more efficient collision iteration, fix eternal shots

vacuum_gambit.p8

@@ -245,13 +245,13 @@ function updategame()
  if not ps.dead then
   ps:move()
   local pbox = hurtbox(ps)
-  for es in all(eship_collider:get_collisions(pbox)) do
+  for es in eship_collider:iterate_collisions(pbox) do
    ps:hitship(es)
    if(es:hitship(ps)) eship_collider:yoink(es)
   end
   ebullets:strip(function(eb)
    -- loopify this when split moves implemented
-   eb:move()
+   if (eb:move()) return true
    if (not collides(pbox, hurtbox(eb))) return
    ps:hitbullet(eb)
    return eb:hitship(ps)
@@ -261,7 +261,7 @@ function updategame()
  end
 
  pbullets:strip(function(pb)
-  for es in all(eship_collider:get_collisions(hurtbox(pb))) do
+  for es in eship_collider:iterate_collisions(hurtbox(pb)) do
    if (es:hitbullet(pb)) eship_collider:yoink(es)
    if (pb:hitship(es)) return true
   end
@@ -1468,22 +1468,28 @@ function collider:yoink(item)
  end
 end
 
-function collider:get_collisions(box)
- local found = { }
+function collider:iterate_collisions(box)
  local seen = { }
  local bucket_ids = collider_indexes(box)
- for b_idx in all(bucket_ids) do
-  local bucket = self[b_idx]
-  if bucket then
-   for candidate in all(bucket) do
-    if not (seen[candidate] or self.suppress[candidate]) then
-     seen[candidate] = true
-     if (collides(box, hurtbox(candidate))) add(found, candidate)
-    end
+ local bii, bidl, bucket, bi, blen = 1, #bucket_ids, false, 1, 0
+ return function()
+  while bii <= bidl do
+   if not bucket then
+    bucket,blen = self[bucket_ids[bii]],0
+    if (bucket) blen=#bucket
    end
+   while bi <= blen do
+    local candidate = bucket[bi]
+    bi += 1
+    if not seen[candidate] then
+     seen[candidate] = true
+     if (not self.suppress[candidate] and collides(box, hurtbox(candidate))) return candidate
+    end
+   end -- done with this bucket
+   bi=1
+   bii += 1
   end
- end
- return found
+ end -- end of closure def
 end
 
 -->8