SDL/src/video/windows/SDL_windowsmouse.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2024 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) && !defined(SDL_PLATFORM_XBOXONE) && !defined(SDL_PLATFORM_XBOXSERIES)

#include "SDL_windowsvideo.h"
#include "SDL_windowsevents.h"
#include "SDL_windowsrawinput.h"

#include "../SDL_video_c.h"
#include "../SDL_blit.h"
#include "../../events/SDL_mouse_c.h"
#include "../../joystick/usb_ids.h"


typedef struct CachedCursor
{
    float scale;
    HCURSOR cursor;
    struct CachedCursor *next;
} CachedCursor;

struct SDL_CursorData
{
    SDL_Surface *surface;
    int hot_x;
    int hot_y;
    CachedCursor *cache;
    HCURSOR cursor;
};

DWORD SDL_last_warp_time = 0;
HCURSOR SDL_cursor = NULL;
static SDL_Cursor *SDL_blank_cursor = NULL;

static SDL_Cursor *WIN_CreateCursorAndData(HCURSOR hcursor)
{
    if (!hcursor) {
        return NULL;
    }

    SDL_Cursor *cursor = (SDL_Cursor *)SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        SDL_CursorData *data = (SDL_CursorData *)SDL_calloc(1, sizeof(*data));
        if (!data) {
            SDL_free(cursor);
            return NULL;
        }
        data->cursor = hcursor;
        cursor->internal = data;
    }
    return cursor;
}

static SDL_Cursor *WIN_CreateDefaultCursor(void)
{
    return WIN_CreateCursorAndData(LoadCursor(NULL, IDC_ARROW));
}

static SDL_bool IsMonochromeSurface(SDL_Surface *surface)
{
    int x, y;
    Uint8 r, g, b, a;

    SDL_assert(surface->format == SDL_PIXELFORMAT_ARGB8888);

    for (y = 0; y < surface->h; y++) {
        for (x = 0; x < surface->w; x++) {
            SDL_ReadSurfacePixel(surface, x, y, &r, &g, &b, &a);

            /* Black or white pixel. */
            if (!((r == 0x00 && g == 0x00 && b == 0x00) || (r == 0xff && g == 0xff && b == 0xff))) {
                return SDL_FALSE;
            }

            /* Transparent or opaque pixel. */
            if (!(a == 0x00 || a == 0xff)) {
                return SDL_FALSE;
            }
        }
    }

    return SDL_TRUE;
}

static HBITMAP CreateColorBitmap(SDL_Surface *surface)
{
    HBITMAP bitmap;
    BITMAPINFO bi;
    void *pixels;

    SDL_assert(surface->format == SDL_PIXELFORMAT_ARGB8888);

    SDL_zero(bi);
    bi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bi.bmiHeader.biWidth = surface->w;
    bi.bmiHeader.biHeight = -surface->h; /* Invert height to make the top-down DIB. */
    bi.bmiHeader.biPlanes = 1;
    bi.bmiHeader.biBitCount = 32;
    bi.bmiHeader.biCompression = BI_RGB;

    bitmap = CreateDIBSection(NULL, &bi, DIB_RGB_COLORS, &pixels, NULL, 0);
    if (!bitmap || !pixels) {
        WIN_SetError("CreateDIBSection()");
        return NULL;
    }

    SDL_memcpy(pixels, surface->pixels, surface->pitch * surface->h);

    return bitmap;
}

/* Generate bitmap with a mask and optional monochrome image data.
 *
 * For info on the expected mask format see:
 * https://devblogs.microsoft.com/oldnewthing/20101018-00/?p=12513
 */
static HBITMAP CreateMaskBitmap(SDL_Surface *surface, SDL_bool is_monochrome)
{
    HBITMAP bitmap;
    SDL_bool isstack;
    void *pixels;
    int x, y;
    Uint8 r, g, b, a;
    Uint8 *dst;
    const int pitch = ((surface->w + 15) & ~15) / 8;
    const int size = pitch * surface->h;
    static const unsigned char masks[] = { 0x80, 0x40, 0x20, 0x10, 0x8, 0x4, 0x2, 0x1 };

    SDL_assert(surface->format == SDL_PIXELFORMAT_ARGB8888);

    pixels = SDL_small_alloc(Uint8, size * (is_monochrome ? 2 : 1), &isstack);
    if (!pixels) {
        return NULL;
    }

    dst = (Uint8 *)pixels;

    /* Make the mask completely transparent. */
    SDL_memset(dst, 0xff, size);
    if (is_monochrome) {
        SDL_memset(dst + size, 0x00, size);
    }

    for (y = 0; y < surface->h; y++, dst += pitch) {
        for (x = 0; x < surface->w; x++) {
            SDL_ReadSurfacePixel(surface, x, y, &r, &g, &b, &a);

            if (a != 0) {
                /* Reset bit of an opaque pixel. */
                dst[x >> 3] &= ~masks[x & 7];
            }

            if (is_monochrome && !(r == 0x00 && g == 0x00 && b == 0x00)) {
                /* Set bit of white or inverted pixel. */
                dst[size + (x >> 3)] |= masks[x & 7];
            }
        }
    }

    bitmap = CreateBitmap(surface->w, surface->h * (is_monochrome ? 2 : 1), 1, 1, pixels);
    SDL_small_free(pixels, isstack);
    if (!bitmap) {
        WIN_SetError("CreateBitmap()");
        return NULL;
    }

    return bitmap;
}

static HCURSOR WIN_CreateHCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    HCURSOR hcursor;
    ICONINFO ii;
    SDL_bool is_monochrome = IsMonochromeSurface(surface);

    SDL_zero(ii);
    ii.fIcon = FALSE;
    ii.xHotspot = (DWORD)hot_x;
    ii.yHotspot = (DWORD)hot_y;
    ii.hbmMask = CreateMaskBitmap(surface, is_monochrome);
    ii.hbmColor = is_monochrome ? NULL : CreateColorBitmap(surface);

    if (!ii.hbmMask || (!is_monochrome && !ii.hbmColor)) {
        SDL_SetError("Couldn't create cursor bitmaps");
        return NULL;
    }

    hcursor = CreateIconIndirect(&ii);

    DeleteObject(ii.hbmMask);
    if (ii.hbmColor) {
        DeleteObject(ii.hbmColor);
    }

    if (!hcursor) {
        WIN_SetError("CreateIconIndirect()");
        return NULL;
    }
    return hcursor;
}

static SDL_Cursor *WIN_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    if (!SDL_SurfaceHasAlternateImages(surface)) {
        HCURSOR hcursor = WIN_CreateHCursor(surface, hot_x, hot_y);
        if (!hcursor) {
            return NULL;
        }
        return WIN_CreateCursorAndData(hcursor);
    }

    // Dynamically generate cursors at the appropriate DPI
    SDL_Cursor *cursor = (SDL_Cursor *)SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        SDL_CursorData *data = (SDL_CursorData *)SDL_calloc(1, sizeof(*data));
        if (!data) {
            SDL_free(cursor);
            return NULL;
        }
        data->hot_x = hot_x;
        data->hot_y = hot_y;
        data->surface = surface;
        ++surface->refcount;
        cursor->internal = data;
    }
    return cursor;
}

static SDL_Cursor *WIN_CreateBlankCursor(void)
{
    SDL_Cursor *cursor = NULL;
    SDL_Surface *surface = SDL_CreateSurface(32, 32, SDL_PIXELFORMAT_ARGB8888);
    if (surface) {
        cursor = WIN_CreateCursor(surface, 0, 0);
        SDL_DestroySurface(surface);
    }
    return cursor;
}

static SDL_Cursor *WIN_CreateSystemCursor(SDL_SystemCursor id)
{
    LPCTSTR name;

    switch (id) {
    default:
        SDL_assert(!"Unknown system cursor ID");
        return NULL;
    case SDL_SYSTEM_CURSOR_DEFAULT:
        name = IDC_ARROW;
        break;
    case SDL_SYSTEM_CURSOR_TEXT:
        name = IDC_IBEAM;
        break;
    case SDL_SYSTEM_CURSOR_WAIT:
        name = IDC_WAIT;
        break;
    case SDL_SYSTEM_CURSOR_CROSSHAIR:
        name = IDC_CROSS;
        break;
    case SDL_SYSTEM_CURSOR_PROGRESS:
        name = IDC_WAIT;
        break;
    case SDL_SYSTEM_CURSOR_NWSE_RESIZE:
        name = IDC_SIZENWSE;
        break;
    case SDL_SYSTEM_CURSOR_NESW_RESIZE:
        name = IDC_SIZENESW;
        break;
    case SDL_SYSTEM_CURSOR_EW_RESIZE:
        name = IDC_SIZEWE;
        break;
    case SDL_SYSTEM_CURSOR_NS_RESIZE:
        name = IDC_SIZENS;
        break;
    case SDL_SYSTEM_CURSOR_MOVE:
        name = IDC_SIZEALL;
        break;
    case SDL_SYSTEM_CURSOR_NOT_ALLOWED:
        name = IDC_NO;
        break;
    case SDL_SYSTEM_CURSOR_POINTER:
        name = IDC_HAND;
        break;
    case SDL_SYSTEM_CURSOR_NW_RESIZE:
        name = IDC_SIZENWSE;
        break;
    case SDL_SYSTEM_CURSOR_N_RESIZE:
        name = IDC_SIZENS;
        break;
    case SDL_SYSTEM_CURSOR_NE_RESIZE:
        name = IDC_SIZENESW;
        break;
    case SDL_SYSTEM_CURSOR_E_RESIZE:
        name = IDC_SIZEWE;
        break;
    case SDL_SYSTEM_CURSOR_SE_RESIZE:
        name = IDC_SIZENWSE;
        break;
    case SDL_SYSTEM_CURSOR_S_RESIZE:
        name = IDC_SIZENS;
        break;
    case SDL_SYSTEM_CURSOR_SW_RESIZE:
        name = IDC_SIZENESW;
        break;
    case SDL_SYSTEM_CURSOR_W_RESIZE:
        name = IDC_SIZEWE;
        break;
    }
    return WIN_CreateCursorAndData(LoadCursor(NULL, name));
}

static void WIN_FreeCursor(SDL_Cursor *cursor)
{
    SDL_CursorData *data = cursor->internal;

    if (data->surface) {
        SDL_DestroySurface(data->surface);
    }
    while (data->cache) {
        CachedCursor *entry = data->cache;
        data->cache = entry->next;
        DestroyCursor(entry->cursor);
        SDL_free(entry);
    }
    if (data->cursor) {
        DestroyCursor(data->cursor);
    }
    SDL_free(data);
    SDL_free(cursor);
}

static HCURSOR GetCachedCursor(SDL_Cursor *cursor)
{
    SDL_CursorData *data = cursor->internal;

    SDL_Window *focus = SDL_GetMouseFocus();
    if (!focus) {
        return NULL;
    }

    float scale = SDL_GetDisplayContentScale(SDL_GetDisplayForWindow(focus));
    for (CachedCursor *entry = data->cache; entry; entry = entry->next) {
        if (scale == entry->scale) {
            return entry->cursor;
        }
    }

    // Need to create a cursor for this content scale
    SDL_Surface *surface = NULL;
    HCURSOR hcursor = NULL;
    CachedCursor *entry = NULL;

    surface = SDL_GetSurfaceImage(data->surface, scale);
    if (!surface) {
        goto error;
    }

    int hot_x = (int)SDL_round(data->hot_x * scale);
    int hot_y = (int)SDL_round(data->hot_x * scale);
    hcursor = WIN_CreateHCursor(surface, hot_x, hot_y);
    if (!hcursor) {
        goto error;
    }

    entry = (CachedCursor *)SDL_malloc(sizeof(*entry));
    if (!entry) {
        goto error;
    }
    entry->cursor = hcursor;
    entry->scale = scale;
    entry->next = data->cache;
    data->cache = entry;

    SDL_DestroySurface(surface);

    return hcursor;

error:
    if (surface) {
        SDL_DestroySurface(surface);
    }
    if (hcursor) {
        DestroyCursor(hcursor);
    }
    SDL_free(entry);
    return NULL;
}

static int WIN_ShowCursor(SDL_Cursor *cursor)
{
    if (!cursor) {
        cursor = SDL_blank_cursor;
    }
    if (cursor) {
        if (cursor->internal->surface) {
            SDL_cursor = GetCachedCursor(cursor);
        } else {
            SDL_cursor = cursor->internal->cursor;
        }
    } else {
        SDL_cursor = NULL;
    }
    if (SDL_GetMouseFocus() != NULL) {
        SetCursor(SDL_cursor);
    }
    return 0;
}

void WIN_SetCursorPos(int x, int y)
{
    /* We need to jitter the value because otherwise Windows will occasionally inexplicably ignore the SetCursorPos() or SendInput() */
    SetCursorPos(x, y);
    SetCursorPos(x + 1, y);
    SetCursorPos(x, y);

    /* Flush any mouse motion prior to or associated with this warp */
#ifdef _MSC_VER /* We explicitly want to use GetTickCount(), not GetTickCount64() */
#pragma warning(push)
#pragma warning(disable : 28159)
#endif
    SDL_last_warp_time = GetTickCount();
    if (!SDL_last_warp_time) {
        SDL_last_warp_time = 1;
    }
#ifdef _MSC_VER
#pragma warning(pop)
#endif
}

static int WIN_WarpMouse(SDL_Window *window, float x, float y)
{
    SDL_WindowData *data = window->internal;
    HWND hwnd = data->hwnd;
    POINT pt;

    /* Don't warp the mouse while we're doing a modal interaction */
    if (data->in_title_click || data->focus_click_pending) {
        return 0;
    }

    pt.x = (int)SDL_roundf(x);
    pt.y = (int)SDL_roundf(y);
    ClientToScreen(hwnd, &pt);
    WIN_SetCursorPos(pt.x, pt.y);

    /* Send the exact mouse motion associated with this warp */
    SDL_SendMouseMotion(0, window, SDL_GLOBAL_MOUSE_ID, SDL_FALSE, x, y);
    return 0;
}

static int WIN_WarpMouseGlobal(float x, float y)
{
    POINT pt;

    pt.x = (int)SDL_roundf(x);
    pt.y = (int)SDL_roundf(y);
    SetCursorPos(pt.x, pt.y);
    return 0;
}

static int WIN_SetRelativeMouseMode(SDL_bool enabled)
{
    return WIN_SetRawMouseEnabled(SDL_GetVideoDevice(), enabled);
}

static int WIN_CaptureMouse(SDL_Window *window)
{
    if (window) {
        SDL_WindowData *data = window->internal;
        SetCapture(data->hwnd);
    } else {
        SDL_Window *focus_window = SDL_GetMouseFocus();

        if (focus_window) {
            SDL_WindowData *data = focus_window->internal;
            if (!data->mouse_tracked) {
                SDL_SetMouseFocus(NULL);
            }
        }
        ReleaseCapture();
    }

    return 0;
}

static SDL_MouseButtonFlags WIN_GetGlobalMouseState(float *x, float *y)
{
    SDL_MouseButtonFlags retval = 0;
    POINT pt = { 0, 0 };
    SDL_bool swapButtons = GetSystemMetrics(SM_SWAPBUTTON) != 0;

    GetCursorPos(&pt);
    *x = (float)pt.x;
    *y = (float)pt.y;

    retval |= GetAsyncKeyState(!swapButtons ? VK_LBUTTON : VK_RBUTTON) & 0x8000 ? SDL_BUTTON_LMASK : 0;
    retval |= GetAsyncKeyState(!swapButtons ? VK_RBUTTON : VK_LBUTTON) & 0x8000 ? SDL_BUTTON_RMASK : 0;
    retval |= GetAsyncKeyState(VK_MBUTTON) & 0x8000 ? SDL_BUTTON_MMASK : 0;
    retval |= GetAsyncKeyState(VK_XBUTTON1) & 0x8000 ? SDL_BUTTON_X1MASK : 0;
    retval |= GetAsyncKeyState(VK_XBUTTON2) & 0x8000 ? SDL_BUTTON_X2MASK : 0;

    return retval;
}

void WIN_InitMouse(SDL_VideoDevice *_this)
{
    SDL_Mouse *mouse = SDL_GetMouse();

    mouse->CreateCursor = WIN_CreateCursor;
    mouse->CreateSystemCursor = WIN_CreateSystemCursor;
    mouse->ShowCursor = WIN_ShowCursor;
    mouse->FreeCursor = WIN_FreeCursor;
    mouse->WarpMouse = WIN_WarpMouse;
    mouse->WarpMouseGlobal = WIN_WarpMouseGlobal;
    mouse->SetRelativeMouseMode = WIN_SetRelativeMouseMode;
    mouse->CaptureMouse = WIN_CaptureMouse;
    mouse->GetGlobalMouseState = WIN_GetGlobalMouseState;

    SDL_SetDefaultCursor(WIN_CreateDefaultCursor());

    SDL_blank_cursor = WIN_CreateBlankCursor();

    WIN_UpdateMouseSystemScale();
}

void WIN_QuitMouse(SDL_VideoDevice *_this)
{
    if (SDL_blank_cursor) {
        WIN_FreeCursor(SDL_blank_cursor);
        SDL_blank_cursor = NULL;
    }
}

/* For a great description of how the enhanced mouse curve works, see:
 * https://superuser.com/questions/278362/windows-mouse-acceleration-curve-smoothmousexcurve-and-smoothmouseycurve
 * http://www.esreality.com/?a=post&id=1846538/
 */
static SDL_bool LoadFiveFixedPointFloats(const BYTE *bytes, float *values)
{
    int i;

    for (i = 0; i < 5; ++i) {
        float fraction = (float)((Uint16)bytes[1] << 8 | bytes[0]) / 65535.0f;
        float value = (float)(((Uint16)bytes[3] << 8) | bytes[2]) + fraction;
        *values++ = value;
        bytes += 8;
    }
    return SDL_TRUE;
}

static void WIN_SetEnhancedMouseScale(int mouse_speed)
{
    float scale = (float)mouse_speed / 10.0f;
    HKEY hKey;
    DWORD dwType = REG_BINARY;
    BYTE value[40];
    DWORD length = sizeof(value);
    int i;
    float xpoints[5];
    float ypoints[5];
    float scale_points[10];
    const int dpi = USER_DEFAULT_SCREEN_DPI; // FIXME, how do we handle different monitors with different DPI?
    const float display_factor = 3.5f * (150.0f / dpi);

    if (RegOpenKeyExW(HKEY_CURRENT_USER, L"Control Panel\\Mouse", 0, KEY_READ, &hKey) == ERROR_SUCCESS) {
        if (RegQueryValueExW(hKey, L"SmoothMouseXCurve", 0, &dwType, value, &length) == ERROR_SUCCESS &&
            LoadFiveFixedPointFloats(value, xpoints) &&
            RegQueryValueExW(hKey, L"SmoothMouseYCurve", 0, &dwType, value, &length) == ERROR_SUCCESS &&
            LoadFiveFixedPointFloats(value, ypoints)) {
            for (i = 0; i < 5; ++i) {
                float gain;
                if (xpoints[i] > 0.0f) {
                    gain = (ypoints[i] / xpoints[i]) * scale;
                } else {
                    gain = 0.0f;
                }
                scale_points[i * 2] = xpoints[i];
                scale_points[i * 2 + 1] = gain / display_factor;
                // SDL_Log("Point %d = %f,%f\n", i, scale_points[i * 2], scale_points[i * 2 + 1]);
            }
            SDL_SetMouseSystemScale(SDL_arraysize(scale_points), scale_points);
        }
        RegCloseKey(hKey);
    }
}

static void WIN_SetLinearMouseScale(int mouse_speed)
{
    static float mouse_speed_scale[] = {
        0.0f,
        1 / 32.0f,
        1 / 16.0f,
        1 / 8.0f,
        2 / 8.0f,
        3 / 8.0f,
        4 / 8.0f,
        5 / 8.0f,
        6 / 8.0f,
        7 / 8.0f,
        1.0f,
        1.25f,
        1.5f,
        1.75f,
        2.0f,
        2.25f,
        2.5f,
        2.75f,
        3.0f,
        3.25f,
        3.5f
    };

    if (mouse_speed > 0 && mouse_speed < SDL_arraysize(mouse_speed_scale)) {
        SDL_SetMouseSystemScale(1, &mouse_speed_scale[mouse_speed]);
    }
}

void WIN_UpdateMouseSystemScale(void)
{
    int mouse_speed;
    int params[3] = { 0, 0, 0 };

    if (SystemParametersInfo(SPI_GETMOUSESPEED, 0, &mouse_speed, 0) &&
        SystemParametersInfo(SPI_GETMOUSE, 0, params, 0)) {
        if (params[2]) {
            WIN_SetEnhancedMouseScale(mouse_speed);
        } else {
            WIN_SetLinearMouseScale(mouse_speed);
        }
    }
}

#endif /* SDL_VIDEO_DRIVER_WINDOWS */