OPENGL ES显示字符串（Windows Mobile）

当然国外有POWERVR提供基于OPENGL ES的SDK封装的APPPRINT3D类来处理字符串显示和GLFONT for windows ce等。

但是我们这里只整理了一个函数：

 

void  glTextShow(WCHAR *fontname, int fontsize, int style, int x, int y, const WCHAR *string)
{
      int len, xx = 0, yy = 0, nbpoints = 0, i;
      GLshort *points;
      GLushort *indices;
      HFONT font;
      LOGFONTW    lf;
      RECT rect;
      static HBITMAP bmp;
      static BYTE *img;
      static HDC hdc = NULL;
      static BITMAPINFO bi;
      SIZE sz;
      static EGLint width, height;

      if(!fontname || !string)
          return;
      if(!string[0])
          return;

      if(!hdc)
      {
          hdc = CreateCompatibleDC(GetDC(hWnd));

          eglQuerySurface(eglDisplay, eglSurface, EGL_WIDTH, &width);
          eglQuerySurface(eglDisplay, eglSurface, EGL_HEIGHT, &height);


          ZeroMemory(&bi, sizeof(BITMAPINFO));
          bi.bmiHeader.biSize=sizeof(BITMAPINFOHEADER);
          bi.bmiHeader.biWidth = width;
          bi.bmiHeader.biHeight = height;
          bi.bmiHeader.biBitCount = 8;
          bi.bmiHeader.biPlanes = 1;
          bi.bmiHeader.biCompression = BI_RGB;

          bmp = CreateDIBSection(hdc, &bi, DIB_RGB_COLORS, &img, NULL, 0);

          SelectObject(hdc, bmp);

          SelectObject(hdc, GetStockObject(BLACK_BRUSH));

          SetBkMode(hdc, TRANSPARENT);
          SetTextColor(hdc, RGB(255, 255, 255));
      }

      Rectangle(hdc, 0, 0, width, height);
      ZeroMemory(img, width * height);

      lf.lfCharSet = DEFAULT_CHARSET;
      lf.lfClipPrecision = CLIP_DEFAULT_PRECIS;
      lf.lfEscapement = 0;
      wcscpy(lf.lfFaceName, fontname);
      lf.lfHeight = -(fontsize * GetDeviceCaps(GetDC(hWnd), LOGPIXELSY) / 72);
      lf.lfItalic = (style & 1) ? TRUE : FALSE;
      lf.lfOrientation = 0;
      lf.lfOutPrecision = OUT_DEFAULT_PRECIS;
      lf.lfPitchAndFamily = DEFAULT_PITCH | FF_DONTCARE;
      lf.lfQuality = DEFAULT_QUALITY;
      lf.lfStrikeOut = FALSE;
      lf.lfUnderline = (style & 4) ? TRUE : FALSE;
      lf.lfWidth = 0;
      lf.lfWeight = (style & 2) ? FW_BOLD : FW_NORMAL;

      font = CreateFontIndirectW(&lf);

      SelectObject(hdc, font);

      len = wcslen(string);

      GetTextExtentPointW(hdc, string, len, &sz);

      rect.left = max(0, min(x, width));
      rect.top = max(0, min(y, height));
      rect.right = min(rect.left + sz.cx, width);
      rect.bottom = min(rect.top + sz.cy, height);

      DrawTextW(hdc, string, len, &rect, DT_LEFT | DT_BOTTOM);

      points = (GLshort*)malloc(sz.cx * sz.cy * 2 * sizeof(short));

      for(yy = rect.top; yy < rect.bottom; yy++)
      {
          for(xx = rect.left; xx < rect.right; xx++)
          {
              if(img[xx + (height - yy) * width] != 0)
              {
                  points[nbpoints * 2 + 0] = xx - x;
                  points[nbpoints * 2 + 1] = (short)(rect.top + sz.cy - (yy - rect.top)) - y;
                  nbpoints++;
              }
          }
      }
      DeleteObject(font);

      indices = (GLushort*)malloc(nbpoints * sizeof(GLushort));
      for(i = 0; i < nbpoints; i++)
          indices[i] = i;

      glMatrixMode(GL_PROJECTION);
      glPushMatrix();
      glLoadIdentity();

      glOrthox(0, _INT2FIXED(width),
              0, _INT2FIXED(height),
              0, _INT2FIXED(1));


      glMatrixMode(GL_MODELVIEW);
      glPushMatrix();
      glLoadIdentity();

      glDisable(GL_DEPTH_TEST);

      glTranslatex(_INT2FIXED(x), _INT2FIXED(y), 0);

      glEnable(GL_ALPHA_TEST);
      glAlphaFuncx(GL_NOTEQUAL, 0);
      glDisableClientState(GL_TEXTURE_COORD_ARRAY);
      glDisableClientState(GL_COLOR_ARRAY);
      glDisableClientState(GL_NORMAL_ARRAY);
      glEnableClientState (GL_VERTEX_ARRAY);
      glVertexPointer(2, GL_SHORT, 0, points);

      glDrawElements(GL_POINTS,
                          nbpoints,
                          GL_UNSIGNED_SHORT,
                          indices);

      glDisable(GL_ALPHA_TEST);

      glEnable(GL_DEPTH_TEST);

      glPopMatrix();
      glMatrixMode(GL_PROJECTION);
      glPopMatrix();
      glMatrixMode(GL_MODELVIEW);

      free(indices);
      free(points);
}