尝试加入取消副手渲染的mixin

src/main/java/net/mcreator/target/mixins/ItemInHandLayerMixin.java

@@ -0,0 +1,54 @@
+package net.mcreator.target.mixins;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import net.mcreator.target.item.gun.GunItem;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.entity.layers.ItemInHandLayer;
+import net.minecraft.client.renderer.entity.layers.PlayerItemInHandLayer;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.entity.HumanoidArm;
+import net.minecraft.world.entity.LivingEntity;
+import net.minecraft.world.entity.player.Player;
+import net.minecraft.world.item.ItemDisplayContext;
+import net.minecraft.world.item.ItemStack;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/**
+ * Author: MrCrayfish
+ */
+@Mixin(ItemInHandLayer.class)
+public class ItemInHandLayerMixin
+{
+    @SuppressWarnings({"ConstantConditions"})
+    @Inject(method = "renderArmWithItem", at = @At(value = "HEAD"), cancellable = true)
+    private void renderArmWithItemHead(LivingEntity entity, ItemStack stack, ItemDisplayContext display, HumanoidArm arm, PoseStack poseStack, MultiBufferSource source, int light, CallbackInfo ci)
+    {
+        if(entity.getType() == EntityType.PLAYER)
+        {
+            InteractionHand hand = Minecraft.getInstance().options.mainHand().get() == arm ? InteractionHand.MAIN_HAND : InteractionHand.OFF_HAND;
+            if(hand == InteractionHand.OFF_HAND)
+            {
+                if(stack.getItem() instanceof GunItem)
+                {
+                    ci.cancel();
+                    return;
+                }
+
+                if(entity.getMainHandItem().getItem() instanceof GunItem) {
+                    ci.cancel();
+                    return;
+                }
+            }
+            if(stack.getItem() instanceof GunItem)
+            {
+                ci.cancel();
+            }
+        }
+    }
+
+}

src/main/resources/mixins.target.json

@@ -8,6 +8,7 @@
     "ClientboundSetEntityMotionPacketMixin"
   ],
   "client": [
+    "ItemInHandLayerMixin",
     "MixinCamera",
     "KeyMappingMixin",
     "GameRendererMixin",