Add SFML example built with CMake

code/mandelbrot_sfml/CMakeLists.txt

@@ -0,0 +1,9 @@
+cmake_minimum_required(VERSION 3.16)
+project(mandelbrot_sfml VERSION 0.1.0)
+
+find_package(SFML 2.5 COMPONENTS graphics REQUIRED)
+
+add_executable(mandelbrot_sfml main.cpp)
+target_compile_options(mandelbrot_sfml PRIVATE -Wall -Wextra -fsanitize=address)
+target_link_libraries(mandelbrot_sfml PRIVATE sfml-graphics)
+target_link_options(mandelbrot_sfml PRIVATE -fsanitize=address)

code/mandelbrot_sfml/main.cpp

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+#include <SFML/Graphics.hpp>
+#include <cassert>
+#include <complex>
+#include <iostream>
+#include <string>
+#include <thread>
+
+using Complex = std::complex<double>;
+
+int mandelbrot(Complex const& c)
+{
+  int i = 0;
+  auto z = c;
+  for (; i != 256 && norm(z) < 4.; ++i) {
+    z = z * z + c;
+  }
+  return i;
+}
+
+auto to_color(int k)
+{
+  return k < 256 ? sf::Color{static_cast<sf::Uint8>(10 * k), 0, 0}
+                 : sf::Color::Black;
+}
+
+class Rendering
+{
+  int m_w;
+  int m_h;
+  std::vector<sf::Color> m_colors;
+
+ public:
+  Rendering(int w, int h) : m_w{w}, m_h{h}, m_colors(w * h)
+  {
+  }
+  sf::Color const& at(int r, int c) const
+  {
+    assert(r >= 0 && r < m_h);
+    assert(c >= 0 && c < m_w);
+    return m_colors[r * m_w + c];
+  }
+  sf::Color& at(int r, int c)
+  {
+    assert(r >= 0 && r < m_h);
+    assert(c >= 0 && c < m_w);
+    return m_colors[r * m_w + c];
+  }
+};
+
+int main()
+{
+  int const display_width{600};
+  int const display_height{600};
+
+  Complex const top_left{-2.3, 1.5};
+  Complex const lower_right{0.8, -1.5};
+  auto const diff = lower_right - top_left;
+
+  auto const delta_x = diff.real() / display_width;
+  auto const delta_y = diff.imag() / display_height;
+
+  sf::RenderWindow window(sf::VideoMode(display_width, display_height),
+                          "Mandelbrot Set");
+
+  Rendering rendering(display_width, display_height);
+
+  sf::RectangleShape point{sf::Vector2f{1.f, 1.f}};
+
+  for (int row = 0; row != display_height; ++row) {
+    for (int column = 0; column != display_width; ++column) {
+      auto k = mandelbrot(top_left + Complex{delta_x * column, delta_y * row});
+      rendering.at(row, column) = to_color(k);
+    }
+  }
+
+  while (window.isOpen()) {
+    sf::Event event;
+    while (window.pollEvent(event)) {
+      if (event.type == sf::Event::Closed) window.close();
+    }
+
+    window.clear();
+
+    for (int row = 0; row != display_height; ++row) {
+      for (int column = 0; column != display_width; ++column) {
+        point.setPosition(column, row);
+        point.setFillColor(rendering.at(row, column));
+        window.draw(point);
+      }
+    }
+
+    window.display();
+
+    using namespace std::chrono_literals;
+    std::this_thread::sleep_for(1000ms);
+  }
+}