[JAVA] [# 1] Make Minecraft with Python. ～ Preliminary research and design ～

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Overview

This is a project to reproduce the world-famous sandbox game "Minecraft" in the programming language "Python".

Next article: [# 2] Make Minecraft with Python. ～ Model drawing and player implementation ～

Trigger

"Minecraft" was the first time I came into contact with programming.

It was over 4 years ago. I was interested in so-called remodeled content called "MOD" in Minecraft, and entered the world of programming saying "I want to make it myself!". With a total play time of over tens of thousands of hours, it is one of many memorable games.

Since I was in the lower grades of elementary school, I have been doing some creative activities, such as creating a website. When you actually program a "thing" using a programming language and it actually works, the impression is tremendous.

Also, my way of thinking about "programming", how to assemble it, and the knowledge to realize it. It was a perfect match for all.

With that in mind, now that four years have passed, let's actually reproduce "Minecraft" itself instead of ** "MOD"! ** ** I stood up.

Attitude

However, reproducing a game of that scale is not easy.

Nowadays, they are called ** game engines ** such as "Unity" and "Unreal Engine". It's an era where you can easily create high-quality games without any coding.

Even coding is visualized with what is called a ** blueprint ** and assembled with a GUI. It is possible to say that. This is amazing.

However, this project does not use such a game engine. ** Make it "from scratch" in the true sense. ** **

Preliminary research

In actual production, you must first know the enemy.

Drawing in Minecraft

If the so-called "drawing system" library called the computer graphics library is famous There are "DirectX" and "OpenGL".

This is the main subject. How does Minecraft draw in Java? ** Minecraft uses one of the game libraries in Java called "LWJGL (Lightweight Java Game Library)". ** ** It's like OpenGL's Wrapper.

Is there such a library in Python? It doesn't have to be the worst. ** If you don't have it, you can make it. If you run out, just add it. ** **

Let's touch LWJGL

Integrated development environment ["Eclipse"](https://ja.wikipedia.org/wiki/Eclipse_(%E7%B5%B1%E5%90%88%E9%96%8B%E7%99%BA%E7% Let's touch LWJGL a little using 92% B0% E5% A2% 83)).

Download from Official Site.

Nostalgic. This screen. For the time being, my eyes get tired, so I chose a dark theme. Window▶Preferences▶Appearance

Make a project appropriately.

Create a class appropriately.

main.java

public class main 
{
	//constructor
	public main() {}
	
	public static void main(String[] args)
	{
		System.out.println("Hello LWJGL!");
	}
}

Operation check is completed for the time being.

LWJGL environment construction

To use LWJGL, you need "JDK (Java Development Kit)".

Reference article: How to install JDK on Windows

You can pass it with javac -version.

Install Maven to build LWJGL environment.

Reference article: How to install Maven on Windows

OK if you pass with mvn -v.

This time I installed Maven 3.

next, mvn archetype:generate -DgroupId=test -DartifactId=test Create a project appropriately with This time, I created it in the working space of ʻEclipse`.

Reference article: Memo of Maven3

Choose org.apache.maven.archetypes:maven-archetype-quickstart version:
1: 1.0-alpha-1
2: 1.0-alpha-2
3: 1.0-alpha-3
4: 1.0-alpha-4
5: 1.0
6: 1.1
7: 1.3
8: 1.4
Choose a number: 8: 8

[INFO] Using property: groupId = test
[INFO] Using property: artifactId = test
Define value for property 'version' 1.0-SNAPSHOT: : 1.0-SNAPSHOT
[INFO] Using property: package = test
Confirm properties configuration:
groupId: test
artifactId: test
version: 1.0-SNAPSHOT
package: test
 Y: : Y

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  06:21 min
[INFO] Finished at: 2020-01-21T08:58:05+09:00
[INFO] ------------------------------------------------------------------------

Reference: Try Hello world with LWJGL (Environment construction)

next, Link LWJGL to pom.xml in the created project

mvn nativedependencies:copy

Download the dynamic link library at

mvn clean eclipse:eclipse -DdownloadSources=true -DdownloadJavadocs=true

Allows Eclipse to load the project. Open Eclipse and import from ʻImport existing projects`.

The library is being built.

Run

The source code is as follows.

Main.java

package test;

import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;

import static org.lwjgl.opengl.GL11.*;

public class Main 
{
	public static final int screen_width = 800;
	public static final int screen_height = 500;
	
	public static void Initialize()
	{
		try 
		{
            Display.setDisplayMode(new DisplayMode(screen_width, screen_height));
            Display.setTitle("Hello LWJGL!");
            Display.create();
        } 
		catch(LWJGLException e) 
		{
            e.printStackTrace();
            return;
        }
		
        try 
        {
            glOrtho(0, screen_width, 0, screen_height, 0, depth);
            glMatrixMode(GL_MODELVIEW);
               
            while (!Display.isCloseRequested()) 
            {
                glClear(GL_COLOR_BUFFER_BIT);
                
                Render();
                
                Display.update();
            }
        } 
        catch(Exception e) 
        {
            e.printStackTrace();
        } 
        finally 
        {
            Display.destroy();
        }
	}
	
	public static void Render()
	{
        glBegin(GL_QUADS);

        glEnd();
	}
	
	public static void main(String[] args) 
	{
        Initialize();
    }  
}

Nothing was drawn for the time being, but it went well.

Draw a line

Draw a red line from the upper right to the lower right of the screen.

Main.java

public static void Render()
{
    glBegin(GL_LINES);
        
    glColor3f(1.0f, 0f, 0f);
    glVertex2f(0, 0);
    glVertex2f(screen_width, screen_height);

    glEnd();
}

You can see that the line is drawn.

Drawing in python

By now, you know that Minecraft uses OpenGL. It seems that OpenGL can be used in Python as well.

Environment

Use an IDE called "PyCharm" (https://www.jetbrains.com/ja-jp/pycharm/).

File ▶ Setting ▶ Project: <project name> ▶ Project Interpreter Add the required libraries. The image loading Pillow on the reference site seems to be out of Python 3.8 support, so I could not install it.

Get in touch with OpenGL in Python

Create and run main.py. The source code is as follows. This Python squishy notation seems to take some time to get used to. </ font>

from OpenGL.GL import *
import glfw


def main():

    if not glfw.init():
        return


    window = glfw.create_window(640, 480, 'Hello World', None, None)
    if not window:
        glfw.terminate()
        print('Failed to create window')
        return


    glfw.make_context_current(window)


    print('Vendor :', glGetString(GL_VENDOR))
    print('GPU :', glGetString(GL_RENDERER))
    print('OpenGL version :', glGetString(GL_VERSION))


    glfw.destroy_window(window)
    glfw.terminate()


if __name__ == "__main__":
    main()

Vendor : b'NVIDIA Corporation'
GPU : b'GeForce GTX 1080/PCIe/SSE2'
OpenGL version : b'4.6.0 NVIDIA 441.08'

Process finished with exit code 0

glfw.make_context_current(window)

glfw.window_hint(glfw.CONTEXT_VERSION_MAJOR, 4)
glfw.window_hint(glfw.CONTEXT_VERSION_MINOR, 0)
glfw.window_hint(glfw.OPENGL_PROFILE, glfw.OPENGL_CORE_PROFILE)

while not glfw.window_should_close(window):

    glClearColor(0, 1, 0, 1)
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

    glfw.swap_buffers(window)
    glfw.poll_events()

public boolean onBlockActivated(World world, int x, int y, int z, EntityPlayer player)

public TileEntity createNewTileEntity(World world)
{
   return new MyTileEntityClass();
}