src/video/win32/SDL_win32events.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2010 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#if (_WIN32_WINNT < 0x601)
#undef _WIN32_WINNT
#define _WIN32_WINNT 0x601
#endif

#include "SDL_config.h"

#include "SDL_win32video.h"
#include "SDL_syswm.h"
#include "SDL_vkeys.h"
#include "../../events/SDL_events_c.h"


#define WMMSG_DEBUG
#ifdef WMMSG_DEBUG
#include <stdio.h>	
#include "wmmsg.h"
#endif
//#include <stdio.h>

/* Masks for processing the windows KEYDOWN and KEYUP messages */
#define REPEATED_KEYMASK    (1<<30)
#define EXTENDED_KEYMASK    (1<<24)

#define VK_ENTER    10          /* Keypad Enter ... no VKEY defined? */

/* Make sure XBUTTON stuff is defined that isn't in older Platform SDKs... */
#ifndef WM_XBUTTONDOWN
#define WM_XBUTTONDOWN 0x020B
#endif
#ifndef WM_XBUTTONUP
#define WM_XBUTTONUP 0x020C
#endif
#ifndef GET_XBUTTON_WPARAM
#define GET_XBUTTON_WPARAM(w) (HIWORD(w))
#endif
#ifndef WM_INPUT
#define WM_INPUT 0x00ff
#endif

extern HCTX *g_hCtx;
extern HANDLE *mice;
extern int total_mice;
extern int tablet;
int pressure = 0;               /* the pressure reported by the tablet */

static WPARAM
RemapVKEY(WPARAM wParam, LPARAM lParam)
{
    int i;
    BYTE scancode = (BYTE) ((lParam >> 16) & 0xFF);

    /* Windows remaps alphabetic keys based on current layout.
       We try to provide USB scancodes, so undo this mapping.
     */
    if (wParam >= 'A' && wParam <= 'Z') {
        if (scancode != alpha_scancodes[wParam - 'A']) {
            for (i = 0; i < SDL_arraysize(alpha_scancodes); ++i) {
                if (scancode == alpha_scancodes[i]) {
                    wParam = 'A' + i;
                    break;
                }
            }
        }
    }

    /* Keypad keys are a little trickier, we always scan for them.
       Keypad arrow keys have the same scancode as normal arrow keys,
       except they don't have the extended bit (0x1000000) set.
     */
    if (!(lParam & 0x1000000)) {
        for (i = 0; i < SDL_arraysize(keypad_scancodes); ++i) {
            if (scancode == keypad_scancodes[i]) {
                wParam = VK_NUMPAD0 + i;
                break;
            }
        }
    }

    return wParam;
}

LRESULT CALLBACK
WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    SDL_WindowData *data;
    RAWINPUT *raw;
    PACKET packet;
    LRESULT returnCode = -1;

    /* Send a SDL_SYSWMEVENT if the application wants them */
    if (SDL_GetEventState(SDL_SYSWMEVENT) == SDL_ENABLE) {
        SDL_SysWMmsg wmmsg;

        SDL_VERSION(&wmmsg.version);
        wmmsg.hwnd = hwnd;
        wmmsg.msg = msg;
        wmmsg.wParam = wParam;
        wmmsg.lParam = lParam;
        SDL_SendSysWMEvent(&wmmsg);
    }

    /* Get the window data for the window */
    data = (SDL_WindowData *) GetProp(hwnd, TEXT("SDL_WindowData"));
    if (!data) {
        return CallWindowProc(DefWindowProc, hwnd, msg, wParam, lParam);
    }

#ifdef WMMSG_DEBUG
    {		
        FILE *log = fopen("wmmsg.txt", "a");		
        fprintf(log, "Received windows message: %p ", hwnd);
        if (msg > MAX_WMMSG) {
            fprintf(log, "%d", msg);
        } else {
            fprintf(log, "%s", wmtab[msg]);
        }
        fprintf(log, " -- 0x%X, 0x%X\n", wParam, lParam);
        fclose(log);
    }

#endif

    switch (msg) {

    case WT_PACKET:
        {
            /* if we receive such data we need to update the pressure */
            SDL_VideoData *videodata = data->videodata;
            if (videodata->wintabDLL
                && videodata->WTPacket((HCTX) lParam, (UINT) wParam, &packet)) {
                SDL_ChangeEnd(tablet, (int) packet.pkCursor);
                pressure = (int) packet.pkNormalPressure;
            }
        }
        break;

    case WT_PROXIMITY:
        {
            /* checking where the proximity message showed up */
            int h_context = LOWORD(lParam);
            POINT point;
            GetCursorPos(&point);
            ScreenToClient(hwnd, &point);

            /* are we in proximity or out of proximity */
            if (h_context == 0) {
                SDL_SendProximity(tablet, point.x, point.y, SDL_PROXIMITYOUT);
            } else {
                SDL_SendProximity(tablet, point.x, point.y, SDL_PROXIMITYIN);
            }
        }
        break;

    case WM_SHOWWINDOW:
        {
            if (wParam) {
                SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_SHOWN, 0, 0);
            } else {
                SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_HIDDEN, 0, 0);
            }
        }
        break;

    case WM_ACTIVATE:
        {
            int index;
            SDL_Keyboard *keyboard;
            BOOL minimized;

            minimized = HIWORD(wParam);
            index = data->videodata->keyboard;
            keyboard = SDL_GetKeyboard(index);
            if (!minimized && (LOWORD(wParam) != WA_INACTIVE)) {
                SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_SHOWN, 0, 0);
                SDL_SendWindowEvent(data->window,
                                    SDL_WINDOWEVENT_RESTORED, 0, 0);
#ifndef _WIN32_WCE              /* WinCE misses IsZoomed() */
                if (IsZoomed(hwnd)) {
                    SDL_SendWindowEvent(data->window,
                                        SDL_WINDOWEVENT_MAXIMIZED, 0, 0);
                }
#endif
                if (keyboard && keyboard->focus != data->window) {
                    SDL_SetKeyboardFocus(index, data->window);
                }
                /* FIXME: Update keyboard state */
            } else {
                if (keyboard && keyboard->focus == data->window) {
                    SDL_SetKeyboardFocus(index, 0);
                }
                if (minimized) {
                    SDL_SendWindowEvent(data->window,
                                        SDL_WINDOWEVENT_MINIMIZED, 0, 0);
                }
            }
        }
        returnCode = 0;
        break;

/* WinCE has no RawInput, so we use the classic mouse events.
   In classic Win32 this is done by WM_INPUT
 */
#ifdef _WIN32_WCE
    case WM_MOUSEMOVE:
        SDL_SendMouseMotion(0, 0, LOWORD(lParam), HIWORD(lParam), 0);
        break;

    case WM_LBUTTONDOWN:
        SDL_SendMouseMotion(0, 0, LOWORD(lParam), HIWORD(lParam), 0);
        SDL_SendMouseButton(0, SDL_PRESSED, SDL_BUTTON_LEFT);
        break;

    case WM_LBUTTONUP:
        SDL_SendMouseMotion(0, 0, LOWORD(lParam), HIWORD(lParam), 0);
        SDL_SendMouseButton(0, SDL_RELEASED, SDL_BUTTON_LEFT);
        break;
#else /* _WIN32_WCE */

    case WM_INPUT:             /* mouse events */
        {
            LPBYTE lpb;
            const RAWINPUTHEADER *header;
            int index = -1;
            int i;
            int size = 0;
            const RAWMOUSE *raw_mouse = NULL;
            POINT point;
            USHORT flags;
            int w, h;

            /* we're collecting raw data to be able to identify the mouse (if there are several) */
            GetRawInputData((HRAWINPUT) lParam, RID_INPUT, NULL, &size,
                            sizeof(RAWINPUTHEADER));
            lpb = SDL_stack_alloc(BYTE, size);
            GetRawInputData((HRAWINPUT) lParam, RID_INPUT, lpb, &size,
                            sizeof(RAWINPUTHEADER));
            raw = (RAWINPUT *) lpb;
            header = &raw->header;
            flags = raw->data.mouse.usButtonFlags;

            /* we're checking which mouse generated the event */
            for (i = 0; i < total_mice; ++i) {
                if (mice[i] == header->hDevice) {
                    index = i;
                    break;
                }
            }
            if (index < 0) {
                /* New mouse?  Should we dynamically update mouse list? */
                returnCode = 0;
                break;
            }

            GetCursorPos(&point);
            ScreenToClient(hwnd, &point);

            SDL_GetWindowSize(data->window, &w, &h);
            if (point.x >= 0 && point.y >= 0 && point.x < w && point.y < h) {
                SDL_SetMouseFocus(index, data->window);
            } else {
                SDL_SetMouseFocus(index, 0);
                /* FIXME: Should we be doing anything else here? */
                break;
            }

            /* if the message was sent by a tablet we have to send also pressure */
            if (index == tablet) {
                SDL_SendMouseMotion(index, 0, point.x, point.y, pressure);
            } else {
                SDL_SendMouseMotion(index, 0, point.x, point.y, 0);
            }
            /* we're sending mouse buttons messages to check up if sth changed */
            if (flags & RI_MOUSE_LEFT_BUTTON_DOWN) {
                SDL_SendMouseButton(index, SDL_PRESSED, SDL_BUTTON_LEFT);
            } else if (flags & RI_MOUSE_LEFT_BUTTON_UP) {
                SDL_SendMouseButton(index, SDL_RELEASED, SDL_BUTTON_LEFT);
            }
            if (flags & RI_MOUSE_MIDDLE_BUTTON_DOWN) {
                SDL_SendMouseButton(index, SDL_PRESSED, SDL_BUTTON_MIDDLE);
            } else if (flags & RI_MOUSE_MIDDLE_BUTTON_UP) {
                SDL_SendMouseButton(index, SDL_RELEASED, SDL_BUTTON_MIDDLE);
            }
            if (flags & RI_MOUSE_RIGHT_BUTTON_DOWN) {
                SDL_SendMouseButton(index, SDL_PRESSED, SDL_BUTTON_RIGHT);
            } else if (flags & RI_MOUSE_RIGHT_BUTTON_UP) {
                SDL_SendMouseButton(index, SDL_RELEASED, SDL_BUTTON_RIGHT);
            }
            if (flags & RI_MOUSE_BUTTON_4_DOWN) {
                SDL_SendMouseButton(index, SDL_PRESSED, SDL_BUTTON_X1);
            } else if (flags & RI_MOUSE_BUTTON_4_UP) {
                SDL_SendMouseButton(index, SDL_RELEASED, SDL_BUTTON_X1);
            }
            if (flags & RI_MOUSE_BUTTON_5_DOWN) {
                SDL_SendMouseButton(index, SDL_PRESSED, SDL_BUTTON_X2);
            } else if (flags & RI_MOUSE_BUTTON_5_UP) {
                SDL_SendMouseButton(index, SDL_RELEASED, SDL_BUTTON_X2);
            }
            if (flags & RI_MOUSE_WHEEL) {
                SDL_SendMouseWheel(index, 0,
                                   (short) raw->data.mouse.usButtonData);
            }
            SDL_stack_free(lpb);
        }
        returnCode = 0;
        break;
#endif /* _WIN32_WCE */

    case WM_MOUSELEAVE:
        {
            int i;

            for (i = 0; i < SDL_GetNumMice(); ++i) {
                SDL_Mouse *mouse = SDL_GetMouse(i);

                if (mouse->focus == data->window) {
                    SDL_SetMouseFocus(i, 0);
                }
            }
        }
        returnCode = 0;
        break;

    case WM_SYSKEYDOWN:
    case WM_KEYDOWN:
        {
            int index;

            /* Ignore repeated keys */
            if (lParam & REPEATED_KEYMASK) {
                returnCode = 0;
                break;
            }

            index = data->videodata->keyboard;
            wParam = RemapVKEY(wParam, lParam);
            switch (wParam) {
            case VK_CONTROL:
                if (lParam & EXTENDED_KEYMASK)
                    wParam = VK_RCONTROL;
                else
                    wParam = VK_LCONTROL;
                break;
            case VK_SHIFT:
                /* EXTENDED trick doesn't work here */
                {
                    Uint8 *state = SDL_GetKeyboardState(NULL);
                    if (state[SDL_SCANCODE_LSHIFT] == SDL_RELEASED
                        && (GetKeyState(VK_LSHIFT) & 0x8000)) {
                        wParam = VK_LSHIFT;
                    } else if (state[SDL_SCANCODE_RSHIFT] == SDL_RELEASED
                               && (GetKeyState(VK_RSHIFT) & 0x8000)) {
                        wParam = VK_RSHIFT;
                    } else {
                        /* Probably a key repeat */
                        wParam = 256;
                    }
                }
                break;
            case VK_MENU:
                if (lParam & EXTENDED_KEYMASK)
                    wParam = VK_RMENU;
                else
                    wParam = VK_LMENU;
                break;
            case VK_RETURN:
                if (lParam & EXTENDED_KEYMASK)
                    wParam = VK_ENTER;
                break;
            }
            if (wParam < 256) {
                SDL_SendKeyboardKey(index, SDL_PRESSED,
                                    data->videodata->key_layout[wParam]);
            }
        }
        returnCode = 0;
        break;

    case WM_SYSKEYUP:
    case WM_KEYUP:
        {
            int index;

            index = data->videodata->keyboard;
            wParam = RemapVKEY(wParam, lParam);
            switch (wParam) {
            case VK_CONTROL:
                if (lParam & EXTENDED_KEYMASK)
                    wParam = VK_RCONTROL;
                else
                    wParam = VK_LCONTROL;
                break;
            case VK_SHIFT:
                /* EXTENDED trick doesn't work here */
                {
                    Uint8 *state = SDL_GetKeyboardState(NULL);
                    if (state[SDL_SCANCODE_LSHIFT] == SDL_PRESSED
                        && !(GetKeyState(VK_LSHIFT) & 0x8000)) {
                        wParam = VK_LSHIFT;
                    } else if (state[SDL_SCANCODE_RSHIFT] == SDL_PRESSED
                               && !(GetKeyState(VK_RSHIFT) & 0x8000)) {
                        wParam = VK_RSHIFT;
                    } else {
                        /* Probably a key repeat */
                        wParam = 256;
                    }
                }
                break;
            case VK_MENU:
                if (lParam & EXTENDED_KEYMASK)
                    wParam = VK_RMENU;
                else
                    wParam = VK_LMENU;
                break;
            case VK_RETURN:
                if (lParam & EXTENDED_KEYMASK)
                    wParam = VK_ENTER;
                break;
            }

            /* Windows only reports keyup for print screen */
            if (wParam == VK_SNAPSHOT
                && SDL_GetKeyboardState(NULL)[SDL_SCANCODE_PRINTSCREEN] ==
                SDL_RELEASED) {
                SDL_SendKeyboardKey(index, SDL_PRESSED,
                                    data->videodata->key_layout[wParam]);
            }
            if (wParam < 256) {
                SDL_SendKeyboardKey(index, SDL_RELEASED,
                                    data->videodata->key_layout[wParam]);
            }
        }
        returnCode = 0;
        break;

    case WM_CHAR:
        {
            char text[4];

            /* Convert to UTF-8 and send it on... */
            if (wParam <= 0x7F) {
                text[0] = (char) wParam;
                text[1] = '\0';
            } else if (wParam <= 0x7FF) {
                text[0] = 0xC0 | (char) ((wParam >> 6) & 0x1F);
                text[1] = 0x80 | (char) (wParam & 0x3F);
                text[2] = '\0';
            } else {
                text[0] = 0xE0 | (char) ((wParam >> 12) & 0x0F);
                text[1] = 0x80 | (char) ((wParam >> 6) & 0x3F);
                text[2] = 0x80 | (char) (wParam & 0x3F);
                text[3] = '\0';
            }
            SDL_SendKeyboardText(data->videodata->keyboard, text);
        }
        returnCode = 0;
        break;

    case WM_INPUTLANGCHANGE:
        {
            WIN_UpdateKeymap(data->videodata->keyboard);
        }
        returnCode = 1;
        break;

    case WM_GETMINMAXINFO:
        {
            MINMAXINFO *info;
            RECT size;
            int x, y;
            int w, h;
            int style;
            BOOL menu;

            /* If we allow resizing, let the resize happen naturally */
            if (SDL_GetWindowFlags(data->window) & SDL_WINDOW_RESIZABLE) {
                returnCode = 0;
                break;
            }

            /* Get the current position of our window */
            GetWindowRect(hwnd, &size);
            x = size.left;
            y = size.top;

            /* Calculate current size of our window */
            SDL_GetWindowSize(data->window, &w, &h);
            size.top = 0;
            size.left = 0;
            size.bottom = h;
            size.right = w;


            style = GetWindowLong(hwnd, GWL_STYLE);
#ifdef _WIN32_WCE
            menu = FALSE;
#else
            /* DJM - according to the docs for GetMenu(), the
               return value is undefined if hwnd is a child window.
               Aparently it's too difficult for MS to check
               inside their function, so I have to do it here.
             */
            menu = (style & WS_CHILDWINDOW) ? FALSE : (GetMenu(hwnd) != NULL);
#endif
            AdjustWindowRectEx(&size, style, menu, 0);
            w = size.right - size.left;
            h = size.bottom - size.top;

            /* Fix our size to the current size */
            info = (MINMAXINFO *) lParam;
            info->ptMaxSize.x = w;
            info->ptMaxSize.y = h;
            info->ptMaxPosition.x = x;
            info->ptMaxPosition.y = y;
            info->ptMinTrackSize.x = w;
            info->ptMinTrackSize.y = h;
            info->ptMaxTrackSize.x = w;
            info->ptMaxTrackSize.y = h;
        }
        returnCode = 0;
        break;

    case WM_WINDOWPOSCHANGED:
        {
            RECT rect;
            int x, y;
            int w, h;
            Uint32 window_flags;

            if (!GetClientRect(hwnd, &rect) ||
                (rect.right == rect.left && rect.bottom == rect.top)) {
                break;
            }
            ClientToScreen(hwnd, (LPPOINT) & rect);
            ClientToScreen(hwnd, (LPPOINT) & rect + 1);

            window_flags = SDL_GetWindowFlags(data->window);
            if ((window_flags & SDL_WINDOW_INPUT_GRABBED) &&
                (window_flags & SDL_WINDOW_INPUT_FOCUS)) {
                ClipCursor(&rect);
            }

            x = rect.left;
            y = rect.top;
            SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_MOVED, x, y);

            w = rect.right - rect.left;
            h = rect.bottom - rect.top;
            SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_RESIZED, w,
                                h);
        }
        break;

    case WM_SETCURSOR:
        {
            Uint16 hittest;

            hittest = LOWORD(lParam);
            if (hittest == HTCLIENT) {
                /* FIXME: Implement the cursor API */
                static HCURSOR cursor;
                if (!cursor) {
                    cursor = LoadCursor(NULL, IDC_ARROW);
                }
                SetCursor(cursor);
                returnCode = TRUE;
            }
        }
        break;

        /* We are about to get palette focus! */
    case WM_QUERYNEWPALETTE:
        {
            /*
                WIN_RealizePalette(current_video);
                returnCode = TRUE;
             */
        }
        break;

        /* Another application changed the palette */
    case WM_PALETTECHANGED:
        {
            /*
               WIN_PaletteChanged(current_video, (HWND) wParam);
             */
        }
        break;

        /* We were occluded, refresh our display */
    case WM_PAINT:
        {
            RECT rect;
            if (GetUpdateRect(hwnd, &rect, FALSE)) {
                ValidateRect(hwnd, &rect);
                SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_EXPOSED,
                                    0, 0);
            }
        }
        returnCode = 0;
        break;

        /* We'll do our own drawing, prevent flicker */
    case WM_ERASEBKGND:
        {
        }
        return (1);

    case WM_SYSCOMMAND:
        {
            /* Don't start the screensaver or blank the monitor in fullscreen apps */
            if ((wParam & 0xFFF0) == SC_SCREENSAVE ||
                (wParam & 0xFFF0) == SC_MONITORPOWER) {
                if (SDL_GetVideoDevice()->suspend_screensaver) {
                    return (0);
                }
            }
        }
        break;

    case WM_CLOSE:
        {
            SDL_SendWindowEvent(data->window, SDL_WINDOWEVENT_CLOSE, 0, 0);
        }
        returnCode = 0;
        break;
	case WM_TOUCH:
		{
			//printf("Got Touch Event!\n");
    
			FILE *log = fopen("wmmsg.txt", "a");
			fprintf(log, "Received Touch Message: %p ", hwnd);
			if (msg > MAX_WMMSG) {
				fprintf(log, "%d", msg);
			} else {
				fprintf(log, "%s", wmtab[msg]);
			}
			fprintf(log, "WM_TOUCH = %d -- 0x%X, 0x%X\n",msg, wParam, lParam);
			fclose(log);
    
		}
		break;
	case WM_GESTURE:
		{
			//printf("Got Touch Event!\n");
    
			FILE *log = fopen("wmmsg.txt", "a");
			fprintf(log, "Received Gesture Message: %p ", hwnd);
			if (msg > MAX_WMMSG) {
				fprintf(log, "%d", msg);
			} else {
				fprintf(log, "%s", wmtab[msg]);
			}
			fprintf(log, "WM_GESTURE = %d -- 0x%X, 0x%X\n",msg, wParam, lParam);
			fclose(log);
    
		}
		break;		
	}

    /* If there's a window proc, assume it's going to handle messages */
    if (data->wndproc) {
        return CallWindowProc(data->wndproc, hwnd, msg, wParam, lParam);
    } else if (returnCode >= 0) {
        return returnCode;
    } else {
        return CallWindowProc(DefWindowProc, hwnd, msg, wParam, lParam);
    }
}

void
WIN_PumpEvents(_THIS)
{
    MSG msg;
    while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

static int app_registered = 0;
LPTSTR SDL_Appname = NULL;
Uint32 SDL_Appstyle = 0;
HINSTANCE SDL_Instance = NULL;

/* Register the class for this application */
int
SDL_RegisterApp(char *name, Uint32 style, void *hInst)
{
    WNDCLASS class;

    /* Only do this once... */
    if (app_registered) {
        ++app_registered;
        return (0);
    }
    if (!name && !SDL_Appname) {
        name = "SDL_app";
        SDL_Appstyle = (CS_BYTEALIGNCLIENT | CS_OWNDC);
        SDL_Instance = hInst ? hInst : GetModuleHandle(NULL);
    }

    if (name) {
        SDL_Appname = WIN_UTF8ToString(name);
        SDL_Appstyle = style;
        SDL_Instance = hInst ? hInst : GetModuleHandle(NULL);
    }

    /* Register the application class */
    class.hCursor = NULL;
    class.hIcon =
        LoadImage(SDL_Instance, SDL_Appname, IMAGE_ICON, 0, 0,
                  LR_DEFAULTCOLOR);
    class.lpszMenuName = NULL;
    class.lpszClassName = SDL_Appname;
    class.hbrBackground = NULL;
    class.hInstance = SDL_Instance;
    class.style = SDL_Appstyle;
    class.lpfnWndProc = DefWindowProc;
    class.cbWndExtra = 0;
    class.cbClsExtra = 0;
    if (!RegisterClass(&class)) {
        SDL_SetError("Couldn't register application class");
        return (-1);
    }

    app_registered = 1;
    return (0);
}

/* Unregisters the windowclass registered in SDL_RegisterApp above. */
void
SDL_UnregisterApp()
{
    WNDCLASS class;

    /* SDL_RegisterApp might not have been called before */
    if (!app_registered) {
        return;
    }
    --app_registered;
    if (app_registered == 0) {
        /* Check for any registered window classes. */
        if (GetClassInfo(SDL_Instance, SDL_Appname, &class)) {
            UnregisterClass(SDL_Appname, SDL_Instance);
        }
        SDL_free(SDL_Appname);
        SDL_Appname = NULL;
    }
}

/* Sets an error message based on GetLastError() */
void
WIN_SetError(const char *prefix)
{
    TCHAR buffer[1024];
    char *message;
    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 0,
                  buffer, SDL_arraysize(buffer), NULL);
    message = WIN_StringToUTF8(buffer);
    SDL_SetError("%s%s%s", prefix ? prefix : "", prefix ? ": " : "", message);
    SDL_free(message);
}

/* vi: set ts=4 sw=4 expandtab: */