Применение Windows API

And here's the implementation of Update. We create a bitmap canvas in memory, making it compatible with the current display canvas. We blit the background image into it, then blit the mask and the sprite (notice the change of position for each frame). Finally, we transfer the complete bitmap into our buffer (overloaded assignment operator at work!).

void View::Update(Canvas& canvas) {

 const double speed = 0.01;

 Bitmap bmp(canvas, _cx, _cy);

 BitmapCanvas bmpCanvas(canvas, bmp);

 RECT rect = { 0, 0, _cx, _cy };

 bmpCanvas.WhiteWash(rect);

 // Do the off-line drawing

 Blitter bltBkg(_background);

 bltBkg.BlitTo(bmpCanvas);

 int xRange = (_widthBkg - _widthSprite) / 2;

 int yRange = (_heightBkg - _heightSprite) / 2;

 int x = xRange + static_cast(xRange * sin(speed * _tick));

 int y = yRange + static_cast(yRange * cos(4 * speed * _tick));

 Blitter bltMask(_mask);

 bltMask.SetMode(SRCPAINT);

 bltMask.SetDest(x, y);

 bltMask.BlitTo(bmpCanvas);

 Blitter bltSprite(_sprite);

 bltSprite.SetMode(SRCAND);

 bltSprite.SetDest(x, y);

 bltSprite.BlitTo(bmpCanvas);

 // update the buffer

 _bitmapBuf = bmp;

}

For completeness, here's the definition of bitmap canvas. You draw directly on this canvas using standard canvas methods, like Line, Text, SetPixel, etc... Here we only blit bitmaps into it.

class BitmapCanvas: public MemCanvas {

public:

 BitmapCanvas(HDC hdc, HBITMAP hBitmap) : MemCanvas(hdc) {

  // convert bitmap to format compatible with canvas

  _hOldBitmap = reinterpret_cast(::SelectObject(_hdc, hBitmap));

 }

 ~BitmapCanvas() {

  ::SelectObject(_hdc, _hOldBitmap);

 }

private:

 HBITMAP _hOldBitmap;

};

class MemCanvas: public Canvas {

public:

 MemCanvas(HDC hdc) : Canvas(::CreateCompatibleDC(hdc)) {}

 ~MemCanvas() {

  ::DeleteDC(_hdc);

 }

};

Now, if you want more speed, read about DirectDraw.