float IndexedTriangle::Compacity(const Point* verts) const
{
if(!verts) return 0.0f;
float P = Perimeter(verts);
if(P==0.0f) return 0.0f;
return (4.0f*PI*Area(verts)/(P*P));
}
//--------------------------------------------------------------------
Real ZFace::Area (const ZVectorCacheArray& v)
// Returns the area of the face
{
Real* ss = Sides(v);
Real p = Perimeter(v)/2;
// Heron's formula
return sqrt (p*(p-ss[0])*(p-ss[1])*(p-ss[2]));
}
//--------------------------------------------------------
double Area(const Point& a, const Point& b,const Point& p)
{
double A, B, C;
A = Length(a, b);
B = Length(b, p);
C = Length(p, a);
double Per = Perimeter(A, B, C) / 2;
return sqrt(Per * (Per - A) * (Per - B) * (Per - C));//шукаєм площу
}
//--------------------------------------------------------------------
Real ZFace::Density (const ZVectorCacheArray& v)
// Returns the Density of the face, which is the fraction of an
// enclosing circle that it fills
{
Real c = Perimeter(v);
Real a = Area(v);
Real r = c/2/GmatMathConstants::PI;
Real pir2 = GmatMathConstants::PI*r*r;
return a/pir2;
}
float3 Polygon::PointOnEdge(float normalizedDistance) const
{
if (p.empty())
return float3::nan;
if (p.size() < 2)
return p[0];
normalizedDistance = Frac(normalizedDistance); // Take modulo 1 so we have the range [0,1[.
float perimeter = Perimeter();
float d = normalizedDistance * perimeter;
for(int i = 0; i < NumVertices(); ++i)
{
LineSegment edge = Edge(i);
float len = edge.Length();
assume(len != 0.f && "Degenerate Polygon detected!");
if (d <= len)
return edge.GetPoint(d / len);
d -= len;
}
mathassert(false && "Polygon::PointOnEdge reached end of loop which shouldn't!");
return p[0];
}
/// radius of its inscribed circle
double Triangle::InRadius() const
{
// r = 2*area/perimeter
return 2*Area()/Perimeter();
}
//------------------------------------------------------------------------------
// Функции вычисления периметра прямоугольника-специализации
double Perimeter(FigRectangle& fr) {
Rectangle& r = fr._spec;
return Perimeter(r);
}
void Compute(void) {
qsort(horizontal, P, sizeof(LINE), compare);
qsort(vertical, P, sizeof(LINE), compare);
L = Perimeter(horizontal) + Perimeter(vertical);
}
