Reorganize game code

examples/simple_game/geometry.hpp

@@ -0,0 +1,99 @@
+#ifndef INC_6502_C_GEOMETRY_HPP
+#define INC_6502_C_GEOMETRY_HPP
+
+#include <cstdint>
+
+namespace geometry {
+struct point
+{
+  std::uint8_t x;
+  std::uint8_t y;
+
+  [[nodiscard]] constexpr auto operator<=>(const point &other) const = default;
+  //  [[nodiscard]] constexpr bool operator==(const point &other) const = default;
+  //  [[nodiscard]] constexpr bool operator!=(const point &other) const = default;
+};
+
+constexpr point operator+(const point &lhs, const point &rhs) noexcept
+{
+  return point{ static_cast<std::uint8_t>(lhs.x + rhs.x), static_cast<std::uint8_t>(lhs.y + rhs.y) };
+}
+
+struct size
+{
+  std::uint8_t width;
+  std::uint8_t height;
+  [[nodiscard]] constexpr bool operator==(const size &other) const = default;
+  [[nodiscard]] constexpr bool operator!=(const size &other) const = default;
+};
+
+struct rect
+{
+  [[nodiscard]] constexpr std::uint8_t left() const noexcept { return tl.x; }
+  [[nodiscard]] constexpr std::uint8_t top() const noexcept { return tl.y; }
+  [[nodiscard]] constexpr std::uint8_t bottom() const noexcept
+  {
+    return static_cast<std::uint8_t>(tl.y + size_.height - 1);
+  }
+  [[nodiscard]] constexpr std::uint8_t right() const noexcept
+  {
+    return static_cast<std::uint8_t>(tl.x + size_.width - 1);
+  }
+
+  [[nodiscard]] constexpr const point &top_left() const noexcept { return tl; }
+  [[nodiscard]] constexpr point bottom_right() const noexcept { return point{ right(), bottom() }; }
+  [[nodiscard]] constexpr point bottom_left() const noexcept { return point{ left(), bottom() }; }
+  [[nodiscard]] constexpr point top_right() const noexcept { return point{ right(), top() }; }
+  [[nodiscard]] constexpr std::uint8_t width() const noexcept { return size_.width; }
+  [[nodiscard]] constexpr std::uint8_t height() const noexcept { return size_.height; }
+
+  [[nodiscard]] constexpr const auto &size() const noexcept { return size_; }
+
+  [[nodiscard]] constexpr auto centered() const noexcept
+  {
+    return rect{
+      { static_cast<std::uint8_t>((40 - size_.width) / 2), static_cast<std::uint8_t>((20 - size_.height) / 2) }, size_
+    };
+  }
+
+  [[nodiscard]] constexpr bool intersects(const rect &other) const noexcept
+  {
+    const auto my_tl = top_left();
+    const auto my_br = bottom_right();
+
+    const auto other_tl = other.top_left();
+    const auto other_br = other.bottom_right();
+
+    return my_tl <= other_tl && my_br >= other_br;
+  };
+
+  point tl;
+  geometry::size size_;
+};
+
+struct point_in_size
+{
+  point p;
+  size s;
+
+  constexpr auto &operator++() noexcept
+  {
+    ++p.x;
+    if (p.x == s.width) {
+      p.x = 0;
+      ++p.y;
+    }
+    return *this;
+  }
+  [[nodiscard]] constexpr bool operator==(const point_in_size &other) const = default;
+  [[nodiscard]] constexpr bool operator!=(const point_in_size &other) const = default;
+  [[nodiscard]] constexpr const point &operator*() const { return p; }
+};
+
+
+constexpr auto begin(const size s) { return point_in_size{ { 0, 0 }, s }; }
+
+constexpr auto end(const size s) { return point_in_size{ { 0, s.height }, s }; }
+}// namespace geometry
+
+#endif// INC_6502_C_GEOMETRY_HPP