Method lookAt

Engine/source/math/mRotation.cpp:131–189

}

void RotationF::lookAt(const Point3F& _origin, const Point3F& _target, const Point3F& _up)
{
   MatrixF mat;

   VectorF newForward = _target - _origin;
   newForward.normalize();

   VectorF up(0.0f, 0.0f, 1.0f);
   VectorF axisX;
   VectorF axisY = newForward;
   VectorF axisZ;

   if (_up != VectorF::Zero)
      up = _up;

   // Validate and normalize input:  
   F32 lenSq;
   lenSq = axisY.lenSquared();
   if (lenSq < 0.000001f)
   {
      //degenerate forward vector
      axisY.set(0.0f, 1.0f, 0.0f);
   }
   else
   {
      axisY /= mSqrt(lenSq);
   }


   lenSq = up.lenSquared();
   if (lenSq < 0.000001f)
   {
      //degenerate up vector - too small
      up.set(0.0f, 0.0f, 1.0f);
   }
   else
   {
      up /= mSqrt(lenSq);
   }

   if (fabsf(mDot(up, axisY)) > 0.9999f)
   {
      //degenerate up vector - same as forward
      F32 tmp = up.x;
      up.x = -up.y;
      up.y = up.z;
      up.z = tmp;
   }

   // construct the remaining axes:  
   mCross(axisY, up, &axisX);
   mCross(axisX, axisY, &axisZ);

   mat.setColumn(0, axisX);
   mat.setColumn(1, axisY);
   mat.setColumn(2, axisZ);

   set(mat);