矢量函数 [英] vector functions
问题描述
你好
如果有人可以向我解释下面的代码会很棒。
//两个向量之间的返回角度
const float inline Angle（const CVector& normal）const
{
返回acosf（* this％normal）;
}
//用正常向量反射此向量表面
const CVector内联反射（const CVector& normal）const
{
const CVector vec（* this | 1）; //规范化这个载体
return（vec - normal * 2.0 *（vec％normal））*！* this;
}
//围绕法线旋转角度
const CVector内联旋转（常量浮动角度，常量CVector&正常）const
{
const float cosine = cosf（angle）;
const float sine = sinf（angle）;
返回CVector（* this * cosine +（（正常） * * this）*（1.0f - 余弦））*
正常+（*这^正常）*正弦）;
}
这产生了以下错误：
vector.h：220：错误：声明没有声明任何内容
vector.h：220：错误：`inline'之前的语法错误'
vector.h：226：错误：ISO C ++禁止在返回类型中定义类型
vector.h：226：错误：语法`inline'之前的错误''
vector.h：233：错误：`inline'之前的语法错误''
vector.h：236：错误：`angle''是未在此范围内声明
vector.h：238：错误：返回'之前'语法错误
％和^产生什么？为什么在
函数定义的末尾还有一个const？
感谢和问候
Michael
Hello
If someone could explain the code below to me would be great.
// return angle between two vectors
const float inline Angle(const CVector& normal) const
{
return acosf(*this % normal);
}
// reflect this vector off surface with normal vector
const CVector inline Reflection(const CVector& normal) const
{
const CVector vec(*this | 1); // normalize this vector
return (vec - normal * 2.0 * (vec % normal)) * !*this;
}
// rotate angle degrees about a normal
const CVector inline Rotate(const float angle, const CVector& normal) const
{
const float cosine = cosf(angle);
const float sine = sinf(angle);
return CVector(*this * cosine + ((normal * *this) * (1.0f - cosine)) *
normal + (*this ^ normal) * sine);
}
This is producing the following errors:
vector.h:220: error: declaration does not declare anything
vector.h:220: error: syntax error before `inline''
vector.h:226: error: ISO C++ forbids defining types within return type
vector.h:226: error: syntax error before `inline''
vector.h:233: error: syntax error before `inline''
vector.h:236: error: `angle'' was not declared in this scope
vector.h:238: error: syntax error before `return''
What do % and ^ produce? Why is there a const also at the end of the
function definition?
THANKS and regards
Michael
推荐答案
" Michael Sgier" < SG *** @ nospam.ch> schrieb im Newsbeitrag
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"Michael Sgier" <sg***@nospam.ch> schrieb im Newsbeitrag
news:43**********************@news.sunrise.ch...
你好
如果有人能解释下面的代码对我来说会很棒。
//两个向量之间的返回角度
const float inline Angle（const CVector& normal） const
返回acosf（* this％normal）;
//用法线向量反射此向量表面
const CVector inline Reflection （const CVector& normal）const
{const CVector vec（* this | 1）; //规范化这个向量
return（vec - normal * 2.0 *（vec％normal））*！* this;
}
//旋转角度约为法线
const CVector inline Rotate（常量浮点角，常量CVector& normal）
const {
const float cosine = cosf（angle）;
const float sine = sinf（angle）; <返回CVector（* this * cosine +（（normal * * this）*（1.0f - cosine））*
normal +（* this ^ normal）* sine）;
}
这产生了以下错误：
vector.h：220：错误：声明没有声明任何内容
vector.h：220：错误：在内联之前的语法错误'
vector.h：226：错误：ISO C ++禁止在返回类型中定义类型
vector.h：226：错误：内联之前的语法错误
vector.h：233：错误：`inline'之前的语法错误'
vector.h：236：错误：`angle''未在此范围内声明
vector.h：238：错误：语法'return''之前的错误
粘贴整个班级。或者更好：尽可能减少你的代码和
然后在这里粘贴你的课程。
％和^会产生什么？
％是模数运算符。它返回除法的余数。
^是按位异或运算符。它比较每一位。如果其中一个
为0而另一个为1，则结果中的相应位也为1，
否则为0.
为什么在
函数定义的末尾还有一个const？
如果将
函数声明为const，则不允许类的函数修改成员变量。
感谢和问候
Michael
Hello
If someone could explain the code below to me would be great.
// return angle between two vectors
const float inline Angle(const CVector& normal) const
{
return acosf(*this % normal);
}
// reflect this vector off surface with normal vector
const CVector inline Reflection(const CVector& normal) const
{
const CVector vec(*this | 1); // normalize this vector
return (vec - normal * 2.0 * (vec % normal)) * !*this;
}
// rotate angle degrees about a normal
const CVector inline Rotate(const float angle, const CVector& normal) const {
const float cosine = cosf(angle);
const float sine = sinf(angle);
return CVector(*this * cosine + ((normal * *this) * (1.0f - cosine)) *
normal + (*this ^ normal) * sine);
}
This is producing the following errors:
vector.h:220: error: declaration does not declare anything
vector.h:220: error: syntax error before `inline''
vector.h:226: error: ISO C++ forbids defining types within return type
vector.h:226: error: syntax error before `inline''
vector.h:233: error: syntax error before `inline''
vector.h:236: error: `angle'' was not declared in this scope
vector.h:238: error: syntax error before `return''
Paste your whole class. Or better: Reduce your code as much as possible and
then paste your class here.
What do % and ^ produce?
% is the modulus operator. It returns the remainder of a division.
^ is the bitwise-exclusive-or operator. It compares each bit. If one of them
is 0 and the other one is 1, the corresponding bit in the result is also 1,
otherwise it is 0.
Why is there a const also at the end of the
function definition?
Functions of a class are not allowed to modify the member variables if a
function was declared as const.
THANKS and regards
Michael
问候Chris
Greetings Chris
/ *
const float inline Angle（const CVector& normal）const
{
返回acosf（* this％normal）;
}
* /
％以上应该是标量乘积，以便计算* this
与正常之间的角度，这通常是使用％来交叉
产品是不好的，它经常被用在像这样的代码中。将它用于
点/标量产品更奇怪。
只要对这种奇怪的评论，如果我知道
哪条线是哪条（例如哪条错误对应哪条线）。我打赌
某些地方的某些声明错过了（也许标题
不是自包含的，或者需要特定的包含顺序，
无论如何，打败我没有看到更多的代码.. :)
/*
const float inline Angle(const CVector& normal) const
{
return acosf(*this % normal);
}
*/
Above the % should be scalar product so that the angle between *this
and normal would be computed, it''s generally a bad to use % for cross
product, which it is often seen used in code like this. Using it for
dot/scalar product is even more strange.
Just commenting on that oddity, I could comment on the errors if I knew
which line was which (eg. which error correspond to which line). I bet
somewhere along the line some declaration was missed (maybe the headers
are not self-contained or require specific order of inclusion,
whatever, beats me w/o seeing more of the code.. :)
我只是无法再拒绝回复..我一直盯着代码
难以置信：真的奇怪地使用了运算符重载。 +， - ，/，* ..
仍然很酷且很有用，因为其含义很容易理解，
但......这里发生的事情是无法相信的。令人难以置信的东西..没有
进攻！ 8P
I just cannot resisting replying again.. I keep staring at the code in
disbelief: really bizarre use of operator overloading. +, -, /, * ..
are are still cool and useful since the meaning is easily understood,
but... what is happening here is beyond belief.. incredible stuff.. no
offence! 8P
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