bool ON_Polyline::CreateStarPolygon(
const ON_Circle& circle,
double other_radius,
int side_count
)
{
bool rc = ( circle.IsValid() && side_count >= 3 && other_radius >= 0.0 )
? true
: false;
if ( rc )
{
SetCapacity(2*side_count+1);
SetCount(2*side_count+1);
double half_a = ON_PI/side_count;
int i;
ON_Circle other_circle = circle;
other_circle.radius = other_radius;
for ( i = 0; i < side_count; i++ )
{
m_a[i*2] = circle.PointAt(half_a*2*i);
m_a[i*2+1] = other_circle.PointAt(half_a*(1+2*i));
}
m_a[side_count*2] = m_a[0];
}
else
Destroy();
return rc;
}
bool ON_Polyline::CreateInscribedPolygon(
const ON_Circle& circle,
int side_count
)
{
bool rc = ( circle.IsValid() && side_count >= 3 ) ? true : false;
if ( rc )
{
SetCapacity(side_count+1);
SetCount(side_count+1);
double a = 2.0*ON_PI/side_count;
int i;
for ( i = 0; i < side_count; i++ )
{
m_a[i] = circle.PointAt(a*i);
}
m_a[side_count] = m_a[0];
}
else
Destroy();
return rc;
}
bool ON_Polyline::CreateCircumscribedPolygon(
const ON_Circle& circle,
int side_count
)
{
bool rc = ( circle.IsValid() && side_count >= 3 ) ? true : false;
if ( rc )
{
SetCapacity(side_count+1);
SetCount(side_count+1);
double half_a = ON_PI/side_count;
int i;
ON_Circle c = circle;
c.radius = circle.radius/cos(half_a);
for ( i = 0; i < side_count; i++ )
{
m_a[i] = c.PointAt(half_a*(1+2*i));
}
m_a[side_count] = m_a[0];
}
else
Destroy();
return rc;
}