From 7f01dc47b0fd322d8c2b3f27eb1a94cd450a26a5 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Mon, 17 Oct 2022 13:28:37 +0200
Subject: a

---
 src/chunk.cpp         |  6 ++++++
 src/chunk.hpp         |  1 +
 src/global-coords.cpp |  9 +++++----
 src/global-coords.hpp | 26 ++++++++++++++++++++++----
 src/world.cpp         | 31 +++++++++++++++++++------------
 src/world.hpp         | 33 +++++++++++----------------------
 6 files changed, 64 insertions(+), 42 deletions(-)

(limited to 'src')

diff --git a/src/chunk.cpp b/src/chunk.cpp
index 95904d81..d8c2d011 100644
--- a/src/chunk.cpp
+++ b/src/chunk.cpp
@@ -4,9 +4,15 @@ namespace floormat {
 
 bool chunk::empty() const
 {
+    if (!_maybe_empty)
+        return false;
+
     for (const tile& x : _tiles)
         if (x.ground_image || x.wall_north || x.wall_west)
+        {
+            _maybe_empty = false;
             return false;
+        }
 
     return true;
 }
diff --git a/src/chunk.hpp b/src/chunk.hpp
index 7ef0bc94..9e41c5fb 100644
--- a/src/chunk.hpp
+++ b/src/chunk.hpp
@@ -41,6 +41,7 @@ struct chunk final
 
 private:
     std::array<tile, TILE_COUNT> _tiles = {};
+    mutable bool _maybe_empty = true;
 };
 
 } // namespace floormat
diff --git a/src/global-coords.cpp b/src/global-coords.cpp
index 997f1c11..e10e921f 100644
--- a/src/global-coords.cpp
+++ b/src/global-coords.cpp
@@ -9,9 +9,10 @@ static_assert(std::is_same_v<decltype(chunk_coords::x), decltype(chunk_coords::y
 
 static_assert(std::is_same_v<decltype(chunk_coords::x), decltype(chunk_coords::y)>);
 
-static_assert(global_coords{{-1, -1}, {2, 3}} == global_coords{((-1 + (1 << 15)) << 4) + 2, ((-1 + (1 << 15)) << 4) + 3});
-static_assert(global_coords{15, 15}.chunk() == global_coords{}.chunk());
-static_assert(global_coords{15, 16}.chunk() != global_coords{}.chunk());
-static_assert(global_coords{(1 + (1<<15)) << 4 | 3, (2 + (1<<15)) << 4 | 4} == global_coords{{1, 2}, {3, 4}});
+static_assert(TILE_MAX_DIM == (1 << 4));
+
+static_assert(global_coords{(int)TILE_MAX_DIM-1, (int)TILE_MAX_DIM-1}.chunk() == global_coords{}.chunk());
+static_assert(global_coords{(int)TILE_MAX_DIM-1, (int)TILE_MAX_DIM}.chunk() != global_coords{}.chunk());
+static_assert(global_coords{(1u + (1<<15)) << 4 | 3, (2u + (1<<15)) << 4 | 4} == global_coords{{1, 2}, {3, 4}});
 
 } // namespace floormat
diff --git a/src/global-coords.hpp b/src/global-coords.hpp
index e51dc6aa..d3c36c96 100644
--- a/src/global-coords.hpp
+++ b/src/global-coords.hpp
@@ -1,6 +1,8 @@
 #pragma once
 #include "local-coords.hpp"
 #include "compat/assert.hpp"
+#include <Magnum/Magnum.h>
+#include <Magnum/Math/Vector2.h>
 
 namespace floormat {
 
@@ -11,31 +13,47 @@ struct chunk_coords final {
 };
 
 struct global_coords final {
-    std::uint32_t x = 0, y = 0;
+    std::uint32_t x = 1 << 15, y = 1 << 15;
 
     constexpr global_coords(chunk_coords c, local_coords xy) :
         x{ std::uint32_t(c.x + (1 << 15)) << 4 | (xy.x & 0x0f) },
         y{ std::uint32_t(c.y + (1 << 15)) << 4 | (xy.y & 0x0f) }
     {}
     constexpr global_coords(std::uint32_t x, std::uint32_t y) noexcept : x{x}, y{y} {}
+    constexpr global_coords(std::int32_t x, std::int32_t y) noexcept :
+          x{std::uint32_t(x + (1 << 15))}, y{std::uint32_t(y + (1 << 15))}
+    {}
     constexpr global_coords() noexcept = default;
 
     constexpr local_coords local() const noexcept;
     constexpr chunk_coords chunk() const noexcept;
 
+    constexpr Vector2i to_signed() const noexcept;
+
     constexpr bool operator==(const global_coords& other) const noexcept = default;
 };
 
 constexpr local_coords global_coords::local() const noexcept
 {
-    return { (std::uint8_t)(x % TILE_MAX_DIM), (std::uint8_t)(y % TILE_MAX_DIM) };
+    return {
+        std::uint8_t(x & 0x0f),
+        std::uint8_t(y & 0x0f),
+    };
 }
 
 constexpr chunk_coords global_coords::chunk() const noexcept
 {
     return {
-        (std::int16_t)(std::int32_t(x >> 4) - (1 << 15)),
-        (std::int16_t)(std::int32_t(y >> 4) - (1 << 15)),
+        std::int16_t((x - (1 << 15)) >> 4),
+        std::int16_t((y - (1 << 15)) >> 4),
+    };
+}
+
+constexpr Vector2i global_coords::to_signed() const noexcept
+{
+    return {
+        std::int32_t(x - (1 << 15)),
+        std::int32_t(y - (1 << 15)),
     };
 }
 
diff --git a/src/world.cpp b/src/world.cpp
index 3057fca8..8337bfba 100644
--- a/src/world.cpp
+++ b/src/world.cpp
@@ -5,7 +5,7 @@ namespace floormat {
 
 struct chunk_pointer_maker final
 {
-    operator std::shared_ptr<chunk>() const { return std::make_shared<chunk>(); }
+    inline operator std::shared_ptr<chunk>() const { return std::make_shared<chunk>(); }
 };
 
 world::world()
@@ -15,22 +15,26 @@ world::world()
 
 std::shared_ptr<chunk> world::operator[](chunk_coords c) noexcept
 {
+    maybe_collect();
+
+    if (_last_chunk)
+    {
+        auto& [ret, pos] = *_last_chunk;
+        if (pos == c)
+            return ret;
+    }
+
     auto [it, inserted] = _chunks.try_emplace(c, chunk_pointer_maker{});
-    const auto ret = it->second;
-    return maybe_collect(), ret;
+    auto ret = it->second;
+    _last_chunk = { ret, c };
+    return ret;
 }
 
-std::shared_ptr<chunk> world::maybe_chunk(chunk_coords c) noexcept
-{
-    if (const auto it = _chunks.find(c); it != _chunks.cend())
-        return it->second;
-    else
-        return nullptr;
-}
 
-std::shared_ptr<const chunk> world::maybe_chunk(chunk_coords c) const noexcept
+std::tuple<std::shared_ptr<chunk>, tile&> world::operator[](global_coords pt) noexcept
 {
-    return const_cast<world&>(*this).maybe_chunk(c);
+    auto c = operator[](pt.chunk());
+    return { c, (*c)[pt.local()] };
 }
 
 bool world::contains(chunk_coords c) const noexcept
@@ -41,6 +45,7 @@ bool world::contains(chunk_coords c) const noexcept
 void world::clear()
 {
     _last_collection = 0;
+    _last_chunk = std::nullopt;
     _chunks.clear();
     _chunks.rehash(initial_capacity);
 }
@@ -61,7 +66,9 @@ void world::collect()
         else
             ++it;
     }
+
     _last_collection = _chunks.size();
+    _last_chunk = std::nullopt;
 }
 
 } // namespace floormat
diff --git a/src/world.hpp b/src/world.hpp
index 1e8469d9..7c256efc 100644
--- a/src/world.hpp
+++ b/src/world.hpp
@@ -1,24 +1,10 @@
 #pragma once
 #include "compat/int-hash.hpp"
 #include "global-coords.hpp"
+#include "tile.hpp"
 #include <unordered_map>
 #include <memory>
-
-namespace std {
-
-template<typename> struct hash;
-
-template<>
-struct hash<floormat::chunk_coords> final
-{
-    constexpr
-    std::size_t operator()(floormat::chunk_coords c) const noexcept
-    {
-        return floormat::int_hash((std::size_t)c.y << 16 | (std::size_t)c.x);
-    }
-};
-
-} // namespace std
+#include <optional>
 
 namespace floormat {
 
@@ -28,20 +14,23 @@ struct world final
 {
     world();
     std::shared_ptr<chunk> operator[](chunk_coords c) noexcept;
-    std::shared_ptr<chunk> maybe_chunk(chunk_coords c) noexcept;
-    std::shared_ptr<const chunk> maybe_chunk(chunk_coords c) const noexcept;
+    std::tuple<std::shared_ptr<chunk>, tile&> operator[](global_coords pt) noexcept;
     bool contains(chunk_coords c) const noexcept;
     void clear();
     void collect();
 
 private:
+    void maybe_collect();
+
     static constexpr std::size_t initial_capacity = 64, collect_every = 32;
     static constexpr float max_load_factor = .5;
-    std::size_t _last_collection = 0;
+    static constexpr auto hasher = [](chunk_coords c) -> std::size_t {
+        return int_hash((std::size_t)c.y << 16 | (std::size_t)c.x);
+    };
 
-    void maybe_collect();
-
-    std::unordered_map<chunk_coords, std::shared_ptr<chunk>> _chunks{initial_capacity};
+    std::size_t _last_collection = 0;
+    mutable std::optional<std::tuple<std::shared_ptr<chunk>, chunk_coords>> _last_chunk;
+    std::unordered_map<chunk_coords, std::shared_ptr<chunk>, decltype(hasher)> _chunks{initial_capacity, hasher};
 };
 
 } // namespace floormat
-- 
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