Thread: DirectX 9 Timing

My work-in-progress Direct3D engine now has the option for each rendered object to have a velocity vector. I calculate the change in position right before rendering, and the timer stops and starts before and after the calculation:

Code:

	//Calc new object positions
	Timer.Stop();
	NewPositions();
	Timer.Start();

	//Render objects
	vector<CRenderObject *>::iterator i;
	for (i=Objects.begin();i!=Objects.end();i++)
	{
		Device->SetRenderState(D3DRS_FILLMODE,FillMode);
		(*i)->Render(mWorld);
	}

Code:

void DrawClass::NewPositions(void)
{
	vector<CRenderObject *>::iterator i;
	float Elapsed=(float)Timer.Elapsed();
	for (i=Objects.begin();i!=Objects.end();i++)
	{
		(*i)->x+=Elapsed*(*i)->vx;
		(*i)->y+=Elapsed*(*i)->vy;
		(*i)->z+=Elapsed*(*i)->vz;
	}
}

However, it does not work. Upon execution, each object travels only for a short period of time, eg less than one second, and then stops. If the window is manipulated, ie, moved or resized, the object moves for a little bit more. I guess that implies that the problem is related to the message loop. Here it is:

Code:

while (msg.message!=WM_QUIT)
{
	dc->Render();
	if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
}

As far as I can tell, it should be continually rendering, and thus updating the object positions. Is there anything that appears incorrectly coded?

The message loop I usually use is like this:

Code:

while(true) 
{
  if(PeekMessage(&msg, hwnd, NULL, NULL, PM_REMOVE))
  {
    if(msg.message == WM_QUIT)
      break;
    
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  else
  {
    // Do all your updates / rendering here
  }
}

I didn't look too much at your timing stuff. If this doesn't fix it then come back and post again and I'll have a look. Also, look at the STL function for_each( ) it's pretty handy. You'll need to #include <algorithm> to use it.