summaryrefslogtreecommitdiff
path: root/Client/ThirdParty/Box2D/src/common/b2_math.cpp
diff options
context:
space:
mode:
authorchai <chaifix@163.com>2021-12-13 00:07:19 +0800
committerchai <chaifix@163.com>2021-12-13 00:07:19 +0800
commit60cbbdec07ab7a5636eac5b3c024ae44e937f4d4 (patch)
treeb2c7b0a868f18159dbc43d8954e1bd7668549a88 /Client/ThirdParty/Box2D/src/common/b2_math.cpp
+init
Diffstat (limited to 'Client/ThirdParty/Box2D/src/common/b2_math.cpp')
-rw-r--r--Client/ThirdParty/Box2D/src/common/b2_math.cpp98
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);
+}