Using floor-based terrain instead of area-based

src/decomp/game/mario_actions_stationary.c

@@ -127,7 +127,7 @@ s32 act_idle(struct MarioState *m) {
     }
 
     if (m->actionState == 3) {
-        if ((m->area->terrainType & TERRAIN_MASK) == TERRAIN_SNOW) {
+        if (m->floor != NULL && m->curTerrain == TERRAIN_SNOW) {
             return set_mario_action(m, ACT_SHIVERING, 0);
         } else {
             return set_mario_action(m, ACT_START_SLEEPING, 0);