Fix rooftop shooting (#52386)

src/ballistics.cpp

@@ -337,14 +337,26 @@ dealt_projectile_attack projectile_attack( const projectile &proj_arg, const tri
         prev_point = tp;
         tp = trajectory[i];
 
-        if( ( tp.z > prev_point.z && here.has_floor( tp ) ) ||
-            ( tp.z < prev_point.z && here.has_floor( prev_point ) ) ) {
-            // Currently strictly no shooting through floor
-            // TODO: Bash the floor
-            tp = prev_point;
-            traj_len = --i;
-            break;
+        if( tp.z != prev_point.z ) {
+            tripoint floor1 = prev_point;
+            tripoint floor2 = tp;
+
+            if( floor1.z < floor2.z ) {
+                floor1.z++;
+            } else {
+                floor2.z++;
+            }
+            // We only stop the bullet if there are two floors in a row
+            // this allow the shooter to shoot adjacent enemies from rooftops.
+            if( here.has_floor( floor1 ) && here.has_floor( floor2 ) ) {
+                // Currently strictly no shooting through floor
+                // TODO: Bash the floor
+                tp = prev_point;
+                traj_len = --i;
+                break;
+            }
         }
+
         // Drawing the bullet uses player g->u, and not player p, because it's drawn
         // relative to YOUR position, which may not be the gunman's position.
         if( do_animation && !do_draw_line ) {