2 files changed, 62 insertions, 0 deletions
diff --git a/src/global-coords.cpp b/src/global-coords.cpp
index 17b8d7fd..694447c1 100644
--- a/src/global-coords.cpp
+++ b/src/global-coords.cpp
@@ -1,4 +1,7 @@
 #include "global-coords.hpp"
+#include "compat/defs.hpp"
+#include <array>
+#include <algorithm>
 
 namespace floormat {
 
@@ -33,6 +36,37 @@ static_assert(g1 - g2 == Vector2i(0, 1));
 static_assert((g1 + Vector2i(0, -1)).chunk() == g2.chunk());
 static_assert(g1 + Vector2i(0, -1) == g2);
 
+constexpr bool test_comparison1()
+{
+    auto a = point{{2, 8, 2}, {0, 0}};
+    auto b = point{{1, 1, 2}, {9, 1}};
+    auto c = point{{1, 0, 2}, {1, 2}};
+    auto d = point{{1, 9, 1}, {1, 9}};
+    auto e = point{{3, 1, 2}, {0, 0}};
+    auto f = point{{9, 8, 0}, {9, 9}};
+    auto g = point{{1, 9, 1}, {9, 0}};
+
+    const auto sorted = std::array{
+        f, g, d, c, b, e, a,
+    };
+    auto array1 = std::array{
+        a, b, c, d, e, f, g,
+    };
+    auto array2 = std::array {
+        a, c, e, g, b, d, f,
+    };
+
+    std::sort(array1.begin(), array1.end());
+    fm_assert(array1 == sorted);
+
+    std::sort(array2.begin(), array2.end());
+    fm_assert(array2 == sorted);
+
+    return true;
+}
+
+static_assert(test_comparison1());
+
 } // namespace
 
 } // namespace floormat
diff --git a/src/global-coords.hpp b/src/global-coords.hpp
index 4d420534..31481ba0 100644
--- a/src/global-coords.hpp
+++ b/src/global-coords.hpp
@@ -1,6 +1,7 @@
 #pragma once
 #include "local-coords.hpp"
 #include "compat/assert.hpp"
+#include <compare>
 #include <concepts>
 #include <Magnum/Magnum.h>
 #include <Magnum/Math/Vector2.h>
@@ -115,6 +116,15 @@ public:
     constexpr Vector2i operator-(global_coords other) const noexcept;
 };
 
+struct point
+{
+    global_coords coord;
+    Vector2b offset;
+
+    constexpr bool operator==(const point&) const = default;
+    friend constexpr std::strong_ordering operator<=>(const point& a, const point& b) noexcept;
+};
+
 constexpr local_coords global_coords::local() const noexcept
 {
     return { uint8_t(x & 0x0f), uint8_t(y & 0x0f), };
@@ -177,4 +187,22 @@ constexpr Vector2i global_coords::operator-(global_coords other) const noexcept
     return to_signed() - other.to_signed();
 }
 
+constexpr std::strong_ordering operator<=>(const point& p1, const point& p2) noexcept
+{
+    auto c1 = p1.coord.to_signed3(), c2 = p2.coord.to_signed3();
+
+    if (auto val = c1.z() <=> c2.z(); val != std::strong_ordering::equal)
+        return val;
+    if (auto val = c1.y() <=> c2.y(); val != std::strong_ordering::equal)
+        return val;
+    if (auto val = c1.x() <=> c2.x(); val != std::strong_ordering::equal)
+        return val;
+    if (auto val = p1.offset.y() <=> p2.offset.y(); val != std::strong_ordering::equal)
+        return val;
+    if (auto val = p1.offset.x() <=> p2.offset.x(); val != std::strong_ordering::equal)
+        return val;
+
+    return std::strong_ordering::equal;
+}
+
 } // namespace floormat