Pong Demo Spec

Goal

Build a Pong demo that exercises simple real-time physics, paddle control, AI opponent behavior, scoring, serve states, pause/restart flow, and persistent interactive launch behavior.

Player Experience

The game opens directly to a two-paddle court. The player controls the left paddle, an AI controls the right paddle, and a ball moves between them. The first side to reach the target score wins, then the player can restart.

Core Rules

• Ball bounces off the top and bottom walls.
• Ball bounces off paddles.
• Missing the ball awards one point to the opposing side.
• After a score, the ball resets to center and waits briefly before serving.
• First side to 10 points wins by default.
• Paddle movement is clamped to the court.
• Ball speed increases slightly after paddle hits up to a maximum.

Controls

• Up or W: move player paddle up.
• Down or S: move player paddle down.
• Space: start serve if waiting, or restart after match end.
• P: pause or resume.
• R: restart match.
• Esc: request close when hosted interactively.

AI Opponent

• AI tracks the ball with limited speed, not perfect teleporting.
• AI may include a small reaction delay or target error so it can miss.
• AI difficulty can increase slowly as rallies get longer.
• AI must be deterministic when seeded.

Scoring

• Score increments by 1 when the opponent misses.
• Rally length may be displayed but does not affect score.
• Winning state appears when either side reaches the target score.

Visual Requirements

• Show a simple court, center line, paddles, ball, player score, AI score, and state text.
• The ball must be high contrast and visible in screenshot evidence.
• The winner message should not obscure the scores.
• Layout must preserve playfield proportions after resizing.

Game State

Track at minimum:

• Player paddle position and velocity intent.
• AI paddle position, target, and reaction state.
• Ball position, velocity, speed multiplier, and serve/waiting state.
• Player score, AI score, rally count, target score, paused flag, match-over flag, elapsed time, and random seed.

Determinism and Evidence

• Accept an optional seed for serve direction and AI imperfection.
• Evidence mode should inject paddle movement and serve input, run enough frames to show ball motion, and exit explicitly.
• Evidence outcome should include frame count, input count, ball position, paddle positions, scores, rally count, game state, and close reason.
• Screenshot evidence should show both paddles, ball, court markings, and scores.

Acceptance Criteria

• Player paddle moves while input is held.
• AI paddle follows the ball with limited speed.
• Ball bounces correctly off walls and paddles.
• Paddle hit location affects outgoing ball angle.
• Missing the ball increments the correct score and resets serve.
• Match ends at target score and can restart.
• Pause freezes ball and paddle simulation.
• Interactive mode remains open until explicitly closed.

Out of Scope

• Multiplayer networking.
• Tournament brackets.
• Complex spin model.
• Required audio.