Go is a popular programming language that is used for building a wide range of applications, including games. While Go is not typically known as a game development language, it offers a number of benefits that make it a great choice for building 2D games. In this tutorial, we will go through the steps of building a 2D game using Go programming.


Prerequisites

Before we begin, there are a few prerequisites that you will need to have in place to follow along with this tutorial:

  • A basic understanding of Go programming.
  • A text editor or integrated development environment (IDE) for writing Go code.
  • A working knowledge of the command line.


Setting up the Environment

The first step to building a 2D game with Go is to set up your development environment. We will be using the Ebiten game library to build our game, so the first thing you will need to do is install it. You can do this by running the following command:

go get github.com/hajimehoshi/ebiten/v2

Once Ebiten is installed, you can create a new project by creating a new directory for your game and creating a new Go module within that directory. You can do this by running the following command:

mkdir mygame
cd mygame
go mod init github.com/myname/mygame

This will create a new directory called mygame and initialize a new Go module with the name github.com/myname/mygame.


Creating the Game Window

The first step in building a 2D game with Ebiten is to create the game window. You can do this by creating a new Go file and importing the Ebiten library. You can then define a function that will create the game window and display it on the screen:

package main

import (
    "github.com/hajimehoshi/ebiten/v2"
)

func main() {
    ebiten.Run(update, 640, 480, 1, "My Game")
}

func update(screen *ebiten.Image) error {
    return nil
}

This code will create a new game window with a size of 640 pixels wide and 480 pixels tall, and a title of "My Game".


Drawing the Game World

Once you have created the game window, you can start drawing the game world. Ebiten provides a number of functions that you can use to draw 2D graphics on the screen. For example, you can draw a rectangle on the screen like this:

ebitenutil.DrawRect(screen, 100, 100, 50, 50, color.White)

This code will draw a white rectangle at position (100, 100) with a width and height of 50 pixels.


Handling Input

To make your game interactive, you will need to handle input from the user. Ebiten provides a number of functions that you can use to handle input, such as the ebiten.IsKeyPressed function which you can use to check if a specific key is currently pressed. For example, you can check if the left arrow key is pressed like this:

if ebiten.IsKeyPressed(ebiten.KeyArrowLeft) {
    // Move the player to the left
}


Updating the Game State

To make your game dynamic, you will need to update the game state on each frame. You can do this by defining an update function that will be called by Ebiten on each frame. This function should update the game state based on input and other factors, such as the passage of time.

For example, you might define an `update function that updates the position of a player character based on user input:

func update(screen *ebiten.Image) error {
    if ebiten.IsKeyPressed(ebiten.KeyArrowLeft) {
        // Move the player to the left
    }
    if ebiten.IsKeyPressed(ebiten.KeyArrowRight) {
        // Move the player to the right
    }
    if ebiten.IsKeyPressed(ebiten.KeyArrowUp) {
        // Move the player up
    }
    if ebiten.IsKeyPressed(ebiten.KeyArrowDown) {
        // Move the player down
    }
    // Update the player's position based on input
    player.update()
    return nil
}

In this code, the update function checks for input from the user and updates the player's position accordingly. The player.update() function is responsible for actually updating the player's position based on input.


Rendering the Game World

Once you have updated the game state, you can render the game world by drawing the various game objects on the screen. You can do this by defining a draw function that will be called by Ebiten on each frame. This function should draw all of the game objects on the screen.

For example, you might define a draw function that draws the player character on the screen:

func draw(screen *ebiten.Image) {
    // Draw the player character
    op := &ebiten.DrawImageOptions{}
    op.GeoM.Translate(player.x, player.y)
    screen.DrawImage(playerImage, op)
}

In this code, the draw function draws the player character on the screen using the playerImage variable. The op.GeoM.Translate(player.x, player.y) line translates the player's position to the correct position on the screen.


Running the Game

Once you have defined the update and draw functions, you can run the game by calling the ebiten.Run function in the main function:

func main() {
    ebiten.Run(update, screenWidth, screenHeight, scale, "My Game")
}

In this code, screenWidth and screenHeight are the width and height of the game window, and scale is the scaling factor for the game window.


Conclusion

In this tutorial, we have gone through the steps of building a 2D game using Go programming and the Ebiten game library. We have covered how to create the game window, draw the game world, handle input, update the game state, and render the game world. By following these steps, you should now have a good understanding of how to build your own 2D games with Go programming.