Minecraft 1.17+ assets patcher for PojavLauncher.

Pojav117AssetsPatcher.java

/*
 * These following steps are not currently automated, so you need to do manually for now.
 * download assets-v0.zip at https://cdn.discordapp.com/attachments/724163890803638277/923349783589056522/assets-v0.zip
 * extract and copy the shaders folder to the resources folder.
 * edit include/light.glsl add `#define texture texture2D` after `#version 100` line
 */

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.util.jar.JarFile;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.util.stream.*;

public class Pojav117AssetsPatcher implements Runnable {
    public void run() {
        File verDir = new File(System.getProperty("user.dir"), "versions");
        if (!verDir.exists()) {
            JOptionPane.showMessageDialog(null, "Minecraft versions directory at " + verDir.getAbsolutePath() + " did not exists.");
            return;
        }
        String[] versionList = verDir.list((dir, name) -> {
            try {
                String jsonModded = new String(Files.readAllBytes(new File(dir, name + File.separator + name + ".json").toPath()), StandardCharsets.UTF_8).replace(" ", "");
                if (!jsonModded.contains("inheritsFrom\":\"")) {
                    System.out.println(name + " doesn't contain inheritsFrom");
                    return jsonModded.contains("javaVersion") && !(jsonModded.contains("jre-legacy") && jsonModded.contains("\"majorVersion\":8"));
                }
                String inheritsFrom = jsonModded.substring(jsonModded.indexOf("inheritsFrom\":\"") + 15);
                inheritsFrom = inheritsFrom.substring(0, inheritsFrom.indexOf("\""));
                String jsonVanilla = new String(Files.readAllBytes(new File(dir, inheritsFrom + File.separator + inheritsFrom + ".json").toPath()), StandardCharsets.UTF_8).replace(" ", "");
                //System.out.println(jsonVanilla);
                return jsonVanilla.contains("javaVersion") && !(jsonVanilla.contains("jre-legacy") && jsonVanilla.contains("\"majorVersion\":8"));
            } catch (IOException e) {
                System.out.println("Could not read " + name);
                e.printStackTrace();
                return false;
            }
        });

        JComboBox optionList = new JComboBox(versionList);
        JPanel panel = new JPanel();
        panel.add(new JLabel("Select installed version:"));
        panel.add(optionList);
        JOptionPane.showOptionDialog(null, panel, "Minecraft 1.17+ shader patcher", JOptionPane.DEFAULT_OPTION, JOptionPane.QUESTION_MESSAGE, null, null, null);
        int n = optionList.getSelectedIndex();

        if (n < 0) {
            System.out.println("Invalid selected index " + n);
            //JOptionPane.showMessageDialog(null, "");
            return;
        }

        try {
            FileSystem sourceFS = FileSystems.newFileSystem(new File(Pojav117AssetsPatcher.class.getProtectionDomain().getCodeSource().getLocation().toURI()).toPath(), null);
            Path sourcePath = sourceFS.getPath("shaders");
            
            FileSystem targetFS = FileSystems.newFileSystem(new File(verDir, versionList[n] + File.separator + versionList[n] + ".jar").toPath(), null);
            Path targetPath = targetFS.getPath("assets/minecraft");
            
            try (Stream<Path> stream = Files.walk(sourcePath)) {
                stream.forEach(source -> {
                    if (Files.isRegularFile(source)) {
                        System.out.println(targetPath.resolve(source.toString().substring(1)));
                        copy(source, targetPath.resolve(source.toString().substring(1)));
                    }
                });
            }
            // Allow re-patching
            try {
                Files.delete(targetFS.getPath("META-INF/MOJANGCS.RSA"));
                Files.delete(targetFS.getPath("META-INF/MOJANGCS.SF"));
            } catch (NoSuchFileException e) {
                e.printStackTrace();
            }
            copy(sourceFS.getPath("manifest.txt"), targetFS.getPath("META-INF/MANIFEST.MF"));
            
            sourceFS.close();
            try {
                targetFS.close();
            } catch (FileSystemException e) {
                // dirty workaround for FAT32 sdcards
                if (e.getMessage().endsWith(": Operation not permitted")) {
                    System.err.println("Error setting permission, applying workaround.");
                    e.printStackTrace();
                    File file = new File(e.getMessage().substring(0, e.getMessage().indexOf(": Operation not permitted")));
                    file.renameTo(new File(file.getParentFile(), versionList[n]));
                } else throw e;
            }
            
            JOptionPane.showMessageDialog(null, "Patched " + versionList[n]);
        } catch (Throwable e) {
            e.printStackTrace();
            JOptionPane.showMessageDialog(null, e);
        }
    }
    
    private void copy(Path source, Path dest) {
        try {
            Files.copy(source, dest, StandardCopyOption.REPLACE_EXISTING);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Pojav117AssetsPatcher());
    }
}