static void SortY(ref Vector2 p1, ref Vector2 p2)
{
if (p1.y > p2.y)
{
ASUI.swapPts(ref p1, ref p2);
}
}
static void SortX(ref Vector2 p1, ref Vector2 p2)
{
if (p1.x > p2.x)
{
ASUI.swapPts(ref p1, ref p2);
}
}
public static Result ClipCohSuth(Vector2 min, Vector2 max, ref Vector2 p1, ref Vector2 p2)
{
byte code1, code2;
bool plotLine = false;
Result result = Result.none;
float m = 0;
int iter = 0;
while (result == Result.none && iter < 4)//顶多处理四次 否则出错
{
code1 = encode(p1, min, max);
code2 = encode(p2, min, max);
if (accept(code1, code2))
{
result = plotLine ? Result.processed : Result.origin;//是否经过处理（相交）
}
else
{
if (reject(code1, code2))
{
result = Result.discard;//丢弃
}
else
{
if (inside(code1))//将窗口外的点标为p1
{
ASUI.swapPts(ref p1, ref p2);
ASUI.swapCodes(ref code1, ref code2);
}
if (p2.x != p1.x)//使用斜率m来算出线和裁剪边的相交点
{
m = (p2.y - p1.y) / (p2.x - p1.x);
}
if ((code1 & leftBit) != 0)
{
plotLine = true;
p1.y += (min.x - p1.x) * m;
p1.x = min.x;
}
else if ((code1 & rightBit) != 0)
{
plotLine = true;
p1.y += (max.x - p1.x) * m;
p1.x = max.x;
}
else if ((code1 & bottomBit) != 0)
{
plotLine = true;
if (p2.x != p1.x)//只需要为不垂直的线更新p1.x
{
p1.x += (min.y - p1.y) / m;
}
p1.y = min.y;
}
else if ((code1 & topBit) != 0)
{
plotLine = true;
if (p2.x != p1.x)
{
p1.x += (max.y - p1.y) / m;
}
p1.y = max.y;
}
}
}
iter++;
}
return(result);
}