From: Lukas Krickl <lukas@krickl.dev>
Date: Thu, 24 Apr 2025 16:10:04 +0000 (+0200)
Subject: bg: fixed issue where the bg update queue would incorrectly process
X-Git-Url: https://git.krickl.dev/?a=commitdiff_plain;h=51aba2b743069c00a680dd654a8e316aadc11057;p=gbrg%2F.git

bg: fixed issue where the bg update queue would incorrectly process
every byte as a single update call

This caused out of bounds writes to seemingly random addresses.
---

diff --git a/src/cells.s b/src/cells.s
index 0af0c3a..98676ed 100644
--- a/src/cells.s
+++ b/src/cells.s
@@ -74,9 +74,6 @@ cell_road_init:
   push bc
   pop hl ; hl = ptr to tile 
   ld a, BUILDING_ROAD_NORTH_SOUTH
-  
-  assert nc, h, 0x80
-  assert c, h, 0xA0
 
   call bg_update_queue_push
   
diff --git a/src/defs.s b/src/defs.s
index 4011df4..3003e60 100644
--- a/src/defs.s
+++ b/src/defs.s
@@ -129,7 +129,7 @@
 .de BT_FARM, 1
 .de BT_LUMBER, 1
 
-#define BGE_MAX 32
+#define BGE_MAX 64
 
   ; max bg updates per frame
 #define BG_UPDATE_MAX 8 
diff --git a/src/update.s b/src/update.s
index 422383a..5919b31 100644
--- a/src/update.s
+++ b/src/update.s
@@ -35,8 +35,6 @@ update:
   ; it processess all tile updates 
   ; until the bg_update_index is 0 
 bg_update_queue_process:
-  ld hl, bg_update_index
-
   ; read index
   ld a, [bg_update_index]
   ld e, a
@@ -53,6 +51,9 @@ bg_update_queue_process:
 @loop:
     push af
     ; index--
+    ; sub length of an entry
+    dec de
+    dec de 
     dec de
 
     ; write to vram