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172 lines
4.2 KiB
C++
172 lines
4.2 KiB
C++
/*
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* Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#ifndef B2GLUE_H
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#define B2GLUE_H
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#include "math_2d.h"
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#include <limits.h>
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namespace b2ConvexDecomp {
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typedef real_t float32;
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typedef int32_t int32;
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static inline float32 b2Sqrt(float32 val) { return Math::sqrt(val); }
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#define b2_maxFloat FLT_MAX
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#define b2_epsilon CMP_EPSILON
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#define b2_pi 3.14159265359f
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#define b2_maxPolygonVertices 16
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#define b2Max MAX
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#define b2Min MIN
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#define b2Clamp CLAMP
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#define b2Abs ABS
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/// A small length used as a collision and constraint tolerance. Usually it is
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/// chosen to be numerically significant, but visually insignificant.
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#define b2_linearSlop 0.005f
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/// A small angle used as a collision and constraint tolerance. Usually it is
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/// chosen to be numerically significant, but visually insignificant.
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#define b2_angularSlop (2.0f / 180.0f * b2_pi)
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/// A 2D column vector.
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struct b2Vec2
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{
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/// Default constructor does nothing (for performance).
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b2Vec2() {}
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/// Construct using coordinates.
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b2Vec2(float32 x, float32 y) : x(x), y(y) {}
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/// Set this vector to all zeros.
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void SetZero() { x = 0.0f; y = 0.0f; }
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/// Set this vector to some specified coordinates.
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void Set(float32 x_, float32 y_) { x = x_; y = y_; }
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/// Negate this vector.
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b2Vec2 operator -() const { b2Vec2 v; v.Set(-x, -y); return v; }
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/// Read from and indexed element.
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float32 operator () (int32 i) const
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{
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return (&x)[i];
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}
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/// Write to an indexed element.
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float32& operator () (int32 i)
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{
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return (&x)[i];
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}
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/// Add a vector to this vector.
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void operator += (const b2Vec2& v)
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{
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x += v.x; y += v.y;
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}
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/// Subtract a vector from this vector.
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void operator -= (const b2Vec2& v)
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{
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x -= v.x; y -= v.y;
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}
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/// Multiply this vector by a scalar.
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void operator *= (float32 a)
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{
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x *= a; y *= a;
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}
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/// Get the length of this vector (the norm).
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float32 Length() const
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{
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return b2Sqrt(x * x + y * y);
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}
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/// Get the length squared. For performance, use this instead of
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/// b2Vec2::Length (if possible).
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float32 LengthSquared() const
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{
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return x * x + y * y;
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}
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bool operator==(const b2Vec2& p_v) const {
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return x==p_v.x && y==p_v.y;
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}
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b2Vec2 operator+(const b2Vec2& p_v) const {
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return b2Vec2(x+p_v.x,y+p_v.y);
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}
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b2Vec2 operator-(const b2Vec2& p_v) const {
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return b2Vec2(x-p_v.x,y-p_v.y);
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}
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b2Vec2 operator*(float32 f) const {
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return b2Vec2(f*x,f*y);
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}
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/// Convert this vector into a unit vector. Returns the length.
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float32 Normalize()
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{
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float32 length = Length();
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if (length < b2_epsilon)
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{
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return 0.0f;
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}
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float32 invLength = 1.0f / length;
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x *= invLength;
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y *= invLength;
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return length;
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}
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///// Does this vector contain finite coordinates?
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//bool IsValid() const
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//{
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// return b2IsValid(x) && b2IsValid(y);
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//}
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float32 x, y;
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};
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inline b2Vec2 operator*(float32 f,const b2Vec2& p_v) {
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return b2Vec2(f*p_v.x,f*p_v.y);
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}
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/// Perform the dot product on two vectors.
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inline float32 b2Dot(const b2Vec2& a, const b2Vec2& b)
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{
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return a.x * b.x + a.y * b.y;
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}
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/// Perform the cross product on two vectors. In 2D this produces a scalar.
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inline float32 b2Cross(const b2Vec2& a, const b2Vec2& b)
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{
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return a.x * b.y - a.y * b.x;
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}
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/// Perform the cross product on a vector and a scalar. In 2D this produces
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/// a vector.
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inline b2Vec2 b2Cross(const b2Vec2& a, float32 s)
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{
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return b2Vec2(s * a.y, -s * a.x);
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}
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}
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#endif
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