IRRLICHT之横移，纵走

IRRLICHT之横移，纵走

这个KEY移动是最傻的，像螃蟹一样！

if (isKeyDown(KEY_KEY_W) || isKeyDown(KEY_UP) && !zooming)
   {
      if (!translating)
         translating = true;
      else
      {
         vector3df movevector = getPosition() - getTarget();
         movevector.Y = 0;
         movevector.normalize();

         setPosition(getPosition() - movevector * translateSpeed);
         setTarget(getTarget() - movevector * translateSpeed);
         updateAbsolutePosition();
      }
   }
   else if (isKeyDown(KEY_KEY_S) || isKeyDown(KEY_DOWN) && !zooming)
   {
      if (!translating)
         translating = true;
      else
      {
         vector3df movevector = getPosition() - getTarget();
         movevector.Y = 0;
         movevector.normalize();

         setPosition(getPosition() + movevector * translateSpeed);
         setTarget(getTarget() + movevector * translateSpeed);
         updateAbsolutePosition();
      }
   }
   else if (isKeyDown(KEY_KEY_A) || isKeyDown(KEY_LEFT) && !zooming)
   {
      if (!translating)
         translating = true;
      else
      {
         vector3df totargetvector = getPosition() - getTarget();
         totargetvector.normalize();
         vector3df crossvector = totargetvector.crossProduct(getUpVector());
         vector3df strafevector = crossvector.normalize();

         setPosition(getPosition() - strafevector * translateSpeed);
         setTarget(getTarget() - strafevector * translateSpeed);
         updateAbsolutePosition();
      }
   }
   else if (isKeyDown(KEY_KEY_D) || isKeyDown(KEY_RIGHT) && !zooming)
   {
      if (!translating)
         translating = true;
      else
      {
         vector3df totargetvector = getPosition() - getTarget();
         totargetvector.normalize();
         vector3df crossvector = totargetvector.crossProduct(getUpVector());
         vector3df strafevector = crossvector.normalize();

         setPosition(getPosition() + strafevector * translateSpeed);
         setTarget(getTarget() + strafevector * translateSpeed);
         updateAbsolutePosition();
      }
   }