NScumm.Scumm.ScummEngine.ScrollEffect C# (CSharp) Метод

        void ScrollEffect(int dir)
        {
            var vs = MainVirtScreen;

            int step;
            var delay = VariableFadeDelay.HasValue ? Variables[VariableFadeDelay.Value] * FadeDelay : PictureDelay;

            if ((dir == 0) || (dir == 1))
                step = vs.Height;
            else
                step = vs.Width;

            step = (step * delay) / Scrolltime;

            int m = _textSurfaceMultiplier;
            int vsPitch = vs.Pitch;

            switch (dir)
            {
                case 0:
                    //up
                    {
                        var y = 1 + step;
                        while (y < vs.Height)
                        {
                            if (_townsScreen != null)
                            {
                                TownsDrawStripToScreen(vs, 0, vs.TopLine + vs.Height - step, 0, y - step, vs.Width, step);
                            }
                            else
                            {
                                MoveScreen(0, -step, vs.Height);

                                var src = vs.Surfaces[0].Pixels;
                                _gfxManager.CopyRectToScreen(src, vsPitch,
                                    0, y - step,
                                    0, (vs.Height - step) * m,
                                    vs.Width * m, step * m);
                                _gfxManager.UpdateScreen();
                            }
                            WaitForTimer(delay);
                            y += step;
                        }
                    }
                    break;
                case 1:
                    // down
                    {
                        var y = 1 + step;
                        while (y < vs.Height)
                        {
                            MoveScreen(0, step, vs.Height);
                            if (_townsScreen != null)
                            {
                                TownsDrawStripToScreen(vs, 0, vs.TopLine, 0, vs.Height - y, vs.Width, step);
                            }
                            else
                            {
                                var src = vs.Surfaces[0].Pixels;
                                _gfxManager.CopyRectToScreen(src,
                                    vsPitch,
                                    0, vs.Height - y,
                                    0, 0,
                                    vs.Width * m, step * m);
                                _gfxManager.UpdateScreen();
                            }
                            WaitForTimer(delay);
                            y += step;
                        }
                    }
                    break;
                case 2:
                    // left
                    {
                        var x = 1 + step;
                        while (x < vs.Width)
                        {
                            MoveScreen(-step, 0, vs.Height);

                            if (_townsScreen != null)
                            {
                                TownsDrawStripToScreen(vs, vs.Width - step, vs.TopLine, x - step, 0, step, vs.Height);
                            }
                            else
                            {
                                var src = vs.Surfaces[0].Pixels;
                                _gfxManager.CopyRectToScreen(src,
                                    vsPitch,
                                    x - step, 0,
                                    (vs.Width - step) * m, 0,
                                    step * m, vs.Height * m);
                                _gfxManager.UpdateScreen();
                            }

                            WaitForTimer(delay);
                            x += step;
                        }
                    }
                    break;
                case 3:
                    // right
                    {
                        var x = 1 + step;
                        while (x < vs.Width)
                        {
                            MoveScreen(step, 0, vs.Height);
                            if (_townsScreen != null)
                            {
                                TownsDrawStripToScreen(vs, 0, vs.TopLine, vs.Width - x, 0, step, vs.Height);
                            }
                            else
                            {
                                var src = vs.Surfaces[0].Pixels;
                                _gfxManager.CopyRectToScreen(src,
                                    vsPitch,
                                    vs.Width - x, 0,
                                    0, 0,
                                    step, vs.Height);
                                _gfxManager.UpdateScreen();
                            }

                            WaitForTimer(delay);
                            x += step;
                        }
                    }
                    break;
            }
        }