Split the branch data into read-only and mutable parts.

As a side effect, branches can now be shortened without breaking major save
compat.

This commit itself doesn't preserve compat though, even though it'd be easy
-- other parts are too nasty already.

1 files changed, 5 insertions, 3 deletions

diff --git a/crawl-ref/source/branch.cc b/crawl-ref/source/branch.cc
index 3ef88405bf..b1a9d7f0ee 100644
--- a/crawl-ref/source/branch.cc
+++ b/crawl-ref/source/branch.cc
@@ -10,14 +10,16 @@
 #include "travel.h"
 #include "branch-data.h"
 
-Branch& your_branch()
+FixedVector<int, NUM_BRANCHES> startdepth, brdepth;
+
+const Branch& your_branch()
 {
     return branches[you.where_are_you];
 }
 
 bool at_branch_bottom()
 {
-    return your_branch().depth == player_branch_depth();
+    return brdepth[you.where_are_you] == player_branch_depth();
 }
 
 level_id branch_entry_level(branch_type branch)
@@ -34,7 +36,7 @@ level_id branch_entry_level(branch_type branch)
     }
 
     const branch_type parent = branches[branch].parent_branch;
-    const int subdepth = branches[branch].startdepth;
+    const int subdepth = startdepth[branch];
 
     // This may be invalid if the branch doesn't exist this game --
     // it's the caller's job to check.