adding math utility header

Point.h

@@ -8,12 +8,12 @@ private:
 public:
     Point(float x, float y) : m_x(x), m_y(y) {}
 
-    float x()
+    float x () const
     {
         return m_x;
     }
 
-    float y()
+    float y () const
     {
         return m_y;
     }

Utility.h

@@ -0,0 +1,53 @@
+#pragma once
+#ifndef UTILITY_H
+
+static float sign (Point &p1, Point &p2, Point &p3)
+{
+    return (p1.x() - p3.x()) * (p2.y() - p3.y()) - (p2.x() - p3.x()) * (p1.y() - p3.y());
+}
+
+static bool IsPointInTriangle(Point &pt, Point &p1, Point &p2, Point &p3)
+{
+    float d1 = sign(pt, p1, p2);
+    float d2 = sign(pt, p2, p3);
+    float d3 = sign(pt, p3, p1);
+
+    bool has_neg = (d1 < 0) || (d2 < 0) || (d3 < 0);
+    bool has_pos = (d1 > 0) || (d2 > 0) || (d3 > 0);
+
+    return !(has_neg && has_pos);
+}
+
+static bool SortForMinXMaxY (const Point& a, const Point& b)
+{
+    if (a.x() != b.x())
+    {
+        return (a.x() < b.x());
+    }
+    return (a.y() > b.y());
+}
+
+static bool SortForMinYMaxX(const Point& a, const Point& b)
+{
+    if (a.y() != b.y())
+    {
+        return (a.x() < b.x());
+    }
+    return (a.y() > b.y());
+}
+
+static void sortPoints (std::vector<Point>& pts)
+{
+    std::sort(pts.begin(), pts.end(), SortForMinXMaxY);
+}
+
+// TODO: what happens if all/more points are on hor/vert line? -> sort for x, than y should handle this
+static std::pair<Point, Point> getMinMaxX(std::vector<Point>& pts)
+{
+    // TODO: check if already sorted? assume array is sorted? call sort utility function???
+    //sortPoints(pts);
+    std::sort(pts.begin(), pts.end(), SortForMinXMaxY);
+
+    return std::make_pair(pts[0], pts[pts.size() - 1]);
+}
+#endif // UTILITY_H

main.cpp

@@ -8,6 +8,7 @@
 #include "Display.h"
 #include "Point.h" // TODO: check if there is a usable SFML or c++ class
 #include "Timing.h"
+#include "Utility.h"
 
 // TODOs:
 // - use SFML vec2 instead of Point class
@@ -43,8 +44,8 @@ int main (int argc, char **argv)
         srand(static_cast <unsigned> (0)); // fixed seed for testing
         for (int i = 0; i < valCount; ++i)
         {
-            float x = static_cast <float> (rand()) / (static_cast <float> (RAND_MAX / WIDTH));
-            float y = static_cast <float> (rand()) / (static_cast <float> (RAND_MAX / HEIGHT));
+            float x = OFFSET + static_cast <float> (rand()) / (static_cast <float> (RAND_MAX / (WIDTH - OFFSET)));
+            float y = OFFSET + static_cast <float> (rand()) / (static_cast <float> (RAND_MAX / (HEIGHT - OFFSET)));
             points.push_back(Point(x, y));
         }
     }
@@ -76,7 +77,8 @@ int main (int argc, char **argv)
         }
     }
 
-    // TODO: need sort here?
+    // TODO: sort here, once and for all? xD
+    sortPoints(points);
     for (Point& pt : points)
     {
         std::cout << "pt: " << pt.x() << ", " << pt.y() << std::endl;
@@ -85,6 +87,10 @@ int main (int argc, char **argv)
     if (vis)
     {
         // TODO: use data as ctor argument? pointer?
+
+        // TEST to check SFML coordinate system
+        points.push_back(Point(0, 0));
+
         Display display;
         display.setData(points);
         display.show();