void Polygon::Compute_Polygon(int number, Vector3d *points)
{
int i;
DBL x, y, z, d;
Vector3d o, u, v, w, N;
MATRIX a, b;
/* Create polygon data. */
if (Data == NULL)
{
Data = reinterpret_cast<POLYGON_DATA *>(POV_MALLOC(sizeof(POLYGON_DATA), "polygon points"));
Data->References = 1;
Data->Number = number;
Data->Points = reinterpret_cast<Vector2d *>(POV_MALLOC(number*sizeof(Vector2d), "polygon points"));
}
else
{
throw POV_EXCEPTION_STRING("Polygon data already computed.");
}
/* Get polygon's coordinate system (one of the many possible) */
o = points[0];
/* Find valid, i.e. non-zero u vector. */
for (i = 1; i < number; i++)
{
u = points[i] - o;
if (u.lengthSqr() > EPSILON)
{
break;
}
}
if (i == number)
{
Set_Flag(this, DEGENERATE_FLAG);
;// TODO MESSAGE Warning("Points in polygon are co-linear. Ignoring polygon.");
}
/* Find valid, i.e. non-zero v and w vectors. */
for (i++; i < number; i++)
{
v = points[i] - o;
w = cross(u, v);
if ((v.lengthSqr() > EPSILON) && (w.lengthSqr() > EPSILON))
{
break;
}
}
if (i == number)
{
Set_Flag(this, DEGENERATE_FLAG);
;// TODO MESSAGE Warning("Points in polygon are co-linear. Ignoring polygon.");
}
u = cross(v, w);
v = cross(w, u);
u.normalize();
v.normalize();
w.normalize();
MIdentity(a);
MIdentity(b);
a[3][0] = -o[X];
a[3][1] = -o[Y];
a[3][2] = -o[Z];
b[0][0] = u[X];
b[1][0] = u[Y];
b[2][0] = u[Z];
b[0][1] = v[X];
b[1][1] = v[Y];
b[2][1] = v[Z];
b[0][2] = w[X];
b[1][2] = w[Y];
b[2][2] = w[Z];
MTimesC(Trans->inverse, a, b);
MInvers(Trans->matrix, Trans->inverse);
/* Project points onto the u,v-plane (3D --> 2D) */
for (i = 0; i < number; i++)
{
x = points[i][X] - o[X];
y = points[i][Y] - o[Y];
z = points[i][Z] - o[Z];
d = x * w[X] + y * w[Y] + z * w[Z];
if (fabs(d) > ZERO_TOLERANCE)
{
Set_Flag(this, DEGENERATE_FLAG);
;// TODO MESSAGE Warning("Points in polygon are not co-planar. Ignoring polygons.");
}
Data->Points[i][X] = x * u[X] + y * u[Y] + z * u[Z];
Data->Points[i][Y] = x * v[X] + y * v[Y] + z * v[Z];
}
N = Vector3d(0.0, 0.0, 1.0);
MTransNormal(S_Normal, N, Trans);
S_Normal.normalize();
Compute_BBox();
}
void Compute_Polygon(POLYGON *Polyg, int Number, VECTOR *Points)
{
int i;
DBL x, y, z, d;
VECTOR o, u, v, w, N;
MATRIX a, b;
/* Create polygon data. */
if (Polyg->Data == NULL)
{
Polyg->Data = (POLYGON_DATA *)POV_MALLOC(sizeof(POLYGON_DATA), "polygon points");
Polyg->Data->References = 1;
Polyg->Data->Number = Number;
Polyg->Data->Points = (UV_VECT *)POV_MALLOC(Number*sizeof(UV_VECT), "polygon points");
}
else
{
Error("Polygon data already computed.");
}
/* Get polygon's coordinate system (one of the many possible) */
Assign_Vector(o, Points[0]);
/* Find valid, i.e. non-zero u vector. */
for (i = 1; i < Number; i++)
{
VSub(u, Points[i], o);
if (VSumSqr(u) > EPSILON)
{
break;
}
}
if (i == Number)
{
Set_Flag(Polyg, DEGENERATE_FLAG);
Warning(0, "Points in polygon are co-linear. Ignoring polygon.");
}
/* Find valid, i.e. non-zero v and w vectors. */
for (i++; i < Number; i++)
{
VSub(v, Points[i], o);
VCross(w, u, v);
if ((VSumSqr(v) > EPSILON) && (VSumSqr(w) > EPSILON))
{
break;
}
}
if (i == Number)
{
Set_Flag(Polyg, DEGENERATE_FLAG);
Warning(0, "Points in polygon are co-linear. Ignoring polygon.");
}
VCross(u, v, w);
VCross(v, w, u);
VNormalize(u, u);
VNormalize(v, v);
VNormalize(w, w);
MIdentity(a);
MIdentity(b);
a[3][0] = -o[X];
a[3][1] = -o[Y];
a[3][2] = -o[Z];
b[0][0] = u[X];
b[1][0] = u[Y];
b[2][0] = u[Z];
b[0][1] = v[X];
b[1][1] = v[Y];
b[2][1] = v[Z];
b[0][2] = w[X];
b[1][2] = w[Y];
b[2][2] = w[Z];
MTimesC(Polyg->Trans->inverse, a, b);
MInvers(Polyg->Trans->matrix, Polyg->Trans->inverse);
/* Project points onto the u,v-plane (3D --> 2D) */
for (i = 0; i < Number; i++)
{
x = Points[i][X] - o[X];
y = Points[i][Y] - o[Y];
z = Points[i][Z] - o[Z];
d = x * w[X] + y * w[Y] + z * w[Z];
if (fabs(d) > ZERO_TOLERANCE)
{
Set_Flag(Polyg, DEGENERATE_FLAG);
Warning(0, "Points in polygon are not co-planar. Ignoring polygons.");
}
Polyg->Data->Points[i][X] = x * u[X] + y * u[Y] + z * u[Z];
Polyg->Data->Points[i][Y] = x * v[X] + y * v[Y] + z * v[Z];
}
Make_Vector(N, 0.0, 0.0, 1.0);
MTransNormal(Polyg->S_Normal, N, Polyg->Trans);
VNormalizeEq(Polyg->S_Normal);
Compute_Polygon_BBox(Polyg);
}
