Renderers

RLGym v2 provides a way to visualize the game state during training or evaluation through the Renderer interface. The renderer is responsible for displaying the current state of the game, including car positions, ball position, boost pads, and other game elements.

Creating a Custom Renderer

Renderers have two methods:

# Must be manually called by the user via RLGym.render(). Arguments are provided automatically by the RLGym environment.
def render(self, state: StateType, shared_info: Dict[str, Any]) -> Any:

# Called once when the environment is closed.
def close(self) -> None:

Here's an example of a simple renderer that prints the ball's position:

from typing import Dict, Any
import numpy as np
from rlgym.api import Renderer
from rlgym.rocket_league.api import GameState

class BallPositionRenderer(Renderer[GameState]):
    """A simple renderer that prints the ball's position."""
    
    def render(self, state: GameState, shared_info: Dict[str, Any]) -> Any:
        print(f"Ball position: {state.ball.position}")
    
    def close(self):
        """Called when the environment is closed."""
        pass

Using Your Renderer

To use a renderer with your environment, just pass an instance of your renderer to the RLGym constructor:

env = RLGym(
    # ... other configuration objects ...
    renderer=BallPositionRenderer()
)

then call env.render() when you want to visualize the current state:

obs = env.reset()
while True:
    actions = {agent_id: env.action_space.sample() for agent_id in env.agents}
    obs, reward, terminated, truncated, info = env.step(actions)
    env.render()  # This will call your renderer's `render` method
    
    if terminated or truncated:
        break

and don't forget to call env.close() when you're done:

env.close()