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Diffstat (limited to 'Client/ThirdParty/Box2D/src/common/b2_math.cpp')
-rw-r--r-- | Client/ThirdParty/Box2D/src/common/b2_math.cpp | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/Client/ThirdParty/Box2D/src/common/b2_math.cpp b/Client/ThirdParty/Box2D/src/common/b2_math.cpp new file mode 100644 index 0000000..a14460c --- /dev/null +++ b/Client/ThirdParty/Box2D/src/common/b2_math.cpp @@ -0,0 +1,98 @@ +// MIT License + +// Copyright (c) 2019 Erin Catto + +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: + +// The above copyright notice and this permission notice shall be included in all +// copies or substantial portions of the Software. + +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +// SOFTWARE. + +#include "box2d/b2_math.h" + +const b2Vec2 b2Vec2_zero(0.0f, 0.0f); + +/// 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 +{ + float det = b2Dot(ex, b2Cross(ey, ez)); + if (det != 0.0f) + { + det = 1.0f / det; + } + b2Vec3 x; + x.x = det * b2Dot(b, b2Cross(ey, ez)); + x.y = det * b2Dot(ex, b2Cross(b, ez)); + x.z = det * b2Dot(ex, b2Cross(ey, 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 +{ + float a11 = ex.x, a12 = ey.x, a21 = ex.y, a22 = ey.y; + float 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; +} + +/// +void b2Mat33::GetInverse22(b2Mat33* M) const +{ + float a = ex.x, b = ey.x, c = ex.y, d = ey.y; + float det = a * d - b * c; + if (det != 0.0f) + { + det = 1.0f / det; + } + + M->ex.x = det * d; M->ey.x = -det * b; M->ex.z = 0.0f; + M->ex.y = -det * c; M->ey.y = det * a; M->ey.z = 0.0f; + M->ez.x = 0.0f; M->ez.y = 0.0f; M->ez.z = 0.0f; +} + +/// Returns the zero matrix if singular. +void b2Mat33::GetSymInverse33(b2Mat33* M) const +{ + float det = b2Dot(ex, b2Cross(ey, ez)); + if (det != 0.0f) + { + det = 1.0f / det; + } + + float a11 = ex.x, a12 = ey.x, a13 = ez.x; + float a22 = ey.y, a23 = ez.y; + float a33 = ez.z; + + M->ex.x = det * (a22 * a33 - a23 * a23); + M->ex.y = det * (a13 * a23 - a12 * a33); + M->ex.z = det * (a12 * a23 - a13 * a22); + + M->ey.x = M->ex.y; + M->ey.y = det * (a11 * a33 - a13 * a13); + M->ey.z = det * (a13 * a12 - a11 * a23); + + M->ez.x = M->ex.z; + M->ez.y = M->ey.z; + M->ez.z = det * (a11 * a22 - a12 * a12); +} |