src/video/windows/SDL_windowsrawinput.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2026 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#if defined(SDL_VIDEO_DRIVER_WINDOWS)

#include "SDL_windowsvideo.h"

#if !defined(SDL_PLATFORM_XBOXONE) && !defined(SDL_PLATFORM_XBOXSERIES)

#include "SDL_windowsevents.h"

#include "../../joystick/usb_ids.h"
#include "../../events/SDL_events_c.h"
#include "../../thread/SDL_systhread.h"

#define ENABLE_RAW_MOUSE_INPUT      0x01
#define ENABLE_RAW_KEYBOARD_INPUT   0x02
#define RAW_KEYBOARD_FLAG_NOHOTKEYS 0x04

typedef struct
{
    bool done;
    Uint32 flags;
    HANDLE ready_event;
    HANDLE done_event;
    HANDLE thread;
} RawInputThreadData;

static RawInputThreadData thread_data = {
    false,
    0,
    INVALID_HANDLE_VALUE,
    INVALID_HANDLE_VALUE,
    INVALID_HANDLE_VALUE
};

static DWORD WINAPI WIN_RawInputThread(LPVOID param)
{
    SDL_VideoDevice *_this = SDL_GetVideoDevice();
    RawInputThreadData *data = (RawInputThreadData *)param;
    RAWINPUTDEVICE devices[2];
    HWND window;
    UINT count = 0;

    SDL_SYS_SetupThread("SDLRawInput");

    window = CreateWindowEx(0, TEXT("Message"), NULL, 0, 0, 0, 0, 0, HWND_MESSAGE, NULL, NULL, NULL);
    if (!window) {
        return 0;
    }

    SDL_zeroa(devices);

    if (data->flags & ENABLE_RAW_MOUSE_INPUT) {
        devices[count].usUsagePage = USB_USAGEPAGE_GENERIC_DESKTOP;
        devices[count].usUsage = USB_USAGE_GENERIC_MOUSE;
        devices[count].dwFlags = 0;
        devices[count].hwndTarget = window;
        ++count;
    }

    if (data->flags & ENABLE_RAW_KEYBOARD_INPUT) {
        devices[count].usUsagePage = USB_USAGEPAGE_GENERIC_DESKTOP;
        devices[count].usUsage = USB_USAGE_GENERIC_KEYBOARD;
        devices[count].dwFlags = 0;
        if (data->flags & RAW_KEYBOARD_FLAG_NOHOTKEYS) {
            devices[count].dwFlags |= RIDEV_NOHOTKEYS;
        }
        devices[count].hwndTarget = window;
        ++count;
    }

    if (!RegisterRawInputDevices(devices, count, sizeof(devices[0]))) {
        DestroyWindow(window);
        return 0;
    }

    // Make sure we get events as soon as possible
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_TIME_CRITICAL);

    // Tell the parent we're ready to go!
    SetEvent(data->ready_event);

    Uint64 idle_begin = SDL_GetTicksNS();
    while (!data->done &&
            // The high-order word of GetQueueStatus() will let us know if there's currently raw input to be processed.
            // If there isn't, then we'll wait for new data to arrive with MsgWaitForMultipleObjects().
           ((HIWORD(GetQueueStatus(QS_RAWINPUT)) & QS_RAWINPUT) ||
            (MsgWaitForMultipleObjects(1, &data->done_event, FALSE, INFINITE, QS_RAWINPUT) == WAIT_OBJECT_0 + 1))) {

        Uint64 idle_end = SDL_GetTicksNS();
        Uint64 idle_time = idle_end - idle_begin;
        Uint64 usb_8khz_interval = SDL_US_TO_NS(125);
        Uint64 poll_start = idle_time < usb_8khz_interval ? _this->internal->last_rawinput_poll : idle_end;

        WIN_PollRawInput(_this, poll_start);

        // Reset idle_begin for the next go-around
        idle_begin = SDL_GetTicksNS();
    }

    if (_this->internal->raw_input_fake_pen_id) {
        SDL_RemovePenDevice(0, SDL_GetKeyboardFocus(), _this->internal->raw_input_fake_pen_id);
        _this->internal->raw_input_fake_pen_id = 0;
    }

    devices[0].dwFlags |= RIDEV_REMOVE;
    devices[0].hwndTarget = NULL;
    devices[1].dwFlags |= RIDEV_REMOVE;
    devices[1].hwndTarget = NULL;
    RegisterRawInputDevices(devices, count, sizeof(devices[0]));

    DestroyWindow(window);

    return 0;
}

static void CleanupRawInputThreadData(RawInputThreadData *data)
{
    if (data->thread != INVALID_HANDLE_VALUE) {
        data->done = true;
        SetEvent(data->done_event);
        WaitForSingleObject(data->thread, 3000);
        CloseHandle(data->thread);
        data->thread = INVALID_HANDLE_VALUE;
    }

    if (data->ready_event != INVALID_HANDLE_VALUE) {
        CloseHandle(data->ready_event);
        data->ready_event = INVALID_HANDLE_VALUE;
    }

    if (data->done_event != INVALID_HANDLE_VALUE) {
        CloseHandle(data->done_event);
        data->done_event = INVALID_HANDLE_VALUE;
    }
}

static bool WIN_SetRawInputEnabled(SDL_VideoDevice *_this, Uint32 flags)
{
    bool result = false;

    CleanupRawInputThreadData(&thread_data);

    if (flags) {
        HANDLE handles[2];

        thread_data.flags = flags;
        thread_data.ready_event = CreateEvent(NULL, FALSE, FALSE, NULL);
        if (thread_data.ready_event == INVALID_HANDLE_VALUE) {
            WIN_SetError("CreateEvent");
            goto done;
        }

        thread_data.done = false;
        thread_data.done_event = CreateEvent(NULL, FALSE, FALSE, NULL);
        if (thread_data.done_event == INVALID_HANDLE_VALUE) {
            WIN_SetError("CreateEvent");
            goto done;
        }

        thread_data.thread = CreateThread(NULL, 0, WIN_RawInputThread, &thread_data, 0, NULL);
        if (thread_data.thread == INVALID_HANDLE_VALUE) {
            WIN_SetError("CreateThread");
            goto done;
        }

        // Wait for the thread to signal ready or exit
        handles[0] = thread_data.ready_event;
        handles[1] = thread_data.thread;
        if (WaitForMultipleObjects(2, handles, FALSE, INFINITE) != WAIT_OBJECT_0) {
            SDL_SetError("Couldn't set up raw input handling");
            goto done;
        }
        result = true;
    } else {
        result = true;
    }

done:
    if (!result) {
        CleanupRawInputThreadData(&thread_data);
    }
    return result;
}

static bool WIN_UpdateRawInputEnabled(SDL_VideoDevice *_this)
{
    SDL_VideoData *data = _this->internal;
    Uint32 flags = 0;
    if (data->raw_mouse_enabled) {
        flags |= ENABLE_RAW_MOUSE_INPUT;
    }
    if (data->raw_keyboard_enabled) {
        flags |= ENABLE_RAW_KEYBOARD_INPUT;
        if (data->raw_keyboard_flag_nohotkeys) {
            flags |= RAW_KEYBOARD_FLAG_NOHOTKEYS;
        }
    }
    if (flags != data->raw_input_enabled) {
        if (WIN_SetRawInputEnabled(_this, flags)) {
            data->raw_input_enabled = flags;
        } else {
            return false;
        }
    }
    return true;
}

bool WIN_SetRawMouseEnabled(SDL_VideoDevice *_this, bool enabled)
{
    SDL_VideoData *data = _this->internal;
    data->raw_mouse_enabled = enabled;
    if (data->gameinput_context) {
        if (!WIN_UpdateGameInputEnabled(_this)) {
            data->raw_mouse_enabled = !enabled;
            return false;
        }
    } else {
        if (!WIN_UpdateRawInputEnabled(_this)) {
            data->raw_mouse_enabled = !enabled;
            return false;
        }
    }
    return true;
}

bool WIN_SetRawKeyboardEnabled(SDL_VideoDevice *_this, bool enabled)
{
    SDL_VideoData *data = _this->internal;
    data->raw_keyboard_enabled = enabled;
    if (data->gameinput_context) {
        if (!WIN_UpdateGameInputEnabled(_this)) {
            data->raw_keyboard_enabled = !enabled;
            return false;
        }
    } else {
        if (!WIN_UpdateRawInputEnabled(_this)) {
            data->raw_keyboard_enabled = !enabled;
            return false;
        }
    }
    return true;
}

typedef enum WIN_RawKeyboardFlag {
    NOHOTKEYS
} WIN_RawKeyboardFlag;

static bool WIN_SetRawKeyboardFlag(SDL_VideoDevice *_this, WIN_RawKeyboardFlag flag, bool enabled)
{
    SDL_VideoData *data = _this->internal;

    switch(flag) {
        case NOHOTKEYS:
            data->raw_keyboard_flag_nohotkeys = enabled;
            break;
        default:
            return false;
    }

    if (data->gameinput_context) {
        return true;
    }

    return WIN_UpdateRawInputEnabled(_this);
}

bool WIN_SetRawKeyboardFlag_NoHotkeys(SDL_VideoDevice *_this, bool enabled)
{
    return WIN_SetRawKeyboardFlag(_this, NOHOTKEYS, enabled);
}

#else

bool WIN_SetRawMouseEnabled(SDL_VideoDevice *_this, bool enabled)
{
    return SDL_Unsupported();
}

bool WIN_SetRawKeyboardEnabled(SDL_VideoDevice *_this, bool enabled)
{
    return SDL_Unsupported();
}

bool WIN_SetRawKeyboardFlag_NoHotkeys(SDL_VideoDevice *_this, bool enabled)
{
    return SDL_Unsupported();
}

#endif // !SDL_PLATFORM_XBOXONE && !SDL_PLATFORM_XBOXSERIES

#endif // SDL_VIDEO_DRIVER_WINDOWS