diff --git a/src/main.c b/src/main.c
index 16c1ff3..6382469 100644
--- a/src/main.c
+++ b/src/main.c
@@ -130,6 +130,10 @@ void castRay(s16 angle){
   while(dof<8){
     mx = fix16ToInt(rx) / 10;
     my = fix16ToInt(ry) / 10;
+    if(rx < 0 || ry < 0){
+      dof = 8;
+      continue;
+    }
     if(mx < 10 && my < 10 && map[my][mx] == 1){
       dof = 8;
       vx = rx;