Fix crash with TrumpetSkeleton Closes #127

Author: modmuss50

src/main/java/me/modmuss50/optifabric/patcher/fixes/HeldItemRendererFix.java

@@ -0,0 +1,54 @@
+package me.modmuss50.optifabric.patcher.fixes;
+
+import me.modmuss50.optifabric.util.RemappingUtils;
+import org.apache.commons.lang3.Validate;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.ClassNode;
+import org.objectweb.asm.tree.InsnList;
+import org.objectweb.asm.tree.InsnNode;
+import org.objectweb.asm.tree.JumpInsnNode;
+import org.objectweb.asm.tree.LabelNode;
+import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
+import org.objectweb.asm.tree.VarInsnNode;
+
+//https://github.com/JamiesWhiteShirt/trumpet-skeleton-fabric/blob/45a1a99169593f0ff0f4a6985769fa108f70bceb/src/main/java/com/jamieswhiteshirt/trumpetskeleton/mixin/client/HeldItemRendererMixin.java
+public class HeldItemRendererFix implements ClassFixer {
+
+	//renderFirstPersonItem(Lnet/minecraft/client/network/AbstractClientPlayerEntity;FFLnet/minecraft/util/Hand;FLnet/minecraft/item/ItemStack;FLnet/minecraft/client/util/math/MatrixStack;Lnet/minecraft/client/render/VertexConsumerProvider;I)V
+	private String renderFirstPersonItemName = RemappingUtils.getMethodName("class_759", "method_3228", "(Lnet/minecraft/class_742;FFLnet/minecraft/class_1268;FLnet/minecraft/class_1799;FLnet/minecraft/class_4587;Lnet/minecraft/class_4597;I)V");
+	//net/minecraft/util/Hand
+	private String handName = RemappingUtils.fromIntermediary("class_1268");
+
+	//Use the vanilla method here, while adding back some of optifines tweaks to it
+	@Override
+	public void fix(ClassNode optifine, ClassNode minecraft) {
+		Validate.notNull(renderFirstPersonItemName, "Failed to find name for renderFirstPersonItem");
+		Validate.notNull(handName, "Failed to find name for handName");
+		MethodNode oldNode = minecraft.methods.stream().filter(methodNode -> methodNode.name.equals(renderFirstPersonItemName)).findFirst().orElse(null);
+		Validate.notNull(oldNode, "Failed to find old " + renderFirstPersonItemName + " method");
+
+		InsnList insnList = new InsnList();
+		insnList.add(getInstList("net/optifine/Config", "isShaders", "()Z"));
+
+		insnList.add(new VarInsnNode(Opcodes.ALOAD, 4));
+		insnList.add(getInstList("net/optifine/shaders/Shaders", "isSkipRenderHand", String.format("(L%s;)Z", handName)));
+
+		oldNode.instructions.insertBefore(oldNode.instructions.getFirst(), insnList);
+
+		//Remove the old method
+		optifine.methods.removeIf(methodNode -> methodNode.name.equals(renderFirstPersonItemName));
+		//Add the replacement method back
+		optifine.methods.add(oldNode);
+	}
+
+	private InsnList getInstList(String owner, String name, String descriptor) {
+		InsnList insnList = new InsnList();
+		insnList.add(new MethodInsnNode(Opcodes.INVOKESTATIC, owner, name, descriptor, false));
+		LabelNode jumpNode = new LabelNode();
+		insnList.add(new JumpInsnNode(Opcodes.IFEQ, jumpNode));
+		insnList.add(new InsnNode(Opcodes.RETURN));
+		insnList.add(jumpNode);
+		return insnList;
+	}
+}

src/main/java/me/modmuss50/optifabric/patcher/fixes/OptifineFixer.java

@@ -24,8 +24,14 @@ private OptifineFixer() {
 		//net/minecraft/client/Keyboard
 		registerFix("class_309", new KeyboardFix());
 
+		//net/minecraft/client/render/item/HeldItemRenderer
+		registerFix("class_759", new HeldItemRendererFix());
+
 		//net/minecraft/client/particle/ParticleManager
 		skipClass("class_702");
+
+		//net/minecraft/client/render/item/HeldItemRenderer$1
+		skipClass("class_759$1");
 	}
 
 	private void registerFix(String className, ClassFixer classFixer) {