From 9c9d02e674231dca8f9b75ea23a0efa0b28f970b Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sat, 29 Oct 2022 02:33:29 +0200
Subject: a

---
 serialize/world-impl.hpp   | 10 ++++++----
 serialize/world-reader.cpp | 14 +++++++++-----
 serialize/world-writer.cpp | 27 +++++++++++++++++++++++----
 3 files changed, 38 insertions(+), 13 deletions(-)

(limited to 'serialize')

diff --git a/serialize/world-impl.hpp b/serialize/world-impl.hpp
index 252f361e..4cff8794 100644
--- a/serialize/world-impl.hpp
+++ b/serialize/world-impl.hpp
@@ -10,7 +10,7 @@ namespace floormat::Serialize {
 namespace {
 
 using tilemeta  = std::uint8_t;
-using imgvar    = decltype(tile_image::variant);
+using varid    = decltype(tile_image::variant);
 using atlasid   = std::uint16_t;
 using chunksiz  = std::uint16_t;
 using enum tile::pass_mode;
@@ -29,9 +29,11 @@ constexpr inline std::underlying_type_t<tile::pass_mode> pass_mask = pass_blocke
 constexpr inline auto pass_bits = std::bit_width(pass_mask);
 
 enum : tilemeta {
-    meta_ground     = 1 << (pass_bits + 0),
-    meta_wall_n     = 1 << (pass_bits + 1),
-    meta_wall_w     = 1 << (pass_bits + 2),
+    meta_ground         = 1 << (pass_bits + 0),
+    meta_wall_n         = 1 << (pass_bits + 1),
+    meta_wall_w         = 1 << (pass_bits + 2),
+    meta_short_atlasid  = 1 << (pass_bits + 3),
+    meta_short_variant  = 1 << (pass_bits + 4),
 };
 
 } // namespace
diff --git a/serialize/world-reader.cpp b/serialize/world-reader.cpp
index b999b5d4..6172703b 100644
--- a/serialize/world-reader.cpp
+++ b/serialize/world-reader.cpp
@@ -65,19 +65,23 @@ void reader_state::read_chunks(reader_t& s)
         for (std::size_t i = 0; i < TILE_COUNT; i++)
         {
             const tilemeta flags = s.read<tilemeta>();
+            tile& t = chunk[i];
+            using uchar = std::uint8_t;
             const auto make_atlas = [&]() -> tile_image {
-                auto atlas = lookup_atlas(s.read<atlasid>());
-                auto id = s.read<imgvar>();
-                fm_assert(id < atlas->num_tiles());
-                return { atlas, id };
+                auto id = flags & meta_short_atlasid ? (atlasid)(s.read<uchar>()) : s.read<atlasid>();
+                auto v  = flags & meta_short_variant ? (varid)  (s.read<uchar>()) : s.read<varid>();
+                auto atlas = lookup_atlas(id);
+                fm_assert(v < atlas->num_tiles());
+                return { atlas, v };
             };
-            tile& t = chunk[i];
+
             if (flags & meta_ground)
                 t.ground = make_atlas();
             if (flags & meta_wall_n)
                 t.wall_north = make_atlas();
             if (flags & meta_wall_w)
                 t.wall_west = make_atlas();
+
             switch (auto x = flags & pass_mask)
             {
             case tile::pass_shoot_through:
diff --git a/serialize/world-writer.cpp b/serialize/world-writer.cpp
index 1739f899..8b33d35e 100644
--- a/serialize/world-writer.cpp
+++ b/serialize/world-writer.cpp
@@ -40,7 +40,7 @@ private:
     std::unordered_map<const void*, interned_atlas> tile_images;
 };
 
-constexpr auto tile_size = sizeof(tilemeta) + (sizeof(atlasid) + sizeof(imgvar))*3;
+constexpr auto tile_size = sizeof(tilemeta) + (sizeof(atlasid) + sizeof(varid)) * 3;
 
 constexpr auto chunkbuf_size =
         sizeof(chunk_magic) + sizeof(chunk_coords) + tile_size * TILE_COUNT;
@@ -100,6 +100,20 @@ void writer_state::serialize_chunk(const chunk& c, chunk_coords coord)
         flags |= meta_wall_n * (img_n != null_atlas);
         flags |= meta_wall_w * (img_w != null_atlas);
 
+        using uchar = std::uint8_t;
+
+        constexpr auto ashortp = [](atlasid id) {
+            return id == null_atlas || id == (uchar)id;
+        };
+        constexpr auto vshortp = [](const tile_image& img) {
+            return !img.atlas || img.variant == (uchar)img.variant;
+        };
+
+        if (flags != 0 && ashortp(img_g) && ashortp(img_n) && ashortp(img_w))
+            flags |= meta_short_atlasid;
+        if (flags != 0 && vshortp(x.ground) && vshortp(x.wall_north) && vshortp(x.wall_west))
+            flags |= meta_short_variant;
+
         fm_debug_assert((x.passability & pass_mask) == x.passability);
         flags |= x.passability;
 
@@ -115,12 +129,17 @@ void writer_state::serialize_chunk(const chunk& c, chunk_coords coord)
         check_atlas(x.wall_west);
 #endif
 
+        const auto write = [&](atlasid x, varid v) {
+            flags & meta_short_atlasid ? s << (uchar) x : s << x;
+            flags & meta_short_variant ? s << (uchar) v : s << v;
+        };
+
         if (img_g != null_atlas)
-            s << img_g << x.ground.variant;
+            write(img_g, x.ground.variant);
         if (img_n != null_atlas)
-            s << img_n << x.wall_north.variant;
+            write(img_n, x.wall_north.variant);
         if (img_w != null_atlas)
-            s << img_w << x.wall_west.variant;
+            write(img_w, x.wall_west.variant);
     }
 
     const auto nbytes = s.bytes_written();
-- 
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