q.X * zs;
float yy = q.Y * ys, yz = q.Y * zs, zz = q.Z * zs;
m = new Matrix(1 - (yy + zz), xy - wz, xz + wy, 0,
xy + wz, 1 - (xx + zz), yz - wx, 0,
xz - wy, yz + wx, 1 - (xx + yy), 0,
m.M41, m.M42, m.M43, 1);
}
public static Quaternion GetRotation(Matrix m)
{
Quaternion q = new Quaternion();
float trace = m.M11 + m.M22 + m.M33;
if (trace > 0)
{
float s = (float)Math.Sqrt(trace + 1);
q.W = s * 0.5f;
s = 0.5f / s;
q.X = (m.M32 - m.M23) * s;
q.Y = (m.M13 - m.M31) * s;
q.Z = (m.M21 - m.M12) * s;
}
else
{
int i = m.M11 < m.M22 ?
(m.M22 < m.M33 ? 2 : 1) :
(m.M11 < m.M33 ? 2 : 0);
int j = (i + 1) % 3;
int k = (i + 2) % 3;
float s = (float)Math.Sqrt(MathHelper.GetElement(m, i, i) - MathHelper.GetElement(m, j, j) - MathHelper.GetElement(m, k, k) + 1);
MathHelper.SetElement(ref q, i, s * 0.5f);
s = 0.5f / s;
q.W = (MathHelper.GetElement(m, k, j) - MathHelper.GetElement(m, j, k)) * s;
MathHelper.SetElement(ref q, j, (MathHelper.GetElement(m, j, i) + MathHelper.GetElement(m, i, j)) * s);
MathHelper.SetElement(ref q, k, (MathHelper.GetElement(m, k, i) + MathHelper.GetElement(m, i, k)) * s);
}
return q;
}
public static Matrix Scaled(Matrix m, Vector3 v)
{
return new Matrix( m.M11 * v.X, m.M12 * v.Y, m.M13 * v.Z, 0,
m.M21 * v.X, m.M22 * v.Y, m.M23 * v.Z, 0,
m.M31 * v.X, m.M32 * v.Y, m.M33 * v.Z, 0,
0, 0, 0, 1);
}
public static Matrix Multiply(Matrix a, Matrix b)
{
/*return btMatrix3x3(
m2.tdot(0, m1[0]), m2.tdot(1, m1[0]), m2.tdot(2, m1[0]),
m2.tdot(0, m1[1]), m2.tdot(1, m1[1]), m2.tdot(2, m1[1]),
m2.tdot(0, m1[2]), m2.tdot(1, m1[2]), m2.tdot(2, m1[2]));*/
return new Matrix(
Dot(b, 0, MathHelper.GetRow(a, 1)), Dot(b, 1, MathHelper.GetRow(a, 1)), Dot(b, 2, MathHelper.GetRow(a, 1)), 0,
Dot(b, 0, MathHelper.GetRow(a, 2)), Dot(b, 1, MathHelper.GetRow(a, 2)), Dot(b, 2, MathHelper.GetRow(a, 2)), 0,
Dot(b, 0, MathHelper.GetRow(a, 3)), Dot(b, 1, MathHelper.GetRow(a, 3)), Dot(b, 2, MathHelper.GetRow(a, 3)), 0,
0, 0, 0, 1);
}
public static float Dot(Matrix m, int c, Vector3 v)
{
return MathHelper.GetElement(m, 0, c) * v.X + MathHelper.GetElement(m, 1, c) * v.Y + MathHelper.GetElement(m, 2, c) * v.Z;
}
public static Matrix Transpose(Matrix m)
{
return new Matrix( m.M11, m.M21, m.M31, 0,
m.M12, m.M22, m.M32, 0,
m.M13, m.M23, m.M33, 0,
0, 0, 0, 1);
}
}
}