public void MoveTo(int x1, int y1)
{
m_x1 = x1;
m_y1 = y1;
if (m_clipping)
{
m_f1 = ClipLiangBarsky.Flags(x1, y1, clipBox);
}
}
//--------------------------------------------------------------------
public void LineTo(int x2, int y2)
{
if (m_clipping)
{
int f2 = ClipLiangBarsky.Flags(x2, y2, clipBox);
if ((m_f1 & 10) == (f2 & 10) && (m_f1 & 10) != 0)
{
// Invisible by Y
m_x1 = x2;
m_y1 = y2;
m_f1 = f2;
return;
}
int x1 = m_x1;
int y1 = m_y1;
int f1 = m_f1;
int y3, y4;
int f3, f4;
switch (((f1 & 5) << 1) | (f2 & 5))
{
case 0: // Visible by X
LineClipY(x1, y1, x2, y2, f1, f2);
break;
case 1: // x2 > clip.x2
y3 = y1 + MulDiv(clipBox.Right - x1, y2 - y1, x2 - x1);
f3 = ClipLiangBarsky.GetFlagsY(y3, clipBox);
LineClipY(x1, y1, clipBox.Right, y3, f1, f3);
LineClipY(clipBox.Right, y3, clipBox.Right, y2, f3, f2);
break;
case 2: // x1 > clip.x2
y3 = y1 + MulDiv(clipBox.Right - x1, y2 - y1, x2 - x1);
f3 = ClipLiangBarsky.GetFlagsY(y3, clipBox);
LineClipY(clipBox.Right, y1, clipBox.Right, y3, f1, f3);
LineClipY(clipBox.Right, y3, x2, y2, f3, f2);
break;
case 3: // x1 > clip.x2 && x2 > clip.x2
LineClipY(clipBox.Right, y1, clipBox.Right, y2, f1, f2);
break;
case 4: // x2 < clip.x1
y3 = y1 + MulDiv(clipBox.Left - x1, y2 - y1, x2 - x1);
f3 = ClipLiangBarsky.GetFlagsY(y3, clipBox);
LineClipY(x1, y1, clipBox.Left, y3, f1, f3);
LineClipY(clipBox.Left, y3, clipBox.Left, y2, f3, f2);
break;
case 6: // x1 > clip.x2 && x2 < clip.x1
y3 = y1 + MulDiv(clipBox.Right - x1, y2 - y1, x2 - x1);
y4 = y1 + MulDiv(clipBox.Left - x1, y2 - y1, x2 - x1);
f3 = ClipLiangBarsky.GetFlagsY(y3, clipBox);
f4 = ClipLiangBarsky.GetFlagsY(y4, clipBox);
LineClipY(clipBox.Right, y1, clipBox.Right, y3, f1, f3);
LineClipY(clipBox.Right, y3, clipBox.Left, y4, f3, f4);
LineClipY(clipBox.Left, y4, clipBox.Left, y2, f4, f2);
break;
case 8: // x1 < clip.x1
y3 = y1 + MulDiv(clipBox.Left - x1, y2 - y1, x2 - x1);
f3 = ClipLiangBarsky.GetFlagsY(y3, clipBox);
LineClipY(clipBox.Left, y1, clipBox.Left, y3, f1, f3);
LineClipY(clipBox.Left, y3, x2, y2, f3, f2);
break;
case 9: // x1 < clip.x1 && x2 > clip.x2
y3 = y1 + MulDiv(clipBox.Left - x1, y2 - y1, x2 - x1);
y4 = y1 + MulDiv(clipBox.Right - x1, y2 - y1, x2 - x1);
f3 = ClipLiangBarsky.GetFlagsY(y3, clipBox);
f4 = ClipLiangBarsky.GetFlagsY(y4, clipBox);
LineClipY(clipBox.Left, y1, clipBox.Left, y3, f1, f3);
LineClipY(clipBox.Left, y3, clipBox.Right, y4, f3, f4);
LineClipY(clipBox.Right, y4, clipBox.Right, y2, f4, f2);
break;
case 12: // x1 < clip.x1 && x2 < clip.x1
LineClipY(clipBox.Left, y1, clipBox.Left, y2, f1, f2);
break;
}
m_f1 = f2;
}
else
{
ras.DrawLine(m_x1, m_y1,
x2, y2);
}
m_x1 = x2;
m_y1 = y2;
}