a-game

commit 7b5566daf81467b540d8d7b4280ce33400338ca7
parent ae068a9ad665bbdb451b6f4665cd232de774908a
Author: amin <dev@aminmesbah.com>
Date:   Mon,  6 May 2019 01:47:53 +0000

Actually interleave bits

FossilOrigin-Name: 849bd91295169ff43a2d0abd34e129dc3a49aa0832b56734213a6d8a342783bd
Diffstat:
M
src/world.c
 | 
3
++-

1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/world.c b/src/world.c
@@ -50,7 +50,7 @@ internal u32 world_index_hash(v2i index)
     // TODO: profile this
     for (u32 i = 0; i < sizeof(u32); i++)
     {
-        morton_code |= (low_x & 1u << 0) << 0 | (low_y & 1u << 0) << (0 + 1);
+        morton_code |= (low_x & 1u << i) << i | (low_y & 1u << i) << (i + 1);
     }
     // NOTE(amin): We're not really after any of the specific cool things about
     // morton codes. I just picked a hash function that seemed sensible given
@@ -119,6 +119,7 @@ internal struct WorldChunk* world_chunk_get_or_create(struct World *world, v2i c
 
 internal size_t world_room_get_index_within_chunk(v2i room_i)
 {
+    static_assert(-1 == ~0, "implementation doesn't use two's complement");
     v2u room_i_lower_bits = {
         room_i.x & CHUNK_MASK_FOR_INTERNAL_ROOM_INDEX,
         room_i.y & CHUNK_MASK_FOR_INTERNAL_ROOM_INDEX,