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#include "triangle.h"
Triangle::Triangle(double _x0, double _y0, double _x1, double _y1, double _x2, double _y2)
{
x0 = _x0;
y0 = _y0;
if ((_x1 - _x0)*(_y1 + _y0) + (_x2-_x1)*(_y2+_y1) + (_x0-_x2)*(_y0+_y2) < 0)
{
x1 = _x1;
x2 = _x2;
y1 = _y1;
y2 = _y2;
} else {
x1 = _x2;
x2 = _x1;
y1 = _y2;
y2 = _y1;
}
// Calculate line test constants
a1 = y1 - y0;
b1 = x0 - x1;
c1 = -y0*b1 - x0*a1;
a2 = y2 - y1;
b2 = x1 - x2;
c2 = -y1*b2 - x1*a2;
a3 = y0 - y2;
b3 = x2 - x0;
c3 = -y2*b3 - x2*a3;
// Extent
minx = std::min(x0, std::min(x1, x2));
miny = std::min(y0, std::min(y1, y2));
maxx = std::max(x0, std::max(x1, x2));
maxy = std::max(y0, std::max(y1, y2));
}
bool Triangle::in_bounds(double x, double y) const
{
return ((x*a1+y*b1+c1 <= 0) && (x*a2+y*b2+c2 <= 0) && (x*a3+y*b3+c3 <= 0));
}
void Triangle::random_point(double& x, double& y) const
{
for (;;)
{
double _x = (rand() % (int)(maxx-minx))+minx;
double _y = (rand() % (int)(maxy-miny))+miny;
if (in_bounds(_x, _y))
{
x = _x;
y = _y;
break;
}
}
}
void Triangle::random_vertex(double& x, double& y) const
{
switch (rand()%3)
{
case 0:
{
x = x0;
y = y0;
break;
}
case 1:
{
x = x1;
y = y1;
break;
}
case 2:
{
x = x2;
y = y2;
break;
}
}
}
double Triangle::getX0() const
{
return x0;
}
double Triangle::getX1() const
{
return x1;
}
double Triangle::getX2() const
{
return x2;
}
double Triangle::getY0() const
{
return y0;
}
double Triangle::getY1() const
{
return y1;
}
double Triangle::getY2() const
{
return y2;
}
Matrix3x3 affineTransform(Triangle from, Triangle to)
{
Matrix3x3 A {{from.getX0(), from.getY0(), 1}, {from.getX1(), from.getY1(), 1}, {from.getX2(), from.getY2(), 1}};
Matrix3x3 B {{to.getX0(), to.getY0(), 1}, {to.getX1(), to.getY1(), 1}, {to.getX2(), to.getY2(), 1}};
return B * A.inv();
}
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