Game Concepts

Overview

Pelota is a 3D tennis simulation game that faithfully recreates the physics and mechanics of professional tennis. Players control realistic tennis strokes with variations in power, spin, and targeting.

Core Game Elements

The Ball

The ball is the central game object with realistic physics properties:

Diameter: Standard tennis ball size
Weight: Realistic mass affecting physics calculations
Spin Properties: Affected by stroke application (sidespin, topspin, forward spin)
Bounce Characteristics: Energy retention based on surface and velocity

The Court

The court follows official tennis dimensions:

Width: 8.11 meters (singles court)
Length: 26.0 meters (baseline to baseline)
Surface: Grass or hard court with realistic bounce characteristics
Net: 0.914 meters high at center

Players

Players are characterized by:

Position: Dynamic 3D position on the court
Movement: CharacterBody3D movement system for realistic locomotion
Stamina: Energy system affecting performance over time
Skills: Attributes determining shot accuracy and power

Stroke Types

Pelota implements several distinct stroke types:

Forehand

Power: High velocity potential
Spin: Topsin or flat
Trajectory: Forward and upward

Backhand

Power: Moderate to high
Variants: Standard backhand or slice (backspin)
Execution: Cross-body motion

Volley

Description: Shot taken at the net before ball bounces
Power: Lower power, high precision required
Advantage: Offensive positioning

Serve

Power: Highest velocity potential (up to 36 m/s in-game)
Spin: Variable sidespin and topspin
Rules: First serve must land in service box, second serve if first fails

Drop Shot

Trajectory: Short distance, high arc
Spin: Backspin (negative topspin)
Purpose: Force opponent to net

Stroke Properties

Each stroke has three primary attributes:

1. Power (velocity_z0)

Range: 8.0 to 36.0 m/s
Impact: Determines how far and fast the ball travels
Factors: Player skill, stamina, ball position

2. Spin (Vector3)

X Component (Sidespin): Horizontal curve (positive right, negative left)
Y Component (Topspin): Vertical rotation (positive down, negative up for backspin)
Z Component (Forward Spin): Forward rotation along travel axis
Effect: Modifies ball trajectory via Magnus effect

3. Target

Vector3 Position: Where the player aims on the court
Calculation: From stroke application point to target
Correction: AI and physics adjust for accuracy

Match Structure

Scoring System

Pelota follows standard tennis scoring:

Points: 0, 15, 30, 40, Deuce (40-40), Advantage, Game
Games: First to 6 with 2-game lead wins set
Sets: Match typically best of 3 or 5 sets

Rally Phases

A rally progresses through distinct phases:

Serve: Server initiates play
Rally: Both players exchange strokes
Point Decision: Ball out of bounds, net contact, or ground contact
Point Reset: Preparation for next point

Game Mechanics

Anticipation & Positioning

Players must:

Anticipate opponent’s shot target
Position themselves optimally on court
Time movement to reach ball for stroke execution

Stamina System

Stamina affects:

Shot Power: Reduced power when fatigued
Movement Speed: Slower court coverage with low stamina
Recovery: Gradual stamina regeneration between points

Trajectory Prediction

The game predicts ball trajectory to:

Inform AI Decision: Help AI decide optimal response
Display Information: Show anticipated landing zone
Collision Detection: Determine if ball will be playable

Shot Intent System

AI players evaluate shots with different strategic intents:

Neutral: Standard play maintaining rally
Attack: Aggressive shot aiming for winner
Defend: Conservative shot recovering position
Approach Net: Offensive move advancing toward net
Serve: Initiating point

Each intent modifies power, spin, and targeting calculations.

Ball States

The ball can be in several states during gameplay:

In Play: Active during rally
Served: Recently served, traveling to opponent
Dead: Out of play (out of bounds, net contact, etc.)
Prediction: Trajectory being calculated for analysis