//
// RecomputeSeg
//
// Fill in the fields 'angle', 'len', 'pdx', 'pdy', etc...
//
void RecomputeSeg(seg_t *seg)
{
seg->psx = seg->start->x;
seg->psy = seg->start->y;
seg->pex = seg->end->x;
seg->pey = seg->end->y;
seg->pdx = seg->pex - seg->psx;
seg->pdy = seg->pey - seg->psy;
seg->p_length = UtilComputeDist(seg->pdx, seg->pdy);
seg->p_angle = UtilComputeAngle(seg->pdx, seg->pdy);
if (seg->p_length <= 0)
InternalError("Seg %p has zero p_length.", seg);
seg->p_perp = seg->psy * seg->pdx - seg->psx * seg->pdy;
seg->p_para = -seg->psx * seg->pdx - seg->psy * seg->pdy;
}
//
// VertexCheckOpen
//
sector_t * VertexCheckOpen(vertex_t *vert, float_g dx, float_g dy)
{
wall_tip_t *tip;
angle_g angle = UtilComputeAngle(dx, dy);
// first check whether there's a wall_tip that lies in the exact
// direction of the given direction (which is relative to the
// vertex).
for (tip=vert->tip_set; tip; tip=tip->next)
{
if (fabs(tip->angle - angle) < ANG_EPSILON ||
fabs(tip->angle - angle) > (360.0 - ANG_EPSILON))
{
// yes, found one
return NULL;
}
}
// OK, now just find the first wall_tip whose angle is greater than
// the angle we're interested in. Therefore we'll be on the RIGHT
// side of that wall_tip.
for (tip=vert->tip_set; tip; tip=tip->next)
{
if (angle + ANG_EPSILON < tip->angle)
{
// found it
return tip->right;
}
if (! tip->next)
{
// no more tips, thus we must be on the LEFT side of the tip
// with the largest angle.
return tip->left;
}
}
InternalError("Vertex %d has no tips !", vert->index);
return FALSE;
}
static void VertexAddWallTip(vertex_t *vert, float_g dx, float_g dy,
sector_t *left, sector_t *right)
{
wall_tip_t *tip = NewWallTip();
wall_tip_t *after;
tip->angle = UtilComputeAngle(dx, dy);
tip->left = left;
tip->right = right;
// find the correct place (order is increasing angle)
for (after=vert->tip_set; after && after->next; after=after->next)
{ }
while (after && tip->angle + ANG_EPSILON < after->angle)
after = after->prev;
// link it in
tip->next = after ? after->next : vert->tip_set;
tip->prev = after;
if (after)
{
if (after->next)
after->next->prev = tip;
after->next = tip;
}
else
{
if (vert->tip_set)
vert->tip_set->prev = tip;
vert->tip_set = tip;
}
}
