src/critter: clean up before implementing pathfinding

4 files changed, 13 insertions, 9 deletions

diff --git a/serialize/world-impl.hpp b/serialize/world-impl.hpp
index f01276be..df0657ce 100644
--- a/serialize/world-impl.hpp
+++ b/serialize/world-impl.hpp
@@ -29,6 +29,7 @@
  * 14) Always store object offset, rework how sc_exact works.
  * 15) Add light alpha.
  * 16) One more bit for light falloff enum.
+ * 17) Switch critter::offset_frac to unsigned.
  */
 
 namespace floormat {
@@ -49,7 +50,7 @@ template<typename T> constexpr inline T int_max = std::numeric_limits<T>::max();
 
 #define file_magic ".floormat.save"
 
-constexpr inline proto_t proto_version = 16;
+constexpr inline proto_t proto_version = 17;
 
 constexpr inline size_t atlas_name_max = 128;
 constexpr inline auto null_atlas = (atlasid)-1LL;
diff --git a/serialize/world-reader.cpp b/serialize/world-reader.cpp
index 53b675ea..b912b5d7 100644
--- a/serialize/world-reader.cpp
+++ b/serialize/world-reader.cpp
@@ -268,9 +268,11 @@ void reader_state::read_chunks(reader_t& s)
                     proto.frame = s.read<uint8_t>();
                 else
                     proto.frame << s;
-                Vector2s offset_frac;
+                Vector2us offset_frac;
                 offset_frac[0] << s;
                 offset_frac[1] << s;
+                if (PROTO < 17) [[unlikely]]
+                    offset_frac = {};
                 const bool exact = id & meta_short_scenery_bit;
                 SET_CHUNK_SIZE();
 
diff --git a/src/critter.cpp b/src/critter.cpp
index 6f324077..ddb98cb1 100644
--- a/src/critter.cpp
+++ b/src/critter.cpp
@@ -151,8 +151,9 @@ Vector2 critter::ordinal_offset(Vector2b offset) const
 void critter::update(size_t i, float dt)
 {
     const auto new_r = arrows_to_dir(b_L, b_R, b_U, b_D);
-    if (new_r == rotation{rotation_COUNT})
+    if (new_r == rotation_COUNT)
     {
+        offset_frac = {};
         delta = 0;
         return;
     }
@@ -169,7 +170,6 @@ void critter::update(size_t i, float dt)
         move_vec(rotation_to_vec(_2)),
     };
 
-
     if (r != new_r)
         if (is_dynamic())
             rotate(i, new_r);
@@ -181,10 +181,11 @@ void critter::update(size_t i, float dt)
         for (auto j = 0uz; j < 3; j++)
         {
             auto vec = move_vecs[j];
-            constexpr auto frac = Vector2(32767);
-            constexpr auto inv_frac = 1.f / frac;
-            auto offset_ = vec + Vector2(offset_frac) * inv_frac;
-            offset_frac = Vector2s(Vector2(std::fmod(offset_[0], 1.f), std::fmod(offset_[1], 1.f)) * frac);
+            constexpr auto frac = 65535u;
+            constexpr auto inv_frac = 1.f / (float)frac;
+            const auto sign_vec = Vector2(sgn(vec[0]), sgn(vec[1]));
+            auto offset_ = vec + Vector2(offset_frac) * sign_vec * inv_frac;
+            offset_frac = Vector2us(Vector2(std::fabs(std::fmod(offset_[0], 1.f)), std::fabs(std::fmod(offset_[1], 1.f))) * frac);
             auto off_i = Vector2i(offset_);
             if (!off_i.isZero())
                 if (can_move_to(off_i))
diff --git a/src/critter.hpp b/src/critter.hpp
index 34ff9b33..3d7375b0 100644
--- a/src/critter.hpp
+++ b/src/critter.hpp
@@ -32,7 +32,7 @@ struct critter final : object
     float depth_offset() const override;
 
     String name;
-    Vector2s offset_frac;
+    Vector2us offset_frac;
     bool b_L : 1 = false, b_R : 1 = false, b_U : 1 = false, b_D : 1 = false;
     bool playable : 1 = false;