public static int ClipSegmentToLine(out ClipVertex[] vOut, ClipVertex[] vIn,
Vec2 normal, float offset)
{
if (vIn.Length != 2)
{
Box2DXDebug.ThrowBox2DXException("vIn should contain 2 element, but contains " + vIn.Length.ToString());
}
vOut = new ClipVertex[2];
// Start with no output points
int numOut = 0;
// Calculate the distance of end points to the line
float distance0 = Vec2.Dot(normal, vIn[0].V) - offset;
float distance1 = Vec2.Dot(normal, vIn[1].V) - offset;
// If the points are behind the plane
if (distance0 <= 0.0f)
{
vOut[numOut++] = vIn[0];
}
if (distance1 <= 0.0f)
{
vOut[numOut++] = vIn[1];
}
// If the points are on different sides of the plane
if (distance0 * distance1 < 0.0f)
{
// Find intersection point of edge and plane
float interp = distance0 / (distance0 - distance1);
vOut[numOut].V = vIn[0].V + interp * (vIn[1].V - vIn[0].V);
if (distance0 > 0.0f)
{
vOut[numOut].ID = vIn[0].ID;
}
else
{
vOut[numOut].ID = vIn[1].ID;
}
++numOut;
}
return(numOut);
}
