map: get_tile now returns a static null tile if oob coordinates are requested

diff --git a/src/map.s b/src/map.s
index ce2eb49cb141c137a88e7da75c434d43ebab210a..baaa29232cd882ad0fc8f62dc745b361cb48bbf4 100644 (file)
--- a/src/map.s
+++ b/src/map.s
@@ -189,6 +189,15 @@ map_draw_tile:
        ;       returns:
        ;               hl: tile
 map_get_tile:
+       ; check if out of bounds
+       ld a, b
+       cp a, MAP_H
+       jp nc, @oob_tile
+
+       ld a, c
+       cp a, MAP_W
+       jp nc, @oob_tile
+
        ld hl, tiles
        
        ld de, MAP_W * t_size
@@ -215,6 +224,11 @@ map_get_tile:
 
        ; hl = tile now
        ret
+
+@oob_tile:
+       ; fallback tile
+       ld hl, tile_null
+       ret
        
        ; prepares tile draw
        ; by writing the expected tiles

diff --git a/src/tiles.s b/src/tiles.s
index e383c9e79d3de620b2f5a90dd37e57db1a343bdf..230b9332af5f3bbd6dfed50e0a79f5643700bace 100644 (file)
--- a/src/tiles.s
+++ b/src/tiles.s
@@ -9,7 +9,10 @@
 tile_id_table:
        dw tile_grass
        dw tile_wall
-
+       
+       ; fallback tile 
+tile_null:
+       tiledef 0, 0, 0
 
 tile_grass:
        tiledef TT_EMPTY, 0, GFX_GRASS