Function ddgr_gdi_surf_Create

dd_grwin32/ddgrWin32GDI.cpp:367–433

//	Creates a GDI DIBitmap

bool ddgr_gdi_surf_Create(ddgr_surface *sf) {
  tGDISurface *bm;

  //	set up bitmap header
  int nw = sf->w;
  if (nw % 4)
    nw = ((sf->w / 4) * 4) + 4;

  bm = new tGDISurface;

  if (sf->bpp == BPP_8) {
    tDIBHeader8 header;

    header.bmi.biSize = sizeof(BITMAPINFOHEADER);
    header.bmi.biWidth = nw;
    header.bmi.biHeight = -sf->h; // Always a top down bitmap!!
    header.bmi.biPlanes = 1;
    header.bmi.biBitCount = sf->bpp;
    header.bmi.biCompression = BI_BITFIELDS;
    header.bmi.biSizeImage = 0;
    header.bmi.biXPelsPerMeter = 0;
    header.bmi.biYPelsPerMeter = 0;
    header.bmi.biClrUsed = 0;
    header.bmi.biClrImportant = 0;

    bm->hbm = CreateDIBSection(GDI_DATA(hOffscreenDC), (BITMAPINFO *)&header, DIB_RGB_COLORS, &bm->data, NULL, 0);
  } else {
    tDIBHeader header;
    header.bmi.biSize = sizeof(BITMAPINFOHEADER);
    header.bmi.biWidth = nw;
    header.bmi.biHeight = -sf->h; // Always a top down bitmap!!
    header.bmi.biPlanes = 1;
    header.bmi.biBitCount = sf->bpp;
    header.bmi.biCompression = BI_BITFIELDS;
    header.bmi.biSizeImage = 0;
    header.bmi.biXPelsPerMeter = 0;
    header.bmi.biYPelsPerMeter = 0;
    header.bmi.biClrUsed = 0;
    header.bmi.biClrImportant = 0;

    //	setup RGB bit masks
    if (sf->bpp == BPP_16) {
      header.red_mask = 0x7c00;
      header.green_mask = 0x03e0;
      header.blue_mask = 0x001f;
      bm->rowsize = nw * 2;
    } else if (sf->bpp == BPP_32 || sf->bpp == BPP_24) {
      header.red_mask = 0x00ff0000;
      header.green_mask = 0x0000ff00;
      header.blue_mask = 0x000000ff;
      bm->rowsize = nw * 4;
    }

    bm->hbm = CreateDIBSection(GDI_DATA(hOffscreenDC), (BITMAPINFO *)&header, DIB_RGB_COLORS, &bm->data, NULL, 0);
  }

  if (!bm->hbm) {
    ddgr_PushError("CreateDIBSection failed.");