Cooperative pong is a game of simple pong, where the objective is to keep the ball in play for the longest time. The game is over when the ball goes out of bounds from either the left or right edge of the screen. There are two agents (paddles), one that moves along the left edge and the other that moves along the right edge of the screen. All collisions of the ball are elastic. The ball always starts moving in a random direction from the center of the screen with each reset. To make learning a little more challenging, the right paddle is tiered cake-shaped by default. The observation space of each agent is its own half of the screen. There are two possible actions for the agents (move up/down). If the ball stays within bounds, each agent receives a reward of max_reward / max_cycles (default 0.11) at each timestep. Otherwise, each agent receives a reward of off_screen_penalty (default -10) and the game ends.

Manual Control

Move the left paddle using the ‘W’ and ‘S’ keys. Move the right paddle using ‘UP’ and ‘DOWN’ arrow keys.

Arguments

cooperative_pong_v4.env(ball_speed=9, left_paddle_speed=12,
right_paddle_speed=12, cake_paddle=True, max_cycles=900, bounce_randomness=False, max_reward=100, off_screen_penalty=-10)

ball_speed: Speed of ball (in pixels)

left_paddle_speed: Speed of left paddle (in pixels)

right_paddle_speed: Speed of right paddle (in pixels)

cake_paddle: If True, the right paddle cakes the shape of a 4 tiered wedding cake

max_cycles: after max_cycles steps all agents will return done

bounce_randomness: If True, each collision of the ball with the paddles adds a small random angle to the direction of the ball, with the speed of the ball remaining unchanged.

max_reward: Total reward given to each agent over max_cycles timesteps

off_screen_penalty: Negative reward penalty for each agent if the ball goes off the screen

Version History

• v5: Fixed ball teleporting bugs
• v4: Added max_reward and off_screen_penalty arguments and changed default, fixed glitch where ball would occasionally teleport, reward redesign (1.14.0)
• v3: Change observation space to include entire screen (1.10.0)
• v2: Misc fixes (1.4.0)
• v1: Fixed bug in how dones were computed (1.3.1)
• v0: Initial versions release (1.0.0)