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Impossible Value Change!

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Here is the source to two functions in my cMouse class... Ttwo private member variables (m_X and m_Y) seem to magically change values! Note that I call no methods of cMouse in between the constructor and Draw. This is baffling me! Here''s the source:
cMouse::cMouse(sDX* pDX)
{
  m_pDX = pDX;

  if(FAILED(D3DXCreateTextureFromFileEx(m_pDX->m_pD3DDevice, "Data/Mouse.tga", D3DX_DEFAULT, D3DX_DEFAULT, 1, 0, D3DFMT_UNKNOWN, D3DPOOL_MANAGED, D3DX_FILTER_NONE, D3DX_FILTER_NONE, D3DCOLOR_ARGB(0,255,255,255), NULL, NULL, &m_Texture)))
    m_Texture = NULL;

  log("About to Init Coords");
  m_X = 0;
  m_Y = 0;
  log("Just Initiated Coords... Here they are:");
  log((int)m_X);
  log((int)m_Y);

  return;
}



void cMouse::Draw(void)
{
  log("Here they are, ready to draw:");
  log((int)m_X);
  log((int)m_Y);
  
  if (FAILED(m_pDX->m_Mouse->GetDeviceState(sizeof(DIMOUSESTATE), (LPVOID)&m_MouseState)))
    return;
      
  if(m_MouseState.lX != 0) m_X += m_MouseState.lX;
  if(m_MouseState.lY != 0) m_Y += m_MouseState.lY;  

  if(m_Texture == NULL) return;
 
  D3DXVECTOR2 translation;
  translation.x = m_X;
  translation.y = m_Y;

  m_pDX->m_pSprite->Draw(m_Texture, NULL, NULL, NULL, 0, &translation, 0xffffffff);
  
  return;
}
log is a function that simply writes data to a log. Here''s the log file after a few frames of runtime. Note that the coords update the way they are supposed to, they just start out with a wacky Y coord.
About to Init Coords
Just Initiated Coords... Here they are:
0
0
Here they are, ready to draw:
0
524288
Here they are, ready to draw:
0
524288
Here they are, ready to draw:
0
524288
Here they are, ready to draw:
0
524287
Here they are, ready to draw:
1
524270
Here they are, ready to draw:
1
524270
Here they are, ready to draw:
1
524270

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The easiest way to do it is to step through the debugger, and always monitor those variables, then you can see when they get modified. And if they aren''t already, make sure they''re private variables. Remember though that if you''re debugging it, make sure you can access them globally, or else its kinda useless, so add a function to your class that returns them.


Also, this is is redundant:
if(m_MouseState.lX != 0) m_X += m_MouseState.lX;
if(m_MouseState.lY != 0) m_Y += m_MouseState.lY;

Instead, it can just be:
m_X += m_MouseState.lX;
m_Y += m_MouseState.lY;

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