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1 files changed, 101 insertions, 0 deletions

diff --git a/src/chunk-collision.cpp b/src/chunk-collision.cpp
new file mode 100644
index 00000000..bec90f32
--- /dev/null
+++ b/src/chunk-collision.cpp
@@ -0,0 +1,101 @@
+#include "chunk.hpp"
+#include "RTree.hpp"
+#include "tile-atlas.hpp"
+#include <bit>
+#include <Corrade/Containers/PairStl.h>
+
+namespace floormat {
+
+namespace {
+
+constexpr Vector2 tile_start(std::size_t k)
+{
+    const auto i = std::uint8_t(k);
+    const local_coords coord{i};
+    return TILE_SIZE2 * Vector2(coord.x, coord.y) - TILE_SIZE2*.5f;
+}
+
+constexpr Pair<Vector2, Vector2> scenery_tile(std::size_t k, const scenery& sc)
+{
+    constexpr auto half = Vector2(TILE_SIZE2)/2;
+    auto center = tile_start(k) + Vector2(sc.bbox_offset) + half;
+    auto start = center - Vector2(sc.bbox_size);
+    auto size = Vector2(sc.bbox_size)*2;
+    return { start, start + size, };
+};
+
+constexpr Pair<Vector2, Vector2> whole_tile(std::size_t k)
+{
+    auto start = tile_start(k);
+    return { start, start + TILE_SIZE2, };
+};
+
+constexpr Pair<Vector2, Vector2> wall_north(std::size_t k)
+{
+    auto start = tile_start(k) - Vector2(0, 1);
+    return { start, start + Vector2(TILE_SIZE2[0], 2), };
+};
+
+constexpr Pair<Vector2, Vector2> wall_west(std::size_t k)
+{
+    auto start = tile_start(k) - Vector2(1, 0);
+    return { start, start + Vector2(2, TILE_SIZE2[1]), };
+};
+
+constexpr std::uint64_t make_id(collision_type type, std::uint64_t id)
+{
+    return std::bit_cast<std::uint64_t>(collision_data { (std::uint64_t)type, id });
+}
+
+} // namespace
+
+void chunk::ensure_passability() noexcept
+{
+    if (!_pass_modified)
+        return;
+    _pass_modified = false;
+
+    _rtree.RemoveAll();
+
+    for (std::size_t i = 0; i < TILE_COUNT; i++)
+    {
+        auto tile = operator[](i);
+        if (auto s = tile.scenery())
+            if (s.frame.passability != pass_mode::pass && Vector2ui(s.frame.bbox_size).product() > 0)
+            {
+                auto [start, end] = scenery_tile(i, s.frame);
+                auto id = make_id(collision_type::scenery, i);
+                _rtree.Insert(start.data(), end.data(), id);
+            }
+    }
+    for (std::size_t i = 0; i < TILE_COUNT; i++)
+    {
+        if (const auto* atlas = ground_atlas_at(i))
+            if (atlas->pass_mode(pass_mode::pass) != pass_mode::pass)
+            {
+                auto [start, end] = whole_tile(i);
+                auto id = make_id(collision_type::geometry, i);
+                _rtree.Insert(start.data(), end.data(), id);
+            }
+    }
+    for (std::size_t i = 0; i < TILE_COUNT; i++)
+    {
+        auto tile = operator[](i);
+        if (const auto* atlas = tile.wall_north_atlas().get())
+            if (atlas->pass_mode(pass_mode::blocked) != pass_mode::pass)
+            {
+                auto [start, end] = wall_north(i);
+                auto id = make_id(collision_type::geometry, i);
+                _rtree.Insert(start.data(), end.data(), id);
+            }
+        if (const auto* atlas = tile.wall_west_atlas().get())
+            if (atlas->pass_mode(pass_mode::blocked) != pass_mode::pass)
+            {
+                auto [start, end] = wall_west(i);
+                auto id = make_id(collision_type::geometry, i);
+                _rtree.Insert(start.data(), end.data(), id);
+            }
+    }
+}
+
+} // namespace floormat