File indexing completed on 2025-06-01 03:50:40

 /*
 * Copyright (c) 2007-2009 Erin Catto http://www.gphysics.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.
 */
 
 #include <Box2D/Common/b2Math.h>
 
 const b2Vec2 b2Vec2_zero(0.0f, 0.0f);
 const b2Mat22 b2Mat22_identity(1.0f, 0.0f, 0.0f, 1.0f);
 const b2Transform b2Transform_identity(b2Vec2_zero, b2Mat22_identity);
 
 /// Solve A * x = b, where b is a column vector. This is more efficient
 /// than computing the inverse in one-shot cases.
 b2Vec3 b2Mat33::Solve33(const b2Vec3& b) const
 {
     qreal det = b2Dot(col1, b2Cross(col2, col3));
     if (det != 0.0f)
     {
         det = 1.0f / det;
     }
     b2Vec3 x;
     x.x = det * b2Dot(b, b2Cross(col2, col3));
     x.y = det * b2Dot(col1, b2Cross(b, col3));
     x.z = det * b2Dot(col1, b2Cross(col2, b));
     return x;
 }
 
 /// Solve A * x = b, where b is a column vector. This is more efficient
 /// than computing the inverse in one-shot cases.
 b2Vec2 b2Mat33::Solve22(const b2Vec2& b) const
 {
     qreal a11 = col1.x, a12 = col2.x, a21 = col1.y, a22 = col2.y;
     qreal det = a11 * a22 - a12 * a21;
     if (det != 0.0f)
     {
         det = 1.0f / det;
     }
     b2Vec2 x;
     x.x = det * (a22 * b.x - a12 * b.y);
     x.y = det * (a11 * b.y - a21 * b.x);
     return x;
 }