I have a serious problem which I haven''t been able to solve: My engine runs smoothly, yet input data coming from DirectInput is terribly delayed, which makes it impossible to control the viewport with the mouse (it''s a first person game). I''m reading buffered mouse data from the DI Device as shown in the SDK tutorial, so I don''t think that''s the fault. In the main menu of my game the mouse moves sometimes perfectly smooth, and sometimes delayed and jerky. I haven''t been able to find out the reason for this behaviour. Yet I noticed something: When I play, say, a mp3 file using MediaPlayer in the background, the mouse moves jerky. I don''t know if this has anything to do with it, since it clearly doesn''t have anything to do with low framerates (the menu runs with over 500 fps). When I load the game and the mouse controls the viewport, viewport changes are jerky all the time (the rest of the game and all animations run smoothly). Sometimes the reaction time to mouse movements is greater than one second. Does anybody have any idea of what''s causing this behaviour?

I remember half life used to have problems like this sometimes, and it was down to DirectSound. There was a workaround, but I can''t remember what it is. Maybe Google could help. All I can suggest is to make sure you have the latest drivers and that they are DirectX compatible. Sorry I can''t help further.

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I don''t use DirectSound, but thank you anyway.

I get the same results on other machines. Any chance that it may have something to do with buffered instead of immediate mouse data?

This is how I initialize DI:

function InitDirectInput(hInst: HINST; hWnd: HWND): HRESULT;var  hr: HRESULT;begin  hr := DirectInput8Create(hInst, DIRECTINPUT_VERSION,          IID_IDirectInput8, Pointer(g_pDI), nil);  if FAILED(hr) then begin    Result:= E_FAIL;    Exit;  end;  hr := g_pDI.CreateDevice(GUID_SysMouse, g_pDIMouse, nil);  if FAILED(hr) then begin    Result := E_FAIL;    Exit;  end;  hr := g_pDIMouse.SetDataFormat(c_dfDIMouse);  if FAILED(hr) then begin    Result := E_FAIL;    Exit;  end;  hr := g_pDIMouse.SetCooperativeLevel(hWnd, DISCL_FOREGROUND or DISCL_EXCLUSIVE);  if FAILED(hr) then begin    Result := E_FAIL;    Exit;  end;  dipdw.diph.dwSize := sizeof(DIPROPDWORD);  dipdw.diph.dwHeaderSize := sizeof(DIPROPHEADER);  dipdw.diph.dwObj := 0;  dipdw.diph.dwHow := DIPH_DEVICE;  dipdw.dwData := 16;  hr := g_pDIMouse.SetProperty(DIPROP_BUFFERSIZE, dipdw.diph);  if FAILED(hr) then begin    Result := E_FAIL;    Exit;  end;  hr := g_pDIMouse.Acquire();  if FAILED(hr) then begin    Result := E_FAIL;    Exit  end;  Result:= S_OK;end; 

This is how I read mouse data:

procedure GetMouseData();var  hr: HRESULT;  od: DIDEVICEOBJECTDATA;  dwElements: DWORD;begin  dwElements := 1;  od.dwData := 0;  od.dwOfs := 0;  case g_pDIMouse.GetDeviceData(sizeof(DIDEVICEOBJECTDATA), @od, dwElements, 0) of    DIERR_NOTACQUIRED:      begin        hr := g_pDIMouse.Acquire();      end;    DIERR_INPUTLOST:      begin        hr := g_pDIMouse.Acquire();      end;    DI_OK:      begin        case od.dwOfs of          DIMOFS_X:            begin              UpdateCursorPosition(LongInt(od.dwData), 0);            end;          DIMOFS_Y:            begin              UpdateCursorPosition(0, LongInt(od.dwData));            end;          DIMOFS_BUTTON0:            begin              if bMouseBtn0 = True then bMouseBtn0 := False              else bMouseBtn0 := True;            end;          DIMOFS_BUTTON1:            begin              if bMouseBtn1 = True then bMouseBtn1 := False              else bMouseBtn1 := True;            end;        end; //case      end;    end; //caseend; 

[edited by - Oxmyx on June 2, 2004 8:25:31 AM]

I''ve tried it with immediate mouse data, now it works. Has it any disadvantage to use immediate data instead of buffered data for a first-person shooter?

I have that 2 but only with the keyboard input, the mouse still runs smooth. I have this problem for a few weeks now and I dont know what the cause is, I havent changed a thing. My programs starts with 250+ fps and after 1sec it drops down to 130 and the movement is very jerky. Mousemove it still smooth though...

I''d look into your interaction with Windows. Ie. if you are simply looping and not handling messages as most people do it *can* totally mess some things up, especially with DirectInput.

MAKE SURE that you are being nice to Windows, or weird things can happen. Even if you have to use the ON_IDLE handler, this is sometimes better than other more messy setups.