clip.cpp

著名SFC模拟器Snes9x的源代码。

			    {
				// Window 1 has one band
				if (BAND_EMPTY(Win1[0]))
				    Bands [B++] = Win1[0];
				else
				if (Window2Enabled == 1)
				{
				    if (BAND_EMPTY (Win2[0]))
					Bands [B++] = Win2[0];
				    else
				    {
					AND_BANDS(Bands[0], Win1[0], Win2[0]);
					B = 1;
				    }
				}
				else
				{
				    AND_BANDS(Bands[0], Win1[0], Win2[0]);
				    AND_BANDS(Bands[1], Win1[0], Win2[1]);
				    B = 2;
				}
			    }
			    else
			    if (Window2Enabled == 1)
			    {
				if (BAND_EMPTY(Win2[0]))
				    Bands[B++] = Win2[0];
				else
				{
				    // Window 1 has two bands.
				    AND_BANDS(Bands[0], Win1[0], Win2[0]);
				    AND_BANDS(Bands[1], Win1[1], Win2[0]);
				    B = 2;
				}
			    }
			    else
			    {
				// Both windows have two bands.
				AND_BANDS(Bands[0], Win1[0], Win2[0]);
				AND_BANDS(Bands[1], Win1[1], Win2[1]);
				B = 2;
				if (BANDS_INTERSECT(Win1[0], Win2[1]))
				{
				    AND_BANDS(Bands[2], Win1[0], Win2[1]);
				    B = 3;
				}
				else
				if (BANDS_INTERSECT(Win1[1], Win2[0]))
				{
				    AND_BANDS(Bands[2], Win1[1], Win2[0]);
				    B = 3;
				}
			    }
			    break;
			case CLIP_XNOR:
			    invert = !invert;
			    // Fall...

			case CLIP_XOR:
			    if (Window1Enabled == 1 && BAND_EMPTY(Win1[0]))
			    {
				B = Window2Enabled;
				memmove (Bands, Win2,
					 sizeof(Win2[0]) * Window2Enabled);
			    }
			    else
			    if (Window2Enabled == 1 && BAND_EMPTY(Win2[0]))
			    {
				B = Window1Enabled;
				memmove (Bands, Win1,
					 sizeof(Win1[0]) * Window1Enabled);
			    }
			    else
			    {
				uint32 p = 0;
				uint32 points [10];
				uint32 i;

				invert = !invert;
				// Build an array of points (window edges)
				points [p++] = 0;
				for (i = 0; i < Window1Enabled; i++)
				{
				    points [p++] = Win1[i].Left;
				    points [p++] = Win1[i].Right;
				}
				for (i = 0; i < Window2Enabled; i++)
				{
				    points [p++] = Win2[i].Left;
				    points [p++] = Win2[i].Right;
				}
				points [p++] = 256;
				// Sort them
				qsort ((void *) points, p, sizeof (points [0]),
				       IntCompare);
				for (i = 0; i < p; i += 2)
				{
				    if (points [i] == points [i + 1])
					continue;
				    Bands [B].Left = points [i];
				    while (i + 2 < p && 
					   points [i + 1] == points [i + 2])
				    {
					i += 2;
				    }
				    Bands [B++].Right = points [i + 1];
				}
			    }
			    break;
			}
			if (invert)
			{
			    int b;
			    int j = 0;
			    int empty_band_count = 0;

			    // First remove all empty bands from the list.
			    for (b = 0; b < B; b++)
			    {
				if (!BAND_EMPTY(Bands[b]))
				{
				    if (b != j)
					Bands[j] = Bands[b];
				    j++;
				}
				else
				    empty_band_count++;
			    }
			    
			    if (j > 0)
			    {
				if (j == 1)
				{
				    j = 0;
				    // Easy case to deal with, so special case it.

				    if (Bands[0].Left > 0)
				    {
					pClip->Left[j][w] = 0;
					pClip->Right[j++][w] = Bands[0].Left + 1;
				    }
				    if (Bands[0].Right < 256)
				    {
					pClip->Left[j][w] = Bands[0].Right;
					pClip->Right[j++][w] = 256;
				    }
				    if (j == 0)
				    {
					pClip->Left[j][w] = 1;
					pClip->Right[j++][w] = 0;
				    }
				}
				else
				{
				    // Now sort the bands into order
				    B = j;
				    qsort ((void *) Bands, B,
					   sizeof (Bands [0]), BandCompare);

				    // Now invert the area the bands cover
				    j = 0;
				    for (b = 0; b < B; b++)
				    {
					if (b == 0 && Bands[b].Left > 0)
					{
					    pClip->Left[j][w] = 0;
					    pClip->Right[j++][w] = Bands[b].Left + 1;
					}
					else
					if (b == B - 1 && Bands[b].Right < 256)
					{
					    pClip->Left[j][w] = Bands[b].Right;
					    pClip->Right[j++][w] = 256;
					}
					if (b < B - 1)
					{
					    pClip->Left[j][w] = Bands[b].Right;
					    pClip->Right[j++][w] = Bands[b + 1].Left + 1;
					}
				    }
				}
			    }
			    else
			    {
				// Inverting a window that consisted of only
				// empty bands is the whole width of the screen.
				// Needed for Mario Kart's rear-view mirror display.
				if (empty_band_count)
				{
				    pClip->Left[j][w] = 0;
				    pClip->Right[j][w] = 256;
				    j++;
				}
			    }
			    pClip->Count[w] = j;
			}
			else
			{
			    for (int j = 0; j < B; j++)
			    {
				pClip->Left[j][w] = Bands[j].Left;
				pClip->Right[j][w] = Bands[j].Right;
			    }
			    pClip->Count [w] = B;
			}
		    }
		    else
		    {
			// Only one window enabled so no need to perform
			// complex overlap logic...

			if (Window1Enabled)
			{
			    if (invert)
			    {
				int j = 0;

				if (Window1Enabled == 1)
				{
				    if (Win1[0].Left <= Win1[0].Right)
				    {
					if (Win1[0].Left > 0)
					{
					    pClip->Left[j][w] = 0;
					    pClip->Right[j++][w] = Win1[0].Left;
					}
					if (Win1[0].Right < 256)
					{
					    pClip->Left[j][w] = Win1[0].Right;
					    pClip->Right[j++][w] = 256;
					}
					if (j == 0)
					{
					    pClip->Left[j][w] = 1;
					    pClip->Right[j++][w] = 0;
					}
				    }
				    else
				    {
					pClip->Left[j][w] = 0;
					pClip->Right[j++][w] = 256;
				    }
				}
				else
				{
				    pClip->Left [j][w] = Win1[0].Right;
				    pClip->Right[j++][w] = Win1[1].Left;
				}
				pClip->Count [w] = j;
			    }
			    else
			    {
				for (uint32 j = 0; j < Window1Enabled; j++)
				{
				    pClip->Left [j][w] = Win1[j].Left;
				    pClip->Right [j][w] = Win1[j].Right;
				}
				pClip->Count [w] = Window1Enabled;
			    }
			}
			else
			if (Window2Enabled)
			{
			    if (invert)
			    {
				int j = 0;
				if (Window2Enabled == 1)
				{
				    if (Win2[0].Left <= Win2[0].Right)
				    {
					if (Win2[0].Left > 0)
					{
					    pClip->Left[j][w] = 0;
					    pClip->Right[j++][w] = Win2[0].Left;
					}
					if (Win2[0].Right < 256)
					{
					    pClip->Left[j][w] = Win2[0].Right;
					    pClip->Right[j++][w] = 256;
					}
					if (j == 0)
					{
					    pClip->Left[j][w] = 1;
					    pClip->Right[j++][w] = 0;
					}
				    }
				    else
				    {
					pClip->Left[j][w] = 0;
					pClip->Right[j++][w] = 256;
				    }
				}
				else
				{
				    pClip->Left [j][w] = Win2[0].Right;
				    pClip->Right[j++][w] = Win2[1].Left + 1;
				}
				pClip->Count [w] = j;
			    }
			    else
			    {
				for (uint32 j = 0; j < Window2Enabled; j++)
				{
				    pClip->Left [j][w] = Win2[j].Left;
				    pClip->Right [j][w] = Win2[j].Right;
				}
				pClip->Count [w] = Window2Enabled;
			    }
			}
		    }

		    if (w != 5)
		    {
			if (pClip->Count [5])
			{
			    // Colour window enabled. Set the
			    // clip windows for all remaining backgrounds to be
			    // the same as the colour window.
			    if (pClip->Count [w] == 0)
			    {
				pClip->Count [w] = pClip->Count [5];
				for (uint32 i = 0; i < pClip->Count [w]; i++)
				{
				    pClip->Left [i][w] = pClip->Left [i][5];
				    pClip->Right [i][w] = pClip->Right [i][5];
				}
			    }
			    else
			    {
			    pClip->Count [w] = pClip->Count [5];
			    for (uint32 i = 0; i < pClip->Count [w]; i++)
			    {
				if (pClip->Left [i][5] >= pClip->Right [i][5])
				{
				    // Colour window has no range, so other
				    // window will have no range as well.
				    pClip->Left [i][w] = pClip->Left [i][5];
				    pClip->Right [i][w] = pClip->Right [i][5];
				}
				else
				if (pClip->Left [i][w] <= pClip->Right [i][w])
				{
				    // Intersect the bands of the two windows.
				    if (pClip->Count [5] == pClip->Count [w])
				    {
					pClip->Left [i][w] = MAX(pClip->Left [i][w], 
								 pClip->Left [i][5]);
					pClip->Right [i][w] = MIN(pClip->Right [i][w], 
								  pClip->Right [i][5]);
				    }
				}
			    }
			    }
			}
		    }
		} // if (w == 5 | ...
	    } // if (!Settings.DisableGraphicWindows)
	} // for (int w...
    } // for (int c...
}