Class that contains time information for simulated data. This information is automatically retrieved as part of the carla.WorldSnapshot the client gets on every frame, but might also be used in many other situations such as a carla.Sensor retrieveing data.
A class that contains every actor present on the scene and provides access to them. The list is automatically created and updated by the server and it can be returned using carla.World.
Filters a list of Actors matching `wildcard_pattern` against their variable __<font color="#f8805a">type_id</font>__ (which identifies the blueprint used to spawn them). Matching follows [fnmatch](https://docs.python.org/2/library/fnmatch.html) standard.
The simulation has some advanced configuration options that are contained in this class and can be managed using carla.World and its methods. These allow the user to choose between client-server synchrony/asynchrony, activation of "no rendering mode" and either if the simulation should run with a fixed or variable time-step. Check [this](adv_synchrony_timestep.md) out if you want to learn about it.
States the synchrony between client and server. When set to true, the server will wait for a client tick in order to move forward. It is false by default.
When enabled, the simulation will run no rendering at all. This is mainly used to avoid overhead during heavy traffic simulations. It is false by default.
Ensures that the time elapsed between two steps of the simulation is fixed. Set this to <b>0.0</b> to work with a variable time-step, as happens by default.
Creates an object containing desired settings that could later be applied through carla.World and its method __<font color="#7fb800">apply_settings()</font>__.
Class that defines attachment options between an actor and its parent. When spawning actors, these can be attached to another actor so their position changes accordingly. This is specially useful for sensors. [Here](ref_code_recipes.md#attach-sensors-recipe) is a brief recipe in which we can see how sensors can be attached to a car when spawned. Note that the attachment type is declared as an enum within the class.
With this fixed attatchment the object follow its parent position strictly. This is the recommended attachment to retrieve precise data from the simulation.
An attachment that expands or retracts the position of the actor, depending on its parent. This attachment is only recommended to record videos from the simulation where a smooth movement is needed. SpringArms are an Unreal Engine component so [check this out](ref_code_recipes.md#attach-sensors-recipe) to learn some more about them. <br><b style="color:red;">Warning:</b> The <b>SpringArm</b> attachment presents weird behaviors when an actor is spawned with a relative translation in the Z-axis (e.g. <code>child_location = Location(0,0,2)</code>).
World objects are created by the client to have a place for the simulation to happen. The world contains the map we can see, meaning the asset, not the navigation map. Navigation maps are part of the carla.Map class. It also manages the weather and actors present in it. There can only be one world per simulation, but it can be changed anytime.
The ID of the episode associated with this world. Episodes are different sessions of a simulation. These change everytime a world is disabled or reloaded. Keeping track is useful to avoid possible issues.
This method is used in [__asynchronous__ mode](https://carla.readthedocs.io/en/latest/adv_synchrony_timestep/). It starts callbacks from the client for the function defined as `callback`, and returns the ID of the callback. The function will be called everytime the server ticks. It requires a carla.WorldSnapshot as argument, which can be retrieved from __<font color="#7fb800">wait_for_tick()</font>__. Use __<font color="#7fb800">remove_on_tick()</font>__ to stop the callbacks.
This method is used in [__synchronous__ mode](https://carla.readthedocs.io/en/latest/adv_synchrony_timestep/), when the server waits for a client tick before computing the next frame. This method will send the tick, and give way to the server. It returns the ID of the new frame computed by the server.
note:>
If no tick is received in synchronous mode, the simulation will freeze. Also, if many ticks are received from different clients, there may be synchronization issues. Please read the docs about [synchronous mode](https://carla.readthedocs.io/en/latest/adv_synchrony_timestep/) to learn more.
This method is used in [__asynchronous__ mode](https://carla.readthedocs.io/en/latest/adv_synchrony_timestep/). It makes the client wait for a server tick. When the next frame is computed, the server will tick and return a snapshot describing the new state of the world.
Determines how fixed and rigorous should be the changes in position according to its parent object.
doc:>
The method will create, return and spawn an actor into the world. The actor will need an available blueprint to be created and a transform (location and rotation). It can also be attached to a parent with a certain attachment type.
Looks up for an actor by ID and returns <b>None</b> if not found.
# --------------------------------------
- def_name:get_actors
return:carla.ActorList
params:
- param_name:actor_ids
type:list
default:None
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The IDs of the actors being searched. By default it is set to <b>None</b> and returns every actor on scene.
doc:>
Retrieves a list of carla.Actor elements, either using a list of IDs provided or just listing everyone on stage. If an ID does not correspond with any actor, it will be excluded from the list returned, meaning that both the list of IDs and the list of actors may have different lengths.
# --------------------------------------
- def_name:get_blueprint_library
return:carla.BlueprintLibrary
doc:>
Returns a list of actor blueprints available to ease the spawn of these into the world.
Returns an array of bounding boxes with location and rotation in world space. The method returns all the bounding boxes in the level by default, but the query can be filtered by semantic tags with the argument `actor_type`.
Freezes or unfreezes all traffic lights in the scene. Frozen traffic lights can be modified by the user but the time will not update them until unfrozen.
This can only be used with walkers. It retrieves a random location to be used as a destination using the __<font color="#7fb800">go_to_location()</font>__ method in carla.WalkerAIController. This location will be part of a sidewalk. Roads, crosswalks and grass zones are excluded. The method does not take into consideration locations of existing actors so if a collision happens when trying to spawn an actor, it will return an error. Take a look at [`spawn_npc.py`](https://github.com/carla-simulator/carla/blob/e73ad54d182e743b50690ca00f1709b08b16528c/PythonAPI/examples/spawn_npc.py#L179) for an example.
Returns an object containing some data about the simulation such as synchrony between client and server or rendering mode.
# --------------------------------------
- def_name:get_snapshot
return:carla.WorldSnapshot
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Returns a snapshot of the world at a certain moment comprising all the information about the actors.
# --------------------------------------
- def_name:get_spectator
return:carla.Actor
doc:>
Returns the spectator actor. The spectator is a special type of actor created by Unreal Engine, usually with ID=0, that acts as a camera and controls the view in the simulator window.
# --------------------------------------
- def_name:get_weather
return:carla.WeatherParameters
doc:>
Retrieves an object containing weather parameters currently active in the simulation, mainly cloudiness, precipitation, wind and sun position.
# --------------------------------------
- def_name:set_weather
params:
- param_name:weather
type:carla.WeatherParameters
doc:>
New conditions to be applied.
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Changes the weather parameteres ruling the simulation to another ones defined in an object.
# --------------------------------------
- def_name:__str__
return:
string
doc:>
The content of the world is parsed and printed as a brief report of its current state.
Helper class part of carla.World that defines methods for creating debug shapes. By default, shapes last one second. They can be permanent, but take into account the resources needed to do so. Check out this [recipe](ref_code_recipes.md#debug-bounding-box-recipe) where the user takes a snapshot of the world and then proceeds to draw bounding boxes for traffic lights.
