[C++/DirectDraw] - cara

[Anduril]

Nevite nekdo, jak nakreslit caru pomoci DirectDraw?
Nebo aspon odkaz...
Nebo neco...

Pokud víš, jak mazat obraz, tak akorát zadáš RECT na velikost tvé čáry a případně změníš barvu. A nebo můžeš využít DC...a pomocí GDI nakreslit čáru. - z paměti to nevím, co to je za fce, ale najdeš to v MSDN.

tim rect, myslis co ? RECT je struktura
mam pocit, ze neco takoveho
typedef RECT {
int left,right,top,bottom;
}
pouziva se pri kresleni obdelniku, treba tak
RECT rect;
Rectangle(hdc, rect.left, rect.top, rect.right, rect.top);

... ee - myslel jsem to takto (C++ a DirectDraw) - kód na vykreslení libovolné čáry:

/*
  BSurface::FillArea (...)
    - fill area (x,y,w,h) with color
*/
void BSurface::FillArea (int x, int y, int w, int h, int color)
{
  DDBLTFX ddBltFx;
  RECT    rDst;

  //Process
  rDst.left = x;
  rDst.top  = y;
  rDst.right = x + w;
  rDst.bottom = y + h;
  
  //Prepare colors
  ddBltFx.dwSize = sizeof(DDBLTFX);
  ddBltFx.dwFillColor = color;
  
  //Fill surface
  lpDDSurface->Blt(&rDst, NULL, NULL, DDBLT_WAIT | DDBLT_COLORFILL, &ddBltFx);
}

/*
  BSurface::Line (...)
    - draw line from x1,y1 to x2,y2 with color
*/
void BSurface::Line (int x1, int y1, int x2, int y2, int color)
{
  double xStep, yStep, dx, dy;
  int    xLength, yLength, xCount, yCount, tempV;

  //Process
    //Horizontal line
    if(y1==y2){
      FillArea (x1, y1, x1 + x2, 1, color);
    }
    //Vertical line
    else if(x1==x2){
      FillArea (x1, y1, 1, y1 + y2, color);
    }
    //Any other line
    else {
      xLength = abs(x2 - y1);
      yLength = abs(y2 - y1);

      if(xLength==0) 
        FillArea (x1, y1, 1, y1 + y2, color); 
      else if(yLength==0) 
        FillArea (x1, y1, x1 + x2, 1, color);
      else if(xLength > yLength) {
   
        if(x1 > x2) {
          tempV = x1; x1 = x2; x2 = tempV;
          tempV = y1; y1 = y2; y2 = tempV;
        }

        yStep = (double)(y2 - y1) / (double)(x2 - x1);
        dy = y1;
  
        //Draw it
        for&#40;xCount = x1; xCount <= x2; xCount++&#41; &#123;
          FillArea &#40;xCount, &#40;int&#41;dy, 1, 1, color&#41;;
          dy += yStep;
        &#125;
                
      &#125;
      else &#123;
      
        if&#40;y1 > y2&#41; &#123;
          tempV = x1; x1 = x2; x2 = tempV;
          tempV = y1; y1 = y2; y2 = tempV;  	
        &#125;

        xStep = &#40;double&#41;&#40;x2 - x1&#41; / &#40;double&#41;&#40;y2 - y1&#41;;
        dx = x1;

        //Draw it
        for&#40;yCount = y1; yCount <= y2; yCount++&#41; &#123;
          FillArea &#40;&#40;int&#41;dx, yCount, 1, 1, color&#41;;
          dx += xStep;
        &#125;        
      &#125;
    &#125;   
&#125;

A nebo třeba takto (C a DirectDraw + GDI):

void DrawLine(LPDIRECTDRAWSURFACE surface, int x1, int y1, int x2, int y2, DWORD color)
{
   HPEN pen;
   HDC  t_dc;
   
   surface->lpVtbl->GetDC(surface, &t_dc);
   if(t_dc == NULL) return; 
   
   pen = CreatePen(PS_SOLID, 0, color);
   SelectObject(t_dc, pen);
   
   MoveToEx(t_dc, x1, y1, NULL);
   LineTo(t_dc, x2, y2);
   
   surface->lpVtbl->ReleaseDC(surface, t_dc);
   DeleteObject(pen);   
}

.. Mělo by to být dobře, doufám.