142D和3D模型

添加物品

在ModItems中：

    public static final Item RUBY_STAFF = registerItem("ruby_staff",
            new Item(new Item.Settings().maxCount(1)));

在mixin包中：

ExampleMixin

@Mixin(MinecraftServer.class)
public class ExampleMixin {
	@Inject(at = @At("HEAD"), method = "loadWorld")
	private void init(CallbackInfo info) {
		// This code is injected into the start of MinecraftServer.loadWorld()V
	}
}

ItemRendererAccessor

@Mixin(ItemRenderer.class)
public interface ItemRendererAccessor {
    @Accessor("models")
    ItemModels mccourse$getModels();
}

ItemRendererMixin

@Mixin(ItemRenderer.class)
public abstract class ItemRendererMixin {
    @ModifyVariable(method = "renderItem", at = @At(value = "HEAD"), argsOnly = true)
    public BakedModel useRubyStaffModel(BakedModel value, ItemStack stack, ModelTransformationMode renderMode, boolean leftHanded, MatrixStack matrices, VertexConsumerProvider vertexConsumers, int light, int overlay) {
        if (stack.isOf(ModItems.RUBY_STAFF) && renderMode != ModelTransformationMode.GUI) {
            return ((ItemRendererAccessor) this).mccourse$getModels().getModelManager().getModel(new ModelIdentifier(DemoMod1.MOD_ID, "ruby_staff_3d", "inventory"));
        }
        return value;
    }
}

ModelLoaderMixin

@Mixin(ModelLoader.class)
public abstract class ModelLoaderMixin {
    @Shadow
    protected abstract void addModel(ModelIdentifier modelId);

    @Inject(method = "<init>", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/render/model/ModelLoader;addModel(Lnet/minecraft/client/util/ModelIdentifier;)V", ordinal = 3, shift = At.Shift.AFTER))
    public void addRubyStaff(BlockColors blockColors, Profiler profiler, Map<Identifier, JsonUnbakedModel> jsonUnbakedModels, Map<Identifier, List<ModelLoader.SourceTrackedData>> blockStates, CallbackInfo ci) {
        this.addModel(new ModelIdentifier(DemoMod1.MOD_ID, "ruby_staff_3d", "inventory"));
    }
}

重点是添加3D模型文件json，在resources/assets/tutorialmod/models/item/ruby_staff_3d.json中进行添加

效果

物品栏为2D，手持为3D