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--- tutorial:reading_mc_code [2021/09/20 00:17] – tweak siglong
+++ tutorial:reading_mc_code [2023/11/17 19:02] – cph101
@@ Line 6: / Line 6: @@
 To read the Minecraft source, you need to generate sources first. See the "Generating Minecraft Sources" section in [[tutorial:setup|Setting up a mod development environment]].
-===== Searching for a Minecraft class ====
+===== Searching for a Minecraft class =====
 To search a Minecraft class, follow these steps.
-==== Intellij IDEA ====
+===== Intellij IDEA =====
-    - Open the search pane with ''Ctrl + N''
+    - Open the search pane with {{https://i.ibb.co/rmztpCy/IMG-0712.png?height=64}} or {{https://i.ibb.co/2SDypGK/kbs-meta-o.png?height=80}} on mac
     - Set the search scope to ''Project and Libraries'' or wider
     - Type the class name in the search box
-==== Visual Studio Code ====
+===== Visual Studio Code =====
     - Open the search pane with ''Ctrl + P''
     - Type the class name with prefix ''#''
+===== Eclipse =====
+    - Open the search pane with ''Ctrl + Shift + R''
 In Visual Studio Code, you can also use ''Ctrl + T'' to open the class search directly.
-===== Tips ======
+===== Finding the class you want to see ====
-    * If you don't know what class to read, take a look at open source mods which are similar to what you want to make.
+Locating the part of code you want to see is a challenging task. Here are some tips.
-    * When you find a method or class but don't understand what they are doing, check the usages or subclasses of them. You might need to check the usages of the usages and such.
-    * You may find an invalid java code such as ''int i = true;''. This is because the decompiler we use is not perfect. Check the corresponding part of bytecodes if needed.
+    * Take full advantage of IDE's ability to find the relevant code such as ''Call hierarchy'', ''Method hierarchy'' or ''Type hierarchy''.
-    * Generated sources is located at the user gradle cache  (i.e. ''~/.gradle/caches/fabric-loom''). If you want to use external tools to mess around with Minecraft source, you can use the sources jar.
+    * Take a look at open source mods which are similar to what you want to make.
+    * If you are adding a new content, there is a good chance you need to access registries defined in ''net.minecraft.util.registry.Registries''.
+    * Keep in mind that everything starts from one main class (''net.minecraft.client.main.Main'' for client, ''net.minecraft.server.Main'' for dedicated server).
+    * Search Minecraft code for translation keys. ''assets/assets/minecraft/lang/en_us.json'' contains all keys used in vanilla.
+===== Reading the bytecode =====
+Reading the bytecode is occasionally required because
+    * Mixin operates on bytecode, not the source code. Understanding the bytecode is essential when you write a complex mixin.
+    * Decompiler (FernFlower) is not perfect. It sometimes produces an invalid java code such as ''int i = true;''.
+If you are not familiar with the java bytecode, reference [[https://docs.oracle.com/javase/specs/jvms/se17/html/jvms-6.html|the JVM specification]].
+To see the bytecode, follow these steps.
+==== Intellij IDEA ====
+    - Open the class of which you want to see the bytecode
+    - Select ''View'' from the main menu
+    - Select ''Show Bytecode''
+==== External Tools ====
+If your IDE doesn't support bytecode viewing, use external bytecode viewers such as https://github.com/Konloch/bytecode-viewer.
+===== FAQ =====
+**Where is the generated sources?**
+It's either in the user gradle cache (''~/.gradle/caches/fabric-loom'') or in the project gradle cache (''./.gradle/loom-cache'').
+You can use the sources jar outside of your IDE.