Remove useless code from box2d file

Maths/b2_math.h

@@ -25,9 +25,6 @@
 
 #include <math.h>
 
-#include "b2_api.h"
-#include "b2_settings.h"
-
 /// This function is used to ensure that a floating point number is not a NaN or infinity.
 inline bool b2IsValid(float x)
 {
@@ -38,7 +35,7 @@ inline bool b2IsValid(float x)
 #define	b2Atan2(y, x)	atan2f(y, x)
 
 /// A 2D column vector.
-struct B2_API b2Vec2
+struct b2Vec2
 {
 	/// Default constructor does nothing (for performance).
 	b2Vec2() {}
@@ -56,13 +53,13 @@ struct B2_API b2Vec2
 	b2Vec2 operator -() const { b2Vec2 v; v.Set(-x, -y); return v; }
 
 	/// Read from and indexed element.
-	float operator () (int32 i) const
+	float operator () (int i) const
 	{
 		return (&x)[i];
 	}
 
 	/// Write to an indexed element.
-	float& operator () (int32 i)
+	float& operator () (int i)
 	{
 		return (&x)[i];
 	}
@@ -102,7 +99,7 @@ struct B2_API b2Vec2
 	float Normalize()
 	{
 		float length = Length();
-		if (length < b2_epsilon)
+		if (length < __FLT_EPSILON__)
 		{
 			return 0.0f;
 		}
@@ -128,588 +125,49 @@ struct B2_API b2Vec2
 	float x, y;
 };
 
-/// A 2D column vector with 3 elements.
-struct B2_API b2Vec3
-{
-	/// Default constructor does nothing (for performance).
-	b2Vec3() {}
-
-	/// Construct using coordinates.
-	b2Vec3(float xIn, float yIn, float zIn) : x(xIn), y(yIn), z(zIn) {}
-
-	/// Set this vector to all zeros.
-	void SetZero() { x = 0.0f; y = 0.0f; z = 0.0f; }
-
-	/// Set this vector to some specified coordinates.
-	void Set(float x_, float y_, float z_) { x = x_; y = y_; z = z_; }
-
-	/// Negate this vector.
-	b2Vec3 operator -() const { b2Vec3 v; v.Set(-x, -y, -z); return v; }
-
-	/// Add a vector to this vector.
-	void operator += (const b2Vec3& v)
-	{
-		x += v.x; y += v.y; z += v.z;
-	}
-
-	/// Subtract a vector from this vector.
-	void operator -= (const b2Vec3& v)
-	{
-		x -= v.x; y -= v.y; z -= v.z;
-	}
-
-	/// Multiply this vector by a scalar.
-	void operator *= (float s)
-	{
-		x *= s; y *= s; z *= s;
-	}
-
-	float x, y, z;
-};
-
-/// A 2-by-2 matrix. Stored in column-major order.
-struct B2_API b2Mat22
-{
-	/// The default constructor does nothing (for performance).
-	b2Mat22() {}
-
-	/// Construct this matrix using columns.
-	b2Mat22(const b2Vec2& c1, const b2Vec2& c2)
-	{
-		ex = c1;
-		ey = c2;
-	}
-
-	/// Construct this matrix using scalars.
-	b2Mat22(float a11, float a12, float a21, float a22)
-	{
-		ex.x = a11; ex.y = a21;
-		ey.x = a12; ey.y = a22;
-	}
-
-	/// Initialize this matrix using columns.
-	void Set(const b2Vec2& c1, const b2Vec2& c2)
-	{
-		ex = c1;
-		ey = c2;
-	}
-
-	/// Set this to the identity matrix.
-	void SetIdentity()
-	{
-		ex.x = 1.0f; ey.x = 0.0f;
-		ex.y = 0.0f; ey.y = 1.0f;
-	}
-
-	/// Set this matrix to all zeros.
-	void SetZero()
-	{
-		ex.x = 0.0f; ey.x = 0.0f;
-		ex.y = 0.0f; ey.y = 0.0f;
-	}
-
-	b2Mat22 GetInverse() const
-	{
-		float a = ex.x, b = ey.x, c = ex.y, d = ey.y;
-		b2Mat22 B;
-		float det = a * d - b * c;
-		if (det != 0.0f)
-		{
-			det = 1.0f / det;
-		}
-		B.ex.x =  det * d;	B.ey.x = -det * b;
-		B.ex.y = -det * c;	B.ey.y =  det * a;
-		return B;
-	}
-
-	/// Solve A * x = b, where b is a column vector. This is more efficient
-	/// than computing the inverse in one-shot cases.
-	b2Vec2 Solve(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;
-	}
-
-	b2Vec2 ex, ey;
-};
-
-/// A 3-by-3 matrix. Stored in column-major order.
-struct B2_API b2Mat33
-{
-	/// The default constructor does nothing (for performance).
-	b2Mat33() {}
-
-	/// Construct this matrix using columns.
-	b2Mat33(const b2Vec3& c1, const b2Vec3& c2, const b2Vec3& c3)
-	{
-		ex = c1;
-		ey = c2;
-		ez = c3;
-	}
-
-	/// Set this matrix to all zeros.
-	void SetZero()
-	{
-		ex.SetZero();
-		ey.SetZero();
-		ez.SetZero();
-	}
-
-	/// Solve A * x = b, where b is a column vector. This is more efficient
-	/// than computing the inverse in one-shot cases.
-	b2Vec3 Solve33(const b2Vec3& b) const;
-
-	/// Solve A * x = b, where b is a column vector. This is more efficient
-	/// than computing the inverse in one-shot cases. Solve only the upper
-	/// 2-by-2 matrix equation.
-	b2Vec2 Solve22(const b2Vec2& b) const;
-
-	/// Get the inverse of this matrix as a 2-by-2.
-	/// Returns the zero matrix if singular.
-	void GetInverse22(b2Mat33* M) const;
-
-	/// Get the symmetric inverse of this matrix as a 3-by-3.
-	/// Returns the zero matrix if singular.
-	void GetSymInverse33(b2Mat33* M) const;
-
-	b2Vec3 ex, ey, ez;
-};
-
-/// Rotation
-struct B2_API b2Rot
-{
-	b2Rot() {}
-
-	/// Initialize from an angle in radians
-	explicit b2Rot(float angle)
-	{
-		/// TODO_ERIN optimize
-		s = sinf(angle);
-		c = cosf(angle);
-	}
-
-	/// Set using an angle in radians.
-	void Set(float angle)
-	{
-		/// TODO_ERIN optimize
-		s = sinf(angle);
-		c = cosf(angle);
-	}
-
-	/// Set to the identity rotation
-	void SetIdentity()
-	{
-		s = 0.0f;
-		c = 1.0f;
-	}
-
-	/// Get the angle in radians
-	float GetAngle() const
-	{
-		return b2Atan2(s, c);
-	}
-
-	/// Get the x-axis
-	b2Vec2 GetXAxis() const
-	{
-		return b2Vec2(c, s);
-	}
-
-	/// Get the u-axis
-	b2Vec2 GetYAxis() const
-	{
-		return b2Vec2(-s, c);
-	}
-
-	/// Sine and cosine
-	float s, c;
-};
-
-/// A transform contains translation and rotation. It is used to represent
-/// the position and orientation of rigid frames.
-struct B2_API b2Transform
-{
-	/// The default constructor does nothing.
-	b2Transform() {}
-
-	/// Initialize using a position vector and a rotation.
-	b2Transform(const b2Vec2& position, const b2Rot& rotation) : p(position), q(rotation) {}
-
-	/// Set this to the identity transform.
-	void SetIdentity()
-	{
-		p.SetZero();
-		q.SetIdentity();
-	}
-
-	/// Set this based on the position and angle.
-	void Set(const b2Vec2& position, float angle)
-	{
-		p = position;
-		q.Set(angle);
-	}
-
-	b2Vec2 p;
-	b2Rot q;
-};
-
-/// This describes the motion of a body/shape for TOI computation.
-/// Shapes are defined with respect to the body origin, which may
-/// no coincide with the center of mass. However, to support dynamics
-/// we must interpolate the center of mass position.
-struct B2_API b2Sweep
-{
-	/// Get the interpolated transform at a specific time.
-	/// @param transform the output transform
-	/// @param beta is a factor in [0,1], where 0 indicates alpha0.
-	void GetTransform(b2Transform* transform, float beta) const;
-
-	/// Advance the sweep forward, yielding a new initial state.
-	/// @param alpha the new initial time.
-	void Advance(float alpha);
-
-	/// Normalize the angles.
-	void Normalize();
-
-	b2Vec2 localCenter;	///< local center of mass position
-	b2Vec2 c0, c;		///< center world positions
-	float a0, a;		///< world angles
-
-	/// Fraction of the current time step in the range [0,1]
-	/// c0 and a0 are the positions at alpha0.
-	float alpha0;
-};
-
-/// Useful constant
-extern B2_API const b2Vec2 b2Vec2_zero;
-
-/// Perform the dot product on two vectors.
-inline float b2Dot(const b2Vec2& a, const b2Vec2& b)
-{
-	return a.x * b.x + a.y * b.y;
-}
-
-/// Perform the cross product on two vectors. In 2D this produces a scalar.
-inline float b2Cross(const b2Vec2& a, const b2Vec2& b)
-{
-	return a.x * b.y - a.y * b.x;
-}
-
-/// Perform the cross product on a vector and a scalar. In 2D this produces
-/// a vector.
-inline b2Vec2 b2Cross(const b2Vec2& a, float s)
-{
-	return b2Vec2(s * a.y, -s * a.x);
-}
-
-/// Perform the cross product on a scalar and a vector. In 2D this produces
-/// a vector.
-inline b2Vec2 b2Cross(float s, const b2Vec2& a)
-{
-	return b2Vec2(-s * a.y, s * a.x);
-}
-
-/// Multiply a matrix times a vector. If a rotation matrix is provided,
-/// then this transforms the vector from one frame to another.
-inline b2Vec2 b2Mul(const b2Mat22& A, const b2Vec2& v)
-{
-	return b2Vec2(A.ex.x * v.x + A.ey.x * v.y, A.ex.y * v.x + A.ey.y * v.y);
-}
-
-/// Multiply a matrix transpose times a vector. If a rotation matrix is provided,
-/// then this transforms the vector from one frame to another (inverse transform).
-inline b2Vec2 b2MulT(const b2Mat22& A, const b2Vec2& v)
-{
-	return b2Vec2(b2Dot(v, A.ex), b2Dot(v, A.ey));
-}
-
 /// Add two vectors component-wise.
 inline b2Vec2 operator + (const b2Vec2& a, const b2Vec2& b)
 {
-	return b2Vec2(a.x + b.x, a.y + b.y);
+    return b2Vec2(a.x + b.x, a.y + b.y);
 }
 
 /// Subtract two vectors component-wise.
 inline b2Vec2 operator - (const b2Vec2& a, const b2Vec2& b)
 {
-	return b2Vec2(a.x - b.x, a.y - b.y);
+    return b2Vec2(a.x - b.x, a.y - b.y);
 }
 
 inline b2Vec2 operator * (float s, const b2Vec2& a)
 {
-	return b2Vec2(s * a.x, s * a.y);
+    return b2Vec2(s * a.x, s * a.y);
 }
 
 inline bool operator == (const b2Vec2& a, const b2Vec2& b)
 {
-	return a.x == b.x && a.y == b.y;
+    return a.x == b.x && a.y == b.y;
 }
 
 inline bool operator != (const b2Vec2& a, const b2Vec2& b)
 {
-	return a.x != b.x || a.y != b.y;
+    return a.x != b.x || a.y != b.y;
 }
 
 inline float b2Distance(const b2Vec2& a, const b2Vec2& b)
 {
-	b2Vec2 c = a - b;
-	return c.Length();
-}
-
-inline float b2DistanceSquared(const b2Vec2& a, const b2Vec2& b)
-{
-	b2Vec2 c = a - b;
-	return b2Dot(c, c);
-}
-
-inline b2Vec3 operator * (float s, const b2Vec3& a)
-{
-	return b2Vec3(s * a.x, s * a.y, s * a.z);
+    b2Vec2 c = a - b;
+    return c.Length();
 }
 
-/// Add two vectors component-wise.
-inline b2Vec3 operator + (const b2Vec3& a, const b2Vec3& b)
-{
-	return b2Vec3(a.x + b.x, a.y + b.y, a.z + b.z);
-}
-
-/// Subtract two vectors component-wise.
-inline b2Vec3 operator - (const b2Vec3& a, const b2Vec3& b)
+/// Perform the cross product on two vectors. In 2D this produces a scalar.
+inline float b2Cross(const b2Vec2& a, const b2Vec2& b)
 {
-	return b2Vec3(a.x - b.x, a.y - b.y, a.z - b.z);
+    return a.x * b.y - a.y * b.x;
 }
 
 /// Perform the dot product on two vectors.
-inline float b2Dot(const b2Vec3& a, const b2Vec3& b)
-{
-	return a.x * b.x + a.y * b.y + a.z * b.z;
-}
-
-/// Perform the cross product on two vectors.
-inline b2Vec3 b2Cross(const b2Vec3& a, const b2Vec3& b)
-{
-	return b2Vec3(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);
-}
-
-inline b2Mat22 operator + (const b2Mat22& A, const b2Mat22& B)
-{
-	return b2Mat22(A.ex + B.ex, A.ey + B.ey);
-}
-
-// A * B
-inline b2Mat22 b2Mul(const b2Mat22& A, const b2Mat22& B)
-{
-	return b2Mat22(b2Mul(A, B.ex), b2Mul(A, B.ey));
-}
-
-// A^T * B
-inline b2Mat22 b2MulT(const b2Mat22& A, const b2Mat22& B)
-{
-	b2Vec2 c1(b2Dot(A.ex, B.ex), b2Dot(A.ey, B.ex));
-	b2Vec2 c2(b2Dot(A.ex, B.ey), b2Dot(A.ey, B.ey));
-	return b2Mat22(c1, c2);
-}
-
-/// Multiply a matrix times a vector.
-inline b2Vec3 b2Mul(const b2Mat33& A, const b2Vec3& v)
-{
-	return v.x * A.ex + v.y * A.ey + v.z * A.ez;
-}
-
-/// Multiply a matrix times a vector.
-inline b2Vec2 b2Mul22(const b2Mat33& A, const b2Vec2& v)
-{
-	return b2Vec2(A.ex.x * v.x + A.ey.x * v.y, A.ex.y * v.x + A.ey.y * v.y);
-}
-
-/// Multiply two rotations: q * r
-inline b2Rot b2Mul(const b2Rot& q, const b2Rot& r)
-{
-	// [qc -qs] * [rc -rs] = [qc*rc-qs*rs -qc*rs-qs*rc]
-	// [qs  qc]   [rs  rc]   [qs*rc+qc*rs -qs*rs+qc*rc]
-	// s = qs * rc + qc * rs
-	// c = qc * rc - qs * rs
-	b2Rot qr;
-	qr.s = q.s * r.c + q.c * r.s;
-	qr.c = q.c * r.c - q.s * r.s;
-	return qr;
-}
-
-/// Transpose multiply two rotations: qT * r
-inline b2Rot b2MulT(const b2Rot& q, const b2Rot& r)
-{
-	// [ qc qs] * [rc -rs] = [qc*rc+qs*rs -qc*rs+qs*rc]
-	// [-qs qc]   [rs  rc]   [-qs*rc+qc*rs qs*rs+qc*rc]
-	// s = qc * rs - qs * rc
-	// c = qc * rc + qs * rs
-	b2Rot qr;
-	qr.s = q.c * r.s - q.s * r.c;
-	qr.c = q.c * r.c + q.s * r.s;
-	return qr;
-}
-
-/// Rotate a vector
-inline b2Vec2 b2Mul(const b2Rot& q, const b2Vec2& v)
-{
-	return b2Vec2(q.c * v.x - q.s * v.y, q.s * v.x + q.c * v.y);
-}
-
-/// Inverse rotate a vector
-inline b2Vec2 b2MulT(const b2Rot& q, const b2Vec2& v)
-{
-	return b2Vec2(q.c * v.x + q.s * v.y, -q.s * v.x + q.c * v.y);
-}
-
-inline b2Vec2 b2Mul(const b2Transform& T, const b2Vec2& v)
-{
-	float x = (T.q.c * v.x - T.q.s * v.y) + T.p.x;
-	float y = (T.q.s * v.x + T.q.c * v.y) + T.p.y;
-
-	return b2Vec2(x, y);
-}
-
-inline b2Vec2 b2MulT(const b2Transform& T, const b2Vec2& v)
-{
-	float px = v.x - T.p.x;
-	float py = v.y - T.p.y;
-	float x = (T.q.c * px + T.q.s * py);
-	float y = (-T.q.s * px + T.q.c * py);
-
-	return b2Vec2(x, y);
-}
-
-// v2 = A.q.Rot(B.q.Rot(v1) + B.p) + A.p
-//    = (A.q * B.q).Rot(v1) + A.q.Rot(B.p) + A.p
-inline b2Transform b2Mul(const b2Transform& A, const b2Transform& B)
-{
-	b2Transform C;
-	C.q = b2Mul(A.q, B.q);
-	C.p = b2Mul(A.q, B.p) + A.p;
-	return C;
-}
-
-// v2 = A.q' * (B.q * v1 + B.p - A.p)
-//    = A.q' * B.q * v1 + A.q' * (B.p - A.p)
-inline b2Transform b2MulT(const b2Transform& A, const b2Transform& B)
-{
-	b2Transform C;
-	C.q = b2MulT(A.q, B.q);
-	C.p = b2MulT(A.q, B.p - A.p);
-	return C;
-}
-
-template <typename T>
-inline T b2Abs(T a)
-{
-	return a > T(0) ? a : -a;
-}
-
-inline b2Vec2 b2Abs(const b2Vec2& a)
-{
-	return b2Vec2(b2Abs(a.x), b2Abs(a.y));
-}
-
-inline b2Mat22 b2Abs(const b2Mat22& A)
-{
-	return b2Mat22(b2Abs(A.ex), b2Abs(A.ey));
-}
-
-template <typename T>
-inline T b2Min(T a, T b)
-{
-	return a < b ? a : b;
-}
-
-inline b2Vec2 b2Min(const b2Vec2& a, const b2Vec2& b)
-{
-	return b2Vec2(b2Min(a.x, b.x), b2Min(a.y, b.y));
-}
-
-template <typename T>
-inline T b2Max(T a, T b)
-{
-	return a > b ? a : b;
-}
-
-inline b2Vec2 b2Max(const b2Vec2& a, const b2Vec2& b)
-{
-	return b2Vec2(b2Max(a.x, b.x), b2Max(a.y, b.y));
-}
-
-template <typename T>
-inline T b2Clamp(T a, T low, T high)
-{
-	return b2Max(low, b2Min(a, high));
-}
-
-inline b2Vec2 b2Clamp(const b2Vec2& a, const b2Vec2& low, const b2Vec2& high)
-{
-	return b2Max(low, b2Min(a, high));
-}
-
-template<typename T> inline void b2Swap(T& a, T& b)
-{
-	T tmp = a;
-	a = b;
-	b = tmp;
-}
-
-/// "Next Largest Power of 2
-/// Given a binary integer value x, the next largest power of 2 can be computed by a SWAR algorithm
-/// that recursively "folds" the upper bits into the lower bits. This process yields a bit vector with
-/// the same most significant 1 as x, but all 1's below it. Adding 1 to that value yields the next
-/// largest power of 2. For a 32-bit value:"
-inline uint32 b2NextPowerOfTwo(uint32 x)
-{
-	x |= (x >> 1);
-	x |= (x >> 2);
-	x |= (x >> 4);
-	x |= (x >> 8);
-	x |= (x >> 16);
-	return x + 1;
-}
-
-inline bool b2IsPowerOfTwo(uint32 x)
-{
-	bool result = x > 0 && (x & (x - 1)) == 0;
-	return result;
-}
-
-// https://fgiesen.wordpress.com/2012/08/15/linear-interpolation-past-present-and-future/
-inline void b2Sweep::GetTransform(b2Transform* xf, float beta) const
-{
-	xf->p = (1.0f - beta) * c0 + beta * c;
-	float angle = (1.0f - beta) * a0 + beta * a;
-	xf->q.Set(angle);
-
-	// Shift to origin
-	xf->p -= b2Mul(xf->q, localCenter);
-}
-
-inline void b2Sweep::Advance(float alpha)
-{
-	b2Assert(alpha0 < 1.0f);
-	float beta = (alpha - alpha0) / (1.0f - alpha0);
-	c0 += beta * (c - c0);
-	a0 += beta * (a - a0);
-	alpha0 = alpha;
-}
-
-/// Normalize an angle in radians to be between -pi and pi
-inline void b2Sweep::Normalize()
+inline float b2Dot(const b2Vec2& a, const b2Vec2& b)
 {
-	float twoPi = 2.0f * b2_pi;
-	float d =  twoPi * floorf(a0 / twoPi);
-	a0 -= d;
-	a -= d;
+    return a.x * b.x + a.y * b.y;
 }
 
 #endif