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nico3000

Rawinput gives me only pixel accuracy

8 posts in this topic

I set up Rawinput to process mouse events like this

        m_rawSize = 0;
        m_pRaw = 0;
        RAWINPUTDEVICE pMouseRid[1];
        pMouseRid->usUsagePage = 0x01;
        pMouseRid->usUsage = 0x02;
        pMouseRid->dwFlags = 0;//RIDEV_NOLEGACY;
        pMouseRid->hwndTarget = m_hwnd;
        if(!RegisterRawInputDevices(pMouseRid, 1, sizeof(RAWINPUTDEVICE)))
        {
            IG_ERROR("RegisterRawInputDevices() failed!");
            return false;
        }
        else
        {
            return true;
        }

And I listen to them like this

UINT dwSize = 0;
        UINT result = GetRawInputData((HRAWINPUT)p_lParam, RID_INPUT, NULL, &dwSize, sizeof(RAWINPUTHEADER));
        if(result != 0)
        {
            IG_WARNING("GetRawInputData() failed (Result " << result << ", lParam " << p_lParam << ").");
            return;
        }
        if(m_rawSize < dwSize)
        {
            SAFE_DELETE_ARRAY(m_pRaw);
            m_pRaw = (RAWINPUT*)(IG_NEW unsigned char[dwSize]);
            m_rawSize = dwSize;
            if(!m_pRaw)
            {
                IG_WARNING("Failed to allocate space.");
                return;
            }
        }
        if(m_pRaw) 
        {
            result = GetRawInputData((HRAWINPUT)p_lParam, RID_INPUT, m_pRaw, &dwSize, sizeof(RAWINPUTHEADER));
            if(result == (UINT)-1)
            {
                IG_WARNING("GetRawInputData() failed.");
                return;
            }
            if(result != dwSize)
            {
                IG_WARNING("GetRawInputData does not return correct size! Expected " << dwSize << ", got " << result);
                return;
            }
            else if(m_pRaw->header.dwType == RIM_TYPEMOUSE)
            {
                WmInput input;
                input.m_message = WM_INPUT;
                input.m_deltaX = m_pRaw->data.mouse.lLastX;
                input.m_deltaY = m_pRaw->data.mouse.lLastY;
                input.m_flags = m_pRaw->data.mouse.usButtonFlags;
                input.m_data = m_pRaw->data.mouse.usButtonData;
                IG_INFO("WM_INPUT " << m_pRaw->data.mouse.lLastX << ", " << m_pRaw->data.mouse.lLastY << ".");
                m_inputs.push(input);
            }
        }

But with this code the WM_INPUT events only come in as the cursor moves one pixel and the lLastX/Y vars do represent that on pixel. So it doesn't have the promised advantage of being more precise than the WM_MOUSEMOVE messages. Am I wrong? What is the proper way to get high resolution input from my mouse?

 

I have a Logitech G500 + Logitech Gaming Software 8.45.88 installed. The DPI is set to 1500.

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How are you supposed to get more precision than pixels? Why would you need that anyway?

 

Cheers :)!

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You used to be able to get mickeys (raw mouse units read from the hardware) but I had a search of MSDN and couldn't find anything, it may be device driver level only. It used to be called MouseGetMickeys I believe, but I dunno where it's gone?

Edited by Paradigm Shifter
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How are you supposed to get more precision than pixels? Why would you need that anyway?

Say your OS/hardware is configured so that every time you move the mouse 1mm, the cursor moves 1 pixel.
In your game (let's say a first-person shooter), you might create a mapping so that every 1px the OS cursor moves, you rotate your player 1 degree.
 
The problem is that modern mice are much more sensitive than that - detecting movements in the range of a few microns, not millimetres!

If your user has such a mouse, it would be nice for you to detect that they moved their cursor the equivalent of 2.1423mm, and rotate your camera by 2.1423 degrees, which will provide much a smoother feel to the camera controller, especially at low speeds.

Edited by Hodgman
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How are you supposed to get more precision than pixels? Why would you need that anyway?

Say your OS/hardware is configured so that every time you move the mouse 1mm, the cursor moves 1 pixel.
In your game (let's say a first-person shooter), you might create a mapping so that every 1px the OS cursor moves, you rotate your player 1 degree.
 
The problem is that modern mice are much more sensitive than that - detecting movements in the range of a few microns, not millimetres!

If your user has such a mouse, it would be nice for you to detect that they moved their cursor the equivalent of 2.1423mm, and rotate your camera by 2.1423 degrees, which will provide much a smoother feel to the camera controller, especially at low speeds.

 

Thanks for the explanation!

 

Cheers :)!

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Yes, I read that before. I think Windows does also use the the high precision data from your mouse and moves the cursor one pixel for each unit of mouse motion IF you set the pointer speed in your mouse properties to the 6th notch. I Set my mouse to 5700dpi and chose the 3rd notch. The cursor has now perfect speed for me in windows and rawinput  gives more than pixel accuracy.

I think the MSDN article is a little bit confusing at that point.

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All MSDN articles are either confusing, incomplete or incorrect. It's a matter of contract.

 

The only time you'll find an MSDN article that clearly explains everything you need to know without errors, the actual implementation of whatever it's discussing will have some bug that renders it ineffective.

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