1 files changed, 123 insertions, 0 deletions

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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();
+}