Function ChopWindingInPlace

code/qcommon/cm_polylib.cpp:188–282

============= ChopWindingInPlace ============= */

=============
*/
void ChopWindingInPlace (winding_t **inout, vec3_t normal, vec_t dist, vec_t epsilon)
{
	winding_t	*in;
	float	dists[MAX_POINTS_ON_WINDING+4] = { 0 };
	int		sides[MAX_POINTS_ON_WINDING+4] = { 0 };
	int		counts[3];
	static	float	dot;		// VC 4.2 optimizer bug if not static
	int		i, j;
	float	*p1, *p2;
	vec3_t	mid;
	winding_t	*f;
	int		maxpts;

	in = *inout;
	counts[0] = counts[1] = counts[2] = 0;

// determine sides for each point
	for (i=0 ; i<in->numpoints ; i++)
	{
		dot = DotProduct (in->p[i], normal);
		dot -= dist;
		dists[i] = dot;
		if (dot > epsilon)
			sides[i] = SIDE_FRONT;
		else if (dot < -epsilon)
			sides[i] = SIDE_BACK;
		else
		{
			sides[i] = SIDE_ON;
		}
		counts[sides[i]]++;
	}
	sides[i] = sides[0];
	dists[i] = dists[0];

	if (!counts[0])
	{
		FreeWinding (in);
		*inout = NULL;
		return;
	}
	if (!counts[1])
		return;		// inout stays the same

	maxpts = in->numpoints+4;	// cant use counts[0]+2 because
								// of fp grouping errors

	f = AllocWinding (maxpts);

	for (i=0 ; i<in->numpoints ; i++)
	{
		p1 = in->p[i];

		if (sides[i] == SIDE_ON)
		{
			VectorCopy (p1, f->p[f->numpoints]);
			f->numpoints++;
			continue;