src/video/windows/SDL_windowsframebuffer.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2011 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
*/
#include "SDL_config.h"

#include "SDL_windowsvideo.h"

#ifndef _WIN32_WCE
#define HAVE_GETDIBITS
#endif

int WIN_CreateWindowFramebuffer(_THIS, SDL_Window * window, Uint32 * format, void ** pixels, int *pitch)
{
    SDL_WindowData *data = (SDL_WindowData *) window->driverdata;
    size_t size;
    LPBITMAPINFO info;
#ifdef HAVE_GETDIBITS
    HBITMAP hbm;
#endif

    /* Free the old framebuffer surface */
    if (data->mdc) {
        DeleteDC(data->mdc);
    }
    if (data->hbm) {
        DeleteObject(data->hbm);
    }

    /* Find out the format of the screen */
    size = sizeof(BITMAPINFOHEADER) + 256 * sizeof (RGBQUAD);
    info = (LPBITMAPINFO)SDL_stack_alloc(Uint8, size);

#ifdef HAVE_GETDIBITS
    SDL_memset(info, 0, size);
    info->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);

    /* The second call to GetDIBits() fills in the bitfields */
    hbm = CreateCompatibleBitmap(data->hdc, 1, 1);
    GetDIBits(data->hdc, hbm, 0, 0, NULL, info, DIB_RGB_COLORS);
    GetDIBits(data->hdc, hbm, 0, 0, NULL, info, DIB_RGB_COLORS);
    DeleteObject(hbm);

    *format = SDL_PIXELFORMAT_UNKNOWN;
    if (info->bmiHeader.biCompression == BI_BITFIELDS) {
        int bpp;
        Uint32 *masks;

        bpp = info->bmiHeader.biPlanes * info->bmiHeader.biBitCount;
        masks = (Uint32*)((Uint8*)info + info->bmiHeader.biSize);
        *format = SDL_MasksToPixelFormatEnum(bpp, masks[0], masks[1], masks[2], 0);
    }
    if (*format == SDL_PIXELFORMAT_UNKNOWN)
#endif
    {
        /* We'll use RGB format for now */
        *format = SDL_PIXELFORMAT_RGB888;

        /* Create a new one */
        SDL_memset(info, 0, size);
        info->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
        info->bmiHeader.biPlanes = 1;
        info->bmiHeader.biBitCount = 32;
        info->bmiHeader.biCompression = BI_RGB;
    }

    /* Fill in the size information */
    *pitch = (((window->w * SDL_BYTESPERPIXEL(*format)) + 3) & ~3);
    info->bmiHeader.biWidth = window->w;
    info->bmiHeader.biHeight = -window->h;	/* negative for topdown bitmap */
    info->bmiHeader.biSizeImage = window->h * (*pitch);

    data->mdc = CreateCompatibleDC(data->hdc);
    data->hbm = CreateDIBSection(data->hdc, info, DIB_RGB_COLORS, pixels, NULL, 0);
    SDL_stack_free(info);

    if (!data->hbm) {
        WIN_SetError("Unable to create DIB");
        return -1;
    }
    SelectObject(data->mdc, data->hbm);

    return 0;
}

int WIN_UpdateWindowFramebuffer(_THIS, SDL_Window * window, SDL_Rect * rects, int numrects)
{
    SDL_WindowData *data = (SDL_WindowData *) window->driverdata;

    BitBlt(data->hdc, 0, 0, window->w, window->h, data->mdc, 0, 0, SRCCOPY);
    return 0;
}

void WIN_DestroyWindowFramebuffer(_THIS, SDL_Window * window)
{
    SDL_WindowData *data = (SDL_WindowData *) window->driverdata;

    if (data->mdc) {
        DeleteDC(data->mdc);
        data->mdc = NULL;
    }
    if (data->hbm) {
        DeleteObject(data->hbm);
        data->hbm = NULL;
    }
}

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