为什么这个pass-by-value参数被破坏了？ （C ++）
我正在传递一个ivec2（2维int矢量）抛出不同类的多个方法调用。所有的价值。然而，在第一次通过后，它开始腐败。由于矢量实现是库的一部分（称为可视化库），我猜我做错了。
这是callstack：
有问题的参数是pixel。它创建于TesselatedHeightField::getHeightAt(vl::fvec2 uv)：
vl::ivec2 pixel = vl::ivec2(
static_cast<int> (std::floor(uv.x() * hfImage_->width())),
static_cast<int> (std::floor(uv.y() * hfImage_->height())));
float patchesHeightPerCent = heightField_->getPatchContainer()->getRelativeHeightAt(pixel);
调试器告诉我像素的值是177和23，这很好。
关闭callstack：
float
PatchContainer::getRelativeHeightAt(vl::ivec2 pixel)
{
float relHeight = 0.0;
for (PatchesVector::iterator iter = patches_.begin(); iter != patches_.end(); ++iter)
{
relHeight += (*iter)->getRelativeHeightAt(pixel);
}
return relHeight;
}
像素已经损坏，显示-1073751104，其值为177。
在Patch::getRelativeHeightAt(vl::ivec2 pixel)中，值为-1073751204和-1073751224。
在Patch::inside(vl::ivec2 pixel)中，值为-1073751316和-1208145864。
关于vl :: ivec2
再次，vl :: ivec2是该库的一部分。
vl :: ivec2是def typedef Vector2<GLint> ivec2;
以下是ivec2实现的内容。 （图书馆的一方，不是我创建的）。
/**************************************************************************************/
/* */
/* Visualization Library */
/* http://www.visualizationlibrary.com */
/* */
/* Copyright (c) 2005-2010, Michele Bosi */
/* All rights reserved. */
/* */
/* Redistribution and use in source and binary forms, with or without modification, */
/* are permitted provided that the following conditions are met: */
/* */
/* - Redistributions of source code must retain the above copyright notice, this */
/* list of conditions and the following disclaimer. */
/* */
/* - Redistributions in binary form must reproduce the above copyright notice, this */
/* list of conditions and the following disclaimer in the documentation and/or */
/* other materials provided with the distribution. */
/* */
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND */
/* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED */
/* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR */
/* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES */
/* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON */
/* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT */
/* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS */
/* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/* */
/**************************************************************************************/
#ifndef Vector2_INCLUDE_ONCE
#define Vector2_INCLUDE_ONCE
#include <vlCore/OpenGLDefs.hpp>
#include <cmath>
#ifdef min
#undef min
#endif
#ifdef max
#undef max
#endif
#ifdef dot
#undef dot
#endif
#ifdef cross
#undef cross
#endif
namespace vl
{
// trigonometric constants
//! Greek Pi constant using \p double precision.
const double dPi = 3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093845;
//! Constant to convert degrees into radians using \p double precision.
const double dDEG_TO_RAD = dPi / 180.0;
//! Constant to convert radians into degrees using \p double precision.
const double dRAD_TO_DEG = 180.0 / dPi;
//! Greek Pi constant using \p float precision.
const float fPi = (float)3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093845;
//! Constant to convert degrees into radians using \p float precision.
const float fDEG_TO_RAD = float(dPi / 180.0);
//! Constant to convert radians into degrees using \p float precision.
const float fRAD_TO_DEG = float(180.0 / dPi);
// fast square root
#if VL_FAST_SQUARE_ROOTS == 1
#define VL_FLOAT_SQRT(x) fast_sqrt(x)
#define VL_FLOAT_INVSQRT(x) fast2_inversesqrt(x)
#else
#define VL_FLOAT_SQRT(x) ((float)::sqrt(x))
#define VL_FLOAT_INVSQRT(x) (1.0f/(float)::sqrt(x))
#endif
// fast square root functions, see Dave Eberly's paper and http://www.beyond3d.com/content/articles/8/
inline float fast1_inversesqrt(float x)
{
float xhalf = 0.5f*x;
union { float f; unsigned int i; } num;
num.f = x;
num.i = 0x5f3759df - (num.i>>1);
x = num.f;
x = x*(1.5f - xhalf*x*x); // single iteration, very quick, but very poor precision
return x;
}
inline float fast2_inversesqrt(float x)
{
float xhalf = 0.5f*x;
union { float f; unsigned int i; } num;
num.f = x;
num.i = 0x5f3759df - (num.i>>1);
x = num.f;
x = x*(1.5f - xhalf*x*x);
x = x*(1.5f - xhalf*x*x); // two iterations, sligthtly better precision
return x;
}
inline float fast_sqrt(float x) { if (x == 0.0f) return 0.0f; else return x * fast2_inversesqrt(x); }
/**
* The Vector2 class is a template class that implements a generic 2 components vector, see also vl::fvec2, vl::dvec2, vl::uvec2, vl::ivec2, vl::svec2, vl::usvec2, vl::bvec2, vl::ubvec2.
* \sa Vector4, Vector3, Matrix4, Matrix3, Matrix2
*/
template<typename T_Scalar>
class Vector2
{
public:
typedef T_Scalar scalar_type;
static const int scalar_count = 2;
Vector2(const Vector2& other) { *this = other; }
Vector2() { x() = y() = 0; }
template<class T>
explicit Vector2(const T& other)
{
x() = (T_Scalar)other.x();
y() = (T_Scalar)other.y();
}
explicit Vector2(T_Scalar x, T_Scalar y)
{
mScalar[0] = x;
mScalar[1] = y;
}
T_Scalar* ptr() { return mScalar; }
const T_Scalar* ptr() const { return mScalar; }
const T_Scalar& x() const { return mScalar[0]; }
const T_Scalar& y() const { return mScalar[1]; }
T_Scalar& x() { return mScalar[0]; }
T_Scalar& y() { return mScalar[1]; }
const T_Scalar& r() const { return mScalar[0]; }
const T_Scalar& g() const { return mScalar[1]; }
T_Scalar& r() { return mScalar[0]; }
T_Scalar& g() { return mScalar[1]; }
const T_Scalar& s() const { return mScalar[0]; }
const T_Scalar& t() const { return mScalar[1]; }
T_Scalar& s() { return mScalar[0]; }
T_Scalar& t() { return mScalar[1]; }
Vector2 operator+(const Vector2& other) const
{
return Vector2(x()+other.x(), y()+other.y());
}
Vector2 operator-(const Vector2& other) const
{
return Vector2(x()-other.x(), y()-other.y());
}
Vector2 operator*(const Vector2& other) const
{
return Vector2(x()*other.x(), y()*other.y());
}
Vector2 operator/(const Vector2& other) const
{
return Vector2(x()/other.x(), y()/other.y());
}
Vector2 operator+(T_Scalar val) const
{
return Vector2(x()+val, y()+val);
}
Vector2 operator-(T_Scalar val) const
{
return Vector2(x()-val, y()-val);
}
Vector2 operator*(T_Scalar val) const
{
return Vector2(x()*val, y()*val);
}
Vector2 operator/(T_Scalar val) const
{
return Vector2(x()/val, y()/val);
}
Vector2 operator-() const
{
return Vector2(-x(), -y());
}
Vector2& operator+=(const Vector2& other)
{
*this = *this + other;
return *this;
}
Vector2& operator-=(const Vector2& other)
{
*this = *this - other;
return *this;
}
Vector2& operator*=(const Vector2& other)
{
*this = *this * other;
return *this;
}
Vector2& operator/=(const Vector2& other)
{
*this = *this / other;
return *this;
}
Vector2& operator+=(T_Scalar val)
{
*this = *this + val;
return *this;
}
Vector2& operator-=(T_Scalar val)
{
*this = *this - val;
return *this;
}
Vector2& operator*=(T_Scalar val)
{
*this = *this * val;
return *this;
}
Vector2& operator/=(T_Scalar val)
{
*this = *this / val;
return *this;
}
Vector2& operator=(const Vector2& other)
{
x() = other.x();
y() = other.y();
return *this;
}
Vector2& operator=(T_Scalar val)
{
x() = y() = val;
return *this;
}
bool operator==(const Vector2& other) const
{
return x() == other.x() && y() == other.y();
}
bool operator!=(const Vector2& other) const
{
return !operator==(other);
}
bool operator<(const Vector2& other) const
{
if (x() != other.x())
return x() < other.x();
else
return y() < other.y();
}
T_Scalar& operator[](unsigned i) { return mScalar[i]; }
const T_Scalar& operator[](unsigned i) const { return mScalar[i]; }
T_Scalar length() const { return ::sqrt(x()*x()+y()*y()); }
T_Scalar lengthSquared() const { return x()*x()+y()*y(); }
bool isNull() const { return !x() && !y(); }
const Vector2& normalize(T_Scalar *len=NULL)
{
T_Scalar l = length();
if (len)
*len = l;
if (l)
*this *= (T_Scalar)(1.0/l);
return *this;
}
protected:
T_Scalar mScalar[scalar_count];
};
template<typename T>
inline const Vector2<T> operator*(T val, const Vector2<T>& v)
{
return v * val;
}
//! A 2 components vector with \p GLint precision.
typedef Vector2<GLint> ivec2;
//! A 2 components vector with \p GLuint precision.
typedef Vector2<GLuint> uvec2;
//! A 2 components vector with \p GLfloat precision.
typedef Vector2<GLfloat> fvec2;
//! A 2 components vector with \p GLdouble precision.
typedef Vector2<GLdouble> dvec2;
//! A 2 components vector with \p GLbyte precision.
typedef Vector2<GLbyte> bvec2;
//! A 2 components vector with \p GLubyte precision.
typedef Vector2<GLubyte> ubvec2;
//! A 2 components vector with \p GLshort precision.
typedef Vector2<GLshort> svec2;
//! A 2 components vector with \p GLushort precision.
typedef Vector2<GLushort> usvec2;
#if VL_PIPELINE_PRECISION == 2
//! Defined as: \p 'typedef \p dvec2 \p vec2'. See also \ref VL_PIPELINE_PRECISION.
typedef dvec2 vec2;
#else
//! Defined as: \p 'typedef \p fvec2 \p vec2'. See also \ref VL_PIPELINE_PRECISION.
typedef fvec2 vec2;
#endif
inline float dot(const fvec2& v1, const fvec2& v2) { return v1.x()*v2.x() + v1.y()*v2.y(); }
inline double dot(const dvec2& v1, const dvec2& v2) { return v1.x()*v2.x() + v1.y()*v2.y(); }
inline float dot(const ivec2& v1, const ivec2& v2) { return (float)(v1.x()*v2.x() + v1.y()*v2.y()); }
inline float dot(const uvec2& v1, const uvec2& v2) { return (float)(v1.x()*v2.x() + v1.y()*v2.y()); }
inline float min(float a, float b) { return a < b ? a : b; }
inline double min(double a, double b) { return a < b ? a : b; }
inline int min(int a, int b) { return a < b ? a : b; }
inline unsigned int min(unsigned int a, unsigned int b) { return a < b ? a : b; }
inline float max(float a, float b) { return a > b ? a : b; }
inline double max(double a, double b) { return a > b ? a : b; }
inline int max(int a, int b) { return a > b ? a : b; }
inline unsigned int max(unsigned int a, unsigned int b) { return a > b ? a : b; }
inline float clamp(float x, float minval, float maxval) { return min(max(x,minval),maxval); }
inline double clamp(double x, double minval, double maxval) { return min(max(x,minval),maxval); }
inline int clamp(int x, int minval, int maxval) { return min(max(x,minval),maxval); }
inline unsigned int clamp(unsigned int x, unsigned int minval, unsigned int maxval) { return min(max(x,minval),maxval); }
inline fvec2 min(const fvec2& a, const fvec2& b)
{
return fvec2( a.x() < b.x() ? a.x() : b.x(),
a.y() < b.y() ? a.y() : b.y());
}
inline fvec2 min(const fvec2& a, float b)
{
return fvec2( a.x() < b ? a.x() : b,
a.y() < b ? a.y() : b);
}
inline dvec2 min(const dvec2& a, const dvec2& b)
{
return dvec2( a.x() < b.x() ? a.x() : b.x(),
a.y() < b.y() ? a.y() : b.y());
}
inline dvec2 min(const dvec2& a, double b)
{
return dvec2( a.x() < b ? a.x() : b,
a.y() < b ? a.y() : b);
}
inline ivec2 min(const ivec2& a, const ivec2& b)
{
return ivec2( a.x() < b.x() ? a.x() : b.x(),
a.y() < b.y() ? a.y() : b.y());
}
inline ivec2 min(const ivec2& a, int b)
{
return ivec2( a.x() < b ? a.x() : b,
a.y() < b ? a.y() : b);
}
inline uvec2 min(const uvec2& a, const uvec2& b)
{
return uvec2( a.x() < b.x() ? a.x() : b.x(),
a.y() < b.y() ? a.y() : b.y());
}
inline uvec2 min(const uvec2& a, unsigned int b)
{
return uvec2( a.x() < b ? a.x() : b,
a.y() < b ? a.y() : b);
}
inline fvec2 max(const fvec2& a, const fvec2& b)
{
return fvec2( a.x() > b.x() ? a.x() : b.x(),
a.y() > b.y() ? a.y() : b.y());
}
inline fvec2 max(const fvec2& a, float b)
{
return fvec2( a.x() > b ? a.x() : b,
a.y() > b ? a.y() : b);
}
inline dvec2 max(const dvec2& a, const dvec2& b)
{
return dvec2( a.x() > b.x() ? a.x() : b.x(),
a.y() > b.y() ? a.y() : b.y());
}
inline dvec2 max(const dvec2& a, double b)
{
return dvec2( a.x() > b ? a.x() : b,
a.y() > b ? a.y() : b);
}
inline ivec2 max(const ivec2& a, const ivec2& b)
{
return ivec2( a.x() > b.x() ? a.x() : b.x(),
a.y() > b.y() ? a.y() : b.y());
}
inline ivec2 max(const ivec2& a, int b)
{
return ivec2( a.x() > b ? a.x() : b,
a.y() > b ? a.y() : b);
}
inline uvec2 max(const uvec2& a, const uvec2& b)
{
return uvec2( a.x() > b.x() ? a.x() : b.x(),
a.y() > b.y() ? a.y() : b.y());
}
inline uvec2 max(const uvec2& a, unsigned int b)
{
return uvec2( a.x() > b ? a.x() : b,
a.y() > b ? a.y() : b);
}
inline fvec2 clamp(const fvec2& x, float minval, float maxval) { return min(max(x,minval),maxval); }
inline fvec2 clamp(const fvec2& x, const fvec2& minval, const fvec2& maxval) { return min(max(x,minval),maxval); }
inline dvec2 clamp(const dvec2& x, double minval, double maxval) { return min(max(x,minval),maxval); }
inline dvec2 clamp(const dvec2& x, const dvec2& minval, const dvec2& maxval) { return min(max(x,minval),maxval); }
inline ivec2 clamp(const ivec2& x, int minval, int maxval) { return min(max(x,minval),maxval); }
inline ivec2 clamp(const ivec2& x, const ivec2& minval, const ivec2& maxval) { return min(max(x,minval),maxval); }
inline uvec2 clamp(const uvec2& x, unsigned int minval, unsigned int maxval) { return min(max(x,minval),maxval); }
inline uvec2 clamp(const uvec2& x, const uvec2& minval, const uvec2& maxval) { return min(max(x,minval),maxval); }
}
#endif
感谢任何帮助。
Visualisation Library Homepage
修改
我确实在Vector2(const Vector2& other) { *this = other; }放了一个断点。
这是debuger的结果：
这叫：
Vector2& operator=(const Vector2& other)
{
x() = other.x();
y() = other.y();
return *this;
}
导致：
在复制构造函数的末尾，调试器大吼大叫不正确的值。
2 个答案:
答案 0 :(得分：2)
这是什么操作系统？这听起来像是调用约定或结构布局不匹配，如果不对所有文件使用相同的编译器版本和选项，则可以轻松获得。
在ivec2复制构造函数中放置一个断点，看看那里的值是否正确。
答案 1 :(得分：0)
您可以从复制构造函数中删除explicit。 但它明确地停止了价值传递，因为这是低效的
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