this was a shitload of code just for drawing one line xD

Display.cpp

@@ -1,16 +1,67 @@
 
-// make sure sfml is installed:
-// linux - sudo apt-get install libsfml-dev
-// windows - manual dl from https://www.sfml-dev.org/download.php
-#include <SFML/Graphics.hpp>
 #include <iostream>
+#include <chrono>
+#include <thread>
 
 #include "Display.h"
 #include "Point.h"
+#include "Utility.h"
 
+#define RADIUS 10.f
+
+Display::Display()
+{
+    if (!m_font.loadFromFile("arial.ttf"))
+    {
+        std::cerr << "font arial.ttf could not be loaded!" << std::endl;
+    }
+
+    m_textStatus.setPosition(OFFSET, HEIGHT - 2*OFFSET);
+    m_textStatus.setFont(m_font);
+    m_textStatus.setString("initializing...");
+    m_textStatus.setCharacterSize(12);
+    m_textStatus.setFillColor(sf::Color::Black);
+}
+
+void Display::drawPoint(sf::RenderWindow& window, size_t index)
+{
+    Point &pt = m_points[index];
+    sf::CircleShape shape(RADIUS);
+    //shape.setOrigin(RADIUS, RADIUS); // handle with origin or manually calc position
+    shape.setPosition(pt.x() - RADIUS, pt.y() - RADIUS);
+    shape.setFillColor(sf::Color::Green);
+    shape.setOutlineThickness(1.f);
+    shape.setOutlineColor(sf::Color::Black);
+    window.draw(shape);
+
+    sf::Text label;
+    label.setPosition(pt.x() - RADIUS/2, pt.y() - RADIUS/2 - 3);
+    label.setFont(m_font);
+    label.setString(std::to_string(index));
+    label.setCharacterSize(12);
+    label.setFillColor(sf::Color::Black);
+    window.draw(label);
+}
+
+// multiple options possible:
+// a) draw every frame, using elapsed time for updates
+//      --> not really needed because we have no animations... also uses a lot of performance
+// b) checking every frame if elapsed time since last tick is larger than a specified offset, then draw the field
+//      --> mostly doing nothing but still uses a lot of performance O_o
+// c) just start a simple (c++11 <3) non-busy sleep
+//      --> may delay user input / events but don't care atm :p
 void Display::show()
 {
-    sf::RenderWindow window(sf::VideoMode(WIDTH, HEIGHT), "SFML works!");
+    sf::ContextSettings settings;
+    settings.antialiasingLevel = 4;
+
+    sf::RenderWindow window(sf::VideoMode(WIDTH, HEIGHT), "ALGO Prog2: Quickhull - visualization", sf::Style::Default, settings);
+    // b)
+    //window.setFramerateLimit(0.2);
+
+    //sf::Clock clock;
+    //sf::Time timeSinceLastUpdate = sf::Time::Zero;
+    //sf::Time frameTime = sf::seconds(2); //sf::seconds(1.f / 60.f)
     while (window.isOpen())
     {
         sf::Event event;
@@ -20,18 +71,95 @@ void Display::show()
                 window.close();
         }
 
-        window.clear();
-        for (auto &pt : m_points)
+        std::cout << "entering gameloop" << std::endl;
+
+        /* b)
+        timeSinceLastUpdate += clock.restart();
+        // only handle every few seconds because we need no animations
+        if (timeSinceLastUpdate > frameTime)
         {
-            sf::CircleShape shape(10.f);
-            shape.setPosition(pt.x(), pt.y());
-            shape.setFillColor(sf::Color::Green);
-            window.draw(shape);
+            // start by getting the most left and right point
+            timeSinceLastUpdate -= frameTime;
+        }*/
+
+        // a)
+        //update(elapsed);
+        update();
+
+        window.clear(sf::Color::White);
+
+        // TODO: refactor -> parse into sf::Vertices or Shapes
+        // always print remaining points
+        size_t points = m_points.size();
+        for (size_t i = 0; i < points; ++i)
+        {
+            drawPoint(window, i);
         }
+
+        // draw already calculated hull
+        //if (step >= 1)
+        {
+            //window.draw(&m_hull[0], m_hull.size(), sf::Lines);
+            window.draw(&m_hull[0], m_hull.getVertexCount(), m_hull.getPrimitiveType());
+        }
+
+        window.draw(m_textStatus);
+
         window.display();
+
+        // c)
+        // choose a simple sleep 
+        std::this_thread::sleep_for(std::chrono::milliseconds(2000));
     }
 }
 
+void Display::update()
+{
+    // TODO: maybe include Akl–Toussaint heuristic first?
+    // https://en.wikipedia.org/wiki/Convex_hull_algorithms#Akl%E2%80%93Toussaint_heuristic
+    if (m_curStep == 1)
+    {
+        // first step: select min - max x coordinates
+        m_textStatus.setString("step " + std::to_string(m_curStep) + ": select min - max x coordinates...");
+        std::pair<Point, Point> minmax = getMinMaxX(m_points);
+        std::cout << "min: " << minmax.first.x() << ", " << minmax.first.y() <<
+            ", max: " << minmax.second.x() << ", " << minmax.second.y() << std::endl;
+
+        m_hull.setPrimitiveType(sf::Lines);
+        m_hull.append(sf::Vertex(sf::Vector2f(minmax.first.x(), minmax.first.y()), sf::Color::Blue));
+        m_hull.append(sf::Vertex(sf::Vector2f(minmax.second.x(), minmax.second.y()), sf::Color::Blue));
+    }
+    else if (m_curStep == 2)
+    {
+        // second step: split board and find furthest point
+        m_textStatus.setString("step " + std::to_string(m_curStep) + ": split board and find furthest point...");
+    }
+    else if (m_curStep == 3)
+    {
+        // third step: draw triangle, remove inner points
+        m_textStatus.setString("step " + std::to_string(m_curStep) + ": draw triangle, remove inner points...");
+    }
+    else if (m_curStep == 4)
+    {
+        // fourth step: remove inner points
+        m_textStatus.setString("step " + std::to_string(m_curStep) + ": remove inner points...");
+    }
+    else if (m_curStep == 5)
+    {
+        // fourth step: remove inner points
+        m_textStatus.setString("step " + std::to_string(m_curStep) + ": finished calculating convex hull");
+    }
+
+    m_curStep++;
+    // if finished removing inner points and there are still points left -> repeat from step 2
+    // TODO: 
+    if (m_curStep == 5 && m_points.size() > 0)
+    {
+        m_curStep = 2;
+    }
+
+}
+
 void Display::setData(std::vector<Point> pts)
 {
     m_points = pts;

Display.h

@@ -1,17 +1,37 @@
 #pragma once
+#ifndef DISPLAY_H
+
+// make sure sfml is installed:
+// linux - sudo apt-get install libsfml-dev
+// windows - manual dl from https://www.sfml-dev.org/download.php
+#include <SFML/Graphics.hpp>
 
 class Point;
 
+#define OFFSET 10
 #define WIDTH 800
 #define HEIGHT 600
 
 class Display
 {
 private:
+    sf::Font m_font;
+    sf::Text m_textStatus;
+
     std::vector<Point> m_points;
+    //std::vector<sf::Vertex> m_hull;
+    sf::VertexArray m_hull;
+
+    void drawPoint(sf::RenderWindow &, size_t);
+
+    int m_curStep = 0;
+    void update();
 
 public:
+    Display();
+
     void show();
 
     void setData (std::vector<Point>);
-};
+};
+#endif // DISPLAY_H

README.md

@@ -1,2 +1,10 @@
 # quickhull
 
+## TODO:
+
+- Point class
+
+    - adding "features" such as "IsInTriangle", ... ?
+
+    - direct member access instead of getters?
+