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--- tutorial:mixin_examples [2022/08/05 16:10] – clomclem
+++ tutorial:mixin_examples [2024/11/18 15:52] (current) – fixed some of the argument names in mixinextra section bemoty
@@ Line 8: / Line 8: @@
 <code java>
 @Mixin(targets = "net.minecraft.client.render.block.BlockModelRenderer$AmbientOcclusionCalculator")
-public class Calculator {
+public class AmbientOcclusionCalculatorMixin {
     // do your stuff here
 }
 </code>
-===== Access `this` instance of the class your mixin is targeting =====
+===== Access the this instance of the class your mixin is targeting =====
+Note: Double casting ''this'' should be avoided when possible. If you intend to use a method or field from the target class, use ''@Shadow''. If the method or field is from a parent of the target class, have your mixin extend the direct parent of the target class.
 Mixin:
 <code java>
@@ Line 20: / Line 22: @@
   @Inject(method = "foo()V", at = @At("HEAD"))
   private void injected(CallbackInfo ci) {
-    ((TargetClass)(Object)this).methodOfTheTargetClass();
+    TargetClass thisObject = (TargetClass)(Object)this;
   }
+}
+</code>
+===== Injecting into the head of a static block =====
+Mixin:
+<code java>
+@Inject(method = "<clinit>", at = @At("HEAD"))
+private void injected(CallbackInfo ci) {
+    doSomething3();
+}
+</code>
+Result:
+<code diff>
+static {
++   injected(new CallbackInfo(“<clinit>”, false));
+    doSomething1();
+    doSomething2();
 }
 </code>
@@ Line 124: / Line 144: @@
 +   injected(new CallbackInfo("foo", false));
     doSomething2();
+  }
+</code>
+===== Injecting into the point with shift amount =====
+Mixin:
+<code java>
+@Inject(method = "foo()V", at = @At(value = "INVOKE", target = "La/b/c/Something;doSomething()V", shift = At.Shift.BY, by = 2))
+private void injected(CallbackInfo ci) {
+  doSomething3();
+}
+</code>
+Result:
+<code diff>
+  public void foo() {
+    doSomething1();
+    Something something = new Something();
+    something.doSomething();
+    doSomething2();
++   injected(new CallbackInfo("foo", false));
   }
 </code>
@@ Line 207: / Line 247: @@
 </code>
+===== Capturing local values =====
+==== Capture locals without MixinExtras ====
+Mixin:
+<code java>
+@Inject(method = "foo()V", at = @At(value = "TAIL"), locals = LocalCapture.CAPTURE_FAILHARD)
+private void injected(CallbackInfo ci, TypeArg1 arg1) {
+  //CAPTURE_FAILHARD: If the calculated locals are different from the expected values, throws an error.
+  arg1.doSomething4();
+}
+</code>
+Result:
+<code diff>
+  public void foo() {
+    TypeArg1 arg1 = getArg1();
+    arg1.doSomething1();
+    arg1.doSomething2();
+    TypeArg2 arg2 = getArg2();
+    arg2.doSomething3();
++   injected(new CallbackInfo("foo", false), arg1);
+  }
+</code>
+==== Capture locals with MixinExtras ====
+:!: See the oficial MixinExtra's [[https://github.com/LlamaLad7/MixinExtras/wiki/Local|Wiki]].
+:!: MixinExtras required Fabric Loader 0.15 or above, or you have to manually specify it in ''build.gradle''.
+:!: If there are multiple locals with that type, you have to specify ''ordinal'' or it will throw an error.
+Mixin:
+<code java>
+@Inject(method = "foo()V", at = @At(value = "TAIL"))
+private void injected(CallbackInfo ci, @Local TypeArg2 arg2) {
+  arg2.doSomething4();
+}
+</code>
+Result:
+<code diff>
+  public void foo() {
+    TypeArg1 arg1 = getArg1();
+    arg1.doSomething1();
+    arg1.doSomething2();
+    TypeArg2 arg2 = getArg2();
+    arg2.doSomething3();
++   injected(new CallbackInfo("foo", false), arg2);
+  }
+</code>
+==== Capturing one of multiple locals of a type ====
+Mixin:
+<code java>
+@Inject(method = "foo()V", at = @At(value = "TAIL"))
+private void injected(CallbackInfo ci, @Local(ordinal = 2) TypeArg arg) {
+  arg.doSomething4();
+}
+</code>
+Result:
+<code diff>
+  public void foo() {
+    TypeArg arg1 = getArg1();
+    TypeArg arg2 = getArg2();
+    TypeArg arg3 = getArg3();
+    TypeArg arg4 = getArg4();
+    doSomething();
++   injected(new CallbackInfo("foo", false), arg3);
+  }
+</code>
+===== Modifying locals =====
+This requires MixinExtras.
+Mixin:
+<code java>
+  @Inject(method = "foo()V", at = @At(value = "INVOKE", target = "doSomething()V", shift = At.Shift.AFTER))
+  private static void injected(CallbackInfo ci, @Local LocalRef<String> localRef) {
+    localRef.set(localRef.get() + " - modified")
+  }
+</code>
+Result:
+<code diff>
+  public void foo() {
+    String s = "example string";
+    doSomething();
++   s = s + " - modified";
+    doSomething2(s);
+  }
+</code>
 ===== Modifying a return value =====
 Mixin: