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Started by SyIH Mar 1, 2004 at 8:06 AM 2 replies 350+ views

Original Post

Mar 1, 2004 at 8:06 AM

Hi to all, i have here a very noob question, plz hrlp me! some code: struct CVector3 { public: CVector3() {} CVector3(float X, float Y, float Z) { x = X; y = Y; z = Z; } CVector3 operator+(CVector3 vVector) { return CVector3(vVector.x + x, vVector.y + y, vVector.z + z); } CVector3 operator-(CVector3 vVector) { return CVector3(x - vVector.x, y - vVector.y, z - vVector.z); } CVector3 operator+=(CVector3 vVector) { return CVector3(x += vVector.x, y += vVector.y, z += vVector.z); } CVector3 operator=(CVector3 vVector) { return CVector3(x = vVector.x, y = vVector.y, z = vVector.z); } CVector3 operator*(float num) { return CVector3(x * num, y * num, z * num); } CVector3 operator/(float num) { return CVector3(x / num, y / num, z / num); } float x, y, z; }; // some where in my code player.cpp CVector3 AVT=CVector(30,0,0); CVector3 BVT=CVector(0,0,0); //somewhere in main.h extern CVector3 AVT; extern CVector3 BVT; //somewhere in WINAPI (in while) main.cpp AVT = NRotate(BVT, AVT, 12, 0, 1, 0); that's means that it shuld give a new AVT every frame, but it dois it only once and give me the same avt again and again and again .arggg PLZ HELP ME [edited by - SyIH on March 1, 2004 9:10:49 AM]

Evil Steve

382

Evil Steve

Mar 1, 2004 at 10:59 AM

Unless NRotate modifys the variables BVT and AVT, it should give you the same result every call, since nothing has changed since the last call.

Qw3r7yU10p!

Mar 1, 2004 at 11:20 AM

your assignment operators are completely wrong.

haven''t time to show you how but someone else will help if you need it.

operator= should modify the member variables as should all the others too.

rypyr

Mar 1, 2004 at 11:29 AM

Basically you need to learn two C++ concepts: 1) "this" and 2) references. Do a search for these two topics related to C++ on google.


CVector3& CVector3::operator=(const CVector3& o) {
  if(&o != this) {
    this->x = o.x;
    this->y = o.y;
    this->z = o.z;
  }
  return *this;
}

CVector3& CVector3::operator+=(const CVector3& o) {
  this->x += o.x;
  this->y += o.y;
  this->z += o.z;
  return *this;
}

And your add/sub functions should use references, otherwise you''re making copies of CVector3 objects all over the place.


CVector3 CVector3::operator+(const CVector3& o) {
  return CVector3(this->x + o.x, this->y + o.y, this->z + o.z);
}

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