[nostalgia] Rename common package to geo

src/nostalgia/geo/vec.hpp

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2016 - 2022 Gary Talent (gary@drinkingtea.net). All rights reserved.
+ */
+
+#pragma once
+
+#if __has_include(<imgui.h>)
+#include <imgui.h>
+#endif
+
+#include <ox/std/types.hpp>
+
+namespace nostalgia::geo {
+
+struct Vec2 {
+	float x = 0;
+	float y = 0;
+
+	constexpr Vec2() noexcept = default;
+
+	constexpr Vec2(float pX, float pY) noexcept: x(pX), y(pY) {
+	}
+
+#if __has_include(<imgui.h>)
+	explicit constexpr Vec2(const ImVec2 &v) noexcept: x(v.x), y(v.y) {
+	}
+#endif
+
+	constexpr auto &operator[](std::size_t i) noexcept {
+		return (&x)[i];
+	}
+
+	constexpr const auto &operator[](std::size_t i) const noexcept {
+		return (&x)[i];
+	}
+
+#if __has_include(<imgui.h>)
+	explicit operator ImVec2() const noexcept {
+		return {x, y};
+	}
+#endif
+};
+
+}