void Winding::Divide(const dplane_t& split, Winding** front, Winding** back)
{
vec_t dists[MAX_POINTS_ON_WINDING];
int sides[MAX_POINTS_ON_WINDING];
int counts[3];
vec_t dot;
int i, j;
int maxpts;
counts[0] = counts[1] = counts[2] = 0;
// determine sides for each point
for (i = 0; i < m_NumPoints; i++)
{
dot = DotProduct(m_Points[i], split.normal);
dot -= split.dist;
dists[i] = dot;
if (dot > ON_EPSILON)
{
sides[i] = SIDE_FRONT;
}
else if (dot < -ON_EPSILON)
{
sides[i] = SIDE_BACK;
}
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
*front = *back = NULL;
if (!counts[0])
{
*back = this; // Makes this function non-const
return;
}
if (!counts[1])
{
*front = this; // Makes this function non-const
return;
}
maxpts = m_NumPoints + 4; // can't use counts[0]+2 because
// of fp grouping errors
Winding* f = new Winding(maxpts);
Winding* b = new Winding(maxpts);
*front = f;
*back = b;
f->m_NumPoints = 0;
b->m_NumPoints = 0;
for (i = 0; i < m_NumPoints; i++)
{
vec_t* p1 = m_Points[i];
if (sides[i] == SIDE_ON)
{
VectorCopy(p1, f->m_Points[f->m_NumPoints]);
VectorCopy(p1, b->m_Points[b->m_NumPoints]);
f->m_NumPoints++;
b->m_NumPoints++;
continue;
}
else if (sides[i] == SIDE_FRONT)
{
VectorCopy(p1, f->m_Points[f->m_NumPoints]);
f->m_NumPoints++;
}
else if (sides[i] == SIDE_BACK)
{
VectorCopy(p1, b->m_Points[b->m_NumPoints]);
b->m_NumPoints++;
}
if (sides[i + 1] == SIDE_ON || sides[i + 1] == sides[i])
{
continue;
}
// generate a split point
vec3_t mid;
unsigned int tmp = i + 1;
if (tmp >= m_NumPoints)
{
tmp = 0;
}
vec_t* p2 = m_Points[tmp];
dot = dists[i] / (dists[i] - dists[i + 1]);
for (j = 0; j < 3; j++)
{ // avoid round off error when possible
if (split.normal[j] < 1.0 - NORMAL_EPSILON)
{
if (split.normal[j] > -1.0 + NORMAL_EPSILON)
{
mid[j] = p1[j] + dot * (p2[j] - p1[j]);
}
else
{
mid[j] = -split.dist;
}
}
else
{
mid[j] = split.dist;
}
}
VectorCopy(mid, f->m_Points[f->m_NumPoints]);
VectorCopy(mid, b->m_Points[b->m_NumPoints]);
f->m_NumPoints++;
b->m_NumPoints++;
}
if (f->m_NumPoints > maxpts || b->m_NumPoints > maxpts)
{
Error("Winding::Divide : points exceeded estimate");
}
f->RemoveColinearPoints();
b->RemoveColinearPoints();
}
void Winding::Clip(const vec3_t normal, const vec_t dist, Winding** front, Winding** back)
{
vec_t dists[MAX_POINTS_ON_WINDING + 4];
int sides[MAX_POINTS_ON_WINDING + 4];
int counts[3];
vec_t dot;
unsigned int i, j;
unsigned int maxpts;
counts[0] = counts[1] = counts[2] = 0;
// determine sides for each point
for (i = 0; i < m_NumPoints; i++)
{
dot = DotProduct(m_Points[i], normal);
dot -= dist;
dists[i] = dot;
if (dot > ON_EPSILON)
{
sides[i] = SIDE_FRONT;
}
else if (dot < -ON_EPSILON)
{
sides[i] = SIDE_BACK;
}
else
{
sides[i] = SIDE_ON;
}
counts[sides[i]]++;
}
sides[i] = sides[0];
dists[i] = dists[0];
if (!counts[0])
{
*front = NULL;
*back = new Winding(*this);
return;
}
if (!counts[1])
{
*front = new Winding(*this);
*back = NULL;
return;
}
maxpts = m_NumPoints + 4; // can't use counts[0]+2 because
// of fp grouping errors
Winding* f = new Winding(maxpts);
Winding* b = new Winding(maxpts);
*front = f;
*back = b;
f->m_NumPoints = 0;
b->m_NumPoints = 0;
for (i = 0; i < m_NumPoints; i++)
{
vec_t* p1 = m_Points[i];
if (sides[i] == SIDE_ON)
{
VectorCopy(p1, f->m_Points[f->m_NumPoints]);
VectorCopy(p1, b->m_Points[b->m_NumPoints]);
f->m_NumPoints++;
b->m_NumPoints++;
continue;
}
else if (sides[i] == SIDE_FRONT)
{
VectorCopy(p1, f->m_Points[f->m_NumPoints]);
f->m_NumPoints++;
}
else if (sides[i] == SIDE_BACK)
{
VectorCopy(p1, b->m_Points[b->m_NumPoints]);
b->m_NumPoints++;
}
if ((sides[i + 1] == SIDE_ON) | (sides[i + 1] == sides[i])) // | instead of || for branch optimization
{
continue;
}
// generate a split point
vec3_t mid;
unsigned int tmp = i + 1;
if (tmp >= m_NumPoints)
{
tmp = 0;
}
vec_t* p2 = m_Points[tmp];
dot = dists[i] / (dists[i] - dists[i + 1]);
#if 0
for (j = 0; j < 3; j++)
{ // avoid round off error when possible
if (normal[j] < 1.0 - NORMAL_EPSILON)
{
if (normal[j] > -1.0 + NORMAL_EPSILON)
{
mid[j] = p1[j] + dot * (p2[j] - p1[j]);
}
else
{
mid[j] = -dist;
}
}
else
{
mid[j] = dist;
}
}
#else
for (j = 0; j < 3; j++)
{ // avoid round off error when possible
if (normal[j] == 1)
mid[j] = dist;
else if (normal[j] == -1)
mid[j] = -dist;
else
mid[j] = p1[j] + dot * (p2[j] - p1[j]);
}
#endif
VectorCopy(mid, f->m_Points[f->m_NumPoints]);
VectorCopy(mid, b->m_Points[b->m_NumPoints]);
f->m_NumPoints++;
b->m_NumPoints++;
}
if ((f->m_NumPoints > maxpts) | (b->m_NumPoints > maxpts)) // | instead of || for branch optimization
{
Error("Winding::Clip : points exceeded estimate");
}
if ((f->m_NumPoints > MAX_POINTS_ON_WINDING) | (b->m_NumPoints > MAX_POINTS_ON_WINDING)) // | instead of || for branch optimization
{
Error("Winding::Clip : MAX_POINTS_ON_WINDING");
}
f->RemoveColinearPoints();
b->RemoveColinearPoints();
}
