Question: What is the difference between a game engine and a physics engine?

Answer

A Game Engine and a Physics Engine are two distinct components commonly used in the development of video games, each serving their specific purposes.

A Game Engine is a software framework designed to facilitate the creation of video games. It provides developers with the necessary tools to create a game without having to develop everything from scratch. Game engines usually include features like rendering for 2D or 3D graphics, physics and collision detection, audio, scripting, animation, artificial intelligence, networking, and much more. Examples of popular game engines are Unity, Unreal Engine, and Godot.

On the other hand, a Physics Engine is a type of software that simulates physical systems in the digital environment. It calculates the effects of forces and the resulting motion, enabling objects in a game to move and interact realistically. This could involve calculating things like gravity, collisions, rigid body dynamics, fluid dynamics, and soft body dynamics. Usually, a physics engine is part of the game engine, providing realistic physics simulation. Some examples of physics engines are PhysX, Box2D, and Havok.

Here's an example of how a Physics Engine might be used in a game developed with Unity:

using UnityEngine;
public class Example : MonoBehaviour
{
    public Rigidbody rb;

    // Upon start of the game, apply force to the object's Rigidbody
    void Start()
    {
        // Applies a force of 500 in the up direction (Y axis)
        rb.AddForce(0, 500, 0);
    }
}

In this script, Unity's built-in physics engine is being used. When the game starts, it applies a force of 500 on the y-axis to the Rigidbody rb, causing it to move upwards.

In conclusion, while both game engines and physics engines are essential components in game development, they serve different purposes. A game engine provides a comprehensive suite of tools for game development, including a physics engine as one of its components, which specifically handles the simulation of physical systems in the games.