Better clarification of WorldSnapshot

- removed deprecated frame_count from example
- also exposed WorldSnapshot.elapsed_seconds

Author: Daraan

Docs/python_api.md

@@ -3934,6 +3934,8 @@ This snapshot comprises all the information for every actor on scene at a certai
 A value unique for every snapshot to differentiate them.  
 - <a name="carla.WorldSnapshot.frame"></a>**<font color="#f8805a">frame</font>** (_int_)  
 Simulation frame in which the snapshot was taken.  
+- <a name="carla.WorldSnapshot.elapsed_seconds"></a>**<font color="#f8805a">elapsed_seconds</font>** (_float<small> - seconds</small>_)  
+Simulated seconds elapsed since the beginning of the current episode.  
 - <a name="carla.WorldSnapshot.timestamp"></a>**<font color="#f8805a">timestamp</font>** (_[carla.Timestamp](#carla.Timestamp)<small> - seconds</small>_)  
 Precise moment in time when snapshot was taken. This class works in seconds as given by the operative system.  
 

PythonAPI/docs/snapshot.yml

@@ -17,6 +17,11 @@
       type: int
       doc: >
         Simulation frame in which the snapshot was taken. 
+    - var_name: elapsed_seconds
+      type: float
+      var_units: seconds
+      doc: >
+        Simulated seconds elapsed since the beginning of the current episode.
     - var_name: timestamp
       type: carla.Timestamp
       var_units: seconds

PythonAPI/examples/V2XDemo.py

@@ -685,11 +685,11 @@ def __init__(self, width, height):
         self._show_ackermann_info = False
         self._ackermann_control = carla.VehicleAckermannControl()
 
-    def on_world_tick(self, timestamp):
+    def on_world_tick(self, world_snapshot):
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, world, clock):
         self._notifications.tick(world, clock)

PythonAPI/examples/automatic_control.py

@@ -282,12 +282,12 @@ def __init__(self, width, height):
         self._info_text = []
         self._server_clock = pygame.time.Clock()
 
-    def on_world_tick(self, timestamp):
-        """Gets informations from the world at every tick"""
+    def on_world_tick(self, world_snapshot):
+        """Gets information from the world at every tick"""
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame_count
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, world, clock):
         """HUD method for every tick"""

PythonAPI/examples/manual_control.py

@@ -685,11 +685,12 @@ def __init__(self, width, height):
         self._show_ackermann_info = False
         self._ackermann_control = carla.VehicleAckermannControl()
 
-    def on_world_tick(self, timestamp):
+    def on_world_tick(self, world_snapshot):
+        """Gets information from the world at every tick"""
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, world, clock):
         self._notifications.tick(world, clock)

PythonAPI/examples/manual_control_carsim.py

@@ -575,11 +575,12 @@ def __init__(self, width, height):
         self._info_text = []
         self._server_clock = pygame.time.Clock()
 
-    def on_world_tick(self, timestamp):
+    def on_world_tick(self, world_snapshot):
+        """Gets information from the world at every tick"""
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, world, clock):
         self._notifications.tick(world, clock)

PythonAPI/examples/manual_control_chrono.py

@@ -594,11 +594,12 @@ def __init__(self, width, height):
         self._info_text = []
         self._server_clock = pygame.time.Clock()
 
-    def on_world_tick(self, timestamp):
+    def on_world_tick(self, world_snapshot):
+        """Gets information from the world at every tick"""
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, world, clock):
         self._notifications.tick(world, clock)

PythonAPI/examples/manual_control_steeringwheel.py

@@ -399,11 +399,12 @@ def __init__(self, width, height):
         self._info_text = []
         self._server_clock = pygame.time.Clock()
 
-    def on_world_tick(self, timestamp):
+    def on_world_tick(self, world_snapshot):
+        """Gets information from the world at every tick"""
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, world, clock):
         self._notifications.tick(world, clock)

PythonAPI/examples/no_rendering_mode.py

@@ -993,7 +993,7 @@ def start(self, hud, input_control):
 
         # Register event for receiving server tick
         weak_self = weakref.ref(self)
-        self.world.on_tick(lambda timestamp: World.on_world_tick(weak_self, timestamp))
+        self.world.on_tick(lambda world_snapshot: World.on_world_tick(weak_self, world_snapshot))
 
     def select_hero_actor(self):
         """Selects only one hero actor if there are more than one. If there are not any, it will spawn one."""
@@ -1081,15 +1081,15 @@ def update_hud_info(self, clock):
         self._hud.add_info('HERO', hero_mode_text)
 
     @staticmethod
-    def on_world_tick(weak_self, timestamp):
+    def on_world_tick(weak_self, world_snapshot):
         """Updates the server tick"""
         self = weak_self()
         if not self:
             return
 
         self.server_clock.tick()
         self.server_fps = self.server_clock.get_fps()
-        self.simulation_time = timestamp.elapsed_seconds
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def _show_nearby_vehicles(self, vehicles):
         """Shows nearby vehicles of the hero actor"""

PythonAPI/examples/rss/manual_control_rss.py

@@ -616,11 +616,12 @@ def __init__(self, width, height, world):
         self._server_clock = pygame.time.Clock()
         self.rss_state_visualizer = RssStateVisualizer(self.dim, self._font_mono, self._world)
 
-    def on_world_tick(self, timestamp):
+    def on_world_tick(self, world_snapshot):
+        """Gets information from the world at every tick"""
         self._server_clock.tick()
         self.server_fps = self._server_clock.get_fps()
-        self.frame = timestamp.frame
-        self.simulation_time = timestamp.elapsed_seconds
+        self.frame = world_snapshot.frame
+        self.simulation_time = world_snapshot.elapsed_seconds
 
     def tick(self, player, clock):
         self._notifications.tick(clock)